Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Desnitrificación del suelo bajo dos tratamientos de riego para estimar el rendimiento y emisión de metano en arroz

Auteur : Chua Valero, Tualee Yazmin

Université de soutenance : Universidad Nacional Agraria La Molina

Grade : Ingeniero Agrícola 2020

Résumé
The objective of this study was to evaluate the process of Denitrification and Decomposition of soil carbon (DNDC) through a biogeochemical model to estimate the emission of CH4 and N2O from rice crop under irrigation management : by flooding (T1) and with controlled dry (T2), through the use of closed static chambers in the UNALM that has representative water scarcity conditions of the Peruvian central coast. The crop yield was 11.96 and 9.42 tha-1 with a water use efficiency of 0.31 and 0.33 kg m-3 generating an accumulated emissionof 673.25 kg CO2-e y 2290.20 kg CO2-e for T1 y T2, respectively. The parameters of theDNDC model with high sensitivity (variation greater than 15 percent) for the emission of CH4 and N2 O, were in decreasing order with their calibrated value : Soil organic carbón (SOC) decrease rate below top soil (dSOC) with 2 and 0.51, the hydraulic conductivity (ks) with 0.020 and 0.024 m hr-1, the microbial activity index (imicro) with 0.4 and 1, the depth of top soil with uniform SOC content (topS) with 0.2 and 0.2 m , the thermal degree days (TDD) with 3430 and 4239 ºC y the maximum biomass productions for grain (prodMx) with 4700 and 3430 kgC ha -1 año -1 for T1 y T2, respectively. The DNDC model exhibited "acceptable" to "satisfactory" performance when simulating CH4, N2O, air biomass and grain yield according to the Nash-Sutcliffe efficiency index (EF) with values of 0.43 and 0.50 for T1 and T2, respectively. In addition, a Pearson’s correlation coefficient (R) of 0.71 (T1) and 0.56 (T2) and Willmott index (d) of 0.95 (T1) and 0.87 (T2). Therefore, the model could be a useful tool in the formulation of climate change mitigation measures in rice producing areas with an arid climate.

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