Contribution of different sources and origins of nitrogen in above- and below-ground structures to the partial nitrogen balance in soybean
Aims: Most studies that quantified the biological N fixation (BNF) and partial N balances of soybean have ignored the belowground structures. Our objectives were to evaluate the contribution of belowground structures to the partial N balance of soybean and to identify the origin (soil or BNF) and source (apparent remobilization or current gain during the seed-filling period) of seed N. Methods: Biomass, BNF, and N uptake coming from different N sources and origins, including belowground structures, were quantified in a two-year field study involving two soybean genotypes (MG IV and V) and two water availability conditions (rainfed and irrigated). Results: The inclusion of BNF-derived N present in belowground components (which averaged +12 kg N ha−1 at R7) changed the results of the partial N balances from negative to positive. BNF was the main origin of seed N, accounting for 73 and 79% of seed N under water stressed and non-stressed conditions, respectively. Regarding the seed N source, apparent remobilization was the main contributor to seed N under water stress, whereas current N gain was the main contributor to seed N in unstressed plants. Conclusions: We conclude that i) the root system retains a relevant proportion of the atmospheric N fixed during the crop cycle and should be included in the partial N balance estimations; and ii) BNF is the main origin of seed N, even under contrasting growing conditions.
| Main Authors: | , , |
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| Format: | info:ar-repo/semantics/artículo biblioteca |
| Language: | eng |
| Published: |
Springer
2022-04
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| Subjects: | Soja, Nitrógeno, Biomasa sobre el Suelo, Biomasa por debajo del Suelo, Fijación Biológica del Nitrógeno, Soybeans, Nitrogen, Above Ground Biomass, Below Ground Biomass, Biological Nitrogen Fixation, |
| Online Access: | http://hdl.handle.net/20.500.12123/11699 https://link.springer.com/article/10.1007/s11104-022-05418-0 https://doi.org/10.1007/s11104-022-05418-0 |
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| Summary: | Aims: Most studies that quantified the biological N fixation (BNF) and partial N balances of soybean have ignored the belowground structures. Our objectives were to evaluate the contribution of belowground structures to the partial N balance of soybean and to identify the origin (soil or BNF) and source (apparent remobilization or current gain during the seed-filling period) of seed N.
Methods: Biomass, BNF, and N uptake coming from different N sources and origins, including belowground structures, were quantified in a two-year field study involving two soybean genotypes (MG IV and V) and two water availability conditions (rainfed and irrigated).
Results: The inclusion of BNF-derived N present in belowground components (which averaged +12 kg N ha−1 at R7) changed the results of the partial N balances from negative to positive. BNF was the main origin of seed N, accounting for 73 and 79% of seed N under water stressed and non-stressed conditions, respectively. Regarding the seed N source, apparent remobilization was the main contributor to seed N under water stress, whereas current N gain was the main contributor to seed N in unstressed plants.
Conclusions: We conclude that i) the root system retains a relevant proportion of the atmospheric N fixed during the crop cycle and should be included in the partial N balance estimations; and ii) BNF is the main origin of seed N, even under contrasting growing conditions. |
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