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1
Russell, CA, and IRP Fillery. "Estimates of lupin below-ground biomass nitrogen, dry matter, and nitrogen turnover to wheat." Australian Journal of Agricultural Research 47, no. 7 (1996): 1047. http://dx.doi.org/10.1071/ar9961047.
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The amount of lupin below-ground biomass (BGB), BGB nitrogen (N) content, and utilization of BGB-N by subsequent wheat was estimated from lupins grown in soil columns. Lupin plants were enriched in situ with 15N-labelled urea through a cotton wick inserted through the stem. Of the applied 15N. 92% was recovered in the lupin plant-soil system at maturity: 87% of this 15N was in lupin aboveground biomass and 13% in the soil columns. Total mature lupin dry matter (DM) approximated 11 t/ha, with 3.0 t/ha (27%) of this DM below ground. Total mature lupin N approximated 321 kg/ha, of which 91 kg/ha (28%) resided below ground. In terms of N and DM, BGB was the largest lupin residue component even though only 35% of this was recoverable as root material. About 13% of the BGB-N was in inorganic form at maturity. The net mineralisation of lupin BGB-N after 2 consecutive years of wheat growth was 27%. and wheat assimilated about 74% of this N (i.e. 20% of BGB-N), with equal quantities assimilated in each year. The contribution of lupin BGB-N to the N in wheat tops ranged from 40% for soil columns receiving no fertiliser N to 15-20% for soil columns fertilised with 30 kg N/ha. The net mineralisation of BGB-N and the assimilation of BGB-N by wheat were unaffected by the application of fertiliser N.
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Abbas, Ahmed Mahmoud, Sameh K. Abd-Elmabod, Soad M. El-Ashry, Wagdi Saber Soliman, Noha El-Tayeh, and Jesus M. Castillo. "Capability of the Invasive Tree Prosopis glandulosa Torr. to Remediate Soil Treated with Sewage Sludge." Sustainability 11, no. 9 (May 13, 2019): 2711. http://dx.doi.org/10.3390/su11092711.
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Sewage sludge improves agricultural soil and plant growth, but there are hazards associated with its use, including high metal(loid) contents. An experimental study was conducted under greenhouse conditions to examine the effects of sewage sludge on growth of the invasive tree Prosopis glandulosa, as well as to determine its phytoremediation capacity. Plants were established and grown for seven months along a gradient of sewage sludge content. Plant traits, soil properties, and plant and soil concentrations of N, P, K, Cd, Pb, Cu, Ni, Zn, Cr, Co, As, and Fe were recorded. The addition of sewage sludge led to a significant decrease in soil pH, and Ni, Co, and As concentrations, as well as an increase in soil organic matter and the concentrations of N, P, Cu, Zn, and Cr. Increasing sewage sludge content in the growth medium raised the total uptake of most metals by P. glandulosa plants due to higher biomass accumulation (taller plants with more leaves) and higher metal concentrations in the plant tissues. P. glandulosa concentrated more Cd, Pb, Cu, Zn, and Fe in its below-ground biomass (BGB) than in its above-ground biomass (AGB). P. glandulosa concentrated Ni, Co, and As in both BGB and AGB. P. glandulosa has potential as a biotool for the phytoremediation of sewage sludges and sewage-amended soils in arid and semi-arid environments, with a potential accumulation capability for As in plant leaves.
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Yang, Yang, and Bingru Liu. "Testing relationship between plant productivity and diversity in a desertified steppe in Northwest China." PeerJ 7 (July 10, 2019): e7239. http://dx.doi.org/10.7717/peerj.7239.
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The rapid global plant diversity and productivity loss has resulted in ecosystem functional degeneration in recent decades, and the relationship between plant diversity and productivity is a pressing issue around the world. Here, we sampled six plant communities that have not been grazed for 20 years, i.e., Agropyron mongolicum, Stipa bungeana, Cynanchum komarovii, Glycyrrhiza uralensis, Sophora alopecuroides, Artemisia ordosica, located in a desertified steppe, northwestern China, and tested the relationship between plant diversity and productivity in this region. We found a positive linear relationship between AGB (above-ground biomass) and BGB (below-ground biomass), and the curves between plant diversity and AGB were unimodal (R2 = 0.4572, p < 0.05), indicating that plant productivity increased at a low level of diversity but decreased at a high level of diversity. However, there was no significant relationship between BGB and plant diversity (p > 0.05). Further, RDA (redundancy analysis) indicated that soil factors had a strong effect on plant diversity and productivity. Totally, GAMs (generalized additive models) showed that soil factors (especially total nitrogen TN, total carbon TC, soil microbial biomass nitrogen SMB-N, soil microbial biomass carbon SMB-C) explained more variation in plant diversity and productivity (78.24%), which can be regarded as the key factors driving plant diversity and productivity. Therefore, strategies aiming to increase plant productivity and protect plant diversity may concentrate on promoting soil factors (e.g., increasing TC, TN, SMB-N and SMB-C) and plant species, which can be regarded as an effective and simple strategy to stabilize ecosystems to mitigate aridity in desertified steppes in northwestern China.
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Khan, Dil F., Mark B. Peoples, Graeme D. Schwenke, Warwick L. Felton, Deli Chen, and David F. Herridge. "Effects of below-ground nitrogen on N balances of field-grown fababean, chickpea, and barley." Australian Journal of Agricultural Research 54, no. 4 (2003): 333. http://dx.doi.org/10.1071/ar02105.
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The objectives of this study were to quantify below-ground nitrogen (BGN) of rainfed fababean (Vicia faba), chickpea (Cicer arietinum), and barley (Hordeum vulgare) and to use the values to determine N balances for the 3 crops. The BGN fraction of legumes in particular represents a potentially important pool of N that has often been grossly underestimated or ignored in calculating such balances. A field experiment was conducted at Breeza on the Liverpool Plains, New South Wales, in which BGN of fababean, chickpea, and barley was estimated using 15N methodologies. Plants were grown in 0.32-m2 microplots and labelled with 15N on 5 occasions during vegetative growth with a total of 1.0 mL of 0.5% 15N urea (98 atom% 15N) using leaf-flap (fababean), leaf-tip (barley), or cut petiole (chickpea) shoot-labelling procedures. At peak biomass (146–170 days after sowing), all plant material and soil to 45 cm depth was sampled from one microplot in each replicate plot and analysed for dry matter (DM), %N, and 15N. At plant maturity, the remaining 3 microplots in each replicate plot were harvested for shoot and grain DM and N. With fababean, 15N enrichments of intact roots and shoots were reasonably uniform at 537‰ and 674‰, respectively. Microplot soil at 0–25 cm depth had a 15N enrichment of 18‰ (natural abundance of 6.1‰). The 25–45 cm soil enrichment was 8.7‰ (natural abundance of 6.3‰). In contrast, 15N enrichment of chickpea shoots was about twice that of recovered roots (685‰ v. 331‰), and the soil enrichment was relatively high (30‰ and 8.8‰ for the 0–25 and 25–45 cm depths, respectively). The 15N enrichments of barley shoots and recovered roots were 2272‰ and 1632‰, respectively, with soil enrichments of 34‰ and 10.7‰ for the 0–25 and 25–45 cm depths, respectively. Estimates of BGN as a percentage of total plant N, after adjusting the 15N shoot-labelling values of fababean and chickpea for uneven distribution of 15N-depleted nodules, were 24% for fababean, 68% for chickpea, and 36% for barley. The BGN values were combined with N2 fixation (fababean and chickpea only) and shoot and grain yield data (all 3 species) to construct N budgets. The inclusion of BGN in the budgets increased N balances by 38 kg N/ha to +36 kg N/ha for fababean and by 93 kg N/ha to +94 kg N/ha for chickpea. As there was no external (N2 fixation) input of N to barley, the inclusion of BGN made no difference to the N balance of the crop of –74 kg N/ha. Such values confirm the importance of BGN of N2-fixing legumes in the N economies of cropping systems.
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Unkovich, MJ, JS Pate, and J. Hamblin. "The nitrogen economy of broadacre lupin in southwest Australia." Australian Journal of Agricultural Research 45, no. 1 (1994): 149. http://dx.doi.org/10.1071/ar9940149.
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The time courses of above- and below-ground accumulation of biomass and N were followed in a crop of narrowleaf lupin (Lupinus angustifolius L. cv. Illyarrie) at Geraldton, W.A., and concurrent N2 fixation assessed using the 15N natural abundance technique. Crop biomass peaked at 10 t DM and 231 kg N ha-1 with 13% of this N below ground. The crop accumulated the bulk (90%) of its N through symbiotic N2 fixation. Of the 164 kg total plant N ha-1 remaining in recoverable biomass at maturity 44% was recovered as grain, 49% as other above-ground residues and 7% as roots. Despite a decrease in recoverable N of 67 kg ha-1 between peak biomass and maturity, 96 kg N ha-1 was returned as crop residues after grain harvest. Investigation of six farm crops in the study region gave values for nitrogen accumulation at peak biomass ranging from 199 to 372 kg ha-1 of which, on average, 86% (222 kg ha-1) was fixed from the atmosphere. Predicted N returns to the soil from fixation averaged 65 kg ha-1, though the range (32-96 kg ha-1) indicated that south-west Australian lupin crops provide somewhat variably sized pools of mineralizeable crop residues for following cereal growth.
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Morgan, K. T., J. M. S. Scholberg, T. A. Obreza, and T. A. Wheaton. "Size, Biomass, and Nitrogen Relationships with Sweet Orange Tree Growth." Journal of the American Society for Horticultural Science 131, no. 1 (January 2006): 149–56. http://dx.doi.org/10.21273/jashs.131.1.149.
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Growth and nitrogen (N) accumulation relationships based on tree size, rather than age, may provide more generic information that could be used to improve sweet orange [Citrus sinensis (L.) Osbeck] N management. The objectives of this study were to determine how orange trees accumulate and distribute biomass and N as they grow, investigate yearly biomass and N changes in mature orange trees, determine rootstock effect on biomass and N distribution, and to develop simple mathematical models describing these relationships. Eighteen orange trees with canopy volumes ranging between 2 and 43 m3 were dissected into leaf, twig, branch, and root components, and the dry weight and N concentration of each were measured. The N content of each tree part was calculated, and biomass and N distribution throughout each tree were determined. The total dry biomass of large (mature) trees averaged 94 kg and contained 0.79 kg N. Biomass allocation was 13% in leaves, 7% in twigs, 50% in branches/trunk, and 30% in roots. N allocation was 38% in leaves, 8% in twigs, 27% in branches/trunk, and 27% in roots. For the smallest tree, above-/below-ground distribution ratios for biomass and N were 60/40 and 75/25, respectively. All tree components accumulated biomass and N linearly as tree size increased, with the above-ground portion accumulating biomass about 2.5 times faster than the below-ground portion due mostly to branch growth. The growth models developed are currently being integrated in a decision support system for improving fertilizer use efficiency for orange trees, which will provide growers with a management tool to improve long-term N use efficiency in orange orchards.
