Measured and modeled nitrogen balances in lowland rice-pasture rotations in temperate South America

dc.contributor.authorCastillo, Jesús
dc.contributor.authorKirk, Guy J. D.
dc.contributor.authorRivero, M. Jordana
dc.contributor.authorFabini, Guillermo
dc.contributor.authorTerra, José A.
dc.contributor.authorAyala, Walter
dc.contributor.authorRoel, Alvaro
dc.contributor.authorIrisarri, Pilar
dc.contributor.authorHaefele, Stephan M.
dc.date.accessioned2023-05-22T12:35:23Z
dc.date.available2023-05-22T12:35:23Z
dc.date.issued2023-04-03
dc.description.abstractRotational rice systems, involving pastures, other crops and/or livestock, are common in temperate South America, exemplified by the rice-pasture-livestock system of Uruguay which combines very high rice yields with tight nitrogen (N) balances. The generally good nutrient use efficiency in these systems provides a template for nutrient management in other mixed farming systems, if the underlying processes can be sufficiently well quantified and understood. Here, we studied N balances in rice–non-rice rotations in a long-term experiment in Uruguay, with the aim of parameterizing and testing the DNDC model of N dynamics for such systems for use in future work. The experiment includes three rotations: continuous rice (RI-CONT), rice-soybean (RI-SOY) and rice-pasture (RI-PAST). We considered 9 years of data on N balances (NBAL), defined as all N inputs minus all N outputs; N surplus (NSURP), defined as all N inputs minus only N outputs in food products; and N use efficiency (NUE), defined as the fraction of N inputs removed in food products. We parameterized DNDC against measured yield and input and output data, with missing data on N losses inferred from the N balance and compared with literature values. The model performance was assessed using standard indices of mean error, agreement and efficiency. The model simulated crop yields and rice cumulative N uptake very well, and soil N reasonably well. The values of NBAL were +45 and−20 kg N ha−1 yr−1 in RI-CONT and RI-SOY, respectively, and close to zero in RI-PAST (−6 kg N ha−1 yr−1). Values of NSURP decreased in the order RI-CONT >> RI-SOY > RI-PAST (+115, +25 and +13 kg N ha−1 yr−1, respectively). Values of NUE (84, 54, and 48% for RI-SOY, RI-PAST, and RI-CONT, respectively) decreased as NBAL increased. The sensitivity of DNDC's predictions to the agronomic characteristics of the different crops, rotations and water regimes agreed with expectations. We conclude that the DNDC model as parameterized here is suitable for exploring how to optimize N management in these systems.en_UK
dc.description.sponsorshipBiotechnology and Biological Sciences Research Council (BBSRC): BB/P02274X/1en_UK
dc.identifier.citationCastillo J, Kirk GJD, Rivero MJ, et al., (2023) Measured and modeled nitrogen balances in lowland rice-pasture rotations in temperate South America, Frontiers in Sustainable Food Systems, Volume 7, 2023, Article number 1103118en_UK
dc.identifier.eissn2571-581X
dc.identifier.urihttps://doi.org/10.3389/fsufs.2023.1103118
dc.identifier.urihttps://dspace.lib.cranfield.ac.uk/handle/1826/19686
dc.language.isoenen_UK
dc.publisherFrontiersen_UK
dc.rightsAttribution 4.0 International*
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/*
dc.subjectnitrogen use effciencyen_UK
dc.subjectDNDC modelen_UK
dc.subjectnitrogen budgetsen_UK
dc.subjectnutrient balancesen_UK
dc.subjectlong-term experimenten_UK
dc.titleMeasured and modeled nitrogen balances in lowland rice-pasture rotations in temperate South Americaen_UK
dc.typeArticleen_UK

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