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1
Fioreze, Claudio. "Liberação de nitrogênio em diferentes solos e épocas de cultivo sob adubação orgânica." Universidade Federal de Santa Maria, 2010. http://repositorio.ufsm.br/handle/1/3316.
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Organic fertilizers promote improvements in soil properties and are important in providing balanced nutrients to plants. The officials parameters adopted by the Commission of Chemistry and Soil Physics in the States of Rio Grande do Sul Santa Catarina to calculate the amount of organic fertilizer are its mean composition and the efficiency index of nutrient release (EINR) to fulfill the demand of each system crops. This indicator is related mainly to the type of organic residual, but the other factors affecting the mineralization are not adequately addressed, such as climatic conditions and soil texture, among others. The expectation of this work is that these factors are especially relevant in regions with large variation of soil types and climatic conditions, such as the South of Brazil region. So, the factors cropping season and soil texture were studied under the application of two different organic sources (pig slurry and chicken litter) in the field and in laboratory experiments. The texture effect was analyzed in an incubation of three soils containing 238, 470 and 605 mg clay kg soil-1, which was evaluated during 112 days of evolution of mineral nitrogen (N-NH4+ + N-NO3-), the net mineralization and % mineralization of total N and organic added. The influence of growing season was tested under field conditions in two crop series starting with the potato (summer and winter), which evaluated the productivity and nutrient cycling in three crops per system. The results of incubation showed that soil type affects the N dynamics in the soil after the addition of organic fertilizers. Most clayey soils make slowly immobilization and nitrification of ammonium, independently of addition of the broiler litter or pig slurry, which reduces the N pollution potential. The net N mineralization was greater in sandy soil due to lower physical-chemical protection of colloids. Also were greater with the chickens litter due to the amount of total N added have been much higher compared to pig slurry. The results of N available to plants (%NAP) and net mineralization of nitrogen in the soil (%Nminnet) with the addition of organic fertilizers indicate that EINR is overestimated in relation to N effectively added to the soils, and can result in depletion of soil organic matter in the long term growing. Also concludes that, to sandy soils or when manure are rich in available N, that must be done a N fractionated application between plantation and cover fertilization. In field experiments, there would significant differences in the efficiency of release of N in cropping systems of "summer" and "winter". The immediate effect was equal in the summer period to all fertilization sources, but in the winter the mineral source was 10-20% more efficient, showing the effect of temperature and soil moisture in the availability of N in soils under organic fertilization. The residual effect of chickens litter in the second crops was lower than expected in comparison to the pig slurry and mineral fertilizer, since the efficiency index of N liberation would be 20% for chickens litter and zero for the slurry. However only in the third crop that litter exceeded the slurry in dry matter production of summer crop (maize) and winter (black oat). Finally, due very different climatic conditions in South of Brazil, the results indicate that it necessary more and integrated studies about the impact of crop date and soil type to refine the parameters of the recommendation of organic fertilizer, making it thus more sustainable.Os adubos orgânicos promovem melhorias nas propriedades do solo e são importantes no fornecimento equilibrado de nutrientes às plantas. Os parâmetros oficiais adotados pela Comissão de Química e Física do Solo dos Estados do Rio Grande do Sul Santa Catarina para calcular a quantidade de adubo orgânico, são a sua composição média e o índice de eficiência de liberação dos nutrientes (IELN) frente à demanda de cada sistema de cultivos. Este último indicador está associado essencialmente ao tipo de resíduo, porém os demais fatores que afetam a mineralização não são devidamente considerados, como as condições climáticas e a textura do solo, entre outros. A expectativa do presente trabalho é de que esses fatores sejam especialmente relevantes em regiões de grande variação edafoclimática, como o Sul do Brasil. Assim, os fatores época de plantio e textura do solo foram estudados sob a aplicação de duas fontes orgânicas distintas (dejeto líquido suíno e cama de aves de corte), a campo e em laboratório. O efeito da textura foi discutido numa incubação de três solos contendo 238, 470 e 605 mg argila kg de solo-1, onde se determinou a evolução do N mineral (N-NH4+ + N-NO3-) durante 112 dias e se calculou a mineralização líquida e a % de mineralização do N total e orgânico adicionados. Já o efeito da época de cultivo foi testado a campo em duas sucessões iniciadas com cultura da batata (denominados de cultivos de verão e de inverno), onde se avaliou a produtividade e a ciclagem de nutrientes de três culturas por sistema. Os resultados da incubação mostraram que o tipo de solo afeta a dinâmica do N no solo após a adição de adubos orgânicos. Solos mais argilosos retardam a imobilização e a nitrificação do amônio, independente de se utilizar cama de aves de corte ou dejeto líquido de suínos, contribuindo para diminuir o potencial poluente do N. A mineralização líquida do N foi maior no solo arenoso devido à menor proteção físico-química da sua fração coloidal. Também foi maior com o uso da cama de aves de corte, em todos os solos, em função quantidade de N total adicionado ter sido bem maior em relação ao dejeto de suínos. Os resultados de N disponível às plantas (%NDP) e de mineralização líquida do N no solo (%NminL), com a adição dos adubos orgânicos, sinalizam que o IELN está superestimado em relação ao N que é efetivamente adicionado aos solos, podendo levar à depleção da matéria orgânica do solo a longo prazo. Também se infere que, para solos mais arenosos ou quando se dispõe de dejetos ricos em N disponível, faça-se a aplicação fracionada do N entre o plantio e em cobertura. Nos experimentos de campo, por sua vez, houve diferenças significativas na eficiência de liberação do N nos sistemas de cultivo de verão e de inverno . O efeito imediato foi igual no verão para as fontes cama de aves, dejeto suíno e adubo mineral, mas no cultivo de inverno a fonte mineral foi entre 10 a 20% mais eficiente, demonstrando o efeito da temperatura e da umidade na disponibilização de N nos solos sob adubação orgânica. O efeito residual da cama de aves no segundo cultivo foi inferior ao esperado na comparação com o dejeto suíno e adubo mineral, visto que o índice de eficiência de N seria de 20% para a cama e zero para o dejeto. Porém, foi só no terceiro cultivo que a cama superou o dejeto na produção de matéria seca no cultivo de verão (milho) e de inverno (aveia preta). Por fim, dada a grande diversidade edafoclimática no Sul do Brasil, os resultados apontam que se devem fazer mais estudos e de forma integrada sobre o impacto da época de plantio e tipo de solo para aperfeiçoar os parâmetros de recomendação da adubação orgânica, tornando-a assim mais sustentável.
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Silvertooth, Jeffrey C. "Early Season Crop Management." College of Agriculture, University of Arizona (Tucson, AZ), 2015. http://hdl.handle.net/10150/558539.
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Revised 06/2015; Originally published: 02/20012 pp.
The approaches and techniques used to produce a cotton crop in Arizona can vary to some degree from county to county, or from farm to farm. However, one of the objectives that has become increasingly common across Arizona is that of achieving earliness with a crop.
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Splichal, Kyla Louise. "High tunnels extend the growing season in warm season crops tomato, cucumber and bell pepper." Thesis, North Dakota State University, 2020. https://hdl.handle.net/10365/31808.
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High tunnels are used to modify the crop environment by trapping solar energy, providing protection from unfavorable weather events, and extending the growing season in temperate regions. This project assessed yield and quality in three independent cultivar trials of warm-season crops tomato (Solanum lycopersicum L.), bell pepper (Capsicum annuum L.) and cucumber (Cucumis sativus L.) grown under high tunnel production compared with an outdoor field in eastern and western North Dakota. Tomato yields in the high tunnel were increased by 1.4 times over the field trial yields. Yields from the pepper cultivar trials both inside the high tunnel and outside field were comparable to one another at 1.24 kg plant-1 and 1.06 kg plant-1, respectively. Cucumber yields in the high tunnel were increased by 1.7 times over the field trial yields. Results indicate that in North Dakota, high tunnels extended the growing season, and increased production relative to field conditions.
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Silvertooth, J. C., and E. R. Norton. "Evaluation of 1997 Late-Season Crop Conditions." College of Agriculture, University of Arizona (Tucson, AZ), 1998. http://hdl.handle.net/10150/210302.
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In the latter part of the 1997 season (August) many fields across Arizona, from Marana to the Mohave Valley, were experiencing premature senescence. In an effort to evaluate the conditions leading to the symptoms and to possibly determine the causes, an extensive series of field examinations were conducted in a number of representative fields in central Arizona. Soil samples were taken from selected fields that ranged in expression of the symptoms from very light to severe. Complete analyses of the soil samples were conducted. Plant tissue samples were also collected and analyzed for plant nutrient levels. No absolute causal agent was identified. However, a factor believed to be of significance was that of low soil K levels, where many of the fields expressing the most severe symptoms also had low soil K levels. It is also important to consider the fact that plants exhibiting K deficiency are very similar in appearance to plants affected by Verticillium wilt, which also appeared to be a primary or contributing factor in many cases.
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Silvertooth, J. C., and A. Galadima. "Late Season Crop Management Effects on Fiber Micronaire." College of Agriculture, University of Arizona (Tucson, AZ), 2003. http://hdl.handle.net/10150/197730.
