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Cottam, Nigel D. "Internal nutrient cycling in evergreen and deciduous tree species." Thesis, University of Aberdeen, 1990. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU027729.
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This thesis compares the cycling of nutrients (N, P, K, Mg and Ca) within twigs and foliage, between the evergreen species Pinus sylvestris L. (Scots pine) and Picea abies (L.) Karst. (Norway spruce), and the deciduous species Quercus petraea (Matt.) Liebl. (oak) and Betula pubescens Ehrh. (birch). In addition, the role of foliage produced in previous seasons as a source of nutrients for current growth, in young stands of Scots pine and lodgepole pine (Pinus contorta Loud.), was investigated by means of defoliation experiments, where various age-classes of foliage were removed. In both evergreen and deciduous species, the main areas of overwinter storage and sources of nutrients to support current growth appear to lie outside the twig/foliage system. Patterns of leaf litter production were similar in both Scots pine, oak and birch, however the deciduous species lost a greater amount of nutrients in leaf litter than did the evergreen species. In comparisons between Scots pine and oak, it was observed that foliage production in spring and summer is much slower, and takes place over a longer period, in the Scots pine, which also maintains a greater amount of nutrients within its foliar biomass. Results from the artificial defoliation experiments, suggested that older needle fractions do not play a major role in supplying nutrients to sites of current growth, however they do appear to provide an essential source of photosynthate to support new biomass production. A mechanism is proposed, whereby evergreen species are able to reduce the level of current nutrient demands in two main ways, firstly by means of their slower more extended growing period, and secondly by maintaining lower foliar nutrient concentrations (thereby reducing nutrient losses via leaf litterfall), at the expense of maintaining a greater amount of nutrients within their biomass.
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Chapman, K. "Interaction between tree species : Decomposition and nutrient release from litters." Thesis, Lancaster University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234635.
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Gindaba, Jiregna. "Water and nutrient relations of selected tree species of Ethiopia." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16050.
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Dissertation (PhD (Bosb))--University of Stellenbosch, 2003.ENGLISH ABSTRACT: This study was conducted to evaluate and compare the water and nutrient relations of three indigenous deciduous tree species, viz., Cordia africana Lam., Croton macrostachyus Del., Millettia ferruginea (Hochst.) Baker and two widely planted eucalypts, viz., Eucalyptus camaldulensis Dehnh and Eucalyptus globulus Labill from Ethiopia. The study was organized as glasshouse and field observations in Ethiopia. Owing to the lack of baseline studies on the water and nutrient relations of the deciduous tree species, the glasshouse experiments involved a wide range of water and nutrient applications. Seedlings were grown with the supply of various levels of water and nutrients during which gas exchange, water potential, relative water content, tissue nutrient content and biomass production were measured. The field observations were limited to the study of surface root distribution and leaf nutrient composition of mature trees and their effects on soil nutrient pool. The observations were made on isolated trees and mixed or pure stands of trees in Badessa area, Eastern Ethiopia. The field site was selected because of the availability of the study species and suitability of the trees for the study. In the glasshouse, increased water deficit significantly reduced predawn leaf water potential, relative water content, stomatal conductance, photosynthetic rate, whole plant water use efficiency, plant height, diameter, leaf area and biomass production. Both of the eucalypts did not grow faster than the deciduous species under well-watered conditions unlike under water stress conditions. C. macrostachyus and C. africana had higher transpiration rates and tissue nutrient accumulations than the other species. They also demonstrated higher biomass allocation to roots than all the other species to support the intensive water and nutrient uptake rate. Due to the ability to re-orient its leaves to avoid direct solar irradiance, M. ferruginea maintained higher tissue water potential and relative water content than all the other species under water stress regimes. The impact of imposed drought was quick and more damaging to the eucalypts compared to the deciduous tree species indicating that the eucalypts may not survive extreme drought conditions unlike the deciduous species that drop their leaves and may remain dormant for weeks. The current study gave new experimental proof that E. globulus was more vulnerable to drought than E. camaldulensis. Soil N stress resulted in an overall reduction of tissue N concentration, N:P ratio, photosynthetic rate, stomatal conductance and photosynthetic water use efficiency in all the species studied. Pants with high foliar nitrogen concentration had higher photosynthetic capacities indicating that N plays a key role in photosynthesis and growth of all the studied species. The current study showed that for all the tree species, more attention has to be given to soil N than to P as soil P had minor effects on the photosynthetic activities of plants of all species compared to N.The investigation on tissue nutrient composition confirmed that N:P ratio could be used to detect Plimitation in plants. However, N:P ratio could not distinguish between N-limitation and combined limitations of N and P. The study of isolated C. africana and C. macrostachyus trees on soils in Badessa, Eastern Ethiopia indicated improved soil N, P and K under tree canopies whereas no effects were observed on the other soil nutrients studied. Similar to glasshouse conditions, C. macrostachyus and C. africana produced extensive surface roots, interfering with crops grown in association. Due to their high nutrient cycling potential the net effect on soil was positive. Comparison of E. camaldulensis woodlot and a mixed stand composed of deciduous species indicated that the fine root biomass in the surface soil under E. camaldulensis was about three times that under the mixed stand. The fine root biomass of E. camaldulensis inside the stand and 10 meters away from the stand were comparable in the surface soils showing the presence of root competition with adjacent crops. Therefore, planting of E. camaldulensis in association or adjacent to croplands should be avoided. Nutrient and carbon pool of soil inside the mixed stand was generally higher than that of E. camaldulensis indicating that trees of the mixed stand recycled more nutrients to the soil.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die verskille tussen water- en voedingstofverhoudings van drie inheemse blaarwisselemde boomsoorte te vergelyk, viz., Cordia africana Lam., Croton macrostachyus Del., Millettia ferruginea (Hochst.) Baker en twee bekende eucalyptus spesies, viz., Eucalyptus camaldulensis Dehnh en Eucalyptus globulus Labil van Etiopië. Die studie het bestaan uit kweekhuis- en veldobservasies in Etiopië. As gevolg van beperkte navorsing ten opsigte van water- en voedingstofverhoudings in bladwisselende boomsoorte, het die kweekhuis-eksperimente bestaan uit 'n wye verkeidenheid water- en voedingstoftoetse. Saailinge is gegroei deur verskillende vlakke van water- en voedingstowwe by te voeg. Gaswisseling, waterpotensiaal, relatiewe hoeveelheid water, hoeveelheid voedingstowwe en produksie van biomassa is gemeet. Die veldobservasies was beperk tot oppervlak-wortelverspreiding en blaarvoedingstof hoeveelhede van volwasse bome, sowel as die effek op grondvoedingstowwe. Observasies was beperk tot geïsoleerde, gemengde en een spesie opstande, in die Badessa area, Oos Etiopië. Die studiearea was gekies op grond van die voorkoms van die gekose boomsoorte, sowel as die toepaslikheid van die bome vir die studie. In die kweekhuis is gevind dat die verhoogte watertekort die pre-sonop blaarwaterpotensiaal, relatiewe hoeveelheid water, stomatiese geleiding, fotosintetiese tempo, heelplant water-gebruikseffektiwiteit, plant hoogte, diameter, blaararea en biomassa produksie beduidend verminder het. Nie een van die eucalyptus spesies het vinniger as die bladwisselende spesies onder voldoende hidrasie gegroei nie. Dit was egter nie die geval onder die waterbeperkte toestande nie. C. macrostachyus en C. africana het ‘n hoër transpirasie tempo sowel as weefselvoedingstof waardes gehad as die ander spesies. Hierdie boomsoorte se wortelbiomassa was ook meer as die ander spesies, om vir die tempo van water- en voedingstofopname te akkomodeer. As gevolg van die vermoë om blare te kan oriënteer om direkte sonlig te vookom, het M. ferruginea ‘n hoër water-weefselpotensiaal en relatiewe waterinname gehad in vergelyking met die ander boomsoorte in beperkte water toestande. Die impak van gëinisieerde droogte het vinnig voorgekom en het meer skade aan die eucalyptus aangerig in vergelyking met die bladwisselende boomsoorte. Dit dui aan dat die eucalyptus-spesie nie ekstreme droogte kan oorleef nie, waar bladwisselende spesies hul blare laat afval en vir weke aan een dormant kan bly. Hierdie studie gee eksperimentele bewyse dat E. globulus minder bestand is teen droogte as E. camaldulensis. Beperkte N in die grond het veroorsaak dat daar ‘n algemene vermindering van weefsel Nkonsentrasie, N:P ratio, fotosintetiese tempo, stomatiese geleiding en fotosintetiese watergebruiks effektiwiteit in al die bestudeerde spesies was. Plante wat oor hoër blaar-stikstofkonsentrasiesbeskik, het hoër fotosintetiese kapasiteite wat aandui dat N ‘n belangrike rol in fotosintese en die groei van al die bestudeerde spesies speel. Die oorhoofse bevindings van die studie was, dat daar meer aandag gegee moet word aan grond-N as P omdat grond-P net ‘n kleiner rol speel in die fotosintetiese aktiwiteite van plante van al die spesies in vergelyking met N. Die ondersoek na weefselvoedingstof hoeveelhede het bewys dat die N:P ratio gebruik kan word om P-tekorte in plante aan te dui. Die N:P ratio kan egter nie die verskil in N-tekorte en gekombineerde tekorte van N en P aandui nie. Die studie van die geïsoleerde C. africana en C. macrostachyus bome op grondtipes in Badessa, Oos Etiopië het verbeterde grond-N, P en K onder kroondak gebiede getoon, daar was egter geen verskille in die ander grondvoedingstowwe wat bestudeer is nie. In toestande gelykstaande aan die van die kweekhuis, het C. macrostachyus en C. africana meer oppervlaksswortels ontwikkel. Die toename aan oppervlakswortels het ingedring op gewasse wat in assosiasie gegroei is, dit het egter ‘n positiewe effek op die grond gehad as gevolg van die hoë voedingstof-siklus-potensiaal. Die E. camaldulensis opstand is gevergelyk met ‘n gemengde opstand van bladwisselende spesies waar daar gevind is dat die fynwortel biomassa in die oppervlak grond onder die E. camaldulensis ongeveer drie keer soveel was as die van onder die gemengde opstand. Kompetisie met aangrensende gewasse is aangeui deurdat die fynwortel biomassa van E. camaldulensis binne die opstand en 10 meter weg van die opstand vergelykbaar was in die oppervlakgronde. Dit dui dus aan dat die plant van E. camaldulensis in assosiasie of aangrensend aan gewasse vermy moet word. Die teenwoordigheid van voedingstowwe en koolstof in die grond van die gemengde opstand was oor die algemeen hoër as die van die E. camaldulensis. Dit is ‘n aanduiding dat die bome van die gemengde opstand meer voedingstowwe aan die grond verskaf.
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Subedi, Suresh Chandra. "Determination of Nutrient Limitation on Trees Growing in Loxahatchee Impoundment Landscape Assessment (LILA) Tree Islands, Florida." FIU Digital Commons, 2011. http://digitalcommons.fiu.edu/etd/350.
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The purpose of this study was to determine the general patterns of response by tree species common to Everglades Tree Islands (TI) when conditions limiting optimal growth are improved by fertilization on LILA tree islands. Experiments were conducted on constructed TI in the Loxahatchee Impoundment Landscape Assessment (LILA). Thirty-six trees of two species, Annona glabra and Chrysobalanus icaco, were randomly selected on each of four tree islands. Two tree islands have peat overlying limestone cores and two are composed solely of peat. Each tree was treated with one of three nutrient regimes: +N, +P, or Control (no addition of nutrients). A highly significant P-treatment effect on growth rate, leaf TP and leaf N:P ratio were observed in both species in comparison to Control trees. In contrast, neither of the species responded to N-fertilization. The mass N:P ratios and δ13C in P-treated trees exhibited a positive correlation with Relative Elevation (RE) for both species. These findings suggested that the tree growth at LILA tree islands was P-limited on both substrates (limestone and peat).
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Ledwaba, Charlotte Ramasela. "Baseline of selected essential nutrient elements of an indigeneous fruit tree (mimusops zeyheri) under natural conditions." Thesis, University of Limpopo (Turfloop Campus), 2008. http://hdl.handle.net/10386/824.
