Developing a Soil Physical Quality Index (SPQi) for lowlands under different deployment times of no-tillage

Diony Alves Reis,Adilson Luís Bamberg,Claudia Liane Rodrigues De Lima

doi:10.1590/1678-992x-2017-0196

Abstract

ABSTRACT: Soil physical quality in lowlands from the Pampa biome under no-tillage (NT) plays an important role; therefore, this study aimed to establish a soil physical quality index (SPQi) from a minimum data set to detect the effects of different deployment times of NT in an Albaqualf. The comparison of areas with one (NT1), three (NT3), five (NT5) and seven (NT7) years of notillage was established using as reference a non-cultivated field plot (NC) for at least thirty years, nearby the sites under NT. Soil samples with undisturbed and disturbed structure were collected to determine the physical quality indicators and soil organic matter (SOM) fractions. The factor analysis (FA) was used to identify and select a minimum data set. The SPQi was elaborated by using the deviations of the measured indicators at different deployment times of NT in relation to NC. The SPQi showed sensibility to identify and explain soil physical quality changes with different deployment times of NT. In well-drained lands, higher deployment times of no-tillage promote the physical quality of lowlands.

Highlights

In Brazil, the Pampa biome occurs in Rio Grande do Sul State (RS), where 5.4 million hectares are lowlands, and Albaqualf is the predominant class (Parfitt et al, 2014)
Soil physical quality in lowlands from the Pampa biome under no-tillage (NT) plays an important role; this study aimed to establish a soil physical quality index (SPQi) from a minimum data set to detect the effects of different deployment times of NT in an Albaqualf
The soybean has been an alternative for the traditional flooded rice-livestock sequence, but there is a concern with the sustainability of this production model, as no-tillage (NT) has proven more profitable and environmentally favorable in rainfed agriculture (Crittenden et al, 2015; Fernández-Romero et al, 2016; Raiesi and Kabiri, 2016) than other management systems

Summary

Introduction

In Brazil, the Pampa biome occurs in Rio Grande do Sul State (RS), where 5.4 million hectares are lowlands, and Albaqualf is the predominant class (Parfitt et al, 2014). Albaqualf has high agricultural and economic importance due to its physical characteristics. The presence of a subsurface layer almost impermeable, with expansive clays and low macro/microporosity ratio, favor irrigated rice and livestock. The agricultural growth of the region is strongly dependent on understanding soil physical properties in this environment. Rainfed crops have been recently introduced into these soils, mostly cultivated under conventional tillage (CT) (Reis et al, 2016). The soybean has been an alternative for the traditional flooded rice-livestock sequence, but there is a concern with the sustainability of this production model, as no-tillage (NT) has proven more profitable and environmentally favorable in rainfed agriculture (Crittenden et al, 2015; Fernández-Romero et al, 2016; Raiesi and Kabiri, 2016) than other management systems

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