Simulating trends in soil organic carbon of an Acrisol under no-tillage and disc-plow systems using the Century model

Soil organic matter (SOM) and its different pools have key importance in nutrient availability, soil structure, in the flux of trace gases between land surface and the atmosphere, and thus improving soil health. This is particularly critical for tropical soils. The rates of accumulation and decomposition of carbon in SOM are influenced by several factors that are best embodied by simulation models. However, little is known about the performance of SOM simulation model in an acid tropical soil under different tillage systems including no-tillage (NT). Our objective was to simulate soil organic matter dynamics on an Acrisol under no-tillage and different plowed systems using Century model. Tillage systems consisted of no-tillage, disc plow, heavy disc harrow followed by disc plow, and heavy disc harrow. Soil C stocks simulated by Century model showed tendency to recovery only under no-tillage. Also, simulated amounts of C stocks of slow and active pools were more sensitive to management impacts than total organic C. The values estimated by Century of soil C stocks and organic carbon in the slow and passive pools fitted satisfactorily with the measured data. Thus fitted, except for the active pool, Century showed acceptable performance in the prediction of SOM dynamics in an acid tropical soil.