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A field experiment was conducted during the 2002 growing season to evaluate a central Arizona grower’s method of addressing cotton fiber micronaire based on the management and timing of his agronomic inputs. The success of his inseason management, irrigation termination decision combined with his method of defoliation has led to a consistent production of premium fiber micronaire in recent years. Steps to accomplish crop defoliation and the subsequent mixing of seed cotton from the top (younger) and lower (older) bolls achieved at harvest are intended to keep the micronaire at premium levels and further prevent discounts on the crop. A companion study was conducted at the University of Arizona Maricopa Agricultural Center (MAC-1,175 ft. elevation) in an effort to duplicate the grower’s late season crop management operations. This study consisted of two treatments, a control (conventional) which received an application of 10 oz. Ginstar combined with ½ pt. surfactant in 20 gal./acre carrier and a treatment which received the conventional treatment in addition to a pre-defoliation Accelerate and a post-defoliation Gramoxone applications consistent with the grower’s methods. Plant growth and development measurements taken inseason revealed that height to node ratio (HNR) and fruit retention (FR) levels estimates were similar for both sites (grower fields and MAC study). Lint yield estimates indicated no difference between the conventional defoliation and the treatment receiving additional compounds at MAC. Results of the analyses performed on final micronaire data also indicated no significant difference in micronaire values between the two methods of defoliation and late season management at MAC. Fiber micronaire values exceeded the premium level (>5.0) for both treatments at MAC. However, results obtained from the cooperator-grower gin records revealed that average fiber micronaire for all of the fields monitored in this project were at premium level (<5.0).
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Silvertooth, J. C., and A. Galadima. "Late Season Crop Management Effect on Fiber Micronaire." College of Agriculture, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/198124.
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A field experiment was conducted during the 2002 and 2003 growing seasons to evaluate a central Arizona grower’s method of addressing high cotton fiber micronaire based on the management and timing of agronomic inputs. In-season management and irrigation termination combined with defoliation methods has led to consistent production of premium fiber micronaire in recent years. Steps to accomplish crop defoliation and the subsequent mixing of seed cotton from the top (younger) and lower (older) bolls achieved at harvest are intended to keep the micronaire at premium levels and further prevent discounts on the crop. A companion study was conducted in 2002 at the University of Arizona Maricopa Agricultural Center (MAC-1,175 ft. elevation) in an effort to duplicate the grower’s late season crop management operations. This study consisted of two treatments, a control (conventional) which received an application of 10 oz. Ginstar combined with 1/2 pt. surfactant in 20 gal./acre carrier and a treatment which received the conventional treatment in addition to a predefoliation of Accelerate and a post-defoliation of Gramoxone, consistent with the grower’s methods. At the grower’s location, data was collected during the 2002 and 2003 seasons. In 2002 and 2003, plant growth and development measurements taken in-season revealed that height to node ratio (HNR) and fruit retention (FR) levels tracked well and were similar for both sites and years (grower’s fields and MAC study). Lint yield estimates indicated no difference between conventional defoliation and the treatment receiving additional compounds at MAC in 2002. Average yield estimates were high for the cooperator-grower fields in both the 2002 and 2003 seasons. Results of the analysis performed on final micronaire data indicated no significant difference in micronaire values between the two methods of defoliation and late season management at MAC. In addition, fiber micronaire values exceeded the premium level (>5.0) for both treatments at MAC. In contrast, the data of 2002 and 2003 obtained from the cooperator-grower gin records revealed consistent results for average fiber micronaire for all of the fields monitored in this project which were at premium levels (<5.0).
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Brown, P., J. Silvertooth, L. Moore, and T. Watson. "Revised Planting Window for Full Season Cototn Varieties." College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/208660.
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A heat-unit-based planting window was introduced in 1991 as a means of reducing early season problems with pink bollworm (PBW). Growers were encouraged to plant full season varieties when the annual heat unit (HU) accumulation ranged between 600 and 900 -- a window designed to ensure 75% suicidal emergence of PBW yet maintain acceptable yield levels. New research findings and a reexamination of past PBW emergence studies now support making an adjustment to the planting window. For 199Z the recommended planting window is 450 - 700 HUs after January 1.
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Stewart, Anna Elizabeth. "Full-Season and Double-Crop Soybean Response to Potassium Fertilizer." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/56473.
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Demand for potassium (K) increases with increasing soybean yield. Little research has been conducted on soybean response to K on coastal plain and piedmont soils of Virginia, especially in double-crop systems. Nineteen full-season and 14 double-crop soybean experiments were conducted in 2013 and 2014 in Virginia and northeastern North Carolina to determine full-season and double-crop soybean (with wheat straw remaining or removed) response to soil test K and K fertilizer application rates. Field moist, air dried, and oven dry soil test K extraction techniques were also compared to predict responsiveness of sites to K applications. Potassium fertilizer increased yield in five of 19 full-season experiments and one of 14 double-crop experiments. Full-season soybean yield plateaued at 88% relative yield and soil test K value of 38.8 mg K kg-1. Full-season plant K critical concentrations were 18.2 g K kg-1 for V5 and 24.6 g K kg-1 for R2. Although critical concentrations could not be determined for double-crop soybean, V5 and R2 concentrations ranged from 17.6 to 35.6 g K kg-1 or 13.2 to 28.1 K kg-1, respectively, most of which were within or above accepted sufficiency levels. Eight of 13 sites resulted in greater soil K concentrations when alternative soil drying methods were compared to air-dry methods. However, differences were not consistent and no single method was superior for these soils. More data is needed for double-crop soybean systems due to lack of response and lack of low soil test K sites in these experiments.Master of Science
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Andersen, Bryce James. "Integrating Faba Bean (Vicia faba Roth) into Cropping Systems as a Cover Crop, Intercrop, and Late-Season Forage Compared with Other Legume Cover Crops in the Upper Midwest." Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/31542.
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Faba bean (Vicia faba Roth) is grown worldwide as a protein source for food, used for animal feed, and is a common cover crop in Europe, but is underutilized in Midwest farming systems. Faba bean, field pea (Pisum sativum L.), and forage pea were evaluated for biomass and chemical composition when sown after wheat. Faba bean, forage pea, balansa clover (Trifolium michelanium Savi), red clover (T. pratense L.), and rye (Secale cereale L.) were evaluated similarly when intersown into maize. Cover crops after wheat had no significant biomass differences, averaging 1210 kg ha-1, enough to support 1.5 animal unit month (AUM) ha-1 for a 450 kg cow with calf. Rye yielded the greatest (374 kg ha-1) of the intercrops with faba bean averaging similarly and other intercrops averaging significantly less. Intercrops did not affect maize yield. Faba bean has similar potential as other commonly used cover crops in the Midwest.
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Alban, Bradley A. "Relationships of Characteristics to Running Performances and Their Changes Throughout Collegiate Cross Country and Track Seasons." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etd/3290.
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A monitoring program is essential in assuring goal attainment and reducing the risk of overtraining or undertraining, establishing long-term athlete development, and ensuring success. This monitoring program needs to be integrated into the training process, developed, and executed by both the sport science and coaching staff. This staff forms the SPEG (sports performance enhancement group), which is athlete centered and coach driven. The purpose of this dissertation was to create an evidence based, or white box approach, to collegiate distance running by identifying key characteristics, utilizing appropriate monitoring tools, and examining the annual plan. Collegiate distance runners took part in a monitoring program through East Tennessee State University, which included vertical jumps, V̇O2max, running economy, anthropometrics, isometric mid-thigh pull, performance results and ultrasound measurements. There were strong correlations between performance results and monitoring data, and there were significant changes that occurred throughout the monitoring program. The results indicate the importance of V̇O2max in collegiate runners and that monitoring variables, including performance, sum of skinfolds, ultrasound and vertical jumps significantly change throughout the competitive season. The results also identify characteristics of a high-level runner and indicate the impact that a strength program can have on monitoring variables and performance. Results further suggest that strength can be a critical component of a training program, can be tracked through systematic monitoring, and is associated with an increase in performance.
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Owono, Joachim Tabi. "Optimising use of early season rainfall for dryland agriculture in northern Cameroon." Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315627.
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Teuber, Winkler Osvaldo Roberto. "Agronomic Studies of Forage Brassicas as Full-Season and Cover Crops for Grazing in North Dakota." Diss., North Dakota State University, 2017. http://hdl.handle.net/10365/26046.
