Water erosion under simulated rainfall in different soil management systems during soybean growth

Fernando Luis Engel,Neroli Pedro Cogo,Ildegardis Bertol,Álvaro Luiz Mafra

doi:10.1590/s0103-90162007000200013

Fernando Luis Engel, Neroli Pedro Cogo + Show 2 more

Open Access

https://doi.org/10.1590/s0103-90162007000200013

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Abstract

Soil management influences soil cover by crop residues and plant canopy, affecting water erosion. The objective of this research was to quantify water and soil losses by water erosion under different soil tillage systems applied on a typical aluminic Hapludox soil, in an experiment carried out from April 2003 to May 2004, in the Santa Catarina highland region, Lages, southern Brazil. Simulated rainfall was applied during five soybean cropstages, at the constant intensity of 64.0 mm h-1. Treatments were replicated twice and consisted of: i) conventional tillage on bare soil - control treatment (CTBS), ii) conventional tillage on cultivated soil (CTCS), iii) no-tillage on non tilled soil with burned crop residue (NTRB), iv) no-tillage in non tilled soil with crop residue desiccated (NTRD), and v) no-tillage on four-years interrupted soil tillage with crop residue desiccated - "traditional no tillage" (NTRT). Regardless of soybean cropstages, water losses were the highest for the CTCS than for the untilled soils, while soil losses were considerably higher in the CTCS treatment only until cropstage 3, in cultivated soil treatments. The NTRT was most effective treatment in terms of both water and soil loss reduction. Water infiltration should also be considered, when considering the soil erosion process caused by rainfall and its associated runoff, due to the management systems usually adopted in cultivated fields.

Highlights

Tillage breaks soil aggregates, increases surface roughness, and diminishes the soil surface cover by crop residues, reducing resistance to water erosion
Soil cover by crop residue in any of the untilled-soil treatments was little reduced throughout the experimental period, ending up with values in the order of 75% to 85% of the existing at the time the experiment was initiated
Soil cover by crop residue in the NTRD and NTRT treatments were low as compared to those commonly observed for other common, annual row-crops (Leite et al, 2004)

Summary

Introduction

Increases surface roughness, and diminishes the soil surface cover by crop residues, reducing resistance to water erosion. Conventional tillage associated with burning previous crop residues can increase soil susceptibility in relation to erosion, in spite of increasing soil surface roughness and total porosity in the plowed layer (Allmaras et al, 1966; Cogo et al, 1984; Bertol et al, 1997). As a result, both surface water retention and infiltration are higher, especially in recently-tilled soil, generally as compared to untilled soils (Cogo et al, 1984). No-tillage keeps crop residues on soil surface, and usually leads toward soil consolidation, increasing the soil resistance to water erosion (Cogo et al, 1984; Mello et al, 2003; Leite et al, 2004)

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