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Xiao, C., I. A. Janssens, Y. Zhou, J. Su, Y. Liang, and B. Guenet. "Strong stoichiometric resilience after litter manipulation experiments; a case study in a Chinese grassland." Biogeosciences 12, no. 3 (February 9, 2015): 757–67. http://dx.doi.org/10.5194/bg-12-757-2015.
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Abstract. Global climate change has generally modified net primary production (NPP) which leads to increasing litter inputs in some ecosystems. Therefore, assessing the impacts of increasing litter inputs on soil nutrients, plant growth and ecological carbon (C) : nitrogen (N) : phosphorus (P) stoichiometry is critical for an understanding of C, N and P cycling and their feedback processes to climate change. In this study, we added plant above-ground litter, harvested near the experimental plots, to the 10–20 cm subsoil layer of a steppe community at rates equivalent to annual litter input of 0, 15, 30, 60 and 120%, respectively, covering the entire range of the expected NPP increases in this region due to climate change (10–60%). We measured the resulting C, N and P content of different pools (above- and below-ground plant biomass, litter, microbial biomass). Small litter additions, which are more plausible compared to the expected increase predicted by Earth system models, had no effect on the variables examined. Nevertheless, high litter addition (120% of the annual litter inputs) significantly increased soil inorganic N and available P, above-ground biomass, below-ground biomass and litter. Our results suggest that while very high litter addition can strongly affect C : N : P stoichiometry, the grassland studied here is resilient to more plausible inputs in terms of stoichiometric functioning.
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McNeill, Ann M., Chunya Zhu, and Ian R. P. Fillery. "Use of in situ 15N-labelling to estimate the total below-ground nitrogen of pasture legumes in intact soil - plant systems." Australian Journal of Agricultural Research 48, no. 3 (1997): 295. http://dx.doi.org/10.1071/a96097.
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A leaf-feeding technique for in situ 15N-labelling of intact soil–pasture plant systems was assessed, using subterranean clover (Trifolium subterraneum L.) and serradella (Ornithopus compressus L.) grown under glasshouse conditions. Total recoveries of fed 15N were 87–100% following leaf-feeding of plants at flowering but were lower (74–84%) following the feed at the vegetative stage. Below-ground recovery of fed 15N ranged from 7 to 26%, with serradella partitioning a greater proportion of labelled N below ground than subterranean clover. Additionally, plants of both species fed at the vegetative stage accumulated a greater proportion of the 15N label below ground than did those fed at flowering. Dry sampling procedures, which utilised freeze-drying, enabled fractionation of the below-ground portion of the system into ‘clean’ nodulated macro-roots with no adhering soil, residual uncleaned root, rhizosphere, and bulk soil. Calculated specific enrichment for the ‘clean’ roots at different depths demonstrated a relatively uniform distribution of 15N label in the subterranean clover roots, whereas the presence of large indeterminate nodules in the crown region of serradella roots contributed to apparent uneven distribution of label. Approximately half of the N in the residual fraction of both species consisted of labelled material, postulated to be mostly fine root. Additionally, 5–20% of the rhizosphere N and 0·5–3% of the N in bulk soil was legume root-derived, with some 15N detected in the extractable total soluble N and microbial N pools. Rhizodeposition of N represented approximately 10% of total plant N and 17–24% of total below-ground N for subterranean clover, whereas values for serradella were 20 and 34–37%, respectively. Estimated total below-ground N of subterranean clover reached a maximum value of 177 mg N/plant at 98 days after sowing, which corresponded with a peak shoot N of 243 mg N. Maximum below-ground N for serradella attained 196 mg N/plant 84 days after sowing with a corresponding shoot biomass of 225 mg N. There was a decline in the total below-ground N of serradella at maturity. Overall, recovered clean root N represented 30–62% of estimated total below-ground N, so it was concluded that standard root recovery procedures might be likely to underestimate severely the total below-ground N accretion and N turnover by legumes. The implications of these results for field estimation of total legume N yield, biological N fixation, and the N benefit from legumes in rotations are discussed.
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Luo, Xi, Yi Zheng, Xiaohong Xu, Rui Xiao, and Hui Guo. "The impacts of warming and nitrogen addition on competitive ability of native and invasive populations of Plantago virginica." Journal of Plant Ecology 13, no. 6 (August 8, 2020): 676–82. http://dx.doi.org/10.1093/jpe/rtaa055.
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Abstract Aims Global change factors (e.g. warming and nitrogen deposition) may influence biological invasions, but how these factors may influence the performance of invasive species and further mediate the interactions with native competitors remain still unknown. Methods Here, we conducted a 5-month greenhouse experiment to examine the effects of warming (using open-top chambers, +0.62°C) and N addition (adding NH4NO3 at a rate of 4.2 g m−2) on the performance of the native and invasive populations of an invasive species Plantago virginica in competition with a native Plantago asiatica. Important Findings Under warming treatment and its interaction with nitrogen addition treatment (W × N), invasive and native populations of P. virginica had different biomass allocation strategies to compete with native competitor P. asiatica. Native population of P. virginica (PV-Na) increased more below-ground biomass, whereas those from the invasive population (PV-In) increased more above-ground biomass. We also found that invasive species P. virginica had stronger responses to warming and N addition than the native species P. asiatica. The competitive ability of the invasive plants was significantly reduced by warming which indicated that the invasive plant were much stronger sensitivity to elevated temperature than native plant. Similarly, N addition and W × N reduced the competitive response of PV-In in below-ground biomass, but increased the competitive response of PV-Na in above-ground and total biomass when they grew with the P. asiatica. The results show that P. virginica have occurred differential biomass allocation strategies during its invasions and invasive population exhibit flexible competition ability to adapt to environmental changes (especially warming). These findings may potentially help to predict plant invasions and make management strategies in a world with changing climate.
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Russell, CA, and IRP Fillery. "In situ 15N labelling of lupin below-ground biomass." Australian Journal of Agricultural Research 47, no. 7 (1996): 1035. http://dx.doi.org/10.1071/ar9961035.
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This paper describes the use of a cotton-wick method to enrich lupin plants with 15N. The method involved the insertion of a cotton thread through the stem and the submergence of the ends of the cotton thread in a solution of highly enriched 15N urea. The distribution of 15N in lupin plant components during pre-reproductive growth and pod filling. and in relation to the frequency of labelling, was determined. The recovery of applied 15N within plant tissues was close to 100% for lupins grown in solution culture, but 15N was not distributed between plant components in the proportions observed for total plant N. Stems and leaves were preferentially labelled with 15N irrespective of the phase of lupin growth when the 15N was applied. Pre-reproductive and mature lupin root biomass was depleted in 15N because of the poor assimilation of 15N within lupin nodules. More applied 15N was found in the root biomass of lupin plants that received fortnightly, compared with weekly, applications of 15N. The distribution of 15N between lupin components was reproducible when 15N-urea was wick-applied to plants of the same age. Recovery of 15N was incomplete when urea was fed to lupins grown in sand culture. Incomplete recovery of root material and loss of 15N associated with root exudates probably contributed to the lower recoveries of 15N in root material in sand compared with solution culture. The ability to manipulate the 15N solution concentration, the volume of solution fed to plants, time of application, and frequency of 15N application underscore the usefulness of the wick technique to label woody legumes with 15N.
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Adcock, P. W., and G. G. Ganf. "Growth Characteristics of Three Macrophyte Species Growing in a Natural and Constructed Wetland System." Water Science and Technology 29, no. 4 (February 1, 1994): 95–102. http://dx.doi.org/10.2166/wst.1994.0166.
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Total, above and below ground biomass, growth, and tissue nutrient concentration of three species growing in two contrasting environments (a horizontal flow, constructed wetland fed tertiary effluent at Bolivar, South Australia, and a natural wetland, Bool Lagoon, south-eastern South Australia) were compared to determine relative performance of each species. Overall Baumea articulata and Phragmites australis performed poorly in trenches compared with natural wetland. Total biomass was 4.0 and 2.7, compared with 7.7 and 10.9 kg/m2 however, above ground (AG)/below ground (BG) ratios were similar at both locations (1 (Baum) and 0.42(Phrag)). Below ground mass was restricted to the top 25cm in the trenches but penetrated to > 50cm in the natural wetland. Phragmites showed a marked decline in standing biomass during the winter period in both environments but Baumea increased standing biomass in the trenches. Although the mean tissue nutrient concentrations of N and P for plants grown in trenches were higher than their natural counterparts [3.18(Baum), 2.56(Phrag) vs. 0.68(Baum), 0.49(Phrag) mg P/g DWt.; 12.99(Baum), 23.06(Phrag) vs. 5.39(Baum), 8.92(Phrag) mg N/g DWt.], this was offset by the lower biomass of the plants in the trenches. In contrast, the semi-emergent Triglochin procerum performed exceptionally well in the trenches, compared with the other species, and with itself growing in Bool Lagoon. Total biomass was 15.4 kg/m2, AG/BG ratio was 6. Triglochin continued to grow vigorously throughout the winter and had a mean tissue concentration of 5.19 mg P, 22.63 mg N and 368 C/g dry weight. These data suggest that the effective removal of nitrogen and phosphorus by harvesting was 5 times higher for Triglochin than for Baumea or Phragmites in the trenches. The nitrogen concentrations in Triglochin suggest a protein content of 16–18% which compares favourably with lucerne.
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Zhu, Zhengjie, Siyuan Song, Pengshan Li, Nasreen Jeelani, Penghe Wang, Hezhong Yuan, Jinghan Zhang, Shuqing An, and Xin Leng. "Growth and physiological responses of submerged plantVallisneria natansto water column ammonia nitrogen and sediment copper." PeerJ 4 (April 21, 2016): e1953. http://dx.doi.org/10.7717/peerj.1953.