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Annual forages represent a good feed resource to extend the grazing season into fall and winter, providing a good quality forage for the livestock, allowing more efficient use of rangeland, and at the same time improving soil properties. Many species in the Brassicaceae family are used as forages for grazing. Forage brassicas are characterized by high forage yield, with high nutritive value, low establishment and harvest cost (direct grazing), while providing many ecosystems services. Forage brassicas can be grown as full season forage crops or as cover crops planted after a grain crop. The objectives of this study were: 1) to identify brassicas species and cultivars with high biomass production and forage quality when grown as full-season and as cover crops in North Dakota; 2) to determine their optimum sowing date, plant density and the response to different N and S fertilization rates. Replicated experiments were conducted at four sites Fargo, Prosper, Carrington and Walcott, ND in 2012-2014. Results indicate swede (Brassica napus L. var. napobrassica) and kale [B.oleraceae L. convar. acephala (DC)] were the highest forage yielding brassicas when established in full-season and turnip [Brassica rapa L. var. rapa (L.) Thell).], cv. ?Appin? was the highest yielding sown after August. In full-season brassicas, delaying sowing date reduced total forage yield in all species but did not influence forage quality. In brassicas sown after August, total forage yield decreased significantly only in radish in the second sowing date. Plant density did not have an effect on forage yield or N accumulation averaged across environments and species in full-season forage brassicas. This was different in brassicas sown after August, where the highest forage yield was obtained with the highest plant density (?200 plants m-2). Kale and swede leaf, root/stem, and dead matter yield increased up to 200 kg N ha-1 in a linear response. Sulfur and the interaction between N and S did not have an effect in forage yield and quality. Both full-season and cover crops forage brassicas have great potential as supplemental high quality forage for grazing in North Dakota.Fulbright Commission
Chilean Government
CONICYT (National Commission for Scientific and Technological Research)
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Nelson, J. M., and Gary Hart. "Effect of Plant Nitrogen Status on Defoliation of Short-Season Upland Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/208668.
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Field studies have been conducted over a four year period at the Maricopa Agricultural Center to determine the influence of nitrogen (N) fertility level on the effectiveness of chemical defoliants for short- season cotton production. Excessive N resulted in dense foliage and cotton that was difficult to defoliate. When plants were deficient in N from mid-season to termination, defoliants were very effective, but lint yields were reduced. The effectiveness of defoliants decreased as the petiole NO₃-N content increased. The optimum fertility program for short-season cotton is one that provides sufficient N during the season to produce maximum lint yields, but allows the crop to become deficient in N at the end of the season, prior to chemical defoliation.
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Greatrex, Helen. "The application of seasonal rainfall forecasts and satellite rainfall estimates to seasonal crop yield forcasting for Africa." Thesis, University of Reading, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.578012.
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Rain-fed agriculture is extremely important in sub-Saharan Africa, thus the ability to forecast and monitor regional crop yields throughout the growing season would be of enormous benefit to decision makers. Of equal importance to be able to assign a measure of uncertainty to the forecast, especially considering that many predictions are made in the context of a complex climate and sparse meteorological and agricultural observations. This work investigates these issues in the context of an operational updating regional crop yield forecast, concentrating in particular on a case study forecasting Ethiopian maize. Part 1 of the work presented a detailed discussion of Ethiopia' s climate and agricultural systems. As real-time ground based weather observations are sparse in Africa, Part 2 contains an investigation into remotely sensed satellite rainfall estimates. A daily TAMSAT calibration and the geostatistical process of sequential simulation were used to create a spatially correlated ensemble of Meteosat-derived rainfall estimates. The ensemble mean was evaluated as a daily deterministic rainfall product and was found to be as good as or better than other products applied in the same region. A validation of the full ensemble showed that they realistically estimated Ethiopian rainfall fields that agreed both with observed spatial correlations and input pixel level statistics. Part 3 of the work includes a discussion on regional crop simulation modelling and presents a new parameterisation of the GLAM crop simulation model for tropical maize. GLAMMAIZE was then driven using individual members of the satellite ensemble; this was shown to exhibit the correct sensitivities to climate inputs and performed reasonably against yield observations. Finally, Part 4 presented a new method of creating stochastic spatially and temporally correlated rainfall fields. This 'regional weather generator' was tested using a case study on Ethiopian April rainfall and a detailed discussion was included about future development plans.
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Nelson, J. M., and G. Hart. "Effect of Plant Nitrogen Status on Effectiveness of Defoliants for Short Season Cotton Production." College of Agriculture, University of Arizona (Tucson, AZ), 1991. http://hdl.handle.net/10150/208323.
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A field study was conducted at the Maricopa Agricultural Center to determine the influence of nitrogen fertility level on the effectiveness of defoliants for short-season cotton production. Increasing the nitrogen fertility level from 30 to 130 lbs N/A decreased lint yields from 3.2 to 26 bales /A. High residual soil N favored the use of a low N fertility rate. Defoliation treatments were most effective at the 30 lbs. N/A fertility level. Increasing the application rate of Dropp from 0.2 to 0.4 lbs. a.i./A increased the percent defoliation. There was a significant linear decrease in the effectiveness of defoliants as the petiole NO₃-N content increased from 300 to 7000 ppm.
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Laub, Curtis A. "Influence of cover crop management on Armyworm, Pseudaletia Unipuncta (Haworth) seasonal abundance, natural enemies, and yield in no-till corn, and diurnal abundance and spatial distribution of Armyworm." Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-05022009-040359/.
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Ampong, Joseph Eric. "Utilization of 'wasted' solar radiation in the potential growing season by the potato crop." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385056.
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Griffiths, Martyn Wynne. "Effects of late-season foliar applications of sulphur, and their interactions with nitrogen, on wheat yield and quality." Thesis, University of Wolverhampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330296.
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Norris, Robert Brooke. "Winter Annual Cover Crops Interseeded into Soybean in Eastern Virginia: Influence on Soil Nitrogen, Corn Yield, and In-Season Soil Nitrogen Tests." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/51173.
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The diverse cropping system of eastern Virginia's coastal plain offers limited opportunity to establish winter annual cover crops (WCC) for nitrogen (N) scavenging. The winter fallow niche after double-crop or full-season soybean (Glycine max L. Merr.) encompasses the majority of acres left fallow. Our objective was to evaluate interseeded WCC N scavenging performance following soybean and N supplying capacity to subsequent corn (Zea mays L.). Field studies were conducted at four different locations in each of the two study years. The experimental design was split plot with cereal rye, hairy vetch, and RV mix WCC as main plots and ten fertilizer nitrogen (FN) rates in a factorial arrangement (0 and 45 kg FN ha-1 as starter; and 0, 45, 90, 135, and 180 kg FN ha-1 at sidedress) to corn as subplots. The highest N uptake for cereal rye at winter dormancy was 18 kg N ha-1, but the average was 6-7 kg N ha-1. At WCC termination average N uptake for cereal rye was 35 and 40 kg N ha-1 in 2013 and 2014, respectively. Average biomass dry matter (DM) at WCC termination for cereal rye, cereal rye + hairy vetch mix (RV mix), and hairy vetch was 2356, 2000, and 1864 kg ha-1 in 2013; and 2055, 2701, and 692 kg ha-1 in 2014, respectively. Average cereal rye N uptake was 35 kg N ha-1 in 2013 and 40 kg N ha-1 in 2014. Significant differences for residual soil nitrogen were most apparent for soil nitrate (NO3-N) at lower depths (15-30 and 30-60 cm) during WCC termination and in the upper 0-15 cm during corn growth stage (GS) V4 of both years. Corn grain yield plateau following hairy vetch WCC was 0.7 and 0.6 Mg ha-1 higher than when following cereal rye WCC at zero and 45 kg ha-1 starter FN, respectively. Average agronomic optimum FN rates (AONR) were 26 and 9 kg ha-1 lower following hairy vetch than cereal rye WCC at zero and 45 kg ha-1 starter FN, respectively. Estimated hairy vetch FN reductions by FN replacement and AONR difference methods were 48 and 18 kg FN ha-1 in plots receiving zero starter FN; and 58 and -43 kg FN ha-1 in plots receiving 45 kg ha-1 starter FN. In-season soil N tests did not offer adequate information in order to predict sidedress FN reductions. These findings suggest that cereal rye and RV mix have the potential to scavenge and conserve residual soil N and hairy vetch is more than capable to supply PAN to subsequent corn when interseeded into soybean.Master of Science
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Nelson, J. M., R. E. Briggs, and G. Hart. "Effect of Plant Nitrogen Status on Effectiveness of Pix and Defoliants for Short-Season Cotton Production." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/208258.
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A field study was conducted at the Maricopa Agricultural Center to determine the effect of nitrogen fertility level on the effectiveness of PIX and defoliants for short- season - cotton production. Increasing the nitrogen fertility level from 90 lbs N/A to 240 lbs N/A increased lint yields from 2.23 to 3.14 bales/A, respectively, in a 157-day growing season. FIX treatments did not promote earliness, and resulted in yield reductions. Increasing the application rates of Dropp from 0.1 to 0.2 lbs a.i./A and Def-6 from 0.75 to 1.13 lbs a.i./A resulted in increases in leaf drop. There was a significant linear decrease in the effectiveness of defoliants as the petiole NO3 N content increased from 850 to 2450 ppm.
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Nelson, J. M., R. E. Briggs, and G. Hart. "Effect of Irrigation Termination Date on Defolation and Yield of Upland Cotton for Short-Season Production." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/208289.
