Soil, water, and nutrient losses from management alternatives for degraded pasture in Brazilian Atlantic Rainforest biome

摘要

The objective of this study was to evaluate sediment, water and nutrient losses from different pasture managements in the Atlantic Rainforest biome. A field study was carried out in Alegre Espirito Santo, Brazil, on a Xanthic Ferralsol cultivated with braquiaria (Brachiaria brizantha). The six pasture managements studied were: control (CON), chisel (CHI), fertilizer (FER), burned (BUR), plowing and harrowing (PH), and integrated crop-livestock (iCL). Runoff and sediment samples were collected and analyzed for calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P) and organic carbon contents. Soil physical attributes and above and below biomass were also evaluated. The results indicated that higher water loss was observed for iCL (129.90 mm) and CON (123.25 mm) managements, and the sediment losses were higher for CON (10.24 t ha~(-1)) and BUR (5.20 t ha~(-1)) managements when compared to the other managements. Majority of the nutrients losses occurred in dissolved fraction (99% of Ca, 99% of Mg, 96% of K, and 65% of P), whereas a significant fraction of organic carbon (80%) loss occurred in a particulate form. Except for P, other nutrients (Ca, Mg and K) and organic carbon losses were higher in coarse sediment compared to fine sediment The greater losses of sediment, organic carbon, and nutrients were observed for CON followed by BUR management (p < 0.05). Our findings indicated that the traditional pasture management adopted in the Atlantic Rainforest needs to be rethought and burned management should be avoided.Based on the water, soil, and nutrient losses from various practices, to reduce pasture degradation, farmers should adopt edaphic practices by applying lime and fertilize to improve pasture growth and soil cover, and reducing soil erosion in the hilly Brazilian Atlantic Rainforest biome.