Water-Covered Depth with the Freeze–Thaw Cycle Influences Fungal Communities on Rice Straw Decomposition

Xiaolong Lin,Chunjie Tian,Lei Tian,Shangqi Xu,Xinguang Wang,Zongmu Yao

doi:10.3390/agriculture11111113

Abstract

Rice is a staple food for the world’s population. However, the straw produced by rice cultivation is not used sufficiently. Returning rice straw to the field is an effective way to help reduce labor and protect the soil. This study focused on the effect of water-covered depth with the freeze–thaw cycle on rice straw decomposition and the soil fungal community structure in a field in Northeast China. The field and controlled experiments were designed, and the fungal ITS1 region was tested by high-throughput sequencing for analyzing the fungal communities in this study. The results showed that water coverage with the freeze–thaw cycle promoted the decomposition of rice straw and influenced the fungal community structure; by analyzing the network of the fungal communities, it was found that the potential keystone taxa were Penicillium, Talaromyces, Fusarium, and Aspergillus in straw decomposition; and the strains with high beta-glucosidase, carboxymethyl cellulase, laccase, lignin peroxidase, and manganese peroxidase could also be isolated in the treated experiment. Furthermore, plant pathogenic fungi were found to decrease in the water-covered treatment. We hope that our results can help in rice production and straw return in practice.

Highlights

Rice straw is one of the most abundant renewable resources in the terrestrial environment
Decomposing rice straw requires the simultaneous action of multiple enzymes derived from decomposers [5], which act in combination during the decomposition process [6] and show noticeable succession changes in the microbial community, mainly dominated by bacterial communities in the early stages [7,8]
Fungi were identified as typical “k”-type microorganisms, it was found that they showed a higher degree of enrichment than the “r”-type after the input of exogenous organic matter, and the fungi were more enriched in exogenous 13C [10]

Summary

Introduction

Rice straw is one of the most abundant renewable resources in the terrestrial environment. Decomposing rice straw requires the simultaneous action of multiple enzymes derived from decomposers [5], which act in combination during the decomposition process [6] and show noticeable succession changes in the microbial community, mainly dominated by bacterial communities in the early stages [7,8]. These have been identified as “r”-type microorganisms with a faster degradation rate that consumes the easy-to-decompose carbon source of straw and synthesizes extracellular enzymes [9].

Methods

Findings

Discussion

Conclusion