Agricultural practices in the cultivation of cassava and the relation to runoff, and soil and water loss

ABSTRACT

The aim of this research was to evaluate the hydraulic characteristics of runoff, and the results of agricultural practices when cultivating cassava, on the control of water erosion in a cohesive allic Yellow Latosol with a sandy-clay loam texture. The experiment was carried out on an area of 240 m² and a slope of 0.07 m m^-1, at the Federal University of Recôncavo da Bahia, in Cruz das Almas, in the state of Bahia, Brazil. The experimental design was completely randomised, with four treatments and three replications, employing erosion plots with an area of 3 m², under three intensities of simulated rainfall: 62 mm h^-1, 90 mm h^-1 (constant intensity), and 40 and 90 mm h^-1 (variable intensity), and types of plant cover. The following treatments were used: Cassava on sloping ground (CS), cassava on sloping ground with mulching (CS+ MU), cassava on level ground intercropped with cowpea (Vigna unguiculata L. Walp.) with mulching (CL+P+MU) and cassava on level ground intercropped with cowpea (CL+P). The runoff regime, classified as slow-flow, made it possible to observe the occurrence of inter-row erosion under the CS and CL+P treatments. The CS treatment proved to be susceptible to water erosion, resulting in a total soil loss of 3,912 kg ha^-1 and water loss of 21.5%, being 8.1 and 9.3 times greater than the CL+P treatment. Under the treatments with mulching there was no water erosion. The application of mulching with intercropping significantly reduced soil and water loss, and can be used by farmers as a technique in the conservation of both soil and water.

Key words:
Rainfall intensity; Water erosion; Mulching; Intercropping