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A field study was conducted at the Maricopa Agricultural Center to determine the influence of plant water stress on the effectiveness of defoliants and yield of short season cotton. Irrigation termination dates of 11, 18 and 24 August were used to achieve different levels of water stress at the time defoliants were applied (1 September). Irrigation termination dates had little effect on the response of cotton to defoliants. Def-6 at the lowest rate tested, 0.75 lbs a.i./A, was less effective in defoliating cotton with a 24 August irrigation termination date than cotton terminated earlier. Dropp resulted in higher defoliation percentages and 30% fewer unopened bolls at harvest than Def-6. Although the irrigation termination dates provided a range of CWSI values at the time of chemical termination, no clear relationship was found between CWSI values and defoliation percentages. Short season cotton (149 days) produced 3.2 bales of lint/A compared to 4.4 bales for a full-season crop (208 days).
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Nelson, J. M., P. G. Bartels, and G. Hart. "Effect of Plant Water Status on Defoliation and Yield of Upland Cotton for Short-Season Production." College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/208667.
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A field study was conducted at the Maricopa Agricultural Center to determine the influence of plant water status at the time of defoliation on the effectiveness of defoliants and yield of short-season cotton. Irrigation termination dates of 14 and 26 August and 10 September were used to achieve different levels of plant water stress at the time defoliants were applied (19 September). Irrigation termination dates had no effect on seedcotton yield for cotton defoliated in September. As the period between the termination irrigation and the date of chemical defoliation was increased the effectiveness of defoliants was increased. CWSI and plant water potential measurements indicated that the irrigation termination dates resulted in large differences in plant water stress at defoliation time. There was a significant increase in the defoliation percentage as CWSI values increased (from 0.32 to 0.96) and water potential decreased (from -1.5 to -3.5 MPa). Short- season cotton (163 days) produced 4,396 lbs. seedcotton /A as compared to 5,299 lbs./A for a full-season crop (212 days).
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Knowles, Tim C., Tim J. Dennehy, and Albert Rovey. "Late Season Pink Bollworm Pressure in the Top Crop of Bt and Non-Bt Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/197248.
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Green bolls (100/field) were sampled from the uppermost internodes within adjacent fields of Bt (Deltapine 33B) and non-Bt refuge (Hyperformer HS 44 or Deltapine 20) experiencing severe pink bollworm pressure late in the growing season. Evidence of 3rd instar or larger pink bollworm larvae survival was higher in susceptible bolls sampled from transgenic Bt cotton late in the 1998 growing season, compared to that observed late in the 1997 growing season.
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Knowles, Tim C., Tim J. Dennehy, and Albert Rovey. "Late Season Pink Bollworm Pressure in the Top Crop of Bt and Non-Bt Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 1998. http://hdl.handle.net/10150/210372.
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Green bolls (100/field) were sampled from the uppermost internodes within adjacent fields of Bt (Deltapine 33B) and non-Bt (Hyperformer HS 44) cotton experiencing severe pink bollworm pressure late in the growing season. Average top crop lint yield reductions ranging from 30 to 70% were observed in the uppermost bolls of the non-Bt cotton variety. Average top crop lint yield reductions ranging from 0 to 40% were observed in the uppermost bolls of the transgenic Bt cotton variety.
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Grumbles, R. L., and L. Hood. "Effects of 3 Irrigation Termination Dates on a Full Season Type of Upland Cotton in Mohave Valley, Arizona." College of Agriculture, University of Arizona (Tucson, AZ), 1991. http://hdl.handle.net/10150/208335.
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A single field experiment was conducted in 1990 on a grower cooperator field to evaluate the response of a full season maturity type of Upland Cotton (DPL 90) to three dates of irrigationtermination. The crop was planted 26 and 27 of March, managed uniformly in all respects until August 1 when earliest irrigation termination wsa imposedThe dates for the second and final irrigationtermination treatments were 15August and 15 September. Each irrigationtermination treatments were given an additional 8 acre inches of water (approximate). Harvest results revealed no significant differences in lint yield on the first two dates but the last date yielded 110 pounds more. All plots received a 2 inch rain 18 August.
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Siegenthaler, Scott J. "The academic achievement of cross-country and long-distance track runners a seasonal comparison /." Online version, 2001. http://www.uwstout.edu/lib/thesis/2001/2001siegenthalers.pdf.
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Minh, Do Viet. "Effect of supplementation, breed, season and location on feed intake and performance of scavenging chickens in Vietnam /." Uppsala : Dept. of Animal Nutrition and Management, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/2005101.pdf.
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Billman, Eric D. "EXAMINING VEGETATIVE GROWTH OF COOL-SEASON FORAGE GRASSES FOR DAIRY CATTLE GRAZING PREFERENCE." UKnowledge, 2015. http://uknowledge.uky.edu/pss_etds/69.
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The objective of this study was to determine dairy cattle preference amongst four species of cool-season forage grasses: eight orchardgrasses (Dactylis glomerata L.), five tall fescues [Schedonorus arundinaceus (Schreb.) Dumort.], five perennial ryegrasses (Lolium perenne L.), and six festuloliums [xFestulolium braunii (K. Richt.) A. Camus.]; 24 cultivars in total. Each grazing trial utilized four Holstein-Friesian heifers over six hours. Maturity differences were eliminated by having animals graze only vegetative material. After six grazing trials (three each in 2014 and 2015), consistent results in animal preference were not found; three of the six trials did show preference (P
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Higgins, Sarah. "Limitations to seasonal weather prediction and crop forecasting due to nonlinearity and model inadequacy." Thesis, London School of Economics and Political Science (University of London), 2015. http://etheses.lse.ac.uk/3191/.
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This Thesis examines the main issues surrounding crop modelling by detailed studies of (i) multi-model ensemble forecasting using a simple dynamical system as a proxy for seasonal weather forecasting, (ii) probabilistic forecasts for crop models and (iii) an analysis of changes in US yield. The ability to forecast crop yield accurately on a seasonal time frame would be hugely beneficial to society in particular farmers, governments and the insurance industry. In addition, advance warning of severe weather patterns that could devastate large areas of crops would allow contingency plans to be put in place before the onset of a widespread famine, potentially averting a humanitarian disaster. There is little experience in the experimental design of ensembles for seasonal weather forecasting. Exploring the stability of the results varying, for example, the sample size aids understanding. For this a series of numerical experiments are conducted in an idealised world based around the Moran Ricker Map. The idealised world is designed to replicate the multi-model ensemble forecasting methods used in seasonal weather forecasting. Given the complexity of the physical weather systems experiments are instead conducted on the Moran Ricker Map [56,70]. Additionally, experiments examine whether including climatology as a separate model or blending with climatology can increase the skill. A method to create probabilistic forecasts from a crop model, the Crop Environment Resource Synthesis Maize model (CERES-Maize) [19, 37] is proposed. New empirical models are created using historical US maize yield. The skill from equally weighting the crop model with a simple empirical model is investigated. Background reviews of weather and yield data is presented in new ways for the largest maize growing state Iowa. A new method separating the impacts of favourable weather from technology increases in a crop yield time series is explored.
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Aragão, Thiago Ricielli de Paula. "Interação testecrosses por épocas de semeadura e implicações para o melhoramento de milho." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11137/tde-25032013-163700/.