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Thesis (M.Sc. Agric. (Horticulture)) --University of Limpopo, 2008The mineral nutrition of indigenous crop species is not well documented like other known crop species, thus making it difficult for one to know how to plant and maintain the crops. Mmupudu (Mimusops zeyheri), which, happens to be a wild crop, is one of the indigenous trees of interest to the Discipline of Plant Production, University of Limpopo. The current study gives baseline information that will be important in various environmental physiology studies of this plant. Physiological studies will be necessary to assess the importance of “limiting” mineral nutrients in the accumulation of certain mineral nutrients in Mmupudu in relation to its productivity. The experiment was arranged as a 2 x 3 factorial in RCBD, with the first and second factors being time of sampling and location, respectively. The three locations where data were collected were Chuenespoort, Bochum and Sekgosese. In each location, the experiment was replicated 10 times. Data were analyzed using ANOVA and means were separated using the least significant difference test. The two-factor interaction was nonsignificant (P ≥ 0.10) for both pH and electrical conductivity. Soil pH was not affected by time in all three locations suggesting that abscised flowers and fruitlets have no effect on pH. Leaf K experienced an increase of 65% at Chuenespoort and a decrease of soil K after fruiting by 44%. Leaf and soil P decreased after fruiting in all locations as was the case with Cu. Chuenespoort and Sekgosese experienced a decrease in leaf Mn after fruiting while soil Mn decreased in all whereas leaf Mg decreased in all locations.
the National Research Foundation and the Department of Water Affairs and Forestry
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Sheppard, Paul A., Pere Cassals, and Emilia Gutiérrez. "Relationships Between Ring-Width Variation and Soil Nutrient Availability at the Tree Scale." Tree-Ring Society, 2001. http://hdl.handle.net/10150/262537.
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Within the framework of the linear aggregate model of dendrochronology, the potential role of soil nutrient availability in explaining multi-decadal variation in radial growth at the tree level was studied in the central Spanish Pyrenees. Increment cores were collected from 20 mature Pinus uncinata Ram. and analyzed dendrochronologically. One ion-exchange resin capsule was buried within the root zone of each sampled tree for just over eight months. The resins were chemically extracted and measured for NH₄, NO PO₄, Ca, and K. Statistical relationships between indexed tree growth and soil nutrient availability were determined with regression analysis and bivariate plots. The single most important soil nutrient with respect to decadal-scale dendrochronological tree-growth variables in this study was N in the form NO which explained 22% of variation of trend in growth since 1950. The 20 values of NO₃ availability fell into two subgroups, one of trees with relatively higher NO₃ availability and the other with lower NO₃ availability. When the tree-growth data were grouped based on NO₃ availability, the two resultant index chronologies had different low-frequency features since 1950. Trees with low NO₃ availability have been growing as expected based on past growth, but trees with high NO availability have been growing better than expected. Measuring and analyzing soil nutrient availability at the tree level might enhance environmental applications of dendrochronological research. With soils information at this spatial scale, it is possible to distinguish between subgroups of trees within a tree-ring site and thereby construct subchronologies that differ significantly, especially for variation at the decadal scale. Subsite-chronologies may then lead to different and presumably more informative environmental interpretations relative to those based on a full-site chronology.
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Ribbons, Relena Rose. "Seeing the forest for the trees : tree species effects on soil microbial communities and nutrient cycling dynamics." Thesis, Bangor University, 2017. https://research.bangor.ac.uk/portal/en/theses/seeing-the-forest-for-the-trees-tree-species-effects-on-soil-microbial-communities-and-nutrient-cycling-dynamics(f3ddf30e-c126-4345-b388-4384cfc8d617).html.
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Tree species influence soils above and belowground communities through leaf litter and root inputs. Soil microbial communities can directly influence tree growth and development through processes such as decomposition of leaves, and indirectly through chemical transformation of nutrients in soils as an influence of altered C:N ratios due to leaf litter and root inputs. This thesis aims to document some of the mechanisms by which trees influence soil microbial communities and nitrogen cycling processes like gross and net ammonification and nitrification. This thesis also aims to determine the role of site nitrogen status in modulating those tree species effects. The effects of tree species on ammonification and nitrification rates in forest floors and mineral soils were explored, and related to functional genetic markers for ammonia-oxidation by archaea and bacteria (amoA AOA and AOB), bacterial denitrification (nirS and nirK), and the general markers for bacteria (16S) and fungi (ITS). Two paired high-resolution laboratory methods were used to investigate the relationships between trees, soils, and the microbial communities, including molecular techniques such as quantitative polymerase chain reaction (qPCR) to target gene abundances in soils, and 15N pool-dilution experiments to understand how ammonium and nitrate are produced and consumed in soils. Soil samples were collected from two common garden experiments, named EP571 in Canada (Ribbons et al. 2016), and in Denmark, and both 15N and qPCR-based techniques were used to determine tree species effects and attribute N cycling processes to the abundances of functional genes. At EP571, western red cedar (Thuja plicata) forest floor nitrogen transformation rates differed from Douglas-fir (Pseudotsuga menziesii), Sitka spruce (Picea sitchensis), and western hemlock (Tsuga heterophylla), which corresponded with western red cedar having highest abundances of bacterial 16S and amoA AOA genes. A manipulative mesocosm (the Rhizotron) in Wales was used to determine how mixtures and monocultures of seedling species influenced tree growth, soil physical properties and soil microbial community structure and function within the first three years of growth. Within the Rhizotron experiment both alder (Alnus rubra) and Douglas-fir grew taller when grown in mixtures compared with monocultures of each species. Sycamore maple (Acer pseudoplatanus) acquired slightly greater aboveground biomass when planted in mixtures with common oak (Quercus robur), which attained less biomass in mixtures than monocultures. C:N ratios of leaves, stems, roots, and rhizospheric soils were determined to see if mixtures influenced C:N in trees. Rhizospheric soil microbial communities (including bacterial and fungal markers and the 4 genes tied to N cycling) were compared among the 4 tree species in the Rhizotron. Soil samples for microbial analyses were collected before seedlings were planted, and just before the experiment was harvested. These data show differences in height, biomass and C:N ratios between species can be observed at a seedling growth stage, but microbial communities may require longer exposure to develop. Lastly, the Bangor Diverse experiment was used to further explore diversity and mixture effects on soil microbial communities and N transformations. We found few mixture or monoculture tree species effects on mineral soil microbial communities or net nitrification or ammonification rates. Collectively, these stories shed light on the important functional role of soil microbes in forest soil N cycling. This thesis also highlights the use of isotope and microbial techniques for parsing out relationships between site, tree species identity and ecosystem functions, with the largest links observed between gross ammonification and microbial communities.
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Wang, Xin. "Linking Hydroperiod with Water Use and Nutrient Accumulation in Wetland Tree Islands." Scholarly Repository, 2011. http://scholarlyrepository.miami.edu/oa_dissertations/531.
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Many large terrestrial ecosystems have patterned landscapes as a result of a positive feedback system between vegetation communities and environmental factors. One example is tree island habitats in the Florida Everglades. Although they only occupy a small portion of the Everglades landscape, tree islands are important features as the focus of nutrient accumulation and wildlife biodiversity in the Everglades ecosystem. The hardwood hammock community on the elevated head of tree island habitats can accumulate high phosphorus concentration in the otherwise P-limited Everglades ecosystem. In this dissertation, I examined two hypotheses derived from the chemohydrodynamic nutrient accumulation model, which suggests that high transpiration of tree island hammock plants is the driving force for nutrient accumulation in tree island soil. According to this model, I hypothesized that tree islands with lower dry season transpiration should have less phosphorus accumulated than the tree islands with higher dry season transpiration. By examining the water use and nutrient status from 18 tree islands in both slough (perennially wet) and prairie (seasonally wet) locations, I was able to compare water availability and nutrient accumulation in slough and prairie tree islands with different marsh hydroperiods. Chapter 1 uses elemental and stable isotope analysis to look at water stress and nutrient concentration in tree island plants. I showed that the prairie tree island plants suffer from drought stress during the dry season, when the marshes in the prairies dry out. Prairie tree islands also have lower soil and plant P concentration than the slough tree islands. Moreover, I showed that foliar N isotope ratio serves as a stable proxy for community level P availability for tree island plants, and prairie tree island plants have less P available than slough tree island plants. In Chapter 2, I showed that the satellite imagery derived normalized difference water index (NDWI) provides a robust indicator of community level canopy water content of these tree islands. NDWI, used as a proxy for water status, was positively related to foliar N isotope ratio, which suggests that water availability is linked to nutrient availability in the tree island hardwood hammock plant communities. These findings are consistent to the chemohydrodynamic nutrient accumulation model. In Chapter 3, I used sap flow sensors on individual trees to provide a real-time measurement of plant transpiration. I showed that tree island plant transpiration is affected by multiple factors including weather fluctuations, marsh water depth regulated by local water management, and canopy structure of different tree islands. Overall, my dissertation establishes a link between tree island plant water use and nutrient accumulation. It could be potentially important for future restoration plan of tree islands and Everglades hydrological management.
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Campbell, John Mark. "Release of carbon and nitrogen from acid peats as influenced by some tree species." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/13300.
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Altinalmazis, kondylis Andreas. "Tree diversity effects on root production, decomposition and nutrient cycling under global change." Thesis, Bordeaux, 2021. http://www.theses.fr/2021BORD0067.
