The Effect of Different Soybean Tillage Systems on Infiltrability and Erosion Susceptibility of an Oxisol in Paraná, Brazil

Abstract

AbstractMeasurements of infiltrability were carried out during the soybean vegetation period in three different tillage systems on an Oxisol, with the aim of estimating relative erosion susceptibility. The tillage systems studied were conventional tillage (disc plow), minimum tillage (chisel plow) and no‐tillage. Infiltration was determined as the difference between rainfall applied with a portable rainfall simulator and runoff collected from mini‐plots.During all growth stages of the soybeans, infiltrability under no‐tillage was higher than under conventional tillage. Minimum tillage took an intermediate position. Lowest overall infiltrability and consequently, highest relative erosion susceptibility was observed in the early growth stage after planting, in a wet year, when the degree of soil cover was also lowest. Infiltrability was mainly affected by degree of surface seal development as a result of natural rainfall energy the soil surface had received prior to measurements, as well as degree of soil cover. Highly significant correlations were found between the calculated sum of erosivity indices one month before measurement and the total infiltration. Differences in bulk density and macroporosity had hardly any effect on infiltrability.The better performance of no‐tillage in controlling erosion observed in Brazil can thus be explained by the higher degree of soil cover in comparison to the other tillage systems studied.