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O cultivo do milho safrinha tem se expandido consideravelmente nos ultimos anos. Porem devido as condicoes ambientais contrastantes entre safra e safrinha, deve ocorrer pronunciada interacao genotipos x safras, indicando que os genotipos selecionados para a safra podem nao ser adequados para a safrinha. Assim, os objetivos deste trabalho foram investigar a magnitude e natureza da interacao genotipos x safras e a necessidade de conduzir programas de melhoramento de milho distintos para o cultivo de safra e safrinha. Foram utilizadas 100 progenies S1fs derivadas do cruzamento entre as linhagens endogamicas L08- 05F e L38-05D, as quais foram retrocruzadas com ambas as linhagens genitoras e, posteriormente, estas foram cruzadas com a linhagem endogamica L02-03D para obtencao de 200 testecrosses (100 RC1 TC e 100 RC2 TC ). Os testecrosses obtidos foram avaliados nos ambientes de safra e safrinha em dois anos agricolas no municipio de Piracicaba/SP no delineamento ?¿-latice com duas repeticoes por ambiente por ano. Os caracteres analisados foram producao de graos (PG), prolificidade (PROL), acamamento e quebramento de plantas (ACQ), altura de planta (AP) e de espiga (AE), posicao relativa da espiga (PRE), florescimento masculino (FM) e feminino (FF) e intervalo entre florescimentos (IF). Diferencas entre as medias nas duas safras foram significativas para todos os caracteres, reduzindo significativamente a PG na safrinha devido a menor disponibilidade hidrica. A variancia genetica dos testecrosses para PG na safrinha foi inferior a da safra para os testecrosses RC2 TC , enquanto que para os testecrosses RC1 TC a variancia genetica nao diferiu de zero na safrinha. Consequentemente, o coeficiente de herdabilidade na safrinha para os RC1 TC nao diferiu de zero e os RC2 TC apresentaram coeficientes de herdabilidade de magnitudes similares nas duas safras. Para os demais caracteres as magnitudes das variancias geneticas e coeficientes de herdabilidade diferiram entre as safras e os dois grupos de testecrosses. As magnitudes dos componentes da interacao testecrosses x safras mostraram que o tipo complexa explica a maior parte da interacao, sendo causada pelas baixas magnitudes de correlacoes entre os caracteres nas diferentes safras. As respostas diretas e indiretas a selecao mostraram que a selecao direta foi mais eficiente que a indireta em todas as situacoes, com excecao daquelas em que nao foi detectada variancia genetica na safrinha. As respostas a selecao baseadas nas medias das safras resultaram em progressos na safra e na safrinha proximos aos observados pela selecao direta. Porem, a coincidencia de testecrosses selecionados em ambas as safras foi muito baixa para os dois testecrosses. Assim, os resultados deste estudo sugerem que os programas de melhoramento de milho devem ser distintos para safra e safrinha.Maize second crop season, known as gsafrinhah, has increased considerably in the last years in Brazil. However, because of the different environmental conditions between the two crop seasons strong genotype by environment interaction is expected to occur, and then maize genotypes selected in the first crop season (known as gsafrah) could not be those ones that would be selected in the safrinha. Thus, objectives of this research were to investigate the magnitude and the nature of the genotype x crop season interaction and whether separate maize breeding programs for each crop season should be conducted. One hundred S1Ls progenies developed from a population produced from the cross of inbred lines L08-05F (P1) and L38-05D (P2), were backcrossed to both parental inbred lines and, subsequently, these backcrosses were crossed to the inbred line L02-03D giving rise to the 200 testcrosses, thereafter named as TBC1 and TBC2 for the backcrosses to P1 and P2, respectively. The testcrosses were evaluated in two crop seasons in two years at the Piracicaba city, Sao Paulo State, in the ?¿-lattice designs with two replications per crop season and year. The traits analyzed were grain yield (GY), prolificacy (PROL), plant lodging (PL), plant (PH) and ear (EH) heights, ear placement (EP), days to anthesis (DA), days to silking (DS), and anthesissilking interval (ASI). Significant differences for the means of all traits in the two crop seasons were detected, and GY reduced significantly in the safrinha because of the moisture stress. The magnitude of the genetic variance for GY in the safrinha was inferior to that in the safra for the TBC2, and for the TBC1 this parameter did not differ from zero in the safrinha. Consequently, the heritability coefficient in the safrinha for the TBC1 did not differ from zero and the TBC2 presented similar magnitudes of the heritability coefficients in both crop seasons. For the other traits, the magnitudes of the genetic variances and of the heritability coefficients were different between the crop seasons and for the two sets of testcrosses. The magnitudes of the components of the interactions testcrosses x crop seasons showed that the complex type i.e., the cross-over interaction type, accounted for the major part of the interactions, which were due to the low magnitudes of the correlations of the traits in the two crop seasons. Estimates of the direct and indirect responses to selection showed that the direct selections were more efficient than the indirect selections, except to that trait in which the genetic variance did not differ from zero in the safrinha. The responses to selection based on the means of the two crop seasons presented similar magnitudes of the direct responses in both crop seasons. However, the coincidence of testcrosses selected in the two crop seasons was very low for both sets of testcrosses. Therefore, the results of this study suggest that separate maize breeding programs should be conducted for each crop season.
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Fraase, Andrew Ron. "Utilizing Annual Forages in a Single and Dual Crop System for Late-Season Grazing in Southcentral North Dakota." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26477.
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Utilizing annual forages to extend the grazing season can improve late-season forage production and quality, cow performance, and soil health; while providing a cost-effective alternative to drylot feeding. A four-year study tested three annual forage treatments using a single, dual, and dual crop with a herbicide burndown response variable (1 L/ha glyphosate, 250 mL/ha dicamba, 250 mL/ha 2,4-D) system. Treatments were foxtail millet (Setaria italica), turnip (Brassica rapa), a cocktail mix of six complementary species, and native range (control). Results found grazing foxtail millet in the single crop system and the dual crop with spray system, plus grazing turnip and cocktail mix in the dual crop with spray system, all provided on average cost-effective grazing options compared to grazing native range and feeding in a drylot system. The opportunity of increasing land-use efficiency was greatest with the dual crop with spray system, which was the most economical option in 2010.
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McCarty, Jessica Lynn. "Seasonal and interannual variability of emissions from crop residue burning in the contiguous United States." College Park, Md.: University of Maryland, 2009. http://hdl.handle.net/1903/9117.
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Thesis (Ph.D.) -- University of Maryland, College Park, 2009.Thesis research directed by: Dept. of Geography. 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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Challinor, Paul Francis. "An evaluation of pumice, unloaded clinoptilolite and nutrient-loaded clinoptilolite zeolites, as plant growth substrates in the intensive production of long season glasshouse crops." Thesis, University of Plymouth, 2003. http://hdl.handle.net/10026.1/2625.
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Annual losses of nitrogen from existing glasshouse crop production substrate systems could be as high as 600 kg ha 1, using an average of 30% drainwater containing a nitrate-nitrogen concentration of 200 mg 1". The use of nutrient recirculation systems such as nutrient film technique (NFT) helped to reduce nutrient losses to the environment but the commercial area of NFT has decreasedd ue to high initial capital costs, concernso ver diseaset ransmissionw ithin the system and an absence of recent research and development. Most substrate systems rely on the provision of liquid nutrient feeds at every watering. This study examines clinoptilolite which is able to selectively store, supply and exchange cations with plant roots. The use of the naturally-occurring volcanic aluminosilicates pumice and clinoptilolite zeolite in the intensive production of edible and ornamental protected crops, tomatoes, sweet peppers and standard carnations was studied. Pumice from Sicily, Italy and clinoptilolite (84-87%) from Beli Plast, Bulgaria were used in the experiments. The management of the pumice and unloaded clinoptilolite systems involved provision of all the plant growth nutrients via a drip irrigation system. In comparison, the nutrient-loaded clinoptilolites were examined using only water in the irrigation cycles which allowed relatively unimpeded cation exchange to take place between the clinoptilolite and the surrounding solution, thus providing nutrients for plant roots. The total cation exchange capacity of clinoptilolite was measured as 132.0-158.3 meq 100g'', compared with 1.8 meq 100g-' for pumice. Unloaded clinoptilolite irrigated with nutrient-balanced liquid feeds gave yields and quality equivalent to those of tomatoes, peppers and standard carnations grown on rockwool, pumice and peat / peat alternatives. For the first nine months of an eighteen month experiment, the yield and quality of standard carnation flowers from high nutrient-loaded clinoptilolite matched those from pumice receiving liquid feeds at every watering. Thereafter, lower concentrations of available nitrogen and, to a lesser extent phosphorus, limited production by up to 25%. Drainwater nutrient concentrations were, however, extremely low and reduced the potential pollution risk to the surrounding environment. Drainwater nitrate-nitrogen concentrations of below 10 mg 1'' were measured, compared with 100-300 mg 1.1 for pumice. Drainwater potassium concentrations were also comparatively low at < 20 mg 1'' for clinoptilolite and 200 mg 1" for pumice. Phosphorus concentrationsi n the drainwater did not exceed1 2 mg 1.1c, omparedw ith a maximum of 70 mg 1'1 in drainwater from pumice. The inclusion of phosphate rock (apatite) in with the clinoptilolite provided a source of phosphorus available to plants and the dissolution of apatite was regulated by the rate of absorption of phosphorus and calcium by plants. In all the experiments, clinoptilolite adsorbed ammonium-nitrogen and potassium, releasing calcium and sodium. However, concentrations of sodium released into the root zone were not harmful to plant growth. The average nitrate-nitrogen concentration of new, fully-expanded carnation leaves was 51.7% lower than the target levels. The nutrient loading of nitrogen and phosphorus regulated the overall yield of the crops evaluated in the experiments. The use of nutrient-loaded clinoptilolite to produce commercial crops and reduce environmental pollution by regulating the concentration of nutrients in the drainwater over long periods of time is further explored in the study.
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Hagen, Ørjan. "Muscle growth and flesh quality of farmed Atlantic halibut (Hippoglossus hippoglossus) in relation to season of harvest." Thesis, St Andrews, 2008. http://hdl.handle.net/10023/642.
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Horne, Susan Elaine. "A Seasonal Shelf Space Reorder Model Decision Support System." Kent State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=kent1291086889.
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Abolgasem, Tounis Maoloud Mohmed. "Effect of variety, fertilisation, rotation, crop protection and growing season on yield and nutritional quality of potato (Solanum tuberosum L.)." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2551.
