Selamento superficial e erosão hídrica em argissolo amarelo na bacia do Alto Ipanema, no semiárido

Abstract

The use of incorrect agricultural techniques has caused serious damages to the soil, especially in the Brazilian semi-arid soil. The lack of ground cover is one of the key accelerators of degradation,without protection the soil is exposed to the impacts of rain drops, desegregating the particles and loading the lower altitude areas,causing the surface sealing that waterproofs the soil, making it difficult to infiltrate. This dissertation aimed to characterize surface sealing and water erosion in a Yellow Argisols in the Alto Ipanema Basin,under different ground covers. Eigth erosion plots were installed, three meters long and one meter wide, which received the following treatments: uncovered soil and soil with Brachiaria decumbens mulch. Three simulated rainfall was applied at intervals of 24 hours, with intensity of 54.63 mm h-1, after which rainfall micromorphology was investigated, as well as erosion.It was observed that the use of mulch reduced surface runoff by up to 42%, soil loss and disintegration rate had reductions of 70% on average.The penetration resistance was reduced by up to 69.32% and infiltration increased by up to 242%. There were significant differences between using or not mulching at the 5% probability level.Due to the lack of soil aggregation, no surface seals were identified, however, mulching was effective in preserving soil porosity and microstructure for the rainfall of 0h.