Straw mulch and orchard grass mediate soil microbial nutrient acquisition and microbial community composition in Ziziphus Jujuba orchard

Abstract

Aims

The utilization of straw mulch and orchard grass in Ziziphus Jujuba orchards significantly influenced soil resource effectiveness, altering soil microbial metabolic limitations and enhancing nutrient accumulation. However, the response of soil microbial community composition to soil nutrient stoichiometry imbalance in Z. jujuba ‘Lingwuchangzao’ orchards is not clear.

Methods

This study investigated stoichiometric characteristics of soil nutrient resources, microbial biomass, and extracellular enzyme activities. Meanwhile, it was combined with soil microbial community diversity and composition under different management practices in Z. jujuba orchards in the arid zone of northern China.

Results

Straw mulch and orchard grass management reduced C:N imbalance, decreased nitrogen limitation and nitrogen use efficiency, and increased soil carbon limitation. These management practices also increased soil microbial diversity (eg. Shannon and ACE indices), with significant between-group differences by non-metric multidimensional scaling analysis. These differences were more significantly affected by relative carbon and nitrogen limitations. Relative carbon and nitrogen limitations were significantly correlated with Proteobacteria, Acidobacteriota, Ascomycota, and Mortierellomycota. In addition, straw mulch and orchard grass management increased the connectivity and complexity of the soil bacterial-fungal co-occurrence network. Random forest analysis further indicated the importance of microbial community diversity and dominant phyla to environmental change. Partial least squares path modeling revealed that changes in soil stoichiometric imbalance had direct or indirect effects on microbial ecoenzymatic stoichiometry, metabolic limitation, nutrient utilization efficiency, and community composition.

Conclusions

The interrelationships between soil nutrient stoichiometric imbalances and microbial communities under straw mulch and orchard grass management in Z. jujuba orchard can improve soil ecological management practices in arid regions.