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Background.The decline of submerged plant populations due to high heavy metal (e.g., Cu) levels in sediments and ammonia nitrogen (ammonia-N) accumulation in the freshwater column has become a significant global problem. Previous studies have evaluated the effect of ammonia-N on submerged macrophytes, but few have focused on the influence of sediment Cu on submerged macrophytes and their combined effects.Methods.In this paper, we selected three levels of ammonia-N (0, 3, and 6 mg L−1) and sediment Cu (25.75 ± 6.02 as the control, 125.75 ± 6.02, and 225.75 ± 6.02 mg kg−1), to investigate the influence of sediment Cu and ammonia-N on submergedVallisneria natans. We measured the relative growth rate (RGR), above- and below- ground biomass, chlorophyll, non-protein thiol (NP-SH), and free proline.Results and Discussion.The below-ground biomass ofV. natansdecreased with increasing Cu sediment levels, suggesting that excessive sediment Cu can result in significant damage to the root ofV. natans. Similarly, the above-ground biomass significantly decreased with increasing ammonia-N concentrations, indicating that excessive water ammonia-N can cause significant toxicity to the leaf ofV. natans. In addition, high ammonia-N levels place a greater stress on submerged plants than sediment Cu, which is indicated by the decline of RGR and chlorophyll, and the increase of (NP-SH) and free proline. Furthermore, high sediment Cu causes ammonia-N to impose greater injury on submerged plants, and higher sediment Cu levels ($\mathrm{Cu}\geq 125.75$ mg kg−1) led to the tolerant values of ammonia-N forV. natansdecreasing from 6 to 3 mg L−1. This study suggests that high sediment Cu restricts the growth of plants and intensifies ammonia-N damage toV. natans.
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Costa, Karen C. P. da, João B. S. Ferraz, Rodrigo P. Bastos, Tatiane Da S. Reis, Marciel J. Ferreira, and Giuliano P. Guimarães. "ESTOQUES DE BIOMASSA E NUTRIENTES EM TRÊS ESPÉCIES DE Parkia EM PLANTIOS JOVENS SOBRE ÁREA DEGRADADA NA AMAZÔNIA CENTRAL." FLORESTA 44, no. 4 (December 31, 2014): 637. http://dx.doi.org/10.5380/rf.v44i4.34135.
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As estratégias de distribuição de biomassa e nutrientes utilizadas pelas espécies florestais podem refletir sua capacidade de sobrevivência em plantios sobre áreas degradadas. O objetivo deste estudo foi quantificar os estoques de biomassa e nutrientes nos compartimentos arbóreos de Parkia multijuga, Parkia nitida e Parkia pendula em plantios sobre área degradada em Manaus, AM. A biomassa foi determinada pelo método destrutivo em seis árvores de cada espécie, que foram compartimentadas em: folhas, galhos finos (Ø <10 cm), galhos grossos (Ø ≥10 cm), fuste, raízes médias (2 mm ≤ Ø <5 cm) e raízes grossas (Ø ≥5 cm). Aos quatro anos, Parkia multijuga exibiu 60% do total de biomassa nos compartimentos aéreos e 40% nos subterrâneos. Parkia nitida exibiu 84% nos compartimentos aéreos e apenas 16% nos subterrâneos. Parkia pendula exibiu 67% nos compartimentos aéreos e 33% nos subterrâneos. A ordem de acúmulo de macronutrientes nos compartimentos foi: N > Ca > K > Mg > P. O fato de Parkia multijuga adotar estratégias de alocação de biomassa e nutrientes que favorecerão seu desempenho sobre sítios com baixa disponibilidade de recursos sustenta sua indicação para a composição de programas de reflorestamento em áreas degradadas na Amazônia.Palavras-chave: Espécies florestais nativas; nutrição florestal; reflorestamento; restauração. AbstractBiomass and nutrients in three species of Parkia plantings on degraded area in Central Amazon. Biomass and nutrients partitioning strategies in tree species may reflect their ability to survive in plantations on degraded areas. The objective of this study was to investigate the content of biomass and nutrients in tree components of Parkia multijuga, Parkia nitida and Parkia pendula on plantings in degraded area in Manaus, AM. The biomass was determined by the harvest method in six trees of each species, which were subdivided into leaves, fine branches (Ø < 10 cm), coarse branches (Ø ≥10 cm), stem wood, medium roots (≤ 2 mm Ø < 5 cm ) and coarse roots (Ø ≥ 5 cm). At 4 years, Parkia multijuga allocated 60% of the total biomass to above-ground components and 40% to below-ground. Parkia nitida allocated 84% to above-ground and 16% to below-ground. Parkia pendula allocated 67% to above-ground components and 33% to below-ground. The order of the nutrient accumulation in tree compartments was: N > Ca > K > Mg > P. Parkia multijuga, by adopting better strategies of distribution of biomass and nutrients, it is a recommended species for reforestation programs on degraded sites in the Amazon.Keywords: Native forest species; forest nutrition; reforestation; restoration.
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McNeill, Ann M., Chunya Zhu, and Ian R. P. Fillery. "A new approach to quantifying the N benefit from pasture legumes to succeeding wheat." Australian Journal of Agricultural Research 49, no. 3 (1998): 427. http://dx.doi.org/10.1071/a97072.
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Vegetative subterranean clover (Trifolium subterraneum L.) and serradella (Ornithopus compressus L.), growing in 1-m soil columns under glasshouse conditions during 1994, were fed 15N tracer by immersion of individual leaves (5 per plant) in a 0·4% (w/w) solution of labelled urea (99·6 atom% 15N). Four replicate soil-plant systems were harvested in late October 1994 at legume peak biomass (41 days after labelling) and in early December 1994 at maturity (90 days after labelling). The shoots were removed and the soil columns fractionated into clean macro-root, residual (root/soil) fraction, and bulk soil; the shoots from the remaining replicates were also harvested at maturity leaving the labelled soil columns intact. These intact columns were kept dry for 5 months during the summer then rewetted and planted with wheat in June 1995. Four replicate soil-plant systems were harvested at planting, tillering, anthesis, and maturity of the wheat and fractionated as before. Mean recovery of fed 15N by the plant{soil systems was 42% for subterranean clover and 64% for serradella. Proportional distribution of the recovered 15N was similar for both plant-soil systems: 67-69% recovered above-ground and 31-33% recovered below-ground for subterranean clover compared with 71-75% above-ground and 25-29% below-ground for serradella. Uniform labelling of below-ground nitrogen (BG N) enabled estimation of total BG N accumulation, under undisturbed conditions, for the two pasture species. Less than 60% of the total legume BG N for both species was recovered as macro-root, with up to 17% recovered in the residual fraction and 33-51% in the bulk soil. Subterranean clover increased its total amount of BG N from 174 to 218 mg/plant between peak biomass and maturity with >65% of this located in the top 10 cm of the soil. Total BG N for serradella was similar at peak biomass (172 mg/plant) and not only decreased slightly by maturity (160 mg/plant) but was also redistributed to depth between the 2 sampling times. The ratio of shoot N to total BG N at peak biomass was 1 : 0·68 for subterranean clover and 1 : 0·60 for serradella. Recovery of labelled legume BG N at harvest by wheat following subterranean clover was 25% and after serradella was 18%. Root residues from subterranean clover appeared to decompose more rapidly than those from serradella, manifest by rapid uptake by the succeeding wheat so that 66% of the total N benefit had accrued by tillering, whereas only 44% of the N benefit from serradella roots had accrued by tillering and 72% by anthesis.
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Leyshon, A. J. "Effect of rate of nitrogen fertilizer on the above- and below-ground biomass of irrigated bromegrass in southwest Saskatchewan." Canadian Journal of Plant Science 71, no. 4 (October 1, 1991): 1057–67. http://dx.doi.org/10.4141/cjps91-148.
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A 9-yr study was conducted on an alluvial clay loam at Swift Current, Saskatchewan to determine the effect of annual applications of urea-N (46-0-0) fertilizer on production, nutrient quality, N use efficiency, root mass, and root distribution of bromegrass (Bromus inermis Leyss.). Nitrogen was applied annually at the rates of 0, 50, 100, and 200 kg ha−1 N to an established stand of bromegrass. Plots were flood irrigated. Forage DM yields increased linearly with rate of N applied. In all years, the slope of the response was similar and averaged 24 kg DM kg−1 N. The average y-intercept value was 1794 kg DM ha−1. In years 1–4, the N concentration in the grass was depressed at low N rates but after 5 yr the N concentration increased at all N rates. Tissue [Formula: see text] levels over 100 ppm occurred at the 200 kg N rate after 3 yr. Applications of N reduced plant P in all years; the extent depended on N rate. Uptake of N increased with increasing N rate as did the apparent N recovery. Nitrogen rate had no effect on root mass or distribution. Root mass totalled 13 888 kg DM ha−1 to 105-cm depth. Approximately 36% of the root mass was in the top 7.5 cm, 11.9% in the 7.5- to 15-cm depth and 16.9% in the 15-to 30-cm depth. Estimates of the soil space occupied by roots indicate that they would occupy a large proportion of the available pore volume. It was concluded that producers growing bromegrass under irrigation on medium- to heavy-textured soils in southern Saskatchewan can consistently expect considerable increases in hay yield of good quality with N fertilizer at rates up to 200 kg N ha−1. While forage production increased linearly in response to N fertilization, root accumulation remained at a constant level. Further studies are needed to establish maximum yields and economic rates of N application. Key words: N rate, N recovery, roots, forage N, forage P
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Wu, G. L., W. Li, L. P. Zhao, Z. H. Shi, and Z. P. Shangguan. "Above- and below-ground response to soil moisture change on an alpine wetland ecosystem in the Qinghai-Tibetan Plateau, China." Biogeosciences Discussions 8, no. 4 (July 19, 2011): 7141–64. http://dx.doi.org/10.5194/bgd-8-7141-2011.
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Abstract. Climate change is expected to affect plant communities worldwide. However, less is known about the consequences of global warming-induced decrease of soil moisture on alpine wetland ecosystem in the Qinghai-Tibetan Plateau. To determine response of natural alpine wetland community to decrease of soil moisture, we did a gradient analysis of soil moisture by sequence space-series variation. We used sequence space-series variation of soil moisture to reflect potential time-series variation of soil moisture in alpine wetland community, by examining the effects of spatial heterogeneity of soil moisture on wetland community, as well as by determining how shifts in above- and below-ground properties of alpine wetland community. We found that vegetation aboveground biomass, cover and height all significantly increased with increase of soil moisture, but species richness was decreased. Soil organic carbon, total nitrogen, available nitrogen, total phosphorus and available phosphorus all significantly increased with increase of soil moisture, but soil pH value, total potassium and available potassium were significantly decreased. Meanwhile, species richness showed significantly positive correlations to aboveground biomass, covers and height. Aboveground biomass, vegetation covers and height were all significant positively related to soil organic carbon, total N, P, and available N, P, but negatively related to total K. But, species richness were significant negatively related to soil organic carbon, total N, P, and available N, P, but positively related to total K. Our observation indicates that decreasing of soil moisture may potentially negatively impact on the above- and below-ground properties in alpine wetland community.