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Potatoes (Solanum tuberosum L.) are the most important food crop in the world after rice and wheat. Potato tubers contain many types of essential nutrients. They contain high concentrations of carbohydrates and also vitamins, minerals and protein. They also contain toxic compounds called glycoalkaloids. Potato is classed as a protective vegetable because of its high vitamin C content. The objectives of this study were to determine the effects of different fertiliser types (composted cattle manure, mineral NPK fertiliser), pre-crop (beans, barley) crop protection protocols (organic, conventional) and growing season on the nutritional quality of vitamin C, glycoalkaloids and minerals and yield of different varieties of potato (Sante, Sarpo Mira, Nicola, Fontane, Agria and Cara). Field experiments were carried out during the 2010 and 2011 growing seasons at Nafferton Farm (Newcastle University). The experiment was a split split split plot-design. The main plot was crop rotation, the sub-plot was crop protection, the sub-sub plot was fertility management and sub-sub-sub plot was variety. The vitamin C content was determined by two different methods of analyses; colorimetric titration and high- performance liquid chromatography (HPLC). Mineral content was assessed by the Dumas combustion method at Sabanci University, Turkey. Total glycoalkaloids were determined according to the AOAC method 997. 13. A significant effect of fertilisation was detected for potato yield for both of years. In plots treated with NPK fertilisers, higher yield, compared to compost was obtained for both seasons. In addition conventional crop protection increased yield in both years. Pre-crop significantly affected yield in both years, with higher yields being recorded after beans than barley in 2010 while, a pre-crop of barley resulted in the significantly higher yield than beans in 2011. However, no significant difference between varieties was detected. Also, no significant interactions were detected for tuber yield in 2010. However a significant 2-way interaction between crop protection and pre-crop was observed in 2011, with a pre-crop of beans resulting in the highest yields under conventional crop protection, while a pre-crop of barley resulted in the significantly higher yield under organic crop protection systems. Results of the second growing season (2011) were based on the NUE potato experiment and showed that there was significant difference (P < 0.05) in yield between varieties, fertilisation iii and crop protection. A significant interaction between fertilisation and variety was detected for the yield. There was a significant effect of variety on tuber vitamin C content (P < 0.001), in 2010 and 2011. The concentrations were higher in Sante than Sarpo Mira. There were no significant influences of other treatments (fertility, rotation, crop protection). However, a 2-way interaction between fertilisation and variety was detected in 2011. In 2011 there was a significant effect of varieties on vitamin C content, but no significant effect of fertility and crop protection treatments. However, a significant interactions between fertility, variety and crop protection treatments was detected but only for the titration analysis for vitamin C content. There were no significant effects (P > 0.05) of fertilisation, pre-crop and crop protection on glycoalkaloid concentrations. However, a significant 3-way interaction between fertilisation, variety and rotation was detected for alpha solanine in 2011. A significant 3-way interaction between crop protection, fertilisation and variety was detected for alpha chaconine in 2010. In 2010 the mineral content (N, P, K, Na and Ca) of potatoes was significantly affected by fertilisation treatments. N, P and Ca contents were significantly increased by NPK application while the K and Na contents were significantly increased by compost application. In 2011 Ca contents were affected by fertilisation treatments only. Effects of variety, rotation and crop protection and interactions between factors were also detected for macro mineral contents. However, in 2011 no effect of pre-crop on tuber macronutrient concentration was detected. There was a significant difference in micronutrient concentration between variety, fertilisation and crop protection. No significant effect of rotations was detected for micronutrient concentrations in both of seasons. In conclusion, in both years, 2010 and 2011, variety significantly affected vitamin C content of potato tubers, but there were no significant effects of fertility, pre-crop and crop protection treatments irrespective of the analytical method (titration and HPLC) analysis. Sante tubers contained about 20% more vitamin C than Sarpo Mira. Therefore, it appears that variety choice is a reliable means of manipulating vitamin C as a component of tuber quality compared with other agronomic treatments. In addition, mineral content was also affected by treatments (fertility, variety, rotation and crop protection) and was highly variable. iv For the two years, similar results were obtained in alpha solanine and alpha chaconine content. Significant interactions between rotation, fertilisation and variety were only detected on alpha solanine content during 2011. Also, significant interactions between variety, fertility and crop protection were observed on alpha chaconine content during 2010. The 2010 and 2011 growing seasons appeared to have a significant effect on alpha solanine, macro minerals and micro minerals but did not appear to affect yield, vitamin C and alpha chaconine contents.
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Blombäck, Karin. "Carbon and nitrogen in catch crop systems : modelling of seasonal and long-term dynamics in plant and soil /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1998. http://epsilon.slu.se/avh/1998/91-576-5478-6.gif.
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Hall, Sarah Lynn. "RESTORATION OF TALL FESCUE PASTURES TO NATIVE WARM SEASON GRASSLANDS: DOES A FUNGAL ENDOPHYTE SYMBIOSIS PLAY A ROLE IN RESTORATION SUCCESS?" UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_diss/196.
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Tall fescue, a cool-season grass native to Europe, central Asia, and northern Africa, has been widely distributed throughout the U.S. for use as turf and forage. Following its widespread planting, its ability to associate with a toxic fungal endophyte, Neotyphodium coenophialum, was discovered. Research has linked this fescue-endophyte association with increased biotic and abiotic stress resistance in endophyte-infected (E+) versus endophyte-free (E-) plants, and these differences may affect the ability of land managers to eradicate tall fescue and restore native grasslands. I conducted three studies to examine whether E+ tall fescue plants respond differently to management than E- plants, and whether the success of planted native species might be impacted via indirect soil effects. My overall hypotheses were that E+ plants would recover from restoration/eradication efforts better than E- plants, and that E+ fescue would reduce microbial symbionts in the soil needed by planted native species.
I first conducted a field study of a tall fescue pasture consisting of four sub-units being restored with different combinations of prescribed burns and/or herbicide applications, as well as an unmanaged control. I found no evidence of E+ plants preferentially surviving restoration management; however this field had unusually low endophyte infection rates to begin with. The second study was a greenhouse experiment in which I measured growth of E+ and E- plants exposed to different watering regimes (wet, dry) and prescribed burn treatments (none, one, or two burns). Watering regime significantly affected all measured growth parameters (wet>dry), but few endophyte effects were found and when present were opposite the hypothesis (E->E+). All burned plants quickly re-grew tiller lengths comparable to the unburned control, with recovery occurring faster following the second burn compared to the first. My final study examined growth and arbuscular mycorrhizal colonization of native species planted by seed into soil from beneath E+ and E- tall fescue. I observed few differences in mycorrhizal colonization or biomass for seedlings between soil from E+ and E- tall fescue. Taken together, my results indicate endophyte status of tall fescue pastures being restored to native grassland species may not be important in governing restoration success.
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Corlay, Herrera Favio Raul. "Seasonal development and natural enemies of an invasive exotic species, the swede midge Contarinia nasturtii (Kieffer), in Quebec." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100787.
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In Quebec, the swede midge (Contarinia nasturtii), a newly invasive pest, was found for the first time in 2003. During a two year study (2004-2005) I studied the seasonal development of the swede midge, the presence of natural enemies and tested entomopathogenic nematodes for its control. Results showed that the overwintering generation of the swede midge emerged during the second half of June. Based on adult captures and abundance of larvae in the field, there were three to four overlapping generations. Late transplants were more heavily attacked by the swede midge and broccoli and cauliflower were the most susceptible crops. No parasitoids were found in the experimental sites during either year of the study and two polyphagous coccinellid predators (Harmonia axyridis and Coccinella septempunctata) were field-collected for further evaluation under laboratory conditions. Although these two coccinellid species fed on swede midge larvae in plastic containers, further experiments demonstrated that H. axyridis was not able to prey on swede midge larvae on infested broccoli plants. The susceptibility of swede midge larvae to three species of entomopathogenic nematodes (Steinernema feltiae, S. carpocapsae, and Heterorhabditis bacteriophora) was also evaluated in laboratory assays. Heterorhabditis bacteriophora was the only species that caused significant mortality to swede midge larvae and, at a concentration of 1000 IJs/larva, caused 90-100% mortality in loam, sandy loam, clay and muck soil. This is the first study describing the seasonal development of the swede midge in Quebec. In addition, the potential use of entomopathogenic nematodes as biological control agents against the swede midge is demonstrated.
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Mkuhlani, Siyabusa. "Integration of seasonal forecast information and crop models to enhance decision making in small-scale farming systems of South Africa." Thesis, Faculty of Science, 2021. http://hdl.handle.net/11427/32708.
