Evaluation of the short-term effect of tillage practices on soil hydro-physical properties

Omid Bahmani

doi:10.17951/pjss.2019.52.1.43

Abstract

Tillage is one of the most important practices that have a significant influence on the soil hydro-physical properties. In this study, the impact of the type and number of input variables with five different methods of the Retc model to predicting the moisture retention curve and soil water content in three surfaces tillage NT (No-tillage), CP (Chisel Plough) and MP (Moldboard Plough) and the impact of tillage systems on soil hydro-physical properties were evaluated. According to results, when the field capacity and wilting point moisture was added to input data in Retc to predict the moisture curve model parameters, the EF was increased in MP (0.977, 0.95) and CP (0.891, 0.86) treatments compare the NT (0.665, 0.608). The Mualem–Van Genuchten model can describe satisfactorily the simulation of soil physical properties. The S-index, which was also affected by tillage, was greater than 0.066 in all tillage treatments, indicating good soil physical quality. Results indicated that NT had the highest and lowest values of bulk density (1.55 Mgr.m-3) and total available water (TAW) (0.038 m.m-1), respectively, and the differences between NT and MP in total porosity was significant. Overall, in most soil layers, tillage practices affected the porosity and total available water in the order MP &gt; CP &gt; NT. Water retention curves indicated that the water retention capacity was greater in tilled than in no-tilled and saturated hydraulic conductivity values were greater in tilled treatments than in NT soil.

Highlights

Understanding of important processes in agriculture and the environment needs to have adequate information on soil physics
The objectives of this study were to evaluate the influence of three different tillage practices – moldboard plow (MP), chisel plow (CP), and NT – on bulk density, total porosity, micro and macro porosity, total available water, hydraulic conductivity and the shape of the water retention curve of a sandy loamy soil in a semi-arid region of Iran and Van Genuchten model was fitted to the experimental data from three tillage systems using the Retention Curve program (RETC)
The S-index, which was affected by tillage, was greater than 0.066 that indicated the good soil physical quality

Summary

Introduction

Understanding of important processes in agriculture and the environment needs to have adequate information on soil physics. One of the most important characteristics that describe the unsaturated soil is the soil water characteristic curve, which in many studies is used as basic information. The soil water characteristic curve is a fundamental soil property employed to quantify plant available water and for modeling water and solute movement in soils. Laboratory and field methods, which developed over the years to measure the hydraulic functions are relatively costly, difficult to implement and time-consuming (Van Genuchten et al 1991). The structure, porosity, pore size distribution of soil and other characteristics of water retention in the soil and water conservation show how different matric for each soil is unique. Matric potential and moisture content changes have a complex relationship with nonlinear function (Van Genuchten 1980, Walczak et al 2006)

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Conclusion