Soil physical and biological properties in an integrated crop-livestock system in the Brazilian Cerrado

João De Andrade Bonetti,Edicarlos Damacena De Souza,Jeander Oliveira Caetano,Marco Aurélio Carbone Carneiro,Helder Barbosa Paulino

doi:10.1590/s0100-204x2018001100006

Abstract

Abstract: The objective of this work was to evaluate the soil physical and biological properties in an integrated crop-livestock system (ICLS), with or without cattle grazing, in different seasons. The experiment was carried out in the Cerrado biome, in Brazil, in a Rhodic Eutrudox. The treatments consisted of grazing areas (Urochloa ruziziensis) at 0.25, 0.35, and 0.45 m heights (with soybean cultivation after grazing) and of nongrazed areas. The ICLS had no negative effects on soil bulk density, total porosity, macroporosity, and microporosity. After ICLS implementation, the values of soil bulk density decreased, and those of soil macroporosity increased, in the grazed and nongrazed areas. However, after three years, bulk density and macroporosity were reestablished to values similar to those before ICLS implementation. Soil penetration resistance was higher in the ICLS, mainly at 0.00-0.05 m soil depth. After four years, ICLS promoted the increase of microbial biomass C and N and the reduction of the metabolic quotient. The microbial biomass carbon and the metabolic quotient were related to the weighted mean diameter. ICLS benefits to soil physical and biological properties are associated with adequate ICLS implementation, adequate grazing height (0.35 m), and maintenance of soil cover.

Highlights

Different systems of soil management directly impact the Brazilian Cerrado agriculture
In 2008, liming was carried out by applying 2.5 Mg ha-1 dolomitic limestone, with 80% PRNT to raise the base saturation to 60%, which was incorporated to the soil with one plowing and two harrowings to implement the integrated crop-livestock system (ICLS) that began to be conducted as no-tillage systems (NTS)
The bulk density (BD) values were higher at the beginning of the study in 2008, with a reduction after soil mobilization and cultivation in the year 2010/2011

Summary

Introduction

Different systems of soil management directly impact the Brazilian Cerrado agriculture. Erosion, and the reduction of soil organic matter (Landers et al, 2013), which are aggravated by the absence of fertilization and liming of forage and grain-crop areas (Lima et al, 2011). These factors, over the years, have reduced the yield capacity, increasing the production costs and, reduced the profitability of rural properties (Freitas & Landers, 2014). The NTS has been shown to be ineffective in maintaining crop rotation due to the higher economic profitability of soybean and maize crops, which, together with the intense use of machinery, restarted soil degradation (Landers et al, 2013; Freitas & Landers, 2014)

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Conclusion