Erosion Control in the Sustainable Cultivation of Maize (Zea mays L.) and Beans (Phaseolus vulgaris L.) at Two Stages of the Agricultural Cycle in Southern Guatemala

Abstract

Agricultural intensification in the mountains of Central America has increased soil vulnerability to erosion by water. This study was undertaken to analyse the erosion that affects the mixed cultivation of maize and beans at two stages of the crop development cycle (at 3 and 6 months after sowing) in southern Guatemala, together with the influence of the ground and crop canopy vegetal cover on soil erosion. The main aim of this analysis is to establish the soil erosion threshold enabling sustainable agriculture. The results obtained show that the soil surface was severely eroded, with mean values of area affected of 88.4% and 73.5% at 3 and 6 months, respectively. In the 3-month plots, the erosion bore scant relation to the factors analysed. Conversely, the area affected by soil erosion in the 6-month plots was significantly related to the degree of ground cover by weeds and litter, and the erosion threshold was located at 80% of vegetal cover. However, plots with this level of cover did not achieve effective erosion control, due to the low level of plant litter cover (15.7%) compared to that of weeds (75.5%). We conclude that this low content of vegetal residue in the soil, together with the tillage practices employed, explains the large surface area affected by erosion and the impossibility of establishing an erosion threshold.