Impacts of continuous and rotational cropping practices on soil chemical properties and microbial communities during peanut cultivation

Abstract

Long-term monocultures have severely inhibited the cultivation of Chinese peanut (Arachis hypogaea L.). In this study, the effects of continuous cropping on soil chemical properties and microbial communities were investigated in peanut fields that had been in crop rotation for 10 years and in monoculture for 10 years. The results found that long-term monoculture increased the activities of available potassium, available phosphorus, available nitrogen, soil organic matter, urease, acid phosphatase and catalase; while decreasing the activity of catalase. The diversity and abundance of soil bacteria and fungi is higher under continuous peanut cultivation. At the genus level, the relative abundance of potentially beneficial microflora genera was higher in the rhizosphere soil of rotational cropping than in continuous cropping, while the opposite was true for the relative abundance of potentially pathogenic fungal genera. Principal coordinates and cluster analysis indicated that continuous cropping altered the structure of the microbial community. The results of the functional predictions showed significant differences in the functioning of the rhizosphere microbial community between continuous and rotational cropping. In conclusion, long-term continuous cropping changed the chemical properties of the soil, altered the structure and function of the soil bacterial and fungal communities in peanut rhizosphere, which to some extent reduced the relative abundance of potentially beneficial microbial genera and increased the relative abundance of potentially pathogenic fungal genera, thus increasing the potential risk of soil-borne diseases and reducing the yield and quality of peanut. Therefore, in the actual production process, attention should be paid not only to the application of chemical fertilizers, but also to crop rotation and the application of microbial fertilizers.

Effects of the Long-Term Continuous Cropping of Yongfeng Yam on the Bacterial Community and Function in the Rhizospheric Soil

“…Changes in richness and evenness ultimately led to the changes in bacterial diversity. This result does not agree with previous studies on sweet potato [ 10 , 38 , 41 ], rice [ 42 ], cotton [ 43 ], Lycium barbarum [ 40 ], and peanut [ 35 ], where bacterial diversity increased or decreased monotonically with continuous cropping time. However, a higher bacterial richness and bacterial diversity were found over 30 years and 10 years cropping with the highest for 30 years cropping of maize [ 44 ].…”

“…To comprehensively understand the rhizospheric soil bacterial community structure of Yongfeng yam in different continuous cultivation years, the Illumina NovaSeq method was used. These results revealed that the bacterial richness increased with the extension of continuous cultivation years, which is consistent with previous finding with peanut [ 35 ], Andrographis paniculate [ 36 ], and Rehmannia glutinosa [ 37 ], but is contrary to findings regarding sweet potato [ 38 ], Panax notoginseng [ 39 ], and Lycium barbarum [ 40 ]. The results of bacterial diversity (Shannon index) decreased first, remained stable, then increased with long-term continuous cropping, indicating a decrease in bacterial diversity up to 15 years of continuous cropping and an increase in bacterial diversity after 20 years.…”

“…Furthermore, PCoA analysis revealed that the continuous cropping of the Yongfeng yam significantly affected bacterial communities, which was consistent with Pang et al who found that the continuous cropping of sugarcane for different times also obviously affected the bacterial community [ 14 ]. This phenomenon was also observed in the continuous cropping of sweet potato [ 38 ], peanut [ 35 ] and alfalfa [ 45 ]. Overall, these results indicated that continuous cropping had certain effects on the composition of the rhizospheric soil bacterial community.…”

“…The phylum Proteobacteria plays a key role in phylogenetic, ecological, and disease-inhibiting functions, and it is the most dynamic taxon associated with rhizoctonia disease suppression. In addition, it is involved in organic matter decomposition and plant growth promotion [ 10 , 35 ]. In our study, the most dominant bacterial phylum in all samples was Proteobacteria, which generally agreed with previous studies [ 10 , 38 , 46 ].…”

“…Acidobacteria was the most abundant bacterial phylum in soils with nutrient limitation [ 48 ]. Long-term continuous cropping leads to soil fertility reduction, which increases the relative abundance of Acidobacteria [ 35 ]. A similar phenomenon appeared in this study, where the relative abundance of Acidobacteria increased significantly ( p < 0.0001) with the extension of continuous cultivation years.…”