Returning Winter Cover Crop Residue Influences Soil Aggregation and Humic Substances under Double-cropped Rice Fields

Haiming Tang,Ke Wang,Xiaoping Xiao,Kaikai Cheng,Chao Li,Wenguang Tang

doi:10.1590/18069657rbcs20160488

Abstract

ABSTRACT Residue management in cropping systems may improve soil quality. However, there are few studies on the effects of residue management on soil aggregation and carbon content in the humin (C-HUM), humic acid (C-HAF) and fulvic acid (C-FAF) fractions in South China. Therefore, the effects on soil aggregation and on the C-HUM, C-HAF, C-FAF from incorporating winter cover crop residues in a double-cropped rice (Oryza sativa L.) system in South China fields were studied. The experiment has been conducted since [...]

Highlights

Soil aggregation is an important facet of soil structure, providing resistance to wind and water erosion, physical protection of organic matter, and microsites for microbial activity
The total organic carbon (TOC) content in the paddy soil under the Ry-R-R, Mv-R-R, Po-R-R, and Ra-R-R systems was significantly higher than the TOC content in the Fa-R-R system
The TOC content was nearly constant within the 0.00-0.20 m layer of Ry-R-R, Mv-R-R, Po-R-R, Ra-R-R, and Fa-R-R soil, while stratification with higher contents in the 0.00-0.05 m layer occurred in Ry-R-R, Mv-R-R, Po-R-R, Ra-R-R, and Fa-R-R soils, compared to 0.05-0.10 m and 0.10-0.20 m (Table 1)

Summary

Introduction

Soil aggregation is an important facet of soil structure, providing resistance to wind and water erosion, physical protection of organic matter, and microsites for microbial activity. Plants affect structure at different scales and through various direct and indirect mechanisms, involving effects on different organic matter fractions (such as fungal biomass, hyphal length, labile polysaccharides, hydrophobic aliphatics, and microbial biomass) (Angers and Caron, 1998). By penetrating the soil, roots create zones of failure, which contribute to fragmentation of the soil and formation of smaller aggregates (Angers and Caron, 1998). Soils under paddy cultivation displayed improved soil aggregate structure and altered the distribution patterns of P fractions in different aggregate size classes (Li et al, 2016)

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