S-Index as an indicator of physical quality in soils of the Paraná state

João H. Caviglione

doi:10.1590/1807-1929/agriambi.v22n7p458-464

Abstract

ABSTRACT From the 1990s, the demand for soil quality indicators has increased with the agricultural sustainability approaches. The S-index was proposed as an indicator of soil physical quality. The objective was to evaluate the sensitivity of S-index as an indicator of soil physical quality and its correlation with bulk density, organic carbon content, macroporosity, microporosity, total porosity and clay, sand and silt contents, under field conditions in the diversity of the Paraná state. Samples were collected from 21 sites with textures from clay and heavy clay, in the layers of 0-0.1 and 0.1-0.2 m, in soil under native forest and in cultivated soil. Eight soil physical attributes were determined. A soil-water retention curve with six moisture points was fitted and the S-index was calculated for each condition. The Wilcoxon Test showed differences in S-index between soil managements with p-value = 0.0015 in the 0-0.1 m layer and less than 0.0001 in the 0.1-0.2 m layer. The observed S-index showed to be a sensitive indicator of soil physical quality and with a significant Pearson correlation with bulk density (‑0.826), macroporosity (0.760), total porosity (0.836), and organic carbon content (0.583).

Highlights

Soil quality is defined by the Soil Science Society of America (SSSA) as “the capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation.” (Karlen et al, 1997)
From 1990, the demand for soil quality indicators has increased. Soil attributes such as bulk density, total porosity, optimal water range, aggregate stability, soil resistance to penetration have been used as physical quality indicators because they are modified by soil use and management, besides being of easy determination and reduced cost (Stefanoski et al, 2013)
This study aimed to evaluate the sensitivity of S-index as indicator of soil physical quality and verify its correlation with bulk density, organic carbon content, macroporosity, microporosity, total porosity and clay, sand and silt contents, under field conditions in the diversity of some soils of the Paraná state

Summary

Introduction

Soil quality is defined by the Soil Science Society of America (SSSA) as “the capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation.” (Karlen et al, 1997). From 1990, the demand for soil quality indicators has increased. Soil attributes such as bulk density, total porosity, optimal water range, aggregate stability, soil resistance to penetration have been used as physical quality indicators because they are modified by soil use and management, besides being of easy determination and reduced cost (Stefanoski et al, 2013). Dexter & Czyż (2007) identified the S value = 0.035 as the limit between soils with good and poor structural quality. They defined other limits; S < 0.02 for soils with very poor quality and S > 0.05 for soils with optimal or very good quality

Objectives

Methods

Results

Conclusion