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L'hypothèse de l'assurance prévoit que les forêts composées de mélanges d'espèces d'arbres pourraient mieux résister aux conditions environnementales stressantes que les forêts composées d'une seule espèce d'arbre. La majorité des travaux antérieurs ont testé cette hypothèse en se focalisant sur la productivité et les variables de réponse associées sans prendre en compte les processus souterrains. L’objectif principal de ma thèse était d’étudier l’effet de la diversité des espèces d’arbres sur les processus souterrains impliqués dans la décomposition des racines à travers des gradients climatiques. J'ai émis l'hypothèse que le mélange d'espèces ayant des systèmes racinaires contrastés entraînerait une faible compétition souterraine, et se traduirait par la production de plus biomasse de racines fines. En outre, j'ai émis l'hypothèse que les racines ayant des caractéristiques chimiques et morphologiques contrastées dans les peuplements mixtes se décomposent plus rapidement. Dans des conditions de stress hydrique, j'ai émis l'hypothèse d'une décomposition plus lente mais d’une atténuation des mélanges d'arbres sur la décomposition en raison de l'amélioration des conditions micro-environnementales. Pour tester ces hypothèses, j'ai examiné la variation des caractéristiques fonctionnelles des racines et leurs conséquences sur les flux de C, N et P à l'échelle de l'écosystème à travers l’étude de : 1) la ségrégation verticale des racines et la biomasse des racines fines, 2) la dynamique des racines fines et les flux de nutriments associés et 3) la décomposition des racines fines et des feuilles mortes. Dans ce cadre, trois deux expériences de terrain ont été réalisé, l'une avec une expérience de plantation d'arbres de 10 ans avec du bouleau et du pin près de Bordeaux (expérience ORPHEE), la seconde le long d'un gradient latitudinal de forêts de hêtres matures dans les Alpes françaises (expérience BIOPROFOR).Les résultats obtenus montrent que les racines de bouleaux et de pins présentaient une distribution verticale similaire et une biomasse souterraine similaire de racines dans les mélanges d'arbres par rapport aux monocultures, contrairement à ma première hypothèse. Cependant, l'attribution plus importante du pin mais pas du bouleau à la croissance des racines dans les horizons du sol supérieur dans des conditions moins limitatives en eau suggère des conditions localement favorables qui peuvent conduire à une compétition asymétrique à la profondeur du sol. De plus, la production et la décomposition des racines fines étaient similaires dans les mélanges et dans les monocultures, en contradiction avec ma deuxième hypothèse. Il est intéressant de noter que les racines de bouleau, mais pas les racines de pin, ont libéré du P pendant leur décomposition, ce qui suggère un rôle important du bouleau dans le cycle du P et pour la nutrition en P des arbres sur ces sols sableux limités en P. Conformément à ma troisième hypothèse, j'ai observé une décomposition plus lente de la litière de feuilles et des racines fines en réponse à une sécheresse estivale prolongée, tout au long du gradient latitudinal dans les Alpes. Cependant, cette décomposition plus lente sous la sécheresse n'a pas été atténuée dans les peuplements forestiers à essences mixtes par rapport aux peuplements à essences uniques. Il est intéressant de noter qu’il y a une libération nette d'azote dans les racines fines en décomposition mais pas dans la litière de feuilles en décomposition, ce qui suggère un rôle distinct des racines fines dans le cycle de l'azote. En conclusion, j'ai constaté que le mélange des espèces d'arbres n'atténue pas les effets négatifs du changement climatique. Cette thèse démontre que la promotion de mélanges peut toujours être bénéfique pour au moins une des espèces d'arbres mélangées, par l'ajout d'espèces, car une espèce d'arbre peut en faciliter la nutrition minérale d’une autre par des flux souterrains de N et de PThe insurance hypothesis predicts that forests with tree species mixtures may resist better to stressful environmental conditions than forests composed of only one tree species. Most of the currently available literature tested this hypothesis for aboveground productivity and its related response variables, but less is known about belowground processes. In my PhD thesis, I studied the drivers of belowground productivity and decomposition across climatic gradients and how they are affected by tree mixtures. I hypothesized that mixing of tree species with contrasting rooting patterns and fine root morphologies, would result in a release of competitive pressure belowground, and translate into higher fine root standing biomass and increased fine root productivity. Moreover, I hypothesized that roots with contrasting chemical and morphological characteristics in mixed stands would decompose faster, which may be particularly important under nutrient-limited conditions. Under water-limiting conditions, such as during extreme summer drought, I hypothesized overall slower decomposition but an attenuating effect of tree mixtures on decomposition due to improved micro-environmental conditions, in particular for leaves, since roots decompose in a more buffered soil environment. To test these hypotheses I examined the variation in tree root functional traits (across- and within-species), and its consequences for fluxes of C, N and P at the ecosystem scale. I addressed three main objectives and associated research questions to quantify the interactive effect of tree mixtures and climate on: 1) vertical root segregation and fine root standing biomass, 2) fine root dynamics and their associated nutrient fluxes and 3) fine root- and leaf litter decomposition. I could benefit from two different field experiments for my work, one with a 10-year-old tree-plantation experiment with birch and pine close to Bordeaux (ORPHEE experiment), the second along a latitudinal gradient of mature beech forests in the French Alps (BIOPROFOR experiment).I observed that roots from the birch and pine tree-plantation showed similar vertical distribution and similar belowground root standing biomass in tree mixtures compared to monocultures, contrary to my first hypothesis. However, the greater allocation of pine but not of birch to root growth within the top soil horizons under less water-limiting conditions suggests locally favourable conditions that may lead to soil depth-specific asymmetric competition. In the same experiment, fine root production and decomposition were similar in mixtures and in monocultures, in contradiction with my second hypothesis. Moreover, I did not observe any interactive effects of tree mixtures with stand density or water availability. Interestingly though, birch roots, but not pine roots released P during root decomposition, which suggests an important role of birch in the P-cycle and for P nutrition of trees on these P-limited sandy soils. In line with my third hypothesis, I observed a slower decomposition of leaf litter and fine roots in response to reinforced and prolonged summer drought, irrespective of the position along the latitudinal gradient in the Alps. However, this slower decomposition under drought was not attenuated in forest stands with mixed tree species compared to single species stands. Compared to leaf litter, fine roots decomposed slower and released less C. Interestingly, I found a net N release in decomposing fine roots but not in decomposing leaf litter, which suggests a distinct role of fine roots in the N cycle. In conclusion, I found that mixing tree species did not attenuate negative effects of climate change. However, this thesis demonstrates that promoting mixtures can still be beneficial for at least one of the admixed tree species, through species addition (i.e., complementing one tree species with another tree species), as one tree species may facilitate another via belowground fluxes of N and P
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Karpiscak, Martin M., Gerald J. Gottfried, and Susan B. Hopf. "Tree Growth and Nutrient Status in a Water Harvesting System Using Potable and Treated Wastewater." Arizona-Nevada Academy of Science, 2002. http://hdl.handle.net/10150/296589.
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Hänninen, K. (Kaarina). "Tree - cover crop interactions: birch growth, competition and soil properties." Doctoral thesis, University of Oulu, 2002. http://urn.fi/urn:isbn:9514267184.
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Abstract
The main objective of this thesis was to investigate tree - cover crop interactions and soil response in an intercropping system, in which leguminous and grass cover crops were used with birch (red-leaved Downy birch Betula pubescens L.). The investigation was conducted in two field experiments in a nursery and in a greenhouse experiment. In the latter the effect of the water supply in interspesific competition was also investigated. The cover crops in the field experiments were perennial clovers Trifolium pratense L., T. repens L. and T. hybridum L. and annual clovers T. incarnatum L., T. resupinatum L. and T. subterraneum L. and perennial Festuca rubra L. The height, stem diameter, leaf area and nutrient status of the birch were determined, as well as soil nutrient status and microbial characteristics. The cover crops in the greenhouse experiment were T. repens, T. subterraeum and F. rubra. The biomass, height, leaf area, leaf area index, specific leaf area and N concentration of the birch, the biomass and N concentration of the cover crops were measured, and soil N and microbial characteristics, as well. Bare ground was the control in all the experiments.
The perennial clovers and Festuca strongly decreased the birch growth and nutrient status, but the annual clovers sown in midsummer in the field experiments provided about as good growth as bare ground. In the greenhouse experiment all cover crops were effective competitors with the birch. The soil NO3-N was, in general, the highest on bare ground and second highest in the annual clover plots. Though there were, in general, only minor differences in the soil nutrient concentrations between the treatments, there were significant differences in the tree growth and nutrient concentrations. The interspecific competition in this kind of intercropping system is mainly belowground. The growth reduction in the birch was mainly due to competition for nitrogen but water seems to play an important role in regulating the competitive interaction between the birch and cover crops. The competition for these resources seems to be most crucial at the beginning of the growing season. The microbial biomasses and soil respiration were greatest in the Festuca and perennial clover treatments, which may indicate that microorganisms together with these cover crops may seriously compete with birch for nutrients.
Intercropping system is complex and comprises both negative and positive influences. In order to minimize negative competition effects, the cover crop should be non-competitive or the ground should be kept free of vegetation at the beginning of the growing season. By improving soil microbial characteristics, the vegetative ground covers make this cropping system one possiblity towards sustainability in the long-term.
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Arvidsson, Helen. "Wood ash application in spruce stands : effects on ground vegetation, tree nutrient status and soil chemistry /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-6305-X.pdf.
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Williams, Stephanie. "Leaf nutrient draw back as a strategy for tree grass co-existence in the savanna biome." Bachelor's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/25877.
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As there is still a major debate on how trees and grasses manage to coexist in the savanna biome, the niche separation by phenology hypothesis (Scholes and Archer 1997) was tested by observing the seasonal variation in carbon and nitrogen concentrations in leaves and young twigs of two deciduous species, Combretum apiculatum and Terminalia sericea. The study was carried out in the sub-tropical savanna biome in southern Kruger National Park, South Africa. Photosynthetic readings show a decrease in leaf activity towards the end of the growing season. There was no significant change in the carbon concentrations over the months for both species sampled but there was a significant decrease in leaf nitrogen for C. apiculatum. T. sericea experienced relatively no nitrogen draw back until a sudden drop at the end of June. Translocated nitrogen in C. apiculatum accumulated in large amounts in the peripheral twigs (branching order one) compared to T. sericea, where nitrogen only increased at the end of June in the same location. There was also a corresponding significant change in the carbon:nitrogen ratio in C. apiculatum, especially in the leaves, showing a decrease in palatability as nitrogen was drawn out. The results observed did not become more pronounced in site 3, which had the highest soil moisture content. Soil moisture availability therefore does not appear to influence the degree of nitrogen reabsorption from the leaves. The hypothesis proposed is that deciduous trees use stored nitrogen from their senescing leaves to leaf out earlier gaining a competitive advantage over grasses, which are waiting for nitrogen to be mineralized in the soil with the onset of the summer rain. This study therefore supports the niche separation by phenology hypothesis to explain how these two growth forms coexist in the savanna biome.
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Jackson, Brian Eugene. "Chemical, Physical, and Biological Factors Influencing Nutrient Availability and Plant Growth in a Pine Tree Substrate." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/29491.
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Pine tree substrate (PTS) produced from freshly harvested loblolly pine (Pinus taeda L.) trees has potential for replacing or reducing the use of aged pine bark (PB) and peat moss as container substrates for horticulture crop production. The objective of this work was to determine the factors influencing nutrient availability in PTS compared to PB or peat substrates. Chapter two reports data on the response of japanese holly and azalea to fertilizer rate when grown in PTS and PB. This study demonstrated that an additional 2.4 kgâ m-3 of Osmocote Plus (15N-3.9P-10K) controlled release fertilizer is required for both species when grown in PTS compared to PB. Data are reported in chapter three on the effects of fertilizer rate, substrate particle size, and peat amendment on growth and floral quality, and on post-production time-to-wilting of poinsettias. Data from this work show that PTS requires an additional 100 mgâ L-1 N to grow poinsettias comparable to plants grown in peat unless the particle size of PTS was decreased or 25% peat was added, in which case no additional fertilizer was needed. Results also indicated that PTS shrinkage was similar to that of peat, and that post-production time-to-wilting in PTS plants was similar as plants grown in peat. Data in chapter four compares nitrogen (N) immobilization rates, substrate carbon dioxide (CO2) efflux levels, and nutrient leaching in peat, PB, and PTS over time. Data from these studies indicated that more N immobilization occurs in PTS than in PB or peat and that the substrate CO2 efflux levels (estimate of microbial activity) corresponds to N immobilization in all substrates. Nutrient availability, changes in physical and chemical properties, substrate shrinkage, and microbial activity in PTS compared to PB during long-term nursery production are reported in chapter five. Results showed that substrate nutrient levels remain lower in PTS and that pH levels of PTS decrease considerably over two growing seasons compared to PB. Results also indicate that PTS does decompose over time in containers, but substrate shrinkage of PTS is similar to that of PL and PB during crop production.Ph. D.
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Simpson, Thomas George. "The effects of deep forest ploughing on soil physical properties, nutrient mobilisation and tree root development." Thesis, University of Aberdeen, 1987. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU010495.
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The effect of deep ploughing indurated upland soils to 90cm was investigated at three sites in North East Scotland. The sites varied in age from recently ploughed to sixteen years old. The profile morphology, disruption of induration and change in rootable volume, the maximum depth of root extension, and root orientation were quantified. The soil moisture regime was monitored over one growing season at Glenbuchat using a series of tensiometers inserted horizontally into the profile face. The deeply buried organic matter remained moist throughout the summer. In contrast organic matter near the surface underwent fluctuating cycles of wetting and drying. The deeper soils showed little response to summer rainfall. The rate of decomposition of the buried organic matter was assessed in three ways. A litterbag study determined the effect of burial on weight loss, nutrient element loss and microbial activity. Anaerobic incubations were used to measure rates of nitrogen mineralisation and the concentration of 'Klason' lignin were used as an indice of decomposition of buried organic matter. At Glenbuchat there was a significant decrease in mineralisable nitrogen and lignin concentration with depth. In contrast the older site at Culloden had the opposite trend with a significant increase with depth. This later result was thought to be due to the death and decay of fine roots.
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Borgatti, Aimee Rachel. "Nutrient enrichment effects on mangrove sediments from differing tree height zones in Bocas del Toro, Panama." College Park, Md. : University of Maryland, 2008. http://hdl.handle.net/1903/8028.
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Thesis (M.S.) -- University of Maryland, College Park, 2008.Thesis research directed by: Marine, Estuarine, Environmental Sciences Graduate Program. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Schmidt, Marcus Verfasser], Edzo [Akademischer Betreuer] Veldkamp, Marife D. [Akademischer Betreuer] Corre, and Christian [Akademischer Betreuer] [Ammer. "Nutrient response efficiency, tree-microbe competition for nutrients and tree neighborhood dynamics in a mixed-species temperate deciduous forest in central Germany / Marcus Schmidt. Betreuer: Edzo Veldkamp ; Marife D. Corre. Gutachter: Edzo Veldkamp ; Christian Ammer." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2015. http://d-nb.info/1078150699/34.