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Climate variability threatens agricultural productivity and household food security, amongst small-scale farmers of South Africa. Managing climate variability is challenging due to the variation of climate parameters and the difficulty in making decisions under such conditions. Integrated seasonal forecast information and crop models have been used as a tool that enhances decision making in some countries. Utilization of such an approach in South Africa can enhance decision making in climate variability management. The study therefore sought to formulate a decision-making approach to enhance climate variability management in small-scale farming systems of South Africa through integrating seasonal forecast information and crop models. Current practices, challenges and opportunities for climate variability management by different small-scale farmer types were identified using focus group discussions and local agricultural extension officers. The Climate Forecast System version 2 (CFSv2) model-based forecasts were integrated with the Decision Support System for Agrotechnology Transfer (DSSAT) v4.7, a mechanistic crop model based on the Global Climate Model (GCM) approach. The GCM approach was the most appropriate technique for integrating seasonal forecast information and the crop model due to the compatibility in the forecast and crop model format. The decision-making process was formulated through assessing the simulation yield patterns under a range of farm management practices and seasonal forecasts for different cropping seasons, crops and farmer types for Limpopo and Eastern Cape, South Africa for 2017/18 season. The study assessed 48 different potential combinations of farm management practices: organic amendments, varieties, fertilizers and irrigation. Benefits of the decision formulation process and specific seasonal forecast-based recommendations were then assessed in the context of the performance of the practices under historical measured data for the conditions; 2011-2017, using percentile ranking. Assessing the yield response patterns under different farm management practices and seasonal forecasts (2017/2018), the study realized a range of decision scenarios. These are (1) low decision capacity and low climate sensitivity where there is low value for decision due to the homogeneous performance of the different management practices given climate forecasts. (2) high decision capacity and low climate sensitivity, where there is higher potential value for decision making as the different practices have uniform performance across climate forecasts. (3) High decision capacity and high climate sensitivity, where the good response to change in practices under changing climate forecasts. Confidence in the decision formulation process v was re-enforced as some of the decision scenarios were also realized under different conditions in the period; 2011-17. The scenario (2): High decision capacity and low climate sensitivity was predominant in locations with low forecast skill. In contrast the scenario (3): High decision capacity and high climate sensitivity was predominant in locations with high forecast skill. The decision formulation process allows for assessment of farm management practices in the seasonal forecast decision space. Although the case study realized some scenarios ahead of others, the process is robust and repeatable under any conditions. Although the process does not always offer recommendation with improved value for decision making, the value of recommendations is greater under decision scenarios with greater decision capacity. Such benefits are crop and location dependent. Improved seasonal forecasting skill increases reliability of the decision-making process, decision scenarios and associated recommendations. Such assertions need to be tested on the field scale to assess their practical feasibility.
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Johnson, Bryan Fisher. "Influence of Several Herbicides on Visual Injury, Leaf Area Index, and Yield of Glyphosate-Tolerant Soybean (Glycine max)." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/32295.
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The occasional failure of glyphosate to control all weeds throughout the entire growing season has prompted growers to sometimes use herbicides other than glyphosate on glyphosate-tolerant soybean. Field studies were conducted in 1999 and 2000 to investigate potential crop injury from several herbicides on glyphosate-tolerant soybean, and to determine the relationship between soybean maturity, planting date, and herbicide treatment on soybean injury, leaf area index (LAI), and yield. Three glyphosate-tolerant soybean cultivars representing maturity groups III, IV and V were planted at dates representing the full-season and double-crop soybean production systems used in Virginia. Within each cultivar and planting date, 15 herbicide treatments, in addition to a control receiving only metolachlor preemergence, were applied to cause multiple levels of crop injury. Results of this study indicate that glyphosate-tolerant soybean generally recovered from early-season herbicide injury and LAI reductions; however, reduced yield occurred with some treatments. Yield reductions were more common in double-crop soybean than in full-season soybean. In full-season soybean, most yield reductions occurred only in the early maturing RT-386 cultivar. These yield reductions may be attributed to the reduced developmental periods associated with early maturing cultivars and double-crop soybean that often lead to reduced vegetative growth and limited LAI. Additional reductions of LAI by some herbicide treatments on these soybean may have coincided with yield reductions; however, reduced LAI did not occur with all yield reducing treatments. Therefore, soybean LAI response to herbicide treatments does not always accurately indicate the potential detrimental effects of herbicides on soybean yield. Further, yield reductions associated with herbicide applications occurred, although soybean sometimes produced leaf area exceeding the critical LAI level of 3.5 to 4.0 which is the minimum LAI needed for soybean to achieve maximum yield.Master of Science
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Santos, Manoel Galdino dos. "Gergelim irrigado em função da adubação nitrogenada em duas safras agrícolas." Universidade Federal Rural do Semi-Árido, 2017. http://bdtd.ufersa.edu.br:80/tede/handle/tede/767.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico
Sesame is an oleaginous that presents great economic potential, due to the possibilities of exploration. It is a crop of low productivity, and may be superior when management in fertilization is appropriate. However, more information about the nutrition of the crop is needed. Nitrogen is one of the nutrients that most limits the production of sesame because it is responsible for important functions of metabolism and nutrition of the crop. Therefore, the objective of this work was to evaluate the cultivars of irrigated sesame in the function of nitrogen fertilization in two agricultural crops. Experiments were conducted at the Experimental Farm Rafael Fernandes, belonging to the Federal Rural Semi-Arid University, Mossoró-RN, from February to May (1st crop) and July to October (2nd crop) in 2016. The experimental design was in randomized complete blocks with four replications in a subdivided plots scheme, being allocated in the plots five nitrogen doses (0, 30, 60, 90 and 120 kg ha-1), and the four sesame cultivars in the subplots (CNPA G2 , CNPA G3, CNPA G4 and BRS Silk). The variables evaluated were: nitrogen content in the leaf diagnosis, plant height, stem diameter, number of leaves and capsules, dry mass (leaf, stem, capsules and plants), seed productivity, agronomic efficiency, oil and protein content. The dose of 120 kg ha-1 of nitrogen provided the best agronomic performance for sesame. The cultivar CNPA G4 had the highest productive performance. The cultivar BRS Silk had a higher oil content. The second crop provided better agronomic performance to the sesame crop
O gergelim é uma oleaginosa que apresenta grande potencial econômico, devido às possibilidades de exploração. É uma cultura de baixa produtividade, podendo ser superior quando há manejo adequado na adubação. Contudo, maiores informações sobre a nutrição da cultura precisam ser obtidas. O nitrogênio é um dos nutrientes que mais limitam a produção do gergelim, por ser responsável por importantes funções do metabolismo e da nutrição da cultura. Diante disso, o objetivo deste trabalho foi avaliar cultivares de gergelim irrigado em função de adubação nitrogenada em duas safras agrícolas. Os experimentos foram conduzidos na Fazenda Experimental Rafael Fernandes, pertencente à Universidade Federal Rural do Semi-Árido, Mossoró-RN, no período de fevereiro a maio (1ª safra agrícola) e julho a outubro (2ª safra agrícola) de 2016. O delineamento experimental foi em blocos completos casualizados com quatro repetições em esquema de parcelas subdivididas, sendo alocadas nas parcelas cincos doses de nitrogênio (0, 30, 60, 90 e 120 kg ha-1), e nas subparcelas as quatros cultivares de gergelim (CNPA G2, CNPA G3, CNPA G4 e BRS Seda). As variáveis avaliadas foram: teor de nitrogênio na folha diagnóstico, altura de plantas, diâmetro do caule, número de folhas e cápsulas, massa seca (folha, caule, cápsulas e plantas), produtividade de sementes, eficiência agronômica, teor de óleo e proteína. A dose de 120 kg ha-1 de nitrogênio propiciou o melhor desempenho agronômico para o gergelim. A cultivar CNPA G4 teve o maior desempenho produtivo. A cultivar BRS Seda teve maior teor de óleo. A 2ª safra agrícola proporcionou melhor desempenho agronômico à cultura do gergelim
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Gaines, David N. "Seasonal abundance and biology of hyperparasites and their hosts associated with Pieris rapae (L.) (Lepidoptera: Pieridae) in the Brassica crop system." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-06102009-063101/.
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DeLong, Candace Nicole. "Pollen Tube Growth Characteristics of Selected Crabapple Cultivars and Managing Apple (Malus x domestica) Crop Load and Early Season Diseases with Organic Bloom Thinning Chemicals." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/64852.
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Reducing apple (Malus x domestica Borkh.) crop load during bloom is a reliable option for increasing fruit quality and return bloom. In this thesis, multiple approaches to improving bloom thinning practices are discussed. The first project analyzed the pollen tube growth of several crabapple cultivars. Previous research had improved the use of bloom thinning chemicals, by coordinating the application timing with the pollen tube growth between pollination and fertilization. However, pollen tube growth rates have only been measured in a few genotypes. In Chapter 2, the pollen tube growth rates of five crabapple cultivars were measured in the styles of 'Fuji', 'Golden Delicious', and 'Pink Lady' flowers, at four temperatures 12, 18, 24 and 30 C. Complex relationships were found among paternal pollen tube growth, maternal cultivar, and temperature. Chapters 3 and 4 describe projects where organically-approved chemicals, including the biofungicide, Regalia, were evaluated for their ability to simultaneously reduce crop load and decrease early season disease infection. These chemicals were applied in conventionally managed orchards (Chapter 3), and in an organically-managed 'Honeycrisp' orchard (Chapter 4). The number of chemicals approved for bloom thinning is limited, especially in the Eastern U.S. where lime sulfur and oil applications are not permitted during bloom. These studies indicate Regalia, applied during bloom, can reduce crop load and provide early season disease control. The research presented in this thesis provides new knowledge that can be incorporated into crop load management practices in both conventional and organic apple orchards.Master of Science
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Nketia, Kwabena Abrefa [Verfasser]. "Space-time modelling of seasonal soil moisture for improved crop production – the case of the Guinea savannah region, Ghana / Kwabena Abrefa Nketia." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1223706281/34.
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Makaudze, Ephias M. "Do seasonal climate forecasts and crop insurance really matter for smallholder farmers in Zimbabwe? Using contingent valuation method and remote sensing applications." Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1110389049.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xiii, 155 p.; also includes map, graphics (some col.) Includes bibliographical references (p. 149-155). Available online via OhioLINK's ETD Center
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Hanyani, Charles Tawanda. "Effect of full and semi-scavenging rearing systems on crop contents and the quality of meat from village chickens during spring season of Eastern Cape, South Africa." Thesis, University of Fort Hare, 2012. http://hdl.handle.net/10353/440.