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Tolley, Seth, and Mohsen Mohammadi. "Variation in Root and Shoot Growth in Response to Reduced Nitrogen." Plants 9, no. 2 (January 23, 2020): 144. http://dx.doi.org/10.3390/plants9020144.
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Recently, root traits have been suggested to play an important role in developing greater nitrogen uptake and grain yield. However, relatively few breeding programs utilize these root traits. Over a series of experiments at different growth stages with destructive plant biomass measurements, we analyzed above-ground and below-ground traits in seven geographically diverse lines of wheat. Root and shoot biomass allocation in 14-day-old seedlings were analyzed using paper roll-supported hydroponic culture in two Hoagland solutions containing 0.5 (low) and 4 (high) mM of nitrogen (N). For biomass analysis of plants at maturity, plants were grown in 7.5 L pots filled with soil mix under two nitrogen treatments. Traits were measured as plants reached maturity. High correlations were observed among duration of vegetative growth, tiller number, shoot dry matter, and root dry matter. Functionality of large roots in nitrogen uptake was dependent on the availability of N. Under high N, lines with larger roots had a greater yield response to the increase in N input. Under low N, yields were independent of root size and dry matter, meaning that there was not a negative tradeoff to the allocation of more resources to roots, though small rooted lines were more competitive with regards to grain yield and grain N concentration in the low-N treatment. In the high-N treatment, the large-rooted lines were correlated to an increase in grain N concentration (r = 0.54) and grain yield (r = 0.43). In low N, the correlation between root dry matter to yield (r = 0.20) and grain N concentration (r = −0.38) decreased. A 15-fold change was observed between lines for root dry matter; however, only a ~5-fold change was observed in shoot dry matter. Additionally, root dry matter measured at the seedling stage did not correlate to the corresponding trait at maturity. As such, in a third assay, below-ground and above-ground traits were measured at key growth stages including the four-leaf stage, stem elongation, heading, post-anthesis, and maturity. We found that root growth appears to be stagnant from stem elongation to maturity.
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Marcinkonis, Saulius, Birutė Karpavičienė, and Michael A. Fullen. "Linking floral biodiversity with nitrogen and carbon translocations in semi-natural grasslands in Lithuani." Ekológia (Bratislava) 34, no. 2 (March 1, 2015): 137–46. http://dx.doi.org/10.1515/eko-2015-0014.
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AbstractThe aim of the present study is to evaluate the long-term effects of long-term piggery effluent application on semi-natural grassland ecotop-phytotop changes (above- and below-ground phytomass production, and carbon and nitrogen allocation in grassland communities) in relation to changes (or variability) in topsoil properties. Analysis of phytomass distribution in piggery effluent irrigated grassland communities showed that dry biomass yield varied from 1.7−5.3 t ha-1. Variability in soil and plant cover created a unique and highly unpredictable site specific system, where long-term anthropogenic influences established successor communities with specific characteristics of above- and below-ground biomass distribution. These characteristics depend more on grassland communities than on soil chemical properties. Families of grasses (Poaceae) dominated the surveyed communities and accumulated most carbon and least nitrogen, while legumes accumulated most nitrogen and lignin and least carbon. Carbon concentrations in above-ground biomass had minor variations, while accumulation of nitrogen was strongly influenced by species diversity (r = 0.94, n = 10, p <0.001) and production of above-ground biomass
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Bloor, Juliette M. G., Antoine Tardif, and Julien Pottier. "Spatial Heterogeneity of Vegetation Structure, Plant N Pools and Soil N Content in Relation to Grassland Management." Agronomy 10, no. 5 (May 16, 2020): 716. http://dx.doi.org/10.3390/agronomy10050716.
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Spatial heterogeneity in plant and soil properties plays a key role for biogeochemical cycling, nutrient losses and ecosystem function. Different management practices are expected to induce varying levels of spatial heterogeneity in agroecosystems, but the effects of contrasting biomass removal regimes and herbivore species on grassland variability and spatial pattern have faced little attention. We carried out a spatially-explicit sampling campaign and geostatistical analyses to quantify the spatial heterogeneity of the biomass and N in plants and soil for three management treatments (mowing, cattle grazing and sheep grazing) within a long-term grassland experiment. All plant and soil properties showed within-site variation, irrespective of management treatment. Within-site variation in plant variables could be ranked as grazing > mowing. Cattle grazing increased variability in vegetation structure, soil mineral N and soil C:N compared with sheep grazing. In addition, the cattle-grazed field had a higher degree of spatial structure and a more coarse-grained pattern of spatial heterogeneity in plant properties than the sheep-grazed field. However, both grazing treatments showed spatial asynchrony in above- and below-ground responses to grazing. These results demonstrate the importance of herbivore species identity as a driver of grassland spatial heterogeneity, with implications for spatial uncoupling of nutrient cycles at the field scale.
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Hocking, P. J. "Seasonal dynamics of production, and nutrient accumulation and cycling by Phragmites asutralis (Cav.) Trin. ex Stuedel in a nutrient-enriched swamp in Inland Australia. I. Whole Plants." Marine and Freshwater Research 40, no. 5 (1989): 421. http://dx.doi.org/10.1071/mf9890421.
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A study was made of the seasonal changes in dry matter production and patterns of nutrient accumulation by Phragmites australis in a nutrient-enriched swamp in inland Australia. The density of live shoots was highest (224 m-2) in October, but the peak standing crop of live shoots (9890 g m-2) occurred in early May. Peak below-ground biomass (21 058 g m-2) occurred in early August. Rhizome biomass constituted 75% of the below-ground biomass, and showed a distinct seasonal pattern. Net annual above-ground primary production (NAAP), estimated by the maximum-minimum method, was 9513 g m-2. Correction for shoot mortality and leaf shedding before, and production after, the maximum standing crop was attained increased NAAP to 12 898 g m-2. Whole plant production estimated by the maximum-minimum method was 9960 g m-2, and the corrected estimate was 14 945 g m-2. A model of dry-matter production indicated that translocation of carbohydrate from rhizomes could have provided 33% of the dry matter of shoots. About 23% of the dry matter of shoots was redistributed to below-ground organs during senescence. Concentrations of N, P, K, S, Cl and Cu declined, but concentrations of Ca, Mg, Na, Fe and Mn increased as shoots aged. Concentrations of N, P and Zn in rhizomes reached maxima in winter, and decreased in spring. Rhizomes usually contained the greatest quantity of a nutrient in the whole plant, and roots usually had less than 25% of the total plant content. There were seasonal fluctuations in the quantities of N, P, K, Zn and Cu in rhizomes. Nutrient accumulation by live shoots was underestimated by 22-55% using the maximum-minimum method. Nutrient budgets showed considerable internal cycling of N, P, K, S and Cu from rhizomes to developing shoots in spring, and from senescing shoots to rhizomes during autumn and winter.
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Thakur, N., K. Verma, and R. Rana. "Effect of Tree-Crop Combinations and Nitrogen levels on velvet bean (Mucuna Pruriens L.) grown in Agrihorti-Silvi-Pasture system of Agroforestry in mid Himalayan Region." Journal of Non-Timber Forest Products 18, no. 4 (December 1, 2011): 303–12. http://dx.doi.org/10.54207/bsmps2000-2011-youzf4.
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Investigations on effect of tree-crop combinations and nitrogen levels on growth, biomass and seed yield of Mucuna pruriens L. were carried out during 2004-2005 and 2005-2006, in experimental farm of Department of Silviculture and Agroforestry, Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh. The tree-crop combinations were T1 (Peach + Grewia + Setaria + M. pruriens), T2 (Peach + Morus + Setaria + M. pruriens), T3 (Peach + Setaria + M. pruriens), T4 (Grewia + Setaria + M. pruriens), T5 (Morus + Setaria + M. pruriens) and T6 (M. pruriens, sole crop). Its length, leaf area and leaf area index was significantly affected due to tree-crop associations giving maximum values as 3.60m, 276.30cm2/leaf and 2.53, respectively under sole cropping system. The nitrogen dose of 120kg/ha produced longest vine (3.80m), with leaf area 330.00cm2/leaf and leaf area index of 2.93. The above ground biomass was significantly higher (15.15t/ha) under sole cropping system followed by T2, T3, T4, and T5, suggesting suitability of tree crop systems for cultivation under these systems too. Similarly, below ground biomass was significantly higher (0.29t/ha) from open grown crop, nevertheless, tree-crop combinations T1, T2 and T5 gave biomass at par. Total biomass was not affected due to various tree-crop treatments. The nitrogen dose 120kg/ha gave maximum above ground (16.76t/ha), below ground (0.30t/ha) and total biomass (17.07t/ha). Although the tree-crop combinations affected biomass yield significantly however, seed yield did not have significant effect. The seed yield ranged 2.17 to 2.21t/ha. The N dose of 120kg/ha gave maximum (2.38t/ha) seed yield. The N levels did not show optimum level. Both tree-crop combinations as well as N doses failed to affect L-DOPA content estimated in the seed. However, L-DOPA content ranges from 4.58 to 5.05 per cent on dry seed weight basis. The L-DOPA content was same in seeds produced from open grown and seeds produced from plants grown under different Agroforestry Systems. Thus, Mucuna can be grown under Agroforestry Systems and fertilizers application to get higher biomass and seed yield without any changes in the active constituent.
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Thakur, N., K. Verma, and R. Rana. "Effect of Tree-Crop Combinations and Nitrogen levels on velvet bean (Mucuna Pruriens L.) grown in Agrihorti-Silvi-Pasture system of Agroforestry in mid Himalayan Region." Journal of Non-Timber Forest Products 18, no. 4 (December 1, 2011): 303–12. http://dx.doi.org/10.54207/bsmps2000-2011-youzf4.
