Effects of Rotted Rice Husk on Physicochemical Properties and Microbial Community of Greenhouse Soil

Purpose To investigate the effects of rotted rice husks on soil physicochemical properties and microbial communities.

Methods Five application amounts of rotted rice husks (CK: 0 t/hm²; C₅: 5 t/hm²; C₁₀: 10 t/hm²; C₁₅: 15 t/hm²; C₂₀: 20 t/hm²) were added to the alkalized and compacted soil in the facility greenhouse. The soil physicochemical properties, plant agronomic traits, and microbial communities were analyzed by variance analysis, Spearman correlation analysis, and redundancy analysis.

Results Compared with the control (CK), the application of rotted rice husks in the 0-30 cm soil layer could increase the field capacity, capillary porosity, organic matter content and the proportