Soil properties, bacterial and fungal community compositions and the key factors after 5-year continuous monocropping of three minor crops.

Pu Yang,Jinfeng Gao,Yang Gao,Xiaoli Gao,Baili Feng,Pengke Wang,Yan Luo,Debarati Bhaduri

doi:10.1371/journal.pone.0237164

Pu Yang, Jinfeng Gao + Show 6 more

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https://doi.org/10.1371/journal.pone.0237164

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Abstract

Minor grain crops are widely cultivated in northwest China and played important roles in local economic. Soil microbes play a central role in ecological function and biological stability and related to soil quality. In order to uncover the soil microbial composition differences and the factors under 5-year continuous monocropping of three minor crops (Proso millet, Common bean and Common buckwheat) in Guan-Zhong Plain, six soil nutrimental parameters, soil pH, soil moisture content, and four soil enzyme activities were analyzed and soil microbial composition were sequenced. The results showed that after 5-years of continuous monocropping, different cover crops influenced most of soil physicochemical properties, expect soil moisture content (P < 0.05), the available nutrients were significant higher in proso millet soil, and the pH was significantly higher in common buckwheat soil. soil ALP, catalase and urease activities were significantly different between soils (P< 0.01), in which soil catalase activities were significantly lower and soil ALP and urease activities were significantly higher than that of proso millet and common buckwheat. A total of 171439 sequences, 9468 OTUs and 29 phylum for bacteria, 128920 sequences, 544 OTUs and 27 phylum for fungi were obtained. In addition, no significantly difference obtained in diversity and richness between soils (P < 0.05). According to relative abundance, Proteobacteria, Chloroflexi, Gemmatimonadetes and Acidobacteria were the dominant bacterial phylum in all samples, moreover, the relative abundance of Caldiserica was significantly different between soils (P < 0.05). Ascomycota (79.04%-90.21%) was dominant phylum in fungal community and phylum Phragmoplastophyta (P < 0.01) and Glomeromycota (P < 0.05) were significantly different between soils. Redundancy analysis indicated that available nutrients Nitrogen and Potassium are the strongest predictors in both bacterial and fungal community. In conclusion, different cover crops influenced soil nutrient properties, soil pH and soil microbial composition, and continuous monocropping decreased soil fertility condition. Moreover, Common bean and Common buckwheat were more sensitive to monocropping treatment.

Highlights

Proso millet (Panicum miliaceum L.), common bean (Phaseolus vulgaris) and common buckwheat (Fagopyrum esculentum Moench) are three important minor grain crops that are beneficial to human health [1]
The pH (8.73–8.82) of common buckwheat (QM) was significantly higher than proso millet (MZ) and common bean (YD)
After 5 years of monocropping, the soil nutrient content differed in soils, suggested that monocropping of different cover crops influenced soil nutrient contents, and total nitrogen (TN), available nitrogen (AN), available phosphorus (AP) and available potassium (AK) were significantly higher in MZ soil (Table 1)

Summary

Introduction

Proso millet (Panicum miliaceum L.), common bean (Phaseolus vulgaris) and common buckwheat (Fagopyrum esculentum Moench) are three important minor grain crops that are beneficial to human health [1]. They are widely cultivated in northwest China and playing important roles in the development of local agricultural economy [2]. Previous studies reported the main factors of soil microbial composition are plot site [24], land management [16], farming system [7, 17], soil physicochemical parameters [25, 26], and cover crops [8]

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