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Lemma, Bekele. "Impact of exotic tree plantations on carbon and nutrient dynamics in abandoned farmland soils of southwestern Ethiopia /." Uppsala : Department of Forest Soils, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/2006108.pdf.
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Finnerty-Rae, Eileen Claire. "The Effects of Mesquite Tree Removal on Soil Microbial and Nutrient Cycling Processes in Semi-Arid Environments." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/195790.
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The expansion of mesquite (Prosopis velutina) in southeastern Arizona and attempts to control or remove mesquite have been well documented. However, removal of woody plants may affect the distribution and quantities of nutrient resources within soil including changes in carbon (C) and nitrogen (N) cycling and changes in the amounts of C and N sequestered in these soils. We hypothesized that mechanical mesquite removal would alter soil microclimate and nutrient inputs, leading to changes in soil C and N cycling and microbial communities and activities.This study was conducted at two separate semi-arid grassland sites south of Tucson, AZ during a three-year period. There were six study plots at each site, three plots from which mature mesquite trees had been mechanically removed and three plots where mature mesquite trees were left intact. We measured the soil temperature and moisture, C and N pools, N2O and CO2 fluxes, N mineralization rate, and microbial resistance and resilience to determine if short term changes in any of these parameters were taking place.No significant differences in N mineralization rate or microbial resistance or resilience were found between the soils under intact mesquite and from plots where mesquite had been mechanically removed. Soil temperature was not statistically analyzed because temperature was taken in only one plot per treatment and without within-treatment replicates, t-tests could not be performed. Statistically significant differences in soil moisture, total soil C and N, microbial biomass C and N, heterotrophic plate counts, and CO2 and N2O fluxes were found between treatments on different dates throughout the experiment. Despite this finding of some significant differences between treatments for some parameters measured, no recognizable pattern of changes was observed during this study. Over the course of the experiment, the data did not support our overall hypothesis, that short term changes in microclimate following mesquite removal would alter soil C and N cycling and microbial communities and activities.
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Nelson-Kaula, Kehauwealani K. "A Comparison of Organic Matter and Nutrient Subsidies Between the Invasive, N2-Fixing Tree Prosopis pallida, and the Native Tree, Thespesia populnea, to Hawaiian Anchialine Ponds." Thesis, University of Hawai'i at Hilo, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1550185.
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Terrestrial litterfall is a well-documented subsidy of nutrients and organic matter to adjacent aquatic ecosystems. Nitrogen-fixing plants increase nutrient dynamics via nitrogen (N) - rich litterfall in both terrestrial and aquatic ecosystems, and the effects are often more pronounced when areas lacking native N2-fixers are invaded. This study examined differences in organic matter and nutrient inputs from the invasive, N2-fixing tree, Prosopis pallida, and the native, non N2-fixing tree, Thespesia populnea, to determine effects on anchialine ponds on Hawai`i Island's leeward coast. My objectives were to quantify: 1) tree basal area and density surrounding the ponds, 2) quality and quantity of P. pallida and T. populnea litter inputs, 3) inorganic N content of soil surrounding the ponds, 4) leached nutrients from P. pallida and T. populnea leaf litter. These response variables were then compared to water nutrient concentrations (i.e., phosphate, nitrate, ammonium, dissolved organic carbon (C), and total dissolved N and phosphorus (P)) in the ponds of interest. Basal area, density, litterfall mass, total N and C inputs, and leachate values were similar between pond types categorized as P. pallida – or T. populnea – dominated. Foliar N concentrations were 28 percent higher in P. pallida – dominated ponds compared to T. populnea – dominated ponds, but foliar P concentrations were three times greater in T. populnea ponds than P. pallida ponds. Total P inputs were greater beneath T. populnea ponds and there was a positive correlation between T. populnea size and abundance and pond water phosphate concentrations. These results suggest that the N if influencing water quality in Hawaiian anchialine ponds more than the invasive N2-fixing species, although high background water nutrient levels may be inhibiting our ability to detect any significant impacts. The transfer of T. populnea's P-rich litter to pond water appears to have a strong influence on ecosystem functioning.
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Jacob, Mascha [Verfasser], Frank [Akademischer Betreuer] Thomas, and Christoph [Akademischer Betreuer] Leuschner. "Productivity and nutrient relations of trees in deciduous forests differing in tree species diversity / Mascha Jacob. Gutachter: Frank Thomas ; Christoph Leuschner. Betreuer: Frank Thomas." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2010. http://d-nb.info/1042638241/34.
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Daradick, Shannon Pearl. "Soil microbial enzyme activity and nutrient availability in response to green tree retention harvesting in Coastal British Columbia." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31430.
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Green Tree Retention (GTR) was evaluated for its potential to retain soil microbial
activity and nutrient availability after harvesting in the Coastal Western Hemlock
biogeoclimatic zone of B.C., Canada. Soil samples were collected from four sizes (5, 10,
20, and 40 m diameter) of GTR patch at the centre, edge, and along a northerly transect to
30 m beyond the groups of live trees prior to and a few months after harvest.
PRS™ Probes were used to determine the availability of nutrients; total nitrogen,
nitrate (NO₃ ̄), ammonium (NH₄⁺) and phosphate (PO₄³ ̄), encountered by plant roots
before and after harvest. Before harvest, total nitrogen, NO₃ ̄, and NH₄⁺ availability was
similar in the organic layer and mineral layers. Phosphate availability was significantly
higher in the organic layer than in the mineral layer before harvest. After harvest,
nitrogen levels increased in both soil layers with NO₃ ̄ levels significantly elevated in the
mineral layer and NH₄⁺ levels significantly elevated in the organic layer. There was no
significant change in PO₄³ ̄after harvest. Nutrient availabilities after harvest varied little
along the transects of the different sizes of retention patches. Increased availability of
total nitrogen, NH₄⁺, and PO₄³ ̄was more noticeable in the smallest (5 m in diameter )
patch size when compared to the larger patch sizes (10 m, 20 m, and 40 m in diameter)
after harvest.
The activities of five soil enzymes important in carbon, nitrogen and phosphorus
cycling - β-glucosidase, chitinase, phosphatase, phenol oxidase and peroxidase - were
measured using colorimetric or fluorimetric substrates and a microplate technique. Before
harvest, hydrolytic enzyme activity (β-glucosidase, chitinase, and phosphatase) was
higher in the organic layer than in the mineral layer. After harvest, hydrolytic enzyme activity was still higher in the organic layer than in the mineral layer, although
glucosidase activity decreased in the organic layer and increased in mineral soil after
harvest, and chitinase activity decreased in the organic layer after harvest. Changes in
glucosidase and chitinase activity (decrease in organic soil activity and increase in
mineral soil activity) were more noticeable in the smallest (5 m in diameter ) patch size
when compared to the larger patch sizes (10 m, 20 m, and 40 m in diameter) after harvest.
Phosphatase activity was significantly lower in the 5 m patch size after harvest and
showed a trend of declining activity with increasing distance from the GTR patches after
harvest in the larger retention patches. Before harvest, oxidative enzyme activity (phenol
oxidase and peroxidase) was higher in the mineral layer than in the organic layer. After
harvest, oxidative enzyme activity was still higher in the mineral layer than in the organic
layer, although phenol oxidase activity increased significantly in mineral soil after
harvest, and peroxidase activity increased significantly in both organic and mineral soil
after harvest. The stimulation of the lignin-degrading oxidative enzymes following
harvest may have been caused by lignin-rich woody substrate from slash left on site. The
increase in phenol oxidase and peroxidase activity after harvest was more noticeable in
the smallest (5 m in diameter ) patch size when compared to the larger patch sizes (10 m,
20 m, and 40 m in diameter) after harvest. The change in enzyme activity and nutrient
availability in response to harvest was greatest in 5 m retention patches for total nitrogen,
NH₄⁺, PO₄³ ̄,β-glucosidase, chitinase, phosphatase, phenol oxidase and peroxidase,
suggesting that a minimum diameter of 10 m for GTR plots may be useful to retain soil
microbial activity and nutrient availability after harvest.Forestry, Faculty of
Graduate
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Norgrove, Lindsey Ann. "Crop, weed and soil response to tree density and implications for nutrient cycling in a tropical agrisilvicultural system." Thesis, King's College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324993.
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Saha, Amartya Kumar. "The Role of Spatiotemporal Heterogeneity in Water and Nutrient Pools in Everglades Plant Community Diversity and Function." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_dissertations/211.
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Spatial and temporal heterogeneity of water and nutrient pools is closely associated with the existence of different plant communities in hydrologically-controlled ecosystems such as the Everglades. These various communities differ in their flooding and fire tolerances as well as nutrient requirements. Upland plant communities are of particular ecological significance since they have high biodiversity and provide habitat to terrestrial fauna, yet comprise less than 10 % of the total area. Restoration and maintenance of such communities requires an understanding of their water and nutrient requirements. Chapter 2 compares water source utilization in hammocks and pine rocklands on the Miami Rock Ridge using stable isotopes of water. Hammocks do not flood, while adjacent pinelands may flood between 2-3 months. In the wet season, hammocks were found to use phosphorus (P) rich soilwater, a local pool of water and nutrients while pineland plants primarily relied upon groundwater, the regional pool. Access to a rich pool of P in the oligotrophic Everglades was associated with higher community-level foliar P concentration in hammocks. However in the dry season, hammocks utilized groundwater, which suggests sensitivity to extended droughts. Chapter 3 compares the hammock (upland or head) and swamp forests (lowland or tail) on tree islands in the Shark River Slough. Uplands were associated with P-rich soilwater uptake in the wet season, with regional water uptake in the dry season. Accordingly, tree island heads are rich in foliar P and thereby P-hotspots in the Everglades. Foliar nutrient concentrations can thus indicate limiting nutrient availability in the Everglades. Chapter 4 looks at how leaf phenology patterns are tied to water and nutrient pools. Leaf fall in ridge hammocks is associated with high foliar carbon isotope values over the dry season, which is not the case for tree island hammocks. However, in some species, high levels of foliar nitrogen are also associated with high foliar C13 values indicating stomatal limitation of photosynthesis. Growing season for most hammock species is the wet season coinciding with high availability of P, as reflected in high foliar P in this season. Linking water sources to foliar nutrients elucidates roles of water and nutrient pools in leading to different plant communities within an ecosystem.
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Gaviria, Julian [Verfasser], and Bettina [Akademischer Betreuer] Engelbrecht. "Influence of herbivory, water, light and nutrient availability in shaping tropical tree distribution patterns / Julian Gaviria. Betreuer: Bettina Engelbrecht." Bayreuth : Universität Bayreuth, 2016. http://d-nb.info/1088513301/34.
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Heineman, Arne M. "Species selection for alley cropping in Western Kenya : system management, nutrient use efficiency and tree-crop compatibility (1988-1995)." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318545.
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Thomas, Dana J. "Morphological Tradeoffs of American Chestnut (Castanea Dentata) and Co-Occurring Hardwoods in Varying Nutrient and Light Regimes." Miami University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=miami1134161439.
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Kleczewski, Nathan Michael. "Nutrient And Drought Effects On Biomass Allocation, Phytochemistry, And Ectomycorrhizae Of Birch." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1230730880.
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Ju, Shu. "Model of Strategies of Tree Carbon Allocation to Roots, Foliage and Defense in Relation to Environmental Conditions." Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/377.
