Patterns of litter and nutrient return to the soil during passive restoration in Cerrado, Brazil

Passive restoration offer better preservation for the diverse legacy of forest ecosystems, but many interactions on the restoration process remain poorly understood. In this study, the seasonality of accumulated litter layer, nutrient content, potential return, and soil quality were evaluated under the initial (subjected to 11-year) and advanced (subjected to 46-year) passive restoration conditions in Cerrado, Brazil. Measurements were carried out for a period of one year. Accumulated litter layer, nutrient content, potential return, and nutrient use efficiency were 50%, 43%, 13%, and 42% higher in the advanced passive restoration site compared to the initial restoration site. For both sites, the annual litter content followed the order: N > Ca > K > Mg > P > Fe > Mn > B > Zn > Cu. Significant increases in soil organic matter and cation exchange capacity were found in the advanced passive restoration. The annual average had shown a higher macronutrient concentration in the soil for the initial restoration, while a higher micronutrient concentration was found for the advanced restoration. The seasonality affected the accumulated litter layer, litter nutrients, potential return and soil quality. Some litter and soil nutrients were significantly correlated, evidencing the nutrient associations between litter and soil. Hence, both the passive restoration stages and rain were factors that regulated the temporal patterns of accumulated litter layer as well as the nutrient cycling in Cerrado passive restoration models.