Grazing lowers soil multifunctionality but boosts soil microbial network complexity and stability in a subtropical grassland of China

Abstract

IntroductionLong-term grazing profoundly affects grassland ecosystems, whereas how the soil microbiome and multiple soil ecosystem functions alter in response to two-decades of grazing, especially how soil microbiome (diversity, composition, network complexity, and stability) forms soil multifunctionality is rarely addressed.MethodsWe used a long-term buffalo grazing grassland to measure the responses of soil physicochemical attributes, stoichiometry, enzyme activities, soil microbial niche width, structure, functions, and networks to grazing in a subtropical grassland of Guizhou Plateau, China.ResultsThe evidence from this work suggested that grazing elevated the soil hardness, available calcium content, and available magnesium content by 6.5, 1.9, and 1.9 times (p = 0.00015–0.0160) and acid phosphatase activity, bulk density, pH by 59, 8, and 0.5 unit (p = 0.0014–0.0370), but decreased the soil water content, available phosphorus content, and multifunctionality by 47, 73, and 9–21% (p = 0.0250–0.0460), respectively. Grazing intensified the soil microbial carbon limitation (+78%, p = 0.0260) as indicated by the increased investment in the soil β-glucosidase activity (+90%, p = 0.0120). Grazing enhanced the complexity and stability of the bacterial and fungal networks but reduced the bacterial Simpson diversity (p < 0.05). The bacterial diversity, network complexity, and stability had positive effects, while bacterial and fungal compositions had negative effects on multifunctionality.DiscussionsThis work is an original attempt to show that grazing lowered multifunctionality via the reduced bacterial diversity and shifted soil bacterial and fungal compositions rather than the enhanced bacterial and fungal network complexities and stability by grazing. Protecting the bacterial diversity from decreasing, optimizing the composition of bacteria and fungi, and enhancing the complexity and stability of bacterial network may be conducive to improving the soil multifunction of grazing grassland, on a subtropical grassland.

Effects of grazing in different intensities and 10‐year grazing exclusion on soil bacterial community composition and interaction complexity in alpine grasslands of the Qinghai‐Tibet Plateau

“…Considering all the treatments, bacteria exhibited a higher number of positive interactions in their co‐occurrence network, indicating a cooperative symbiotic relationship (Figure 3 and Table S2). Consistent with previous research (Ding et al, 2022), our results showed that the cooperative relationships were reduced in light and moderate grazing plots, but increased in heavy grazing plots, possibly due to the survival strategy of microorganisms under grazing stress (Lupatini et al, 2014). Grazing led to a decrease in bacterial network complexity, with the lowest complexity observed in heavily grazed areas.…”

Biocontrol agents establishment and their impact on rhizosphere microbiome and induced grapevine defenses is highly soil-dependent

“…Soils treated with Ta SC1, presented more complex and stable networks, with a higher number of positive correlations. These results agree with Gao et al [93] that showed Trichoderma viride was bene cial to increase the complexity of co-occurrence network and maintained the stability of network, improved resistance to external disturbances, such as biotic and abiotic stresses [92]. However, Gao et al [93] demonstrated that Trichoderma viride increased the number of negative interactions in rhizosphere microbial network, while in our study, Ta SC1 increased the number of positive correlations, especially on clay soil.…”

“…For that reason, we studied microbiome co-occurrence networks in BCA treated and non-treated soils, to evaluate the effect of BCA applications on microorganism dynamics within the soil rhizospheric microbiome. Our data point to more complex networks within bacterial communities that were not impacted by any BCA inoculation, as high complexity of the rhizosphere microbial network represents increased community organization that can improve resistance to external disturbances [92]. Fungal correlation networks were less complex, but highly impacted by Ta SC1 application.…”

Drought influences the fungal community structure, diversity, and functionality inhabiting the grapevine xylem and enhances the abundance ofPhaeomoniella chlamydospora

“…The intricacy of the co-occurrence network plays a crucial role in maintaining network stability and enhancing resistance to external disturbances, including both biotic and abiotic stresses (Ding et al 2023). This underscores the notion that water deficit can heighten grapevine susceptibility to a range of biotic and abiotic stresses.…”