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Three general questions are studied regarding plant carbon allocation strategies. (1) The R* Rule states that the superior competitor in a plant community should exclude all others by minimizing available limiting nutrient concentration below the level needed for survival of its competitors. I asked whether a plant carbon allocation strategy that minimizes the concentration of available limiting nutrient is consistent with Lotka's (1922) conjecture that ecosystems should evolve to maximize total energy flow (primary production). (2) In landscapes such as the Everglades, areas of landscape with higher energy flow (primary production) than the surrounding area also have higher available concentrations of limiting nutrient, rather than lower concentrations, which might be expected from the R* rule. I asked whether this pattern can be explained. (3) I asked how optimal allocation of carbon to plant defense allocation strategies might depend on different conditions of nutrient availability, shading, and herbivory. To address all three questions, I used a model revised from the G'DAY model (Comins and McMurtrie 1993) to study tree allocation of carbon resources between foliage, roots, and defense. With regard to the first question, I found that the allocation strategy that leads to minimum concentration of available nutrients is the same as the strategy for which energy flux to roots, rather than total energy flux, is maximized. Further, I found that the strategy that was competitively dominant was neither the strategy for which total energy flux was maximized, nor that for which available nutrient concentration was minimized. With regard to the second question, I found that, if a patch of vegetation on a landscape is able to capture nutrients from the surrounding landscape, for example, through relatively higher evapotranspiration, it could lead to the opposite of what is expected from the R* rule; that is, available limiting nutrient concentration is maximized when carbon flow to the roots is maximized. With regard to the last question, I found that under high herbivory, the optimal plant strategy for allocation of carbon to defense depends on the available nutrient concentration and amount of radiation to the plant, in agreement with some theoretical predictions.
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Thomas, Dana Jeanette. "Morphological tradeoffs of American chesnut (Castanea dentata) and co-occurring hardwoods in varying nutrient and light regimes." Connect to this document online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1134161439.
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Thesis (M.S.)--Miami University, Dept. of Botany, 2005.Title from first page of PDF document. Document formatted into pages; contains [1], v, 38 p. : ill. Includes bibliographical references (p. 35-38).
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Walsh, Brice D. (Brice David). "Mulch management systems in organic dwarf apple orchards and their effects on soil physical properties, soil nutrient availability, and tree nutrition." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55402.
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An alternative to herbicides in dwarf apple orchards (Malus pumila Mill.) is the use of mulches. Research objectives were to compare several mulch systems (Festuca rubra L., Lupinus albus L. plus Daucus carota L.; straw, manure compost, geotextile) with soil cultivation as to soil physical properties and plant nutrient levels in soils, leaves and fruit. Studies carried out in 1992 and 1993 on three dwarf apple orchards on the Macdonald Campus of McGill University showed that straw mulch increased soil water contents and exchangeable K, but reduced exchangeable Mg compared to Festuca mulch. Straw mulch reduced soil temperatures in summer relative to geotextile or cultivation. Festuca reduced leaf N contents but increased leaf P contents-elative to geotextile treatments. Soil nitrate N contents were correlated with soil water contents, and the ratios N/Ca and K/Ca in the fruit were unaffected by treatment. Straw and geotextile mulches increased soil water content and nitrate-N levels during peak sowing periods and thus were the superior treatments.
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Acebes, Angelita L. "Host plant effects on the biology, behavior and ecology of brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae)." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/64910.
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Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is a polyphagous, invasive, and highly significant pest of mid-Atlantic fruit orchards. Its capacity to invade orchards season-long is believed to be facilitated by the availability of wild host plants near orchards and the high dispersal capacity of adults and nymphs. Interactions between H. halys and its hosts were investigated via laboratory and field experiments. Rearing H. halys nymphs in the laboratory on several of its known wild and tree fruit hosts used alone and in combination showed that peach was much more suitable for nymphal development and survival than was apple, tree of heaven, or catalpa and that nymphal performance was enhanced on mixed host diets. Nymphs reared on different host plant diets yielded adults that differed in protein, sugar or lipid content, offering new insights into plant diet effects on H. halys nutrition. The majority of tree species identified from unmanaged woodlands next to apple orchards in Virginia and West Virginia were known hosts of H. halys. Passive trunk traps were developed to capture H. halys nymphs walking up and down tree trunks and used to measure their temporal patterns of movement onto and off of wild and tree fruit hosts at the orchard-woodland interface via weekly assessments during two consecutive seasons. More upward- than downward-walking nymphs were captured, which may be partially explained by the positively phototactic and negatively geotactic behavior of H. halys nymphs demonstrated in laboratory studies. Most nymphs captured while walking up and down trunks were second instars, although the data also reflected temporal changes in the distribution of instars and temporal variation in the numbers of nymphs captured. A field study to characterize injuries to apple and peach fruit at harvest from feeding by young or older nymphs early or late in the season revealed that feeding by young nymphs early in the season resulted in least injury to both crops. In combination, these studies greatly improve our understanding of the biology and ecology of H. halys in eastern fruit orchards and provide relevant data that will inform the development of ecologically-based management programs for it.Ph. D.
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FREIRE, Joelma de Lira. "Deposição,composição química e decomposição de liteira em um bosque de sabiá (Mimosa caesalpiniifolia Benth) , Itambé-PE." Universidade Federal Rural de Pernambuco, 2008. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/6794.
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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
The objective of this experiment was to evaluate the deposition, chemical composition, and decomposition of litter in a sabiá (Mimosa caesalpiniifolia Benth) canopy. The experiment was carried out at the Experimental Station of Itambé-IPA. The evaluation of existing and deposited litter was carried through the period of August of 2006 until July of 2007, every 28 days. Twenty squares with 1m² were used, in random points to each evaluation. The nylon bag technique was used for litter decomposition evaluation, incubating the following litter fractions: just-fallen leaves, “aging” leaves already deposited and in the beginning of the mineralization, and branches. The incubation periods were 0, 4, 8, 16, 32, 64, 100, and 256 days, being the same procedure carried through in 2006 and 2007. Treatments were distributed in randomized block design with five replications. Leaf deposition reached the value of 15,167 kg OM/ha, presenting greater deposition in the rainy period. Leaves represented the greater proportion of litter deposited, with average ratio of 87% of predominance in the majority of the evaluations. Branches and leaves presented average nitrogen concentration of 1.4% and 2. 7%, respectively, demonstrating that leaves were the maincontributors of nutrients via litter. The C/N ratio of leaves was below 30, branches presented C/N ratio between 30 and 40, likely favoring the nitrogen immobilization by ground microorganisms. The relationship between litter deposition and litter accumulation in the last month of evaluation was 0.30 indicating that it presented greater accumulation than deposition. In the decomposition assay, branches presented lesser mineralization than leaves both for total biomass and nitrogen, with leaf and branch decomposition varying with the incubation periods. The decomposition of substrata was influenced by the rainfall amount occurred in the evaluation period. In a general way, it was concluded that the litter component is essential in the process of nutrient recycling in a sabiá canopy, however, the mineralization occurs in relatively slow taxes, being this fact relevant in the reduction of nutrient losses by leaching, contributing for the maintenance of this ecosystem.
O objetivo deste trabalho foi avaliar a deposição, composição química e decomposição de liteira em um bosque de sabiá (Mimosa caesalpiniifolia Benth). O experimento foi realizado na Estação Experimental de Itambé-IPA. A avaliação de liteira existente e depositada foi realizada no período de agosto de 2006 a julho de 2007 a cada 28 dias. Foram utilizados 20 quadrados com 1m2, em pontos aleatórios a cada avaliação. Para avaliação da decomposição de liteira, foram utilizadas bolsas de “nylon”, sendo incubadas as seguintes frações: folhas recém-caídas, folhas senescentes já depositadas e no início da mineralização e ramos. Os tempos de incubação foram 0, 4, 8, 16, 32, 64, 100 e 256 dias, sendo o mesmo procedimento realizado em 2006 e 2007. Os tratamentos foram distribuídos em delineamento de blocos ao acaso com 5 repetições. A deposição de folhas atingiu valor de 15.167 kg MO/ha, tendo maior deposição no período chuvoso. As folhas representaram a maior contribuição na deposição de liteira, com proporção média de 87% predominando na maioria das avaliações. Os ramos e folhas apresentaram teores médios de nitrogênio de 1,4% e 2,7% respectivamente, demonstrando assim que as folhas foram os principais contribuintes de nutrientes da liteira. A relação C/N de folhas ficou abaixo de 30; os ramos apresentaramrelação mais elevada entre 30 e 40, favorecendo assim a imobilização de nitrogênio pelos microorganismos do solo. A relação entre a deposição e o acúmulo de liteira no último mês de avaliação foi de 0,30 indicando assim que houve maior acúmulo do que deposição. No ensaio de decomposição, os ramos apresentaram taxa de mineralização menor que as folhas tanto para biomassa total como para nitrogênio, tendo as decomposições de folhas e ramos variando de acordo com os períodos de incubação. A decomposição dos substratos foi influenciada pela quantidade de chuvas ocorridas ao longo do período de avaliação. De maneira geral, conclui-se que o componente liteira é essencial no processo de reciclagem de nutrientes em um bosque de sabiá, todavia a mineralização ocorre a taxas relativamente lentas, sendo esse fato relevante na redução de perdas de nutrientes por lixiviação, contribuindo para a manutenção desse sistema
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Abate, Asferachew. "Biomass and nutrient studies of selected tree species of natural and plantation forests implications for a sustainable management of the Munessa-Shashemene Forest, Ethiopia /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971864020.
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MacKenzie, Michael Derek. "The effect of Mechanical Site Preparation on soil properties, nutrient dynamics and tree growth, tenth year results for two sites in northern British Columbia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ51405.pdf.
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Morris, Kendalynn Ann [Verfasser], Susan [Gutachter] Trumbore, Kirsten [Gutachter] Küsel, and Andreas [Gutachter] Richter. "Influence of nutrient availability on soil respiration and microbial activity in a tree-grass ecosystem / Kendalynn Ann Morris ; Gutachter: 113914099X, Kirsten Küsel, Andreas Richter." Jena : Friedrich-Schiller-Universität Jena, 2020. http://d-nb.info/1217711287/34.
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Langenbruch, Christina. "Effects of nutrient cycling through litter of different broadleaved deciduous tree species on soil biochemical properties and the dynamics of carbon and nitrogen in soil." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2012. http://hdl.handle.net/11858/00-1735-0000-000D-F1C2-F.
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Seven, Jasmin [Verfasser], Andrea [Akademischer Betreuer] Polle, and Christoph [Akademischer Betreuer] Leuschner. "Mycorrhizal fungi in deciduous forests of differing tree species diversity and their role for nutrient transfer / Jasmin Seven. Gutachter: Andrea Polle ; Christoph Leuschner. Betreuer: Andrea Polle." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2014. http://d-nb.info/1054542287/34.
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Oliveira, Flavia de. "AVALIAÇÃO DA CICLAGEM DE NUTRIENTES EM SISTEMAS INTEGRADOS DE PRODUÇÃO AGROPECUÁRIA NO SUBTRÓPICO BRASILEIRO." Universidade Estadual de Ponta Grossa, 2018. http://tede2.uepg.br/jspui/handle/prefix/2678.
