Soil organic matter as affected by management systems, phosphate fertilization, and cover crops

Géssica Pereira de Souza,Cícero Célio de Figueiredo,Djalma Martinhão Gomes de Sousa

doi:10.1590/s0100-204x2016000900067

Géssica Pereira de Souza, Cícero Célio de Figueiredo + Show 1 more

Open Access

https://doi.org/10.1590/s0100-204x2016000900067

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Abstract

Abstract The objective of this work was to evaluate the effects of soil management systems, cover crops, and phosphate fertilization on soil humic fractions in a long-term experiment. The treatments consisted of conventional tillage and no-tillage with pearl millet (Pennisetum glaucum) or velvet bean (Mucuna aterrima) as cover crops, at two doses of phosphorous: 0 and 100 kg ha-1 P2O5 per year. Soil samples were taken 11 years after the establishment of the experiment and analyzed for soil total organic carbon and carbon content of humic fractions at 0.00-0.05, 0.05-0.10, and 0.10-0.20-m depths. The humic fractions are sensitive to soil management, except free fulvic acid, which was the only one that did not reduce its carbon contents on the surface layer (0.00-0.05 m) with conventional tillage. The main changes occurred on the soil surface layer, in which the no-tillage system with pearl millet as a cover crop provided the highest carbon levels in humic fractions. Long-term phosphate fertilization under no-tillage, with pearl millet as a cover crop, promotes the accumulation of organic carbon in soil humic fractions.

Highlights

The use of technology is a key factor for obtaining high yields in Cerrado (Brazilian savanna) soils and for preserving soil quality, by protecting soil organic matter (SOM) contents
Organic matter is the soil component that is most affected by the use of the no-tillage system (Nunes et al, 2011; Guareschi et al, 2012; Gazolla et al, 2015; Sá et al, 2015)
The objective of this work was to evaluate the effects of soil management systems, cover crops, and phosphate fertilization on soil humic fractions in a long-term experiment

Summary

Introduction

The use of technology is a key factor for obtaining high yields in Cerrado (Brazilian savanna) soils and for preserving soil quality, by protecting soil organic matter (SOM) contents. Over the past three decades, the Cerrado region has been increasingly adopting advanced technologies that include conservational tillage systems combined with the use of cover crops (Carvalho et al, 2012). Of these systems, the main and most comprehensive one is no-tillage, which provides several advantages that increase yield and reduce the impacts of farming on the environment (Ramos et al, 2013; Sá et al, 2015). SOM plays an important role in evaluating the changes promoted by the use of no-tillage combined or not with other technologies, such as cover crops and phosphate fertilization.

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