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Field Crop Recovery and Modeling of Nitrogen Mineralized from Labeled Sorghum Residues
Author(s) -
Vigil M. F.,
Kissel D. E.,
Smith S. J.
Publication year - 1991
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1991.03615995005500040024x
Subject(s) - sorghum , residue (chemistry) , crop residue , agronomy , crop , nitrogen , organic matter , mathematics , fertilizer , nutrient , chemistry , biology , agriculture , ecology , biochemistry , organic chemistry
Efficient use of fertilizer N requires an assessment of the N contribution from decomposing crop residues. The objectives of this study were to quantify and model the amount of mineralized N recovered by a growing crop from 15 N‐labeled sorghum ( Sorghum bicolor [L.] Moench) residues of variable N concentration and composition. The residues were incorporated into the surface soil of field microplots. The microplots were double‐cropped with sorghum and wheat ( Triticum aestivum L.) for a 3‐yr period. The 15 N tag in the crop residue was used to distinguish between residue‐derived N and that from soil organic matter. Between 4.5 and 25% of the residue N applied (36–83 kg N ha −1 was applied as crop residue N) was recovered by a sorghum crop 110 d after incorporation. This constituted 56 to 77% of the total N recovered during a 3‐yr period. Accumulated N recovered over time was described by modified first‐order models. Regression analysis indicated that 93% of the variability in N recovered by 110 d could be explained using the C/N ratio and acid‐detergent fiber contents of the residues. Measurements of N mineralized, using the method described above, were compared with predicted N mineralized, using MINIMO (a subroutine of the CERES‐Maize model). After adjusting MINIMO parameters using data collected 110 d after residue incorporation, the slope and intercept of a linear fit between measured and MINIMO‐predicted N mineralized 1097 d after residue incorporation were not different from one and zero, respectively.