Simulation of soil organic carbon changes in crop systems with castor bean using the RothC model

Abstract

The objective of this work was to simulate, by the RothC model, the changes in soil organic carbon (SOC) caused by changes of land use – from the traditional maize‑squash (TMC) association to systems with castor bean (Ricinus communis): multilayer (MUL), alleys (CALL) and monoculture (HIG). SOC simulations were performed for 0–20 and 0–40 cm soil depths, for the period 1980–2040, considering the TMC system as the base line. SOC change rates estimated with RothC, for both soil depths, were 0.5–1.2, 0.4–0.8, 0.3–0.5 and 0.04–0.1 Mg ha^-1 C per year in the HIG, MUL, CALL and TMC systems, respectively, and were consistent with those reported in the literature. RothC perfomance had 89% efficiency (EF) and R² = 0.9, which shows that this model can be used with scarce SOC temporal information, information on the history of land use, and with input measurements of aerial and underground plant residues in the soil.