Full textAbstract:
Investigations on effect of tree-crop combinations and nitrogen levels on growth, biomass and seed yield of Mucuna pruriens L. were carried out during 2004-2005 and 2005-2006, in experimental farm of Department of Silviculture and Agroforestry, Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh. The tree-crop combinations were T1 (Peach + Grewia + Setaria + M. pruriens), T2 (Peach + Morus + Setaria + M. pruriens), T3 (Peach + Setaria + M. pruriens), T4 (Grewia + Setaria + M. pruriens), T5 (Morus + Setaria + M. pruriens) and T6 (M. pruriens, sole crop). Its length, leaf area and leaf area index was significantly affected due to tree-crop associations giving maximum values as 3.60m, 276.30cm2/leaf and 2.53, respectively under sole cropping system. The nitrogen dose of 120kg/ha produced longest vine (3.80m), with leaf area 330.00cm2/leaf and leaf area index of 2.93. The above ground biomass was significantly higher (15.15t/ha) under sole cropping system followed by T2, T3, T4, and T5, suggesting suitability of tree crop systems for cultivation under these systems too. Similarly, below ground biomass was significantly higher (0.29t/ha) from open grown crop, nevertheless, tree-crop combinations T1, T2 and T5 gave biomass at par. Total biomass was not affected due to various tree-crop treatments. The nitrogen dose 120kg/ha gave maximum above ground (16.76t/ha), below ground (0.30t/ha) and total biomass (17.07t/ha). Although the tree-crop combinations affected biomass yield significantly however, seed yield did not have significant effect. The seed yield ranged 2.17 to 2.21t/ha. The N dose of 120kg/ha gave maximum (2.38t/ha) seed yield. The N levels did not show optimum level. Both tree-crop combinations as well as N doses failed to affect L-DOPA content estimated in the seed. However, L-DOPA content ranges from 4.58 to 5.05 per cent on dry seed weight basis. The L-DOPA content was same in seeds produced from open grown and seeds produced from plants grown under different Agroforestry Systems. Thus, Mucuna can be grown under Agroforestry Systems and fertilizers application to get higher biomass and seed yield without any changes in the active constituent.
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Xiao, C. W., I. A. Janssens, Y. Zhou, J. Q. Su, Y. Liang, and B. Guenet. "Strong stoichiometric resilience after litter manipulation experiments; a case study in a Chinese grassland." Biogeosciences Discussions 11, no. 7 (July 4, 2014): 10487–512. http://dx.doi.org/10.5194/bgd-11-10487-2014.
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Abstract. Global climate change has generally increased net primary production which leads to increasing litter inputs. Therefore assessing the impacts of increasing litter inputs on soil nutrients, plant growth and ecological Carbon (C) : nitrogen (N) : phosphorus (P) stoichiometry is critical for an understanding of C, N and P cycling and their feedback processes to climate change. In this study, we added plant litter to the 10–20 cm subsoil layer under a steppe community at rates equivalent to 0, 150, 300, 600 and 1200 g (dry mass) m−2 and measured the resulting C, N and P content of different pools (above and below ground plant biomass, litter, microbial biomass). High litter addition (120% of the annual litter inputs) significantly increased soil inorganic N and available P, aboveground biomass, belowground biomass and litter. Nevertheless small litter additions, which are more realistic compared to the future predictions, had no effect on the variables examined. Our results suggest that while very high litter addition can strongly affect C : N : P stoichiometry, the grassland studied here is quite resilient to more realistic inputs in terms of stoichiometric functioning. This result highlights the complexity of the ecosystem's response to climate change.
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Imai, Nobuo, Kanehiro Kitayama, and Jupiri Titin. "Distribution of phosphorus in an above-to-below-ground profile in a Bornean tropical rain forest." Journal of Tropical Ecology 26, no. 6 (October 11, 2010): 627–36. http://dx.doi.org/10.1017/s0266467410000350.
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Abstract:Ecosystem pool of phosphorus (P) was determined as the sum of above-ground vegetation, roots, necromass and soils to 1 m deep in a tropical rain forest in Sabah, Malaysia. Relationships among soil P fractions, acid phosphatase activity and fine-root biomass across soil horizons were also determined to understand P availability. Ecosystem pools of P, and of simultaneously quantified nitrogen (N) and carbon (C) were 3.4, 12 and 370 Mg ha−1, respectively. Only 2.6% of the total ecosystem P was in the above-ground vegetation, contrasting to C (60%) and N (16%). Canopy foliage of dominant tree species showed an extremely high N to P ratio of 31.5, which implied the excessively short supply of P compared with ample N. Soil P primarily consisted of recalcitrant occluded fractions (78–91%) and only 4% was labile. Approximately three-quarters of labile soil P was an organic fraction (Po). The concentration of labile Po did not differ between soil horizons, while both phosphatase activity and fine-root density were the greatest in the topsoil (top 5 cm) and dramatically decreased with depth. This suggests that trees depend on the acquisition of P from the labile Po in the topsoil, despite a greater amount of labile P in the subsoil. Trees with a high foliar N/P ratio may invest N to acquire P from the topsoil by secreting phosphatase that consists of proteins, rather than investing C to extending roots to scavenge P in the subsoil.
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Szczepanek, Małgorzata, Zofia Stypczyńska, Andrzej Dziamski, and Dorota Wichrowska. "Above- and Below-Ground Part Growth in Chewings and Strong Creeping Red Fescue Grown for Seed Resulting from Retardants and N Fertilization." Agronomy 10, no. 1 (December 18, 2019): 4. http://dx.doi.org/10.3390/agronomy10010004.
Full textAbstract:
Generative tillers are a source of assimilates necessary for the seed formation. However, their excessive elongation, especially under high doses of nitrogen, increases the susceptibility to lodging. The growth of generative shoots depends, among others on the root biomass affecting nutrient uptake, and on the ability to form rhizomes, as well as on the competitiveness of parallel developing vegetative tillers. Two-replicate field experiments were performed in Poland (53°09′ N, 17°35′ E), to determine the effect of plant growth regulators (PGRs) (single application of chloromequat chloride (CCC) at BBCH 30-31 or sequential treatment CCC at BBCH 30-31 + ethephon (ET) or CCC at BBCH 30-31 + trinexapac-ethyl (TE) at BBCH 37-39, and N fertilization (40 and 70 kg ha−1) on the length of generative tillers, the weight of generative and vegetative tillers, the canopy height, the weight of roots and rhizomes, and on N uptake in Festuca rubra L ssp. rubra (strong creeping red fescue) and F. r. L ssp. commutata (Chewings red fescue). Chewings red fescue turned to be more sensitive to the retardants. Generative tillers were shorter after single application of CCC as well as sequential treatment CCC + ET or TE. The tillers of strong creeping red fescue were shortened only after the application of CCC + TE. In every PGR treatments the canopy height at harvest was greater than in the control. Increasing the N rate from 40 to 70 kg ha−1 caused the reduction canopy height of strong creeping red fescue. Increased production of above-ground biomass, especially generative tillers, resulted in an increase in N accumulation in Chewings red fescue, as compared with strong creeping. Increasing the nitrogen rate from 40 to 70 kg ha−1, despite the reduction of root dry matter weight, stimulated generative tiller dry matter accumulation but it did not affect the biomass of vegetative tillers.
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Alber, N. B., G. E. Brink, and R. D. Jackson. "Temperate grass response to extent and timing of grazing." Canadian Journal of Plant Science 94, no. 5 (July 2014): 827–33. http://dx.doi.org/10.4141/cjps2013-404.
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Alber, N. B., Brink, G. E. and Jackson, R. D. 2014. Temperate grass response to extent and timing of grazing. Can. J. Plant Sci. 94: 827–833. Considerable differences exist among cool-season grass species in their production potential and response to management variables. We examined the effects of grazing management on forage and root production of two temperate perennial grasses, meadow fescue [Schedonorus pratensis (Huds.) P. Beauv.] and orchardgrass (Dactylis glomerata L.). Grazing factors studied were extent of defoliation (50 or 100% biomass removal) and stage of maturity (vegetative or mature) at grazing. In 2009 and 2010, orchardgrass produced more above-ground biomass than meadow fescue despite yearly precipitation differences. In the drier year (2009), both grasses produced greater above-ground biomass under 100% extent of defoliation at either maturity stage. In 2010, orchardgrass produced greater above-ground biomass when grazed at a mature stage for either extent of defoliation, while few differences existed among grazing treatments imposed on meadow fescue. Grazing treatments had no effect on below-ground growth of orchardgrass either year. Meadow fescue root production was effected in 2010 only; grazing at a mature stage increased below-ground growth for either extent of defoliation. Results suggest that grazing at maturity to remove 100% of biomass maximizes above-ground production of both meadow fescue and orchardgrass, but lengthens the grazing interval and may have a deleterious effect on grass persistence and nutritive value.
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Zhang, Miaomiao, Shun Liu, Miao Chen, Jian Chen, Xiangwen Cao, Gexi Xu, Hongshuang Xing, Feifan Li, and Zuomin Shi. "The below-ground carbon and nitrogen cycling patterns of different mycorrhizal forests on the eastern Qinghai-Tibetan Plateau." PeerJ 10 (September 14, 2022): e14028. http://dx.doi.org/10.7717/peerj.14028.
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Mycorrhizal fungi can form symbiotic associations with tree species, which not only play an important role in plant survival and growth, but also in soil carbon (C) and nitrogen (N) cycling. However, the understanding of differences in soil C and N cycling patterns among forests with different mycorrhizal types is still incomplete. In order to determine the similarities and differences of soil C and N cycling patterns in different mycorrhizal forest types, three primary forests dominated by ectomycorrhizal (EcM), arbuscular mycorrhizal (AM) and ericoid mycorrhizal (ErM) trees respectively were studied on the eastern Qinghai-Tibetan Plateau. Indicators associated with soil C and N cycling, including leaf litter quality, soil C and N contents, soil C and N fluxes, and soil microbial biomass C and N contents were measured in each mycorrhizal type forest. The results showed that leaf litter quality was significantly lower with high C:N ratio and lignin: N ratio in ErM forest than that in AM and EcM forests. Soil CO2 flux (508.25 ± 65.51 mg m−2 h−1) in AM forest was significantly higher than that in EcM forest (387.18 ± 56.19 mg m−2 h−1) and ErM forest (177.87 ± 58.40 mg m−2 h−1). Furthermore, soil inorganic N content was higher in the AM forest than that in EcM and ErM forests. Soil net N mineralization rate (−0.02 ± 0.03 mg kg−1 d−1) was lower in ErM forest than that in EcM and AM forests. We speculated that AM and EcM forests were relatively characterized by rapid soil C cycling comparing to ErM forest. The soil N cycling in EcM and ErM forests were lower, implying they were ‘organic’ N nutrition patterns, and the pattern in ErM forest was more obvious.
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Irving, Louis John, and Sayuki Mori. "Effects of Light, N and Defoliation on Biomass Allocation in Poa annua." Plants 10, no. 9 (August 26, 2021): 1783. http://dx.doi.org/10.3390/plants10091783.
