Effects of intensifying organic manuring and tillage practices on penetration resistance and infiltration rate

Abstract

Soil erosion, along with the contributing factors of soil crusting and sealing, have received minimal scientific attention to date in Latin America. This study was conducted in an Andean hillside environment to determine how the local organic manuring and tillage practices influence the development of soil crusting and sealing, and the extent to which these practices influence soil water infiltration. The aim of this study was to identify treatments that prevented superficial soil structural constraints, i.e. treatments which maintain infiltration and therefore reduce potential soil erosion and run-off. Treatment results were measured with a pocket penetrometer and a mini-rain simulator on nine different cropping systems, mainly based on cassava ( Manihot esculenta Crantz), from February to November 2000 and 2001. The cropping systems were laid out on a Ferrallic Cambisol, an acid, vulcanically influenced soil of the Andean region. In both cropping cycles, treatments with chicken manure application developed superficial soil crusts during the dry season. For a treatment manured with 8 t ha −1 chicken manure, this crust meant an increase in penetration resistance from 2.3 kg cm −2 in April 2000 to 16.2 kg cm −2 in July 2000. The change in superficial soil structure created a notable reduction in final infiltration from 92 to 42.2 mm h −1. A minimum tillage treatment which displayed the highest penetration resistance during the dry periods of up to 46.4 kg cm −2 presented no restricting effects on soil water intake (76.2 mm h −1 final infiltration in 2000) due to an optimal aggregate development during 10 years of consecutive conservation practice. Measurements of penetration resistance and infiltration showed that soil conserving treatments, such as minimum tillage and crop rotations, improved the physical soil status and prevented soil crusting developing along with its negative effects on infiltration. These methods can therefore be strongly recommended to farmers.