Soil Microbial Community Driven by Soil Moisture and Nitrogen in Milk Vetch (Astragalus sinicus L.)–Rapeseed (Brassica napus L.) Intercropping

Abstract

The soil microbial community is not only driven by plant composition but is also disturbed by the soil environment. Intercropping affects the soil microenvironment through plant interaction, but the understanding of the relationship between soil microbial community and environment in intercropping is still weak. In this study, milk vetch intercropping with rapeseed was used to explore the interaction between soil microorganisms and environment. The results showed that the soil moisture content of intercropping was higher than that of monoculture during the reproductive period of rapeseed growth (flowering and podding stages). The contents of soil total nitrogen and alkali-hydrolyzable nitrogen in intercropping were higher than those in monoculture. The dominant soil microbial communities in intercropping were the same as in monoculture and included Chloroflexi, Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes, Gemmatimonates and Bacteroidetes. However, intercropping increased the Shannon index and decreased the Simpson’s index of the soil microbial community. The changes in the soil microbial community were mainly related to soil temperature, moisture, pH, total nitrogen, alkali-hydrolyzable nitrogen and available potassium. Moreover, there was a negative correlation between soil moisture and microorganisms and a positive correlation between nitrogen and microorganisms. Thus, milk vetch–rapeseed intercropping could not only improve soil nitrogen content, but also change soil microbial community diversity. In dryland red soil, the effect of milk vetch–rapeseed intercropping on soil moisture and nitrogen was the key factor contributing to the changes in the soil microbial community. When planting rapeseed in the future, we could consider the application of intercropping with milk vetch, which can contribute to regulating the soil nitrogen pool and improving microbial diversity.

Intercropping enhances microbial community diversity and ecosystem functioning in maize fields

“…We measured soil physiochemical variables. Soil moisture was determined by oven-drying, soil pH with a pH electrode, total organic carbon (TOC) with potassium dichromate oxidation, total nitrogen (TN) with the Kjeldahl method, total phosphorus (TP) with NaOH melting molybdenum antimony anti-colorimetry, total potassium (TK) with NaOH melting flame photometer, soil available nitrogen (AN) with the alkaline hydrolysis diffusion method, soil available phosphorus (AP) with sodium bicarbonate extraction, soil available potassium (AK) with ammonium acetate extraction and flame photometry, and soil aggregates with wet-sieving ( Bao, 2000 ; Du et al, 2015 ; Zeng et al, 2018 ; Tian et al, 2019 ; Liu Z. et al, 2022 ). Soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) were determined by the chloroform-fumigation extraction method ( Vance et al, 1987 ).…”

Microbial community and network differently reshaped by crushed straw or biochar incorporation and associated with nitrogen fertilizer level

“…For example, WC was the driver for the SD‐M0, SD‐M1, and BC‐M0, which suggested that microbial module community and function was related to soil moisture. Straw return can enhance soil water content and water retention, and then influence the substrates and energy substances available to soil microorganisms, finally improving their growth and activities (Hagemann et al, 2017; Liu, Li, et al, 2022; Siedt et al, 2021). In addition, BD was the only shared driver for the BC‐M1 and BC‐M3 but not for SD modules.…”

Wild pollinator communities benefit from mixed cultivation of oilseed rape and milk vetch

“…Mixed cultivation, which creates structural heterogeneity may therefore be particularly beneficial for these vulnerable groups, with additional benefits from the limited use of agrochemicals associated with milk vetch cultivation. Considering the wide distribution of this crop mix in China (Liu et al., 2022) and other Asian countries (Sakai & Matsuka, 1982), understanding the potential benefits of mixed cultivation practices involving milk vetch for wild pollinator diversity and its potential to mitigate the negative impacts of ongoing agricultural intensification (Shi et al., 2021; Shi, Axmacher, et al., 2022) is a high priority.…”