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Sistemas integrados de produção agropecuária (SIPA) integram em um mesmo espaço vários componentes, tais como lavoura, pastagens, animais, bem como árvores de forma sinérgica. Quando bem manejado, pode trazer a sustentabilidade para a propriedade. Um dos desafios em tais sistemas é o entendimento da dinâmica de nutrientes e o possível reaproveitamento destes pela cultura sucessora. O objetivo deste trabalho foi avaliar o aporte de liteira e dos macronutrientes, como nitrogênio (N), fósforo (P), potássio (K) e enxofre (S) em SIPA, com ausência e presença de árvores (~159 árvores ha-1), submetidos a doses de nitrogênio (90 e 180 kg N ha-1, N90 e N180, respectivamente) na fase pastagem. O experimento foi conduzido no Instituto Agronômico do Paraná, município de Ponta Grossa, Paraná. O delineamento experimental utilizado foi o de blocos ao acaso com quatro tratamentos e três repetições. De modo a melhor representar o ambiente arborizado, foi feita a subdivisão da unidade experimental em três posições entre linha das árvores. O experimento iniciou em 2006, com o plantio de árvores em arranjo de 14 x 3m. Durante o inverno cultiva-se aveia preta e azevém, pastejada por bovinos de corte, e, durante o verão, soja/milho. O presente experimento iniciou na fase pastagem de 2013, a qual antecedeu a cultura do milho (safra 2013/2014), estendendo-se até a fase pastagem no inverno de 2014. Durante a lavoura de milho e pastagem (2014), foram inseridos litter bags com os resíduos da cultura anterior, no momento das suas respectivas semeaduras. Aos 8, 15, 30, 60, 90, 120, 153 e 165 dias após a semeadura do milho e da pastagem foram coletadas as amostras dos litter bags, pesadas suas respectivas massas secas (MS) e quantificados os macronutrientes. Também foram calculadas as taxas de decomposição do resíduo e da liberação de macronutrientes. Em geral, a quantidade inicial de resíduo, tanto da pastagem como do milho, foi inferior nos tratamentos com árvores (-28%). Diferenças significativas foram observadas entre os tratamentos nos teores iniciais em N (variando de 12 no ILPF N90 até 14 g/kg no ILPF N180) do resíduo da pastagem e para os teores iniciais de K (variando entre 6,5 no ILP N90 até 12 g/kg no ILPF N90) e S (variando de 0,68 ILPF N90 até 0,91g/kg ILP N90) no resíduo do milho. As posições entre as linhas das árvores afetaram apenas os teores iniciais de N e S dos resíduos. Em relação a dinâmica de decomposição dos resíduos e liberação de macronutrientes, diferenças significativas entre os tratamentos foram observadas somente para decomposição do resíduo da pastagem e liberação de P do mesmo. A fração ativa da MS da pastagem variou entre 44 (ILPF N90) a 59 % (ILP N180). O tempo de meia vida (T1/2) variou entre 11 (ILP N90) e 54 (ILPF N180) dias para MS e entre 6 (ILP N90) e 21 (ILPF N90) dias para o P. O T1/2 do N foi de 19 dias, enquanto que para K e S foi de 13 dias. Em relação ao resíduo do milho, o T1/2 variou entre 5 (no caso de N) e 24 (no caso de P) dias. No mínimo 44% do resíduo proveniente da pastagem foi decomposto ao longo dos 165 dias de exposição à campo dos litter bags. Em relação ao resíduo do milho, 30% foi decomposto ao longo de 90 dias, independente do tratamento. Máximas liberações (37; 2,8; 62 e 2,5 kg/há de N, P, K e S, respectivamente) de nutrientes foram observadas no ILP N180 para o resíduo da pastagem, principalmente em função da maior quantidade de resíduo inicial neste tratamento. Para o resíduo do milho, máximas liberações ocorreram no ILP N90 para N (48 kg/ha), P (17,4 kg/ha) e S (4,8 kg/ha), em função da maior quantidade de resíduo inicial neste tratamento, e no ILPF N90 para K (82 kg/ha), em função do maior teor inicial em K. Portanto, tais quantidades cicladas devem ser consideradas no manejo da fertilização. Desbastes precisam ser intensificados no ILPF para reduzir o nível de sombreamento e evitar grandes reduções nas quantidades de resíduo, para otimizar os benefícios da ciclagem de nutrientes.
Integrated Crop Livestock Systems (ICLS) comprehend in a same space several components, such as grain and forages crops, animals and tree component of synergistic form. When well managed, it can bring sustainability to the property. One of the challenges in such systems is the understanding of the nutrient dynamics and the possible reutilization of these by the successor culture. The objective of this study was to evaluate the contribution of litter and macronutrients, such as nitrogen (N), phosphorus (P), potassium (K) and sulfur (S) in ICLS, with absence and presence of trees ), submitted to nitrogen doses (90 and 180 kg N ha-1, N90 and N180, respectively) in the pasture phase. The experiment was carried out at the Agronomic Institute of Paraná, municipality of Ponta Grossa, Paraná. The experimental design was a randomized block design with four treatments (ILP N90, ILP N180, ILPF N90 and ILPF N180, being ILP, integration of livestock and ILPF, integration of livestock and forest) and three replications. In order to better represents the wooded environment, the experimental unit was subdivided into three positions (1m, 3.5m and 7m distance from the tree line). The experiment began in 2006 with the planting of trees in arrangement of 14 x 3m. During winter, black oats and ryegrass are grazed by beef cattle and, in the summer, soybean/corn. The present experiment started in the pasture phase of 2013, which preceded the corn crop (crop 2013/2014), extending until the pasture stage in the winter of 2014. During maize and pasture (2014), litter bags were inserted with the residues from the previous crop, at the time of their respective sowing. The samples were collected at 8, 15, 30, 60, 90, 120, 153, and 165 days after sowing of maize and pasture. The samples were performed to dry masses (DM) measure and macronutrients determination. The rates of decomposition of the residue and the release of macronutrients were also calculated. Overall, the initial amount of residue from both pasture and maize was lower in tree treatments (-28%). Differences were observed between treatments at initial N contents (ranging from 12 in ILPF N90 to 14 g / kg in ILPF N180) of the pasture residue and for the initial K contents (ranging from 6.5 in ILP N90 to 12 g / kg in ILPF N90) and S (ranging from 0.68 ILPF N90 to 0.91 g / kg ILP N90) in the corn residue. The positions between the tree lines affected only the initial N and S contents of the residues. In relation to the dynamics of the decomposition of the residues and the release of macronutrients, significant differences between the treatments were observed only for the decomposition of the pasture residue and the release of P from the same. The active fraction of DM from pasture ranged from 44 (ILPF N90) to 59% (ILP N180). The half-life time (T1/2) varied between 11 (ILP N90) and 54 (ILPF N180) days for MS and between 6 (ILP N90) and 21 (ILPF N90) days for P. O T1/2 of N was 19 days, whereas for K and S it was 13 days. In relation to maize residue, T1/2 ranged from 5 (in the case of N) to 24 (in the case of P) days. At least 44% of the pasture residue was decomposed during the 165 days of exposure to litter bags. Regarding corn residue, 30% was decomposed over 90 days, regardless of the treatment. The maximum nutrient release (37, 2.8, 62 and 2.5 kg/ha of N, P, K and S respectively) was observed in the ILP N180 for the pasture residue, mainly due to the higher amount of initial residue in this treatment. For the maize residue, maximum releases occurred in ILP N90 for N (48 kg/ha), P (17.4 kg/ha) and S (4.8 kg / ha), due to the higher amount of initial residue in this treatment, and in ILPF N90 for K (82 kg / ha), as a function of the higher starting content in K. Therefore, such cycled quantities should be considered in the management of fertilization. Slabs need to be intensified in the ILPF to reduce the level of shading and avoid large reductions in residue amounts to optimize the benefits of nutrient cycling.
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Knust, Christine. "Einsatz von Rinde-Asche-Pellets zur Erhaltung von Stoffkreisläufen bei intensivierter Holznutzung in der Oberlausitz." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-209786.
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Im Zuge der zunehmenden energetischen Holznutzung fällt vermehrt Holzasche als Abfallprodukt an. Obwohl die Asche potenziell für die Nährstoffrückführung in Wälder genutzt werden könnte, findet dies in Deutschland aktuell kaum statt, da negative ökologische Auswirkungen befürchtet werden, die Handhabbarkeit von Holzasche schwierig ist und hinsichtlich des Nährstoffhaushalts der Wälder keine Notwendigkeit gesehen wird. Durch eine Verarbeitung der Asche zu Rinde-Asche-Pellets (RIA-Pellets) sollte die ökologische Verträglichkeit erhöht und die Handhabbarkeit verbessert werden.
Im Rahmen der vorliegenden Arbeit wurde untersucht, wie RIA-Pellets auf bodenchemische Parameter sowie den Ernährungszustand der Bäume wirken. Dazu wurden zwei Versuchsflächen in der Oberlausitz (Ostsachsen) etabliert: ein 38-jähriger Kiefernbestand auf einem Braunerde-Podsol aus eiszeitlichem Elbschotter im Tiefland sowie drei Fichtenbestände im Alter von 36 bis 49 Jahren auf einer Braunerde aus Lösslehm über Granodioritzersatz im Hügelland. Im Jahr 2011 wurde eine Behandlung mit 4 t ha-1 RIA-Pellets durchgeführt und auf dem Hügellandsstandort zusätzlich eine Vergleichsvariante mit 3,5 t ha-1 Dolomitkalk angelegt. Daraufhin wurden bodenchemische Parameter (pH-Wert, AKe, Nährstoff-Gesamtgehalte, C/N-Verhältnis) sowie Nadelspiegelwerte der Bäume untersucht. Außerdem wurde der zu erwartende Nährstoffverlust mittelalter Nadelholzbestände im Rahmen der Durchforstungen in den kommenden 20 Jahren abschätzend quantifiziert und den sonstigen Stoffflüssen der untersuchten Standorte gegenübergestellt.
Auf dem sorptionsschwachen Tieflandsstandort mit Kiefer führten RIA-Pellets in einer Dosis von 4 t ha-1 innerhalb von zwei Jahren zu einer moderaten Erhöhung des pH-Werts um 0,6 Einheiten, einer Zunahme der Kationenaustauschkapazität von 267 auf 338 mmolc kg-1 sowie einer Erhöhung der Basensättigung von 45 auf 90 %. Zudem war eine signifikante Erhöhung der Gesamtgehalte von Ca, Mg und Mn zu verzeichnen. Auf dem sorptionsstarken Boden des Hügellandsstandort mit mittelalten Fichtenbeständen hatte die gleiche Dosis von RIA-Pellets ebenfalls zwei Jahre nach der Ausbringung zu wesentlich geringeren Effekten geführt. Zwar war auch hier ein pH-Anstieg um 0,3 Einheiten zu verzeichnen. Die RIA-Pellets beeinflussten jedoch die AKe und die Basensättigung nicht und die Nährstoff-Gesamtgehalte nur bei Ca und Mn. Alle Effekte waren auf beiden Versuchsflächen auf die Humusauflage begrenzt. Im Vergleich zu einer Kalkung trat die Wirkung der RIA-Pellets langsamer ein und fiel geringer aus. Die Behandlung mit RIA-Pellets führte nach zwei Jahren zu keiner Veränderung der Nadelspiegelwerte auf beiden Versuchsflächen.
Die Untersuchung der oberirdischen Bestandesbiomasse zeigte, dass bereits mittelalte Nadelbaumbestände im Rahmen von Durchforstungen bei intensiven Aushaltungsszenarien erhebliche Nährstoffentzüge zu verkraften haben. So stieg die Biomasseentnahme bei Vollbaumnutzung gegenüber konventioneller Nutzung nur um den Faktor 1,3, während die Nährstoffentzüge um den Faktor 1,8 (Ca) bis 4,0 (P, Kiefer) stiegen. Die Nährstoffzusammensetzung der RIA-Pellets unterschied sich aufgrund der Herkunft der Asche (Verbrennung von Rinde und Holz in einem Sägewerk) von der eines Vollbaums.
Daher läge der Kompensationsbedarf für die Nährstoffentzüge in den nächsten 20 Jahren bei Vollbaumnutzung im Kie-fernbestand bei 0,7 (Ca) bis 2,0 t ha-1 (P) und im mittelalten Fichtenbestand bei 1,3 (Ca) bis 12,8 t ha-1 (P). Der Vergleich der drei untersuchten unterschiedlich alten Fichtenbestände hat gezeigt, dass der Waldrestholzanteil und somit auch die zusätzliche Biomasse- und Nährstoffentnahme umso höher ist, je jünger bzw. geringer dimensioniert der Bestand ist. Die Betrachtung von Kiefern- und Fichtenbestände zeigte baumartenspezifische Unterschiede bei der Verteilung der oberirdischen Bestandesbiomasse auf die einzelnen Biomassekompartimente sowie der Nährstoffgehalte in den jeweiligen Kompartimenten.
Die überschlägigen Nährstoffbilanzen für beide Versuchsflächen haben gezeigt, dass die Nährstoffentzüge mit der geernteten Biomasse bei Vollbaumnutzung in einer ähnlichen Größenordnung lagen, wie die Verluste mit dem Sickerwasser und die Festlegung im Biomassezuwachs. Auch ohne die Berücksichtigung von Nährstoffentzügen mit der Biomassenutzung wiesen die Standorte aufgrund des Nachwirkens historischer Säureeinträge bereits negative Stoffbilanzen für Ca und Mg auf.
