Cover Cropping Impacts Soil Microbial Communities and Functions in Mango Orchards

Zhiyuan Wei,Quanchao Zeng,Wenfeng Tan

doi:10.3390/agriculture11040343

Abstract

Soil microbes play critical roles in nutrient cycling, net primary production, food safety, and climate change in terrestrial ecosystems, yet their responses to cover cropping in agroforestry ecosystems remain unknown. Here, we conducted a field experiment to assess how changes in cover cropping with sown grass strips affect the fruit yields and quality, community composition, and diversity of soil microbial taxa in a mango orchard. The results showed that two-year cover cropping increased mango fruit yields and the contents of soluble solids. Cover cropping enhanced soil fungal diversity rather than soil bacterial diversity. Although cover cropping had no significant effects on soil bacterial diversity, it significantly influenced soil bacterial community compositions. These variations in the structures of soil fungal and bacterial communities were largely driven by soil nitrogen, which positively or negatively affected the relative abundance of both bacterial and fungal taxa. Cover cropping also altered fungal guilds, which enhanced the proportion of pathotrophic fungi and decreased saprotrophic fungi. The increase in fungal diversity and alterations in fungal guilds might be the main factors to consider for increasing mango fruit yields and quality. Our results indicate that cover cropping affects mango fruit yields and quality via alterations in soil fungal diversity, which bridges a critical gap in our understanding of the linkages between soil biodiversity and fruit quality in response to cover cropping in orchard ecosystems.

Highlights

IntroductionCover cropping (i.e., sown grass strips) has been used as an important and effective method to improve soil fertilizer and soil carbon stacks [1]
The impacts of cover cropping with sown grass strips on soil properties depended on the types of sown grass and soil layers
The application of sown grass strips had no significant effects on soil pH, Soil organic matter (SOM) and AVK at both soil layers (Table 1)

Summary

Introduction

Cover cropping (i.e., sown grass strips) has been used as an important and effective method to improve soil fertilizer and soil carbon stacks [1]. A 12-year field experiment indicated that cover cropping increased soil organic carbon (SOC) stocks [1]. Compared with monospecies cover crops, cover crop mixtures sequestered more SOC [2]. Elevated SOC is associated with improved soil health and fertility; increasing SOC may help to enhance agricultural productivity [3]. Not all studies found that cover cropping results in SOC accumulation. Some studies demonstrated that the introduction of cover crops resulted in losses of SOC due to the faster growth of cover crops [4]. In addition to an increased carbon input, cover crops have been shown to increase biodiversity [5]

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Conclusion