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Plants allocate biomass to above- and below-ground organs in response to environmental conditions. While the broad patterns are well-understood, the mechanisms by which plants allocate new growth remain unclear. Modeling approaches to biomass allocation broadly split into functional equilibrium type models and more mechanistically based transport resistance type models. We grew Poa annua plants in split root boxes under high and low light levels, high and low N supplies, with N supplied equally or unequally. Our data suggest that light level had the strongest effect on root mass, with N level being more important in controlling shoot mass. Allocation of growth within the root system was compatible with phloem partitioning models. The root mass fraction was affected by both light and N levels, although within light levels the changes were primarily due to changes in shoot growth, with root mass remaining relatively invariant. Under low light conditions, plants exhibited increased specific leaf area, presumably to compensate for low light levels. In a follow-up experiment, we showed that differential root growth could be suppressed by defoliation under low light conditions. Our data were more compatible with transport resistance type models.
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Teixeira, Gelza Carliane Marques, Renato de Mello Prado, Kamilla Silva Oliveira, Antonio Carlos Buchelt, Antonio Márcio Souza Rocha, and Michelle de Souza Santos. "Nutritional deficiency in scarlet eggplant limits its growth by modifying the absorption and use efficiency of macronutrients." PLOS ONE 16, no. 6 (June 4, 2021): e0252866. http://dx.doi.org/10.1371/journal.pone.0252866.
Full textAbstract:
The intensity damages caused by nutritional deficiency in growing plants can vary with nutrients. The effects caused by nutrient omission in the plant nutritional efficiency in relation to the absorption and use of the missing nutrient, and the reasons why these damages reflect in other nutrients have not yet been reported in the culture of scarlet eggplant. A better understanding of the nutritional mechanisms involved may clarify why certain nutrients cause greater limitations than other during plants growth. Thus, this study was designed with the aim of evaluating the damages caused by macronutrients deficiency in the culture of scarlet eggplant in the accumulation of these nutrients, nutritional deficiency, plants growth and in visual symptoms. The experiment was carried out in a controlled environment where plants were cultivated in a hydroponic system. Treatments consisted of supplying a complete Hoagland and Arnon solution (CS), and other nutrient solutions with individual omissions of nitrogen (-N), phosphorus (-P), potassium (-K), calcium (-Ca), magnesium (-Mg) and sulphur (-S). When a nutrient deficiency arose, nutritional analyses, growth and visual symptoms were analyzed. The omissions of N, S and K in the nutrient solution resulted in lower accumulation of all macronutrients in both the above and below ground biomass. Individual omissions resulted in nutritional imbalances with reflexes in the absorption efficiencies and use of the missing nutrient, as well as of other nutrients, revealing that the metabolism involves multiple nutritional interactions. Losses of nutritional efficiencies of macronutrients caused detrimental effects on plants growth, with reduced height, stem diameter, number of leaves, leaf area, and biomass production in above ground and below ground. From the losses in production in above ground biomass, the order of macronutrients limitation was N, S, K, Ca, Mg, and P, with reductions of 99, 96, 94, 76, 51 and 46%, respectively, in comparison to plants cultivated in CS. The most limiting nutrients were N, S, and K, seen that its deficiencies affected the metabolism of all other nutrients. This study demonstrates the importance of an adequate nutritional management of N, S, and K in the cultivation of scarlet eggplant.
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Thomas, Andrew L., Robert Kallenbach, Thomas J. Sauer, David K. Brauer, David M. Burner, Mark V. Coggeshall, Christian Dold, Wendi Rogers, Sougata Bardhan, and Shibu Jose. "Carbon and nitrogen accumulation within four black walnut alley cropping sites across Missouri and Arkansas, USA." Agroforestry Systems 94, no. 5 (January 24, 2020): 1625–38. http://dx.doi.org/10.1007/s10457-019-00471-8.
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Abstract Agroforestry systems that integrate useful long-lived trees have been recognized for their potential in mitigating the accumulation of atmospheric fossil fuel-derived carbon (C). Black walnut (Juglans nigra) is frequently planted and cultivated in North America for its valuable lumber and edible nuts, and is highly amenable to the integration of understory crops or livestock in agroforestry systems. However, little is known about C content in black walnut trees, including the amounts of C assimilated into lignocellulosic tissues within different tree compartments. Therefore, allometric equations for above- and below-ground compartments of 10-year-old black walnut trees across diverse locations were developed. Ten grafted black walnut trees from each of four sites across the midwestern USA were destructively harvested for above- and below-ground biomass, and dry biomass weight (DWw), C (Cw) and nitrogen (N; Nw) stocks were quantified. Soils surrounding the harvested trees were sampled and analyzed for soil organic C (SOC) and total N (TN). Total DWw ranged from 27 to 54 kg tree−1, with woody tissues containing an average of 467 g kg−1 C and 3.5 g kg−1 N. Woody tissues differed in Cw and Nw across location, and above-ground sections contained more C and less N compared with most root tissues. The slopes of the allometric equations did not differ significantly among locations, while intercepts did, indicating that trees only differed in initial size across locations. SOC and TN did not vary in distance from the trees, likely because the trees were not yet old enough to have impacted the surrounding soils. Our results establish a foundation for quantifying C and N stocks in newly established black walnut alley cropping systems across diverse environments.
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Arthur, Mary A., and Timothy J. Fahey. "Biomass and nutrients in an Engelmann spruce–subalpine fir forest in north central Colorado: pools, annual production, and internal cycling." Canadian Journal of Forest Research 22, no. 3 (March 1, 1992): 315–25. http://dx.doi.org/10.1139/x92-041.
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Biomass and nutrient dynamics were examined in a subalpine Piceaengelmannii Parry–Abieslasiocarpa (Hook.) Nutt. forest within Loch Vale watershed in north central Colorado by quantifying annual above- and below-ground production, biomass, nutrient pools, and internal nutrient transfers. Subalpine forest covers only 6% of the watershed, and the values reported here refer only to the forested area. Total ecosystem biomass was 42 kg•m−2, of which 30% was soil organic matter, 33% was detrital biomass (including deadwood and forest floor), and 36% was living biomass. Total forest biomass (not including soil organic matter) was 28.9 kg•m−2, of which root biomass was 11%. Net primary production was 520 g•m−2•year−1, of which fine root production was about 27% and foliar production was 30%. Much more N was recycled via fine root turnover than via aboveground litter fall (1.6 versus 0.9 g•m−2•year−1), whereas four times more Ca was returned via litter fall than via fine roots. Compared with other temperate coniferous forests, this subalpine forest had low production. Nutrient resorption contributed between 35 and 38% of the annual requirements of N, P, and K, but only 9% of Ca and 12% of Mg. Although a higher percentage of annual N requirement was met by resorption, this forest used N less efficiently than a similar forest in southwestern Alberta.
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Soon, Y. K., and M. A. Arshad. "Tillage, crop residue and crop sequence effects on nitrogen availability in a legume-based cropping system." Canadian Journal of Soil Science 84, no. 4 (November 1, 2004): 421–30. http://dx.doi.org/10.4141/s04-023.
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A field study was conducted to determine the effects and interactions of crop sequence, tillage and residue management on labile N pools and their availability because such information is sparse. Experimental treatments were no-till (NT) vs. conventional tillage (CT), and removal vs. retention of straw, imposed on a barley (Hordeum vulgare L.)-canola (Brassica rapa L.)-field pea (Pisum sativum L.) rotation. 15N-labelling was used to quantify N uptake from straw, below-ground N (BGN), and fertilizer N. Straw retention increased soil microbial biomass N (MBN) in 2 of 3 yr at the four-leaf growth stage of barley, consistent with observed decreases in extractable soil inorganic N at seeding. However, crop yield and N uptake at maturity were not different between straw treatments. No tillage increased soil MBN, crop yield and N uptake compared to CT, but had no effect on extractable soil inorganic N. The greater availability of N under NT was probably related to soil moisture conservation. Tillage effects on soil and plant N were mostly independent of straw treatment. Straw and tillage treatments did not influence the uptake of N from its various sources. However, barley following pea (legume/non-legume sequence) derived a greater proportion of its N from BGN (13 to 23% or 9 to 23 kg N ha-1) than canola following barley (nonlegumes) (6 to 16% or 3 to 9 kg N ha-1). Fertilizer N constituted 8 to 11% of barley N uptake and 23 to 32% of canola N uptake. Straw N contributed only 1 to 3% of plant N uptake. This study showed the dominant influence of tillage on N availability, and of the preceding crop or cropping sequence on N uptake partitioning among available N sources. Key words: Crop residue, crop sequence, labile nitrogen, nitrogen uptake, pea, tillage
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Lu, Xuyang, Yan Yan, Jihui Fan, Yingzi Cao, and Xiaodan Wang. "Dynamics of above- and below-ground biomass and C, N, P accumulation in the alpine steppe of Northern Tibet." Journal of Mountain Science 8, no. 6 (November 19, 2011): 838–44. http://dx.doi.org/10.1007/s11629-011-2182-8.
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Ajal, James, and Martin Weih. "Nutrient Accumulation Pattern in Mixtures of Wheat and Faba Bean Is Strongly Influenced by Cultivar Choice and Co-Existing Weeds." Biology 11, no. 5 (April 20, 2022): 630. http://dx.doi.org/10.3390/biology11050630.
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Cereal–legume mixtures are often associated with higher yields than the components grown as sole crops, but the underlying mechanisms are unclear. The study aims to evaluate how different cultivars in a two-species wheat–faba bean mixture influence above- and below-ground nitrogen (N) accumulation in the plant biomass, whether crop mixing affected the accumulation of other nutrients relative to the accumulation of N and phosphorus (P), and how the nutrient accumulation pattern in sole crops and mixtures is influenced by weed competition. Using a growth container experiment, we investigate nutrient accumulation patterns on specific wheat and faba bean cultivars grown as sole crops and mixtures, and with and without weed competition. We found that cereals in the mixture accumulated more N than in the sole crops, and the cultivar used influenced biomass accumulation in the legumes. Competition from weeds reduced the amount of plant N pools accumulated in the crop plant biomass. Based on stoichiometric scaling exponents, the plant neighbor affected the accumulation of other nutrients relative to the accumulation of N and P. These results are relevant for species and cultivar selection, all of which are important prerequisites for maximizing mixture performance.
