No-tillage implementation: Analyzis on water-based sediment flow in the Marombas River, Brazil

Eder A S Sá,Daiane T Schier,Silvio L Rafaeli Neto,Ildegardis Bertol

doi:10.1590/1807-1929/agriambi.v26n3p204-211

Abstract

ABSTRACT Water erosion is influenced by climate, soil, soil cover and soil conservation practices. These factors can be modified by natural (especially climate) and/or anthropogenic (especially soil, soil cover and conservation practices) actions. The relief factor also influences the water erosion and can also be partially modified by anthropic action. This study aimed to evaluate the impact of anthropogenic action due to the introduction of soil crop in no-tillage system on water erosion, and on the consequent flow of sediments in the water. The study was carried out in the Marombas river basin with an area of 3,939 km², using the Soil Water Assessment Tools (SWAT) model. The calibration and validation of the model for sediment production was carried out with a historical series of synthetic data. The data from this series were estimated by linear regression from sediment value load and the average daily flow obtained punctually in the basin’s outlet. The SWAT model was calibrated on a daily scale with data from 1979 to 1989 and was validated with data from 1994 and 1997. The SWAT model was suitable to represent the average daily flow and sediment flow in the Marombas watershed. The hypothesis of reduced sediment production with increasing soil crop in no-tillage system was accepted.

Highlights

Water erosion is the most intense form of soil degradation, reducing its productive capacity and causing serious environmental damage (Dechen et al, 2015; Erkossa et al, 2015; Nigussie et al, 2017)
Water erosion is the result of a combination of factors: climate, soil, topography, soil cover and management, and conservation practices (Rodrigues et al, 2017)
This means that this model has a high capacity to estimate sediment flow, and that these results justify the use of historical sediment series synthetically obtained by this type of regression equation for Soil Water Assessment Tools (SWAT) calibration

Summary

Introduction

Water erosion is the most intense form of soil degradation, reducing its productive capacity and causing serious environmental damage (Dechen et al, 2015; Erkossa et al, 2015; Nigussie et al, 2017). Soil crop increases soil losses (SL) in relation to forest areas and the no-tillage (NT) reduce SL in relation to conventional tillage (CT) (Schick et al, 2017). The NT in 2014 was present around 86% of the Brazilian agricultural area of soy, corn (1st harvest) and beans (1st harvest) reducing the process of erosion and siltation of water resources (EMBRAPA, 2018). Water erosion is the result of a combination of factors: climate, soil, topography, soil cover and management, and conservation practices (Rodrigues et al, 2017). These factors vary in temporal and spatial scale, which makes water erosion spatially dependent. The definition of scale relationships as well as knowledge of the processes governing water and sediment flows at each scale is critical to water and soil management (Mayor et al, 2011)

Objectives

Methods

Results