Simulação dos estoques de Carbono e Nitrogênio pelo Modelo Century em Latossolos, no Cerrado Brasileiro

Abstract

The use of mathematical models can be useful for understanding the changes in the use and management of soil and provide aid in testing future scenarios, making it possible to develop management strategies which have less impact on the environment. The objectives of this study were: (a) to apply the Century Model v4.5 in order to simulate the effects of usages and managements on carbon stocks and soil nitrogen in different compartments; (b) compare both the observed stocks and those simulated by the Century Model; (c) to test the impact of future scenarios until the year 2100. The treatments evaluated were of Pine, under both no-tillage and conventional tillage, using historical data from the areas up until when the soil was sampled (2004). For the pine, three future scenarios were tested, one by simulating the management adopted up to the time the soil was sampled, another by reducing the fire events, as well as by soil usage without any preparation when replanting. For both no-tillage and conventional tillage, two future scenarios were simulated: one with corn and soybean rotation, and the other with a monoculture of corn. The Century model was sensitive to the changes in management which were adopted, the more labile compartments showing greater sensitivity (the active and the slow) than the most stable (passive). In relation to stocks of C, the model simulated values close to those measured in the field, with a minimum error of 0.36%. For stocks of N, the simulated values s howed an error of 5.71% for the more labile compartments. For pine, the future scenarios demonstrated the importance of preventing fires, and the use of monocultures.