Die vorliegende Arbeit verdeutlicht, dass die Holzascherückführung in Wälder keinen drastischen Eingriff in die Stoffflüsse natürlicher Ökosysteme darstellt. Vielmehr handelt es sich um den Versuch, die Folgen der aktuellen menschlichen Aktivitäten im Bereich intensiver Biomassenutzung zumindest hinsichtlich der Nährstoffnachhaltigkeit abzumildern. Die intensive Biomassenutzung reiht sich dabei als eine weitere Form menschlichen Eingreifens in die Stoffflüsse des Ökosystems Wald in eine seit Jahrhunderten stattfindende Nutzungs- und damit Störungsgeschichte durch Streunutzung, Waldumbau zu Nadelholzforsten und atmosphärische Säure- und Stoffeinträge ein.
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Langenbruch, Christina [Verfasser], Heiner [Akademischer Betreuer] Flessa, and Edzo [Akademischer Betreuer] Veldkamp. "Effects of nutrient cycling through litter of different broadleaved deciduous tree species on soil biochemical properties and the dynamics of carbon and nitrogen in soil / Christina Langenbruch. Gutachter: Heiner Flessa ; Edzo Veldkamp. Betreuer: Heiner Flessa." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://d-nb.info/104404778X/34.
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Silva, Juliano Quarteroli. "Sazonalidade da produção e características da borracha natural de clones de seringueira (Hevea brasiliensis) em diferentes estádios fenológicos." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-15082012-132659/.
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O conhecimento das diferentes fases do ciclo básico de vida da espécie vegetal constitui uma ferramenta eficaz de manejo e que uma vez identificados possibilita alcançar boas produtividades e melhor qualidade ao produto comercial. O objetivo deste trabalho foi avaliar o desempenho produtivo e as características químicas da borracha de quatro clones de seringueira, sob diferentes sistemas de sangria, estádios fenológicos e condições edafoclimáticas. O experimento foi instalado na área experimental do Departamento de Produção Vegetal da Escola Superior de Agricultura Luiz de Queiroz, da ESALQ/USP, no município de Piracicaba, SP (2242`30``S, 4738`00``W) e na Agência Paulista de Tecnologia dos Agronegócios (APTA) - Pólo Regional do Desenvolvimento Tecnológico de Agronegócios do Noroeste Paulista, no município de Votuporanga, SP (20°20S, 49°50W). O delineamento experimental adotado foi o de blocos casualizados em esquema parcela subdividida com três ou quatro réplicas. Os tratamentos principais (clones GT 1, PB 235, IAN 873 e RRIM 600) foram alocados nas parcelas e os tratamentos secundários (sistemas de sangria: ½S d/2; ½S d/4 ET 2,5%; ½S d/7 ET 2,5%) constituíram as subparcelas. As variáveis analisadas foram: produção de borracha seca, teores de cinzas e de macronutrientes e micronutrientes da borracha natural. As amostras de borracha natural foram obtidas nos estádios fenológicos: refolhamento; folhas maduras e senescência de folhas. Concluiu-se que a produção e as características da borracha são influenciadas pelas condições edafoclimáticas, pelos sistemas de sangria dependendo do estádio fenológico. A produção e os teores de nutrientes são mais influenciados pela prática de sangria do que pelo material genético, no estádio de senescência e em condições restritivas para a planta.The knowledge of the different phases of the basic life cycle of plant species is an effective tool of management and that once identified possible to obtain good yields and better quality to the commercial product. The objective of this work was to evaluate the yield performance and chemical characteristics of the rubber of four rubber tree clones under different tapping systems, phenological stages and edaphoclimatic conditions. The experiment was carried in experimental area of the Departamento de Produção Vegetal da Escola Superior de Agricultura Luiz de Queiroz, da ESALQ/USP, Brazil (2242`30``S, 4738`00``W) and in Agência Paulista de Tecnologia dos Agronegócios (APTA) - Pólo Regional do Desenvolvimento Tecnológico de Agronegócios do Noroeste Paulista, in Votuporanga city São Paulo State, Brazil (20 ° 20\'S, 49 ° 50\'W). The experimental design was in randomized block design with split plot and three or four replicates. The main treatments (GT 1, PB 235, IAN 873 and RRIM 600 clones) were allocated in the plots and secondary treatments (tapping systems: ½S d/2; ½S d/4 ET 2.5%; ½ S d/7 ET 2.5%) constituted the subplots. The analyzed variables were: dry rubber yield, ash content, macronutrients and micronutrients of the natural rubber. Samples of natural rubber were obtained in the phenological stages: leaves development, mature leaves and leaves senescence. It was concluded that the yield and chemical characteristics of the rubber are influenced by the edaphoclimatic conditions, by the tapping systems and depending of the phenological stages. The yield and nutrients content of natural rubber is more influenced by the tapping practice than the genetic material in the leaves senescence stage and under restrictive conditions for the plant.
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Sobral, Pedro Miguel Alarico. "Avaliação de tecnologias para monitorizar a influência das árvores na evolução do padrão espacial de pastagens sob montado." Master's thesis, Universidade de Évora, 2017. http://hdl.handle.net/10174/20863.
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Este trabalho teve como objectivo principal avaliar tecnologias que permitam monitorizar o efeito das árvores sobre a dinâmica dos nutrientes no solo e sobre a variabilidade da produtividade e da qualidade de uma pastagem integrada no ecossistema de montado. O processo de amostragem foi realizado entre Novembro de 2015 e Julho de 2016. O estudo revelou um efeito positivo das árvores sobre as propriedades do solo e sobre a qualidade da pastagem. Foram também encontradas correlações significativas entre as medições da capacitância, realizadas pela sonda “Grassmaster II”, ou do NDVI, realizadas pelo sensor óptico activo “OptRx”, e parâmetros da produtividade ou da qualidade da pastagem, respectivamente. Os resultados obtidos mostram o potencial das técnicas e equipamentos de agricultura de precisão para monitorizar e interpretar a variabilidade espacial da produtividade e da qualidade das pastagens; Evaluation of technologies for monitoring the influence of trees in the evolution of the spatial pattern of pastures under montado.
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The main purpose of this work was to evaluate technologies that allow monitoring the effect of trees on the dynamic of soil nutrients and on the variability of productivity and quality of a pasture integrated in the montado ecosystem. The sampling process was carried out between November 2015 and July 2016. The study revealed the positive effect of the trees on the soil properties and on the quality of the pasture. Significant correlations were found between the capacitance measurements carried out by the “Grassmaster II”, or NDVI measurements carried out by the “OptRx”active optical sensor, and the productivity parameters or those of the quality of the pasture, respectively. The results show the potential of the precision agriculture techniques and equipment for monitoring and understanding the spatial variability of productivity and quality of the pastures.
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Bertoncello, Ricardo. "Restauração ecológica e processos estruturadores de comunidades vegetais." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/41/41134/tde-28092016-102207/.
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Interações interespecíficas são consideradas importantes forças estruturadoras da vegetação. Enquanto a competição aparentemente prevalece em ambientes com menor estresse abiótico, a facilitação tende a aumentar em importância em ambientes de maior estresse. Consequentemente, é esperado que a facilitação desempenhe um papel importante em áreas tropicais degradadas, nas quais as condições abióticas, envolvendo altos níveis de irradiação, temperatura e evapotranspiração, são muito distintas das condições ótimas para a maioria das espécies florestais. Além disso, face à complexidade dos processos estruturadores de comunidades florestais tropicais altamente diversas, os ecólogos têm percebido a necessidade de simplificação. Um caminho promissor para isso é por meio do uso de características funcionais, que podem ser medidas para qualquer espécie e comparadas em diferentes sistemas e locais. No entanto, em áreas degradadas ainda é incerta a relação entre as características funcionais e o desempenho das espécies. Neste contexto, planejamos um projeto de restauração na planície costeira do sudeste brasileiro para comparar o crescimento e a sobrevivência de mudas de árvores plantadas em diferentes densidades (sistema isolado ou sistema agregado) em um experimento fatorial com adição de nutrientes. No primeiro capítulo analisamos a sobrevivência, altura, diâmetro ao nível do solo e projeção da copa de 4.132 mudas de 19 espécies de diferentes classificações sucessionais, durante um período de 18 meses. Usamos modelos de efeitos mistos para analisar a relação entre o desempenho de espécies e os tratamentos e selecionamos os melhores modelos utilizando o critério de informação de Akaike (AIC). Verificamos uma maior sobrevivência nos sistemas agregados para as espécies não-pioneiras, indicando o predomínio do processo de facilitação. Em contrapartida, constatamos um menor crescimento em diâmetro nos sistema de plantio agregado, indicando o predomínio de competição. A adição de nutrientes não afetou a sobrevivência nos sistemas agregados, mas, surpreendentemente, teve um efeito negativo sobre as plantas isoladas. Além disso, a adição de nutrientes teve um efeito positivo sobre crescimento, diâmetro e projeção da copa nos sistemas de plantio agregado (indicando a redução da competição), especialmente para espécies pioneiras. Uma vez que o estabelecimento de espécies não-pioneiras em áreas degradadas pode ser bastante difícil, a facilitação para a sobrevivência dessas espécies em sistemas agregados pode ser utilizada como instrumento para melhorar os modelos de restauração. No segundo capítulo utilizamos algumas características funcionais que são facilmente mensuráveis para investigar sua relação com o crescimento e sobrevivência das mudas. Além disso, testamos o efeito das interações interespecíficas na relação das características funcionais com o desempenho das plantas. Para espécies pioneiras, uma maior área foliar específica (SLA - Specific leaf area), foi relacionada com uma maior taxa de sobrevivência. Entretanto, ao considerarmos as relações interespecíficas (sistemas agregados), maior SLA foi relacionada com uma menor taxa de sobrevivência. Em geral, as características funcionais explicaram apenas parcialmente o desempenho de mudas no contexto de restauração de áreas degradadas. Nosso trabalho contribuiu para a discussão sobre o potencial da aplicação prática da abordagem funcional na escolha das espécies para a recuperação de áreas degradadas. O caráter manipulativo da restauração ecológica baseada no plantio de mudas amplia as perspectivas para implementar experimentos que visem testar novas hipóteses em ecologia e refinar modelos de restauraçãoInterspecific interactions are considered to be important structuring forces in early successional vegetation. Whereas competition seems to prevail in less severe environments, facilitation tends to increase in importance in harsh environments. Hence, facilitation is expected to play an important role in degraded tropical areas with high irradiance, heat loads, and evapotranspiration, where conditions are far from optimum for most forest species. Moreover, in order to understand complex structuring process of high diverse tropical forests, ecologists have realized the need for simplification. A promising way to do that is through the use of functional traits, which can be measured for any species and compared in different systems and different locations around the world. However, in these conditions, little is known about the role of species interaction on the relation of functional traits and species performance. In this scenario, we planned a restoration project on the southeastern Brazilian coastal plain to compare growth and survival of tree seedlings planted at two densities (isolated or aggregated) in a factorial experiment with nutrient addition. In the first chapter we analyzed survival, height, ground level diameter, and crown projection of 4,132 saplings from 19 species that ranged along a successional gradient, over an 18-month period. We used mixed-effect models to analyze the relationship between species performance and treatments, and Akaike\'s information criterion (AIC) to select the models. The best model showed higher survival in aggregated plantations (indicating facilitation) for non-pioneer species. In contrast, we found lower diameter growth in aggregated plantation (indicating competition). Fertilizer addition did not affect survival in clusters, but, surprisingly, it had a negative effect on isolated plants of both pioneer and non-pioneer species. On the other hand, fertilizer addition had a positive effect on diameter and crown projection growth in aggregated plantations (reducing competition), especially for pioneer species. Thus, whether facilitation or competition was the predominant interaction depended on the response analyzed. We concluded that, as establishment of non-pioneer species in disturbed sites can be challenging, restoration designs could take advantage of higher survival rates in clusters and use resource addition to ameliorate growth and decrease competition for limited resources. In the second chapter we used the core simple-measurable traits to investigate whether functional traits were related to growth and survival and whether there was a difference in the effect of the functional traits on plant performance of isolated individuals or of individuals subjected to interaction with neighbors. Our main findings were that for pioneer species, the greater the specific leaf areas (SLA), the greater the survival rates, but, under aggregated conditions, the greater the SLA the lower the survival rates. However, functional traits only partially explained saplings performance in a restoration context and more research is needed to understand its role in predicting seedlings outcomes, especially considering the potential applicability of this methodological approach. The manipulative character of ecological restoration broadens perspectives to use experiments to generate and test new hypotheses in ecology and to refine restoration models
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Campos, Henrique Ferraz de. "Deposição e concentração de nutrientes da serapilheira de seis espécies nativas do Pontal do Paranapanema: uso da biodiversidade funcional em sistemas agroflorestais." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-26052015-094123/.