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The objective of this study was to compare the nutrient status of full scavenging and semi-scavenging village chicken production systems. The semi-scavenging chickens were given broiler finisher mash between 14-24 weeks of age, whilst the full scavenging relied on natural foraging. The study also sought to compare the quality of meat from chickens from the two systems. After slaughtering the chickens, the crop contents were physically separated and analysed for chemical composition. Meat pH and colour were measured on the breast muscle of individual carcasses and a consumer sensory evaluation was also done on the breast muscle. The mean crop content weights per day were significantly higher in full scavenging chickens (±16.7g/day biomass) than in semi-scavenging chickens (±9.14g/day). Dry matter, calcium, and phosphorus levels were higher in the crop contents of the full than in the semi-scavenging chickens but crude protein, crude fibre and metabolisable energy were higher in the latter system. Semi-scavenging (1.3 ± 0.05kg) carcasses were heavier (P<0.05) than full scavenging ones (1.0 ± 0.06kg). The ultimate pH (24h) (pHu) of meat from full scavenging chickens (6.0 ± 0.03) was higher (P<0.05) than that of meat from the semi-scavenging chickens (5.7 ± 0.04). Meat from the full scavenging chickens had higher L* values (60 ± 1.2) than meat from the semi-scavenging chickens (47 ± 0.8). The a* value of meat of full scavenging chickens was significantly (P<0.05) less (4 ± 0.4) than that of meat from semi-scavenging chickens (15 ± 1.3). There was a significant positive (0.60) correlation between pHu and L* of meat from village chickens across rearing systems. The semi-scavenging system meat had better sensory attributes than the meat from the full scavenging system. Female consumers scored the typical flavour of village chicken meat across rearing systems higher (P< 0.05) than male consumers. The Shona consumers scored the meat higher (P< 0.05) than the Xhosa, Zulu, Ndebele and other tribes for initial juiciness, first bite impression and muscle fibre and tenderness of the chicken across rearing systems. Consumers scored of the meat from the semi-scavenging system higher (P<0.05) on initial juiciness (4.3 ± 0.20), first bite impression (4.2 ± 0.197), muscle fibre tenderness (4.5 ± 0.217) than meat from the full scavenging chickens. There were positive correlations (0.46) between aroma intensity and overall flavour intensity across both rearing systems. The semi-scavenging system produced better carcass characteristics, lighter (L*) meat and more consumer acceptable meat than full scavenging chickens. Therefore the full scavenging rearing system had better nutrient composition in its scavenging feed resource base, although the semi-scavenging systems produced chickens with better carcass, meat pH, colour and sensory characteristics than the full scavenging chickens.
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Dewi, Elsa Rakhmi [Verfasser], Anthony [Akademischer Betreuer] Whitbread, Klaus [Gutachter] Dittert, and Reimund [Gutachter] Roetter. "Intensifying rice-fallow systems in Southeast and South Asia with grain legumes and/or dry season crops: analysis using field experiment and simulation / Elsa Rakhmi Dewi. Betreuer: Anthony Whitbread. Gutachter: Klaus Dittert ; Reimund Roetter." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://d-nb.info/1109046405/34.
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Boyard-Micheau, Joseph. "Prévisibilité potentielle des variables climatiques à impact agricole en Afrique de l'Est et application au sorgho dans la région du mont Kenya." Thesis, Dijon, 2013. http://www.theses.fr/2013DIJOS075/document.
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Dans les pays du Sud ruraux et à faibles revenus, la vulnérabilité des zones agricoles pluviales, face à la variabilité pluviométrique, nécessite de trouver des solutions efficaces pour limiter les effets des aléas climatiques sur les récoltes. La prévision des caractéristiques des saisons des pluies quelque temps avant leur démarrage devrait aider à l’établissement de stratégies agricoles d’adaptation aux aléas pluviométriques. C’est à cet objectif que s’attache ce travail, appliqué à l’Afrique de l’Est (Kenya et nord de la Tanzanie), et articulé en 3 parties :- Définir et comprendre le comportement des descripteurs intra saisonniers (DIS) qui feront l’objet de l’étude de prévisibilité. Un travail spécifique a permis le développement d’une nouvelle approche méthodologique dans la manière de définir les démarrages (DSP) et fins (FSP) de saisons des pluies à l’échelle régionale. Cette approche basée sur une analyse multivariée, permet de s’affranchir des choix subjectifs de seuils pluviométriques imposés par les définitions communément utilisée en agro-climatologie. Une analyse de cohérence spatiale à l’échelle inter annuelle montre que, pour les deux saisons des pluies (long rains et short rains), le cumul saisonnier et le nombre de jours de pluie présentent une forte cohérence spatiale, tandis qu’elle est plus modérée pour le démarrage et fin des saisons et faible pour l’intensité quotidienne moyenne.- Analyser la prévisibilité des DIS aux 2 échelles spatiales régionale et locale en s’appuyant sur les simulations numériques du modèle climatique global ECHAM 4.5. Les précipitations quotidiennes simulées par le modèle, même après correction des biais, ne permettent pas d’appréhender correctement la variabilité interannuelle des DIS. Une spécification de la variabilité des DSP et FSP menée par le biais de modèles statistiques construits à partir d’indices climatiques observés, présuppose une prévisibilité modérée des deux descripteurs à l’échelle locale (régionale), et cela quelle que soit la saison. Le développement de modèles statistico-dynamiques à partir des champs de vents simulés par ECHAM 4.5, en mode forcé par les températures marines observées d’une part et prévues d’autre part, montre également des performances faibles localement et régionalement. - Explorer la manière dont la variabilité spatio-temporelle des paramètres climatiques et environnementaux module la variabilité des rendements de sorgho. Ces rendements sont simulés par le modèle agronomique SARRA-H à partir de données climatiques observées (1973-2001) dans 3 stations localisées à différentes altitudes le long des pentes orientales du Mt Kenya. Le cumul précipité et la durée de la saison expliquent une part importante de la variabilité des rendements. D’autres variables apparaissent comme jouant un rôle non négligeable ; le nombre de jours de pluies, l’intensité quotidienne moyenne ou encore certains DIS relatifs à l’organisation temporelle des pluies au sein d’une saison en font partie. L’influence des autres variables météorologiques est seulement visible pour les ‘long rains’ avec une covariation négative entre les rendements et les températures maximales ou, le rayonnement global. La date de semis semble jouer un rôle dans la modulation des rendements pour les stations de haute et moyenne altitudes, mais avec des différences notables entre les deux saisons des pluiesIn Southern countries with rural low income populations, the vulnerability of rainfed agriculture to rainfall variability requires effective solutions to mitigate the effects of climatic hazards on crops. Predicting the characteristics of rainy seasons some time before they start should help the establishment of agricultural adaptation strategies to rainfall hazards. This is the objective of the present study, focused on East Africa (Kenya and northern Tanzania), and divided in three parts:- Define and document intra-seasonal descriptors (ISD) that will be considered in the predictability study. A new methodological approach has been developed in order to define the onset date (ORS) and the cessation date (CRS) of the rainy seasons at the regional level. Based on a multivariate analysis, it eliminates the subjective choice of rainfall thresholds imposed by the definitions commonly used in agroclimatology. An analysis of spatial coherence at interannual time-scale shows that for the two rainy seasons ("long rains" and "short rains"), the seasonal amount and the number of rainy days have a high spatial coherence, while it is medium for the onset and cessation dates and low for the average daily rainfall intensity.- Analyze the predictability of the ISD at both regional and local scales based on numerical simulations from the global climate model ECHAM 4.5. Daily precipitation simulated by the model, even after bias correction, do not correctly capture the IDS interannual variability. A specification of the ORS and CRS variability using statistical models applied to observed climate indices, suggests quite a low predictability of the descriptors at the local (regional) scale, regardless of the season. The development of statistical-dynamical models from wind fields simulated by ECHAM 4.5, in experiments forced by either observed or predicted sea temperatures, also shows quite poor skills locally and regionally.- Explore how the space-time variability of climatic and environmental factors modulate the variations of sorghum yields. Crop yields are simulated by the agronomic model SARRA-H using observed climate data (1973-2001) at three stations located at different elevations along the eastern slopes of Mt Kenya. The seasonal rainfall accumulation and the duration of the season account for a large part of the yields variability. Other rainfall variables also play a significant role, among which the number of rainy days, the average daily intensity and some ISD related to the temporal organization of rainfall within the season. The influence of other meteorological variables is only found during the long rains, in the form of a negative correlation between yields and both maximum temperature and global radiation. Sowing dates seem to play a role in modulating yields for high and medium altitude stations, but with notable differences between the two rainy seasons
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Khanizadeh, Shahrokh. "Effects of crop load on seasonal variation in protein, amino acid, and carbohydrate composition, and spring frost hardiness of apple flower buds (Malus pumila Mill. cv. McIntoshM7)." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74065.
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