Response of soil fungi and biological processes to crop residues in no-tillage system

Priscila De Oliveira,Murillo Lobo Junior,Adriano Stephan Nascente,João Kluthcouski,Enderson Petrônio De Brito Ferreira

doi:10.1590/1983-40632016v4638374

Priscila De Oliveira, Murillo Lobo Junior + Show 3 more

Open Access

https://doi.org/10.1590/1983-40632016v4638374

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Abstract

ABSTRACT Soil management and crop rotation can directly affect the soil microbial community. This study aimed at determining soil quality indicators and soilborne fungi in a no-tillage system. A randomized blocks design, in a 3 × 2 factorial arrangement, was used. Three cover crops (palisade grass, millet and common bean) provided straw and root residues to the following crops of corn and soybean. The common bean-soybean sequence provided little soil covering and higher metabolic quotient and soil basal respiration and total enzymatic activity, as well as a general increase of soilborne fungi. The principal component analysis revealed that 76.61 % of the variance can be explained by the three first components, with cover crops, soil basal respiration and metabolic quotient regarded as the main qualitative and quantitative sources of variance in the first component. Carbon from the microbial biomass was the soil quality indicator best correlated to crop yield and negatively correlated to Fusarium solani density. The Rhizoctonia solani population was correlated with higher metabolic quotient and soil total enzymatic activity and basal respiration. The palisade grass crop favored soil fungistasis and enhancement of antagonist Trichoderma spp. populations. The multivariate approach demonstrated the association of soil fungi with soil quality indicators, as well as a higher influence of cover crops on the variance observed, in comparison to cash crops.

Highlights

Sustainable crop management involves the careful choice of cover crops that avoid organic matter loss and population growth of soilborne harmful microorganisms
Corn yield was higher after common bean (8,133 kg ha-1), differing from millet (6,601 kg ha-1) and palisade grass (6,801 kg ha-1) (Oliveira et al 2013b)
The soil enzymatic activity was significantly higher for common bean, if compared to palisade grass

Summary

Introduction

Sustainable crop management involves the careful choice of cover crops that avoid organic matter loss and population growth of soilborne harmful microorganisms. The soil microbial community presents a vast array of fungal and bacterial species, including soil organic matter decomposers (Moreira & Siqueira 2006) and root pathogens such as Rhizoctonia solani and pathogenic formae specialis of F. oxysporum (Van Bruggen & Semenov 2000). Sustainable practices to avoid yield losses include the boost of antagonists and biological processes to promote soil suppressiveness (Anees et al 2010). Despite many goals on soil health reported with composts and other practices (Veeken et al 2005), the recovery of infested fields remains challenging, especially in tropical regions where two or three annual harvests favor the buildup of a complex population of soil pathogens (Termorshuizen et al 2006)

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