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Na elaboração de arranjos de sistemas agroflorestais devem ser buscadas interações benéficas entre as espécies utilizadas, com o intuito de atingir os objetivos desses sistemas em otimizar a eficiência do uso dos recursos naturais como: luz solar, a água e os nutrientes. Essas interações benéficas em SAFs são, muitas vezes, obtidas através da utilização de princípios e funcionamentos semelhantes ao ecossistema natural da região. Um dos funcionamentos chaves para garantir a sustentabilidade dos ecossistemas florestais é a dinâmica da serapilheira. A dinâmica quantitativa e qualitativa da produção de serapilheira é fortemente influenciada pela composição de espécies. Poucos estudos evidenciam o papel individual de cada espécie, sobretudo das árvores nativas, nessa dinâmica. Nesse sentido, este estudo teve o objetivo de aprofundar o conhecimento do papel individual na deposição e concentração de nutrientes da serapilheira de 6 espécies nativas da floresta estacional semidecidual, para uso racional desse conhecimento em sistemas agroflorestais, principalmente para a agricultura familiar e assentamentos rurais da região do Pontal do Paranapanema. O experimento foi desenvolvido em um plantio de restauração ecológica no município de Presidente Epitácio, São Paulo, Brasil. A pesquisa foi realizada durante o período de maio de 2013 a abril de 2014. As espécies estudadas foram: Anadenanthera colubrina (angico), Enterolobium contortisiliquum (tamboril), Inga laurina (ingá), Luehea divaricata (açoita cavalo), Croton urucurana (sangra d\'água), Schinus terebentifolius (Aroeira pimenteira). Foram selecionados aleatoriamente, no talhão experimental, em área de restauração, 10 indivíduos de cada espécie. Para todos os 60 indivíduos selecionados foram instalados coletores de serapilheira. Durante o período de estudo, a cada 2 meses, todo o material coletado foi retirado dos coletores e teve o seu peso seco determinado. Em dois dos períodos de coleta parte do material foi submetido ao processo de análise química dos macronutrientes (N, P, K, Ca, Mg e S). As 6 espécies alvo deste estudo se comportaram de forma semelhante em termos de quantidade de deposição de serapilheira ao longo do ano. O fluxo anual de deposição de serapilheira não apresentou variações sazonais significativas, analisando-se cada espécie de forma separada. No entanto, na análise do conjunto das espécies verificou-se uma maior deposição de serapilheira durante o período mais seco do ano. A espécie Sangra d\'Água considerada pioneira quanto à classe sucessional , teve o maior valor de deposição anual seguido da aroeira pimenteira espécie também considerada de fase mais inicial na sucessão em comparação com as demais. Para todos os macronutrientes com exceção do enxofre houve interação significativa entre espécie e época de coleta. As espécies de início de sucessão aportaram mais nutrientes durante o ano de estudo que as espécies mais tardias. Uma maior diversidade de espécie proporciona maiores possibilidades de complementaridade na disponibilidade de recursos, visto que, houveram diferenças na dinâmica da concentração de macronutrientes na serapilheira das espécies. Estudos adicionais são necessários para contribuir no entendimento da dinâmica quantitativa e qualitativa de deposição da serapilheira de diferentes espécies, bem como suas interações em sistemas agroflorestais.In the elaboration of Agroforestry Systems arrangements should be sought beneficial interactions among species used, in order to achieve the objectives of these systems by optimizing the efficiency of natural resources use, such as: sunlight, water and nutrients. These beneficial interactions in Agroforestry Systems are often obtained through the use of principles and functioning similar to the natural region ecosystem. One key functioning to ensure forest sustainability of ecosystems is the litterfall dynamics. The quantitative and qualitative dynamics of litter production is strongly influenced by species composition. Few researches have demonstrated the individual role of each species, mainly of native trees, on this dynamic. In this sense, the present study aimed to deepen the knowledge of the individual role in the deposition and concentration of nutrients from litter of 6 native tree species from the Semideciduous Mesophytic Atlantic Forest for rational use of this knowledge in agroforestry systems, mainly for family farms and rural settlements in the region of the Pontal do Paranapanema. The experiment was conducted in an ecological restoration planting in the city of Presidente Epitácio in São Paulo state, Brazil. The survey was also conducted during one year period, from May 2013 to April 2014. The species studied were: Anadenanthera colubrina, Enterolobium contortisiliquum, Inga laurina, Luehea divaricata, Croton urucurana, Schinus terebentifolius. It was selected randomly in the experimental field, 10 individuals of each species. For all 60 individuals selected were installed litter collectors. During the study period, every 2 months all collected litter material was removed from collectors and its dry weight determined. In two period of time collection part of the material was subjected to the process of chemical analysis of macronutrients (N, P, K, Ca, Mg, S). The 6 species targeted for this study behaved similarly in terms of amount of litter deposition throughout the year. The annual flow litter deposition has not shown significant seasonal variations by analyzing each species separately. However, in the analysis of all joint species there were a greater deposition of litter during the driest period of the year. The species considered pioneer as the successional class, the Croton urucurana had the greatest annual deposition followed by Schinus terebentifolius, species also considered in the Initial stage in the succession, in comparison to the others. For all macronutrients except sulfur there was significant interaction between species and time of collection. The early successional species supplied more nutrients than later species during the year of this research. Greater species diversity provide better possibility of complementary effects in resource availability, as there were differences on macronutrients concentration dynamics in litter of these species studied. Additional studies are needed to contribute on quantitative and qualitative dynamics understanding of litter deposition of different species as well as their interactions in agroforestry systems.
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Phombeya, Henry Stevie Kondwani. "Nutrient recycling and sourcing by Faidherbia albida trees in Malawi." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325098.
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Krige, Graeme Tertius. "Nutrient management strategies for nectarine orchards." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/21667.
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Thesis (MScAgric)--University of Stellenbosch, 2007.ENGLISH ABSTRACT: The macro-element uptake and distribution by higher density central leader ‘Donnarine’ nectarine trees was studied through the sequential excavation of trees. A large portion, 41.5%, of the nitrogen manifested in the new growth from dormancy up to pit-hardening, originated from nitrogen reserves in the permanent structure. The permanent structure was also an important source of phosphorous reserves. Of the phosphorous in the fruit, leaves and new shoots at pit-hardening, 35.0% came from reserves in the permanent structure. Potassium did not act as an important reserve in the nectarine trees and was taken up throughout the season. From pit hardening to harvest the fruit represented the most important sink for potassium. Calcium and magnesium, like potassium, did not play significant roles as reserves in the nectarine tree and must be available for uptake from the beginning of the season for new growth and development as well as fruit quality. The micro-element uptake and distribution was also studied through the sequential excavation of the same ‘Donnarine’ nectarine trees. Little scientific data is available on this topic. Manganese and iron was found to act as important reserves in the tree with 46.2% of manganese and 59.5% of the iron found in the new growth at pithardening coming from reserves translocated from the permanent structure. Zinc and boron reserves also play a role in nectarine trees, but to a lesser extent than manganese and iron. The seasonal mineral nutrient demand of the same ‘Donnarine’ nectarine trees was determined through the sequential excavation of trees and losses and fixation was calculated. Guidelines regarding nutritional requirements per ton of fruit produced per hectare by higher density nectarine orchards are respectively 3.82kg nitrogen, 0.35kg phosphorous, 4.43kg potassium, 1.53kg calcium, 0.52kg magnesium, 32.45g sodium, 9.44g manganese, 37.46g iron, 3.24g copper, 13.95g zinc and 10.52g boron. Sodium is not commonly considered to be essential to higher plants, but was included in the trial. Nutrient solutions with four different EC (electrical conductivity) levels were applied to ‘Donnarine’ nectarine trees under pulsating drip fertigation for three periods of different lengths, before harvest. Raising the nutrient solution EC to positively affect fruit quality is a technique widely utilised in the vegetable industry. This technique did, however, not have similar positive effects on nectarine fruit grown under a pulsating drip fertigation system. Good production practices such as accurate nutrition and irrigation as well as the correct horticultural inputs should be the primary focus of producers who wish to alter or improve the fruit quality of their crop.
AFRIKAANSE OPSOMMING: Voedingbestuur strategieë in nektarien boorde Die makro-element opname en verspreiding deur hoër digtheid sentrale leier ‘Donnarine’ nektarien bome is bestudeer d.m.v. opeenvolgende opgrawings van volledige bome en die ontleding van monsters. ‘n Groot hoeveelheid, 41.5%, van die stikstof wat tydens pitverharding in die nuwe groei teenwoordig was, is d.m.v. translokasie vanuit die permanente struktuur van die boom afkomstig. Die permanente struktuur was ook ‘n belangrike bron van fosfaat reserwes. Teen pitverharding was 35.0% van die fosfaat in die nuwe groei afkomstig vanuit die permanente struktuur. Bevindings het getoon dat kalium nie as ‘n reserwe in die nektarien bome opgetree het nie en dié element is deur die groeiseisoen opgeneem. Vanaf pitverharding tot en met oestyd was die vrugte die sterkste setel van aanvraag vir kalium. Kalsium en magnesium het, soos in die geval van kalium, nie ‘n belangrike rol as reserwe vertolk nie. Beskikbaarheid van hierdie elemente vir opname vanaf die begin van die groeiseisoen is dus baie belangrik vir nuwe groei en ontwikkeling asook vrugkwaliteit. Die mikro-element opname en distribusie van dieselfde ‘Donnarine’ nektarien bome is ook bestudeer d.m.v. opeenvolgende opgrawings en analise van volledige bome. Min wetenskaplike literatuur oor hierdie onderwerp is beskikbaar. Bevindings het getoon dat mangaan asook yster baie belangrike reserwes in die nektarien boom is. Tydens pitverharding was 46.2% van die mangaan en 59.5% van die yster wat in die nuwe groei teenwoordig was, afkomstig vanaf reserwes uit die permanente struktuur van die boom. Verder het sink en boor ook as reserwes opgetree, maar tot ‘n mindere mate as mangaan en yster. Die seisoenale behoeftes aan minerale voeding van dieselfde ‘Donnarine’ nektarien bome is bepaal d.m.v. opeenvolgende opgrawings en analise van volledige bome asook die bepaling van verwyderingsverliese en vaslegging. Voedingsriglyne is vasgestel i.t.v. die hoeveelheid voedingstof wat per hektaar benodig word om een ton nektariens te produseer. Die riglyne is as volg: 3.82kg stikstof, 0.35kg fosfaat, 4.43kg kalium, 1.53kg kalsium, 0.52kg magnesium, 32.45g natrium, 9.44g mangaan, 37.46g yster, 3.24g koper, 13.95g sink en 10.52g boor. Natrium word nie in die algemeen as ‘n essensiële plantvoedingselement beskou nie, maar is by die berekeninge ingesluit. Voedingsoplossing met vier verskillende vlakke van EG (elektriese geleiding) is vir drie periodes van verskillende lengtes aan ‘Donnarine’ nekarien bome toegedien. Die verhoging van die EG van voedingsoplossings ten einde kwaliteit te verbeter is ‘n tegniek wat met groot suskses in die groentbedryf toegepas word. Hierdie tegniek het egter nie soortgelyke positiewe effekte op die nektarien vrugkwaliteit gehad nie. Produsente wat hul vrugkwaliteit wil verbeter behoort primêr te fokus op goeie produksiepraktyke soos akkurate voeding en besproeiing asook die korrekte tuinboukundige insette.
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McTiernan, Kevin B. "The effect of climate on the decomposition of chemical constituents of tree litters." Thesis, Lancaster University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266812.
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Doucet, Kristine. "Compostitional [sic] nutrient diagnosis of forest trees in north western Quebec." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0020/MQ37115.pdf.
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