Residue decomposition and fate of nitrogen-15 in a wheat crop under different previous crops and tillage systems
Nitrogen (N) management may be improved by a thorough understanding of the nutrient dynamics during previous-crop residue decomposition and its impact on fertilizer N fate in the soil-plant system. An experiment was conducted in the Argentine Pampas to evaluate the effect of maize and soybean as pre...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2008 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/131255 |
| Acceso en línea: | http://hdl.handle.net/11336/131255 |
| Access Level: | acceso abierto |
| Palabra clave: | 15N RECOVERY N FERTILIZATION RESIDUE DECOMPOSITION TILLAGE SYSTEMS WHEAT https://purl.org/becyt/ford/4.1 https://purl.org/becyt/ford/4 |
| Sumario: | Nitrogen (N) management may be improved by a thorough understanding of the nutrient dynamics during previous-crop residue decomposition and its impact on fertilizer N fate in the soil-plant system. An experiment was conducted in the Argentine Pampas to evaluate the effect of maize and soybean as previouscrops and plow-till and no-till methods on N dynamics and 15N-labeled fertilizer uptake during a wheat growing season. Maize and soybean residues released N under both tillage treatments, but N release was faster from soybean residues and when residues were buried by tillage. Net immobilization of N on decomposing residues was not detected. A regression model that accounted for 92% of remaining N variability included time, previous crop, and tillage treatment as independent variables. The rapid residue decomposition with N release was attributed to the high temperatures of the agroecosystem. The recovery of 15N-labeled fertilizer in the wheat crop, soil organic matter, and decomposing residues was not statistically different between previous crop treatments or tillage systems. Crop uptake of fertilizer N averaged 52% across treatments. Forty percent of fertilizer N was removed in grains. Immobilization of labeled N on soil organic matter was substantial, averaging 34% of the 15N-labeled fertilizer retained, but was very small on decomposing residues, averaging 0.2-3.0%. Fertilizer N not accounted for at harvest in the soil-plant system was 12% and was ascribed to losses. Previous crop or tillage system had no impact on wheat yield, but when soybean was the previous crop, N content of grain and straw+roots increased. Discussion is presented on the potential availability of N retained in wheat straw, roots, and soil organic matter for future crops. |
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