Modeling symbiotic biological nitrogen fixation in grain legumes globally with LPJ-GUESS (v4.0, r10285)

Abstract. Biological nitrogen fixation (BNF) from grain legumes is of significant importance in global agricultural ecosystems. Crops with BNF capability are expected to support the need increase food production while reducing (N) fertilizer input for sustainability, but quantification N fixing rates and crop yields remains inadequate on a scale. Here we incorporate two legume crops (soybean faba bean) into dynamic vegetation model LPJ-GUESS (Lund–Potsdam–Jena General Ecosystem Simulator). The performance this new implementation evaluated against observations range water management trials. generally captures observed response these practices biomass production, soil uptake, fixation, despite some deviations cases. Globally, simulated dominated by moisture temperature, as well addition. Annual inputs through modeled be 11.6±2.2 Tg soybean 5.6±1.0 all pulses, total 17.2±2.9 yr?1 during period 1981–2016 Our estimates show good agreement previous statistical relatively high compared pulses. This study highlights accounting process when modeling C–N interactions ecosystems, particularly it comes combined effects climate land-use change terrestrial cycle.