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HAKALA, K., M. KESKITALO, and C. ERIKSSON. "Nutrient uptake and biomass accumulation for eleven different field crops." Agricultural and Food Science 18, no. 3-4 (January 3, 2009): 366–87. http://dx.doi.org/10.23986/afsci.5947.
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Oil hemp (Cannabis sativa L.), quinoa (Chenopodium quinoa Willd.), false flax (Camelina sativa (L.) Crantz), caraway (Carum carvi L.), dyers woad (Isatis tinctoria L.), nettle (Urtica dioica L.), reed canary grass (RCG) (Phalaris arundinacea L.), buckwheat (Fagopyrum esculentum Moench), linseed (Linum usitatissimum L.), timothy (Phleum pratense L.) and barley (Hordeum vulgare L.) were grown under uniform conditions in pots containing well fertilised loam soil. Dry matter (DM) accumulation was measured repeatedly, and contents of minerals N, P, K, Ca and Mg at maturity. Annual crops accumulated above-ground biomass faster than perennials, while perennials had higher DM accumulation rates below ground. Seeds had high concentrations of N and P, while green biomass had high concentrations of K and Ca. Stems and roots had low concentrations of minerals. Concentrations of K and P were high in quinoa and caraway, and that of P in buckwheat. Hemp and nettle had high Ca concentrations, and quinoa had high Mg concentration. N and P were efficiently harvested with seed, Ca and K with the whole biomass. Perennials could prevent soil erosion and add carbon to the soil in the long term, while annuals compete better with weeds and prevent erosion during early growth. Nutrient balances in a field could be modified and nutrient leaching reduced by careful selection of the crop and management practices.;
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Xiao, Ruihan, Xiuling Man, Beixing Duan, and Tijiu Cai. "Short-Term Litter Manipulations have Strong Impact on Soil Nitrogen Dynamics in Larix gmelinii Forest of Northeast China." Forests 11, no. 11 (November 16, 2020): 1205. http://dx.doi.org/10.3390/f11111205.
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Changes in above-ground litterfall can influence below-ground biogeochemical processes in forests, which substantially impacts soil nitrogen (N) and nutrient cycling. However, how these soil processes respond to the litter manipulation is complex and poorly understood, especially in the N-limiting boreal forest. We aimed to examine how soil N dynamics respond to litter manipulations in a boreal larch forest. A litter manipulation experiment including control, litter exclusion, and litter addition was performed in the Larix gmelinii forest on the north of the Daxing’an Mountains in China. Monthly soil inorganic N, microbial biomass and the rate of net N mineralization in both 0–10 cm and 10–20 cm layers, and N2O flux were analyzed from May 2018 to October 2018. In 0–20 cm soil layer the average soil inorganic N contents, microbial biomass N (MBN) contents, the rate of net N mineralization (Rmin), and the soil N2O emission in the litter addition plot were approximately 40.58%, 54.16%, 128.57%, and 38.52% greater, respectively than those in the control. While litter exclusion reduced those indexes about 29.04%, 19.84%, 80.98%, and 31.45%, respectively. Compared with the dynamics of the 10–20 cm soil layer, the N dynamics in 0–10 cm soil were more sensitive to litter manipulation. Rmin and N2O emissions were significantly correlated with MBN in most cases. Our results highlight the short-term effects of litter manipulations on soil N dynamics, which suggests that the influence of litter on soil N process should be considered in the future defoliation management of the boreal larch forest.
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Mahieu, S., F. Germon, A. Aveline, H. Hauggaard-Nielsen, P. Ambus, and E. S. Jensen. "The influence of water stress on biomass and N accumulation, N partitioning between above and below ground parts and on N rhizodeposition during reproductive growth of pea (Pisum sativum L.)." Soil Biology and Biochemistry 41, no. 2 (February 2009): 380–87. http://dx.doi.org/10.1016/j.soilbio.2008.11.021.
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Myster, Randall W. "Light and nutrient effects on growth and allocation of Inga vera (Leguminosae), a successional tree of Puerto Rico." Canadian Journal of Forest Research 36, no. 5 (May 1, 2006): 1121–28. http://dx.doi.org/10.1139/x06-006.
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With the aim of acquiring a better understanding of ecological growth and biomass allocation of Neo tropical trees, I inoculated Inga vera Willd. (Leguminosae) plants from cuttings with Rhizobium spp. and arbuscular mycorrhizal fungi and grew them in a greenhouse for 8 months under varying light (L), phosphorus (P), and nitrogen (N) treatments. I obtained the following results: (1) L, P × N, and L × P × N treatments affected every response variable, but most increases occurred under full light; that is, light levels influenced growth of Inga vera to a greater extent than did P and N additions by themselves; (2) response variables showed a high degree of similarity in regard to which combination of treatment levels had the greatest positive response (full light low N high P) and which combination led to other significant increases (full light low N no P, full light high N no P); and (3) percent AM colonization was affected mainly by light, not P levels. I conclude that growth responses of Inga vera are primarily controlled by light availability, which can interact with nutrient addition to affect biomass allocation to both above- and below-ground structures.
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Coetsee, Corli, Emma F. Gray, Julia Wakeling, Benjamin J. Wigley, and William J. Bond. "Low gains in ecosystem carbon with woody plant encroachment in a South African savanna." Journal of Tropical Ecology 29, no. 1 (December 5, 2012): 49–60. http://dx.doi.org/10.1017/s0266467412000697.
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Abstract:Total ecosystem carbon storage has frequently been found to increase with woody encroachment in savannas. However the loss of grass roots associated with woody encroachment can lead to a decrease in below-ground carbon storage which is not compensated for by an increase in above-ground carbon. To investigate how the extent of total woody cover affected ecosystem carbon, soil and above-ground carbon storage along eight thicket–savanna and five forest–grassland boundaries were measured. To investigate whether changes in soil carbon concentrations were related to the percentage of C4 (grass) roots to total roots and root quantity and quality, we measured fine-root biomass, root C : N ratios, root N, and % C4 roots at three different depths across thicket patches of different ages (n = 189). Forests contained significantly more carbon than adjacent grasslands in both above-ground carbon (mean difference 12.1 kg m−2) and in the top 100 cm of the soil (mean difference 4.54 kg m−2). Thickets contained significantly more above-ground carbon than adjacent savannas (3.33 kg m−2) but no significant differences in soil carbon were evident. Total fine-root biomass appeared to be more important than root quality (root C : N) in determining soil carbon concentrations during the encroachment process (i.e. in thicket of different ages). Similarly for thickets, the % C4 roots had no significant effect on soil carbon concentrations. In conclusion, thicket invading into open savanna vegetation did not lead to significant gains in ecosystem carbon at this study site. Significant gains were only evident in mature forest, suggesting that the process may take place very slowly.
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Biligetu, B., and Bruce Coulman. "Responses of Three Bromegrass (Bromus) Species to Defoliation under Different Growth Conditions." International Journal of Agronomy 2010 (2010): 1–5. http://dx.doi.org/10.1155/2010/515807.
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Bromegrass species are important forage crops in temperate regions of world. This study compared responses of three bromegrass species to defoliation in the greenhouse and field to determine if the former could predict responses in the latter. Experiments were conducted in 2006 and 2007 in Saskatoon (52°07′N,106°38′W), Canada on meadow bromegrass (Bromus ripariusRehm.), smooth bromegrass (Bromus inermisLeyss.), and hybrid bromegrass (B. ripariusX B.inermis) following defoliation to 5 cm stubble height. When defoliated at the vegetative stage, above-ground biomass was similar among the three species in the field, but meadow bromegrass produced greater above-ground biomass than smooth bromegrass in the greenhouse. When defoliated at the stem elongation stage, meadow bromegrass produced greater above-ground biomass than smooth bromegrass in both environments. In the field, for all defoliation treatments, tiller number was greatest in meadow bromegrass, intermediate in hybrid bromegrass, and least in smooth bromegrass. In the greenhouse, however, the three species did not differ in tiller number. Similar results were found for below-ground biomass. Thus, testing the effect of defoliation in the greenhouse environment did not accurately predict the effect in the field environment.
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Zhu, Haiqiang, Lu Gong, Zhaolong Ding, and Yuefeng Li. "Effects of litter and root manipulations on soil carbon and nitrogen in a Schrenk’s spruce (Picea schrenkiana) forest." PLOS ONE 16, no. 2 (February 25, 2021): e0247725. http://dx.doi.org/10.1371/journal.pone.0247725.
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Plant detritus represents the major source of soil carbon (C) and nitrogen (N), and changes in its quantity can influence below-ground biogeochemical processes in forests. However, we lack a mechanistic understanding of how above- and belowground detrital inputs affect soil C and N in mountain forests in an arid land. Here, we explored the effects of litter and root manipulations (control (CK), doubled litter input (DL), removal of litter (NL), root exclusion (NR), and a combination of litter removal and root exclusion (NI)) on soil C and N concentrations, enzyme activity and microbial biomass during a 2-year field experiment. We found that DL had no significant effect on soil total organic carbon (SOC) and total nitrogen (TN) but significantly increased soil dissolved organic carbon (DOC), microbial biomass C, N and inorganic N as well as soil cellulase, phosphatase and peroxidase activities. Conversely, NL and NR reduced soil C and N concentrations and enzyme activities. We also found an increase in the biomass of soil bacteria, fungi and actinomycetes in the DL treatment, while NL reduced the biomass of gram-positive bacteria, gram-negative bacteria and fungi by 5.15%, 17.50% and 14.17%, respectively. The NR decreased the biomass of these three taxonomic groups by 8.97%, 22.11% and 21.36%, respectively. Correlation analysis showed that soil biotic factors (enzyme activity and microbial biomass) and abiotic factors (soil moisture content) significantly controlled the change in soil C and N concentrations (P < 0.01). In brief, we found that the short-term input of plant detritus could markedly affect the concentrations and biological characteristics of the C and N fractions in soil. The removal experiment indicated that the contribution of roots to soil nutrients is greater than that of the litter.
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Manderscheid, Remy, Cathleen Frühauf, Andreas Pacholski, and Hans Joachim Weigel. "Data from the Braunschweig FACE (free-air CO2 enrichment) experiments on sugar beet at adequate and low levels of nitrogen supply." Open Data Journal for Agricultural Research 5 (June 3, 2019): 11–15. http://dx.doi.org/10.18174/odjar.v5i0.16225.
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Sugar beet was grown within a crop rotation over two rotation cycles (2001, 2004) at ambient and elevated atmospheric CO2 concentration (375 and 550 ppm) with practical (126, 156 kg N ha-1) and low levels (63, 78 kg N ha-1) of nitrogen supply. In the second year another cultivar was used to prevent infestation by rhizomania, which occured on one half of the field plots at the end of the season of 2001. In 2004, shading was included as an additional treatment. The objectives were to investigate the growth response of sugar beet to elevated CO2 concentration at high and low nitrogen availability. Data set includes data on management, soil condition, weather, below and above ground growth (individual leaves, leaf area index, total biomass, beet yield and composition, water soluble carbohydrates, root biomass).
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Dinka, Mária, Anita Kiss, Norbert Magyar, and Edit Ágoston-Szabó. "Effects of the introduction of pre-treated wastewater in a shallow lake reed stand." Open Geosciences 8, no. 1 (January 1, 2016): 62–77. http://dx.doi.org/10.1515/geo-2016-0008.
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AbstractReed stands may be employed in the amelioration of water quality or even in the treatment of wastewater. In this study, the nutrient concentrations of (i) the above- and below-ground Common Reed (Phragmites australis) biomass, and (ii) surface and interstitial water were analyzed in a natural stand used in wastewater treatment. The reed stand was located in Hungarian part of Lake Fertő/Neusiedler See, by the shore near Fertőrákos Bay. The nitrate, phosphate and dissolved organic nitrogen concentrations of surface water were found to be higher on the inlet side of the reed stand compared to the outlet. The N and P concentrations in the above-ground biomass and P concentrations in the below-ground biomass increased after the introduction of pre-treated wastewater. The inter-annual differences in the characteristics of sediment interstitial water and in the nutrient content of reed tissues were assessed using statistical methods. The samples taken before and after the introduction of the pre-treated wastewater in the parcel formed different clusters. The results of the study provide further evidence that the nutrient retention capacity of natural stands of P. australis may be employed in the treatment of wastewater while protecting and preserving the valuable natural assets of the lake.
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Merilä, Päivi, Kaisa Mustajärvi, Heljä-Sisko Helmisaari, Sari Hilli, Antti-Jussi Lindroos, Tiina M. Nieminen, Pekka Nöjd, Pasi Rautio, Maija Salemaa, and Liisa Ukonmaanaho. "Above- and below-ground N stocks in coniferous boreal forests in Finland: Implications for sustainability of more intensive biomass utilization." Forest Ecology and Management 311 (January 2014): 17–28. http://dx.doi.org/10.1016/j.foreco.2013.06.029.
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Wilder, Kris L., J. M. Hart, Arthur Poole, and David D. Myrold. "FATE OF APPLIED NITROGEN FERTILIZER ON OREGON CRANBERRIES." HortScience 25, no. 9 (September 1990): 1148c—1148. http://dx.doi.org/10.21273/hortsci.25.9.1148c.
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Little work has been done to establish the rate and timing of nitrogen fertilizer applications to optimize return from fertilizer expenditures and minimize potential for ground and surface water pollution in Oregon cranberries (Vaccinium macrocarpon Ait.). Predicting cranberry N requirements is difficult because cranberries require little N and soil tests for N are not helpful for perennial crops, especially when grown in shallow sandy soils. We used 15N-labeled ammonium sulfate to measure both plant uptake and movement of fertilizer N in a south coastal Oregon cranberry bed. A bed planted to the Stevens variety was fertilized with 15N-labelled ammonium sulfate at two rates (18 kg/ha and 36 kg/ha) applied at five phonological stages: popcorn, hook, flowering, early bud, and late bud. Plant N uptake and translocation were measured throughout the growing season in uprights, flowers, berries, and roots, Initial results indicate that when N was applied at popcorn stage approximately 12% of the N was present in the above-ground vegetative biomass at harvest. Incorporation of fertilizer N into the duff and mineral soil was measured. An estimate of fertilizer N leaching was made by trapping inorganic N below the root zone using ion exchange resin bags.
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Louvieaux, Julien, Antoine Leclercq, Loïc Haelterman, and Christian Hermans. "In-Field Observation of Root Growth and Nitrogen Uptake Efficiency of Winter Oilseed Rape." Agronomy 10, no. 1 (January 10, 2020): 105. http://dx.doi.org/10.3390/agronomy10010105.
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Field trials were conducted with two nitrogen applications (0 or 240 kg N ha−1) and three modern cultivars of winter oilseed rape (Brassica napus L.) previously selected from a root morphology screen at a young developmental stage. The purpose is to examine the relationship between root morphology and Nitrogen Uptake Efficiency (NUpE) and to test the predictiveness of some canopy optical indices for seed quality and yield. A tube-rhizotron system was used to incorporate below-ground root growth information. Practically, clear tubes of one meter in length were installed in soil at an angle of 45°. The root development was followed with a camera at key growth stages in autumn (leaf development) and spring (stem elongation and flowering). Autumn was a critical time window to observe the root development, and exploration in deeper horizons (36–48 cm) was faster without any fertilization treatment. Analysis of the rhizotron images was challenging and it was not possible to clearly discriminate between cultivars. Canopy reflectance and leaf optical indices were measured with proximal sensors. The Normalized Difference Vegetation Index (NDVI) was a positive indicator of biomass and seed yield while the Nitrogen Balance Index (NBI) was a positive indicator of above-ground biomass N concentration at flowering and seed N concentration at harvest.
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Li, Xuefeng, and Shijie Han. "Preservation of broadleaf species in Korean pine (Pinus koraiensis) plantations affects soil properties, carbon storage, biomass allocation, and available nitrogen storage." Canadian Journal of Forest Research 38, no. 8 (August 2008): 2227–35. http://dx.doi.org/10.1139/x08-052.
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We analyzed forest floor mass, soil properties, soil organic carbon (SOC) storage, soil available nitrogen (NO3–-N and NH4+-N) (SAN) storage, litter production and decomposition, tree biomass, and the growth rate of Korean pine ( Pinus koraiensis Sieb. et Zucc.) to determine the impacts of keeping broadleaf species in the Korean pine plantation on Korean pine growth and identify the interactions of plants and soil. Forest biomass and litter production were significantly higher in the broadleaf mixed Korean pine plantation (KBP) than in the pure Korean pine plantation (KP). Broadleaf species redistributed carbon from forest floor to mineral soil via its fast litter decomposition rate with the result of a smaller forest floor mass and a greater SOC storage in KBP than in KP. KBP had significantly higher SOC and SAN storages, SOC and SAN concentrations, and pH, and lower soil bulk density than KP. Such differences can be largely explained by the input of broadleaf litter into KBP. The Korean pine in KBP had a greater growth rate and allocated a smaller proportion of biomass below ground, indicating that the broadleaf species influenced the Korean pine growth and biomass allocation pattern by changing soil properties. There was a positive feedback among litter N release rate, SAN storage, and plant growth rates.
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Lan, Zhichun, and Yongfei Bai. "Testing mechanisms of N-enrichment-induced species loss in a semiarid Inner Mongolia grassland: critical thresholds and implications for long-term ecosystem responses." Philosophical Transactions of the Royal Society B: Biological Sciences 367, no. 1606 (November 19, 2012): 3125–34. http://dx.doi.org/10.1098/rstb.2011.0352.
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The increase in nutrient availability as a consequence of elevated nitrogen (N) deposition is an important component of global environmental change. This is likely to substantially affect the functioning and provisioning of ecosystem services by drylands, where water and N are often limited. We tested mechanisms of chronic N-enrichment-induced plant species loss in a 10-year field experiment with six levels of N addition rate. Our findings on a semi-arid grassland in Inner Mongolia demonstrated that: (i) species richness (SR) declined by 16 per cent even at low levels of additional N (1.75 g N m –2 yr −1 ), and 50–70% species were excluded from plots which received high N input (10.5–28 g N m −2 yr −1 ); (ii) the responses of SR and above-ground biomass (AGB) to N were greater in wet years than dry years; (iii) N addition increased the inter-annual variations in AGB, reduced the drought resistance of production and hence diminished ecosystem stability; (iv) the critical threshold for chronic N-enrichment-induced reduction in SR differed between common and rare species, and increased over the time of the experiment owing to the loss of the more sensitive species. These results clearly indicate that both abundance and functional trait-based mechanisms operate simultaneously on N-induced species loss. The low initial abundance and low above-ground competitive ability may be attributable to the loss of rare species. However, shift from below-ground competition to above-ground competition and recruitment limitation are likely to be the key mechanisms for the loss of abundant species, with soil acidification being less important. Our results have important implications for understanding the impacts of N deposition and global climatic change (e.g. change in precipitation regimes) on biodiversity and ecosystem services of the Inner Mongolian grassland and beyond.
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Campion, J. M., M. Nkosana, and M. C. Scholes. "Biomass and N and P pools in above- and below-ground components of an irrigated and fertilisedEucalyptus grandisstand in South Africa." Australian Forestry 69, no. 1 (January 2006): 48–57. http://dx.doi.org/10.1080/00049158.2006.10674987.
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Tang, Liuyan, Lin Chen, and Zhen’an Yang. "Artificial Measures Are Not Necessarily Better Than Natural Recovery for the Extremely Degraded Alpine Meadow: The Results of Simulated Degradation Restoration After Three Years." Journal of Biobased Materials and Bioenergy 15, no. 2 (April 1, 2021): 224–30. http://dx.doi.org/10.1166/jbmb.2021.2041.
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Natural and artificial restoration measures are widely used to restore degraded ecosystems, such as degraded alpine meadow. The objective of this research was to evaluate the advantages and disadvantages of natural and artificial measures for extremely degraded alpine meadows. We removed the surface soil (0–10 cm) of the alpine meadow to simulate the extremely degraded “black soil beach,” and set artificial measures (planting Festuca sinensis (E) and Elymus sibircus L. cv. chuan-cao No. 1 (F)) and natural recovery (N) (without any artificial auxiliary measures) in the northeastern part of the Qinghai-Tibet Plateau (QTP), China. After 3 years, we determined the characteristics of community and soil in the artificial and natural treatment. The results show that the species number, above-and below-ground biomass (AB, BB), root-shoot ratio (R/S) in N is significantly higher than that in artificial restoration (E and F); while the community coverage and concentration of soil total carbon, total nitrogen, microbial biomass carbon, microbial biomass nitrogen and microbial biomass phosphorus (TC, TN, MBC, MBN and MBP) in artificial restoration is significantly higher than that in N. In conclusion, compared with N, artificial measures (E and F) are not completely beneficial to the development of plant community diversity and the restoration of soil nutrients in the extremely degraded meadow. Thus, the establishment of artificial grassland is not necessarily better than natural recovery for the extremely degraded alpine meadow.