Soil Physical Quality After 21 Years of Cultivation in a Brazilian Cerrado Latosol

Aristides O Ngolo,Raphael B A Fernandes,Maurílio F Oliveira,Igor R Assis,Genelício C Rocha

doi:10.5539/jas.v11n3p124

Abstract

Long-term studies aiming soil quality evaluation under different soil management strategies are no common. Long-term evaluations provided more reliable contributions to decision-making and practices adoption. This study evaluated the soil physical quality of a Brazilian Cerrado Latosol after 21 years of three different soil management strategies: disc plowing (DP), no-tillage (NT), and disc harrowing+subsoiling (DHS). In comparison to the reference, a soil from a native Cerrado area, the removal of the original vegetation and the implementation of the three soil management strategies increased the soil bulk density (Bd) and reduced soil porosity, macroporosity, soil organic carbon (SOC) and the size of water-stable aggregates, but did not change the glomalin-related soil protein (GRSP) contents and clay flocculation. Similar effects were diagnosed on soil physical quality when is considered only the three different management strategies, especially on soil porosity, Bd, size of water-stable aggregates, SOC and GRSP contents. Strategies of DP and NT increased soil resistance to penetration in the superficial layers, while the annual use of DHS reduced this soil mechanical characteristic. The NT system did not provide increasing of soil organic carbon in comparison to other management practices evaluated. In conclusion, removing the native vegetation affected soil physical quality, but the Brazilian Cerrado soil is resilient to physical damage even when different intensive farming practices are implemented for more than two decades. The limitation of the NT system in improving the soil physical quality is related to climate conditions that determine the non-maintenance of straw on the soil surface.

Highlights

The Latosols in the Cerrado biome located in the central region of Brazil are well-developed pedogenetically, homogeneous, and present small variations between horizons
In contrast to air and water quality, which is measured by its degree of contamination (Andrews et al, 2002), soil quality is defined by its ability to function within the limits of the ecosystem and land use to ensure biological productivity, maintaining environmental quality, and promoting plant and animal health (Doran & Parkin, 1994)
The removal of the native vegetation in the cultivated areas and the use of maintaining soil management practices for two decades reduced the average size of the aggregates, the differences between the three cultivated areas (NT, disc plowing (DP), and disc harrowing+subsoiling (DHS)) were not significant

Summary

Introduction

The Latosols in the Cerrado biome located in the central region of Brazil are well-developed pedogenetically, homogeneous, and present small variations between horizons. In contrast to air and water quality, which is measured by its degree of contamination (Andrews et al, 2002), soil quality is defined by its ability to function within the limits of the ecosystem and land use to ensure biological productivity, maintaining environmental quality, and promoting plant and animal health (Doran & Parkin, 1994). The cultivation practices can promote soil losses from erosion, as indicated by Doetterl et al (2016) as the tillage erosion. This type of erosion produced by intensive and mechanized management can reach levels similar to those of water erosion

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Results