Perdas de Água e Solo Utilizando Chuva Simulada em Diferentes Coberturas Superficiais e Condições de Umidade no Semiárido Paraibano

Abstract

The rainfall simulator is a useful tool to generate quick and satisfactory information on infiltration, streamflow and soil loss under different surface conditions, at much less cost and time. Thus, this article aims to analyze the losses of soil and water in the semiarid area of Paraiba state, under different cover and surface moisture conditions. The experiment was performed on erosion plots within Sao Joao do Cariri Experimental Basin, where simulated rainfalls were applied with a mean intensity of 53 mm/h, under different soil moisture and surface cover conditions. The simulated rainfalls were applied to the following type of cover: native vegetation, bare soil, corn and beans, under the following moisture condition: (a) dry condition (DC) with 60-min rainfall, (b) wet condition (WC), performed 24 h after the end of the simulation in the DC, with 30-min rainfall, (c) very wet condition (VWC), initiated 30 min after the end of the simulation in WC, with 30-min rainfall. The results showed that the runoff for all types of surface cover increased when the moisture content was higher and the sediment yield was higher for the DC. The values of water and soil losses for the WC and VWC were similar for all types of surface cover studied. The results showed that native vegetation was more effective to protect the soil, when compared to the other types of cover. Corn and beans presented the highest water and soil loss values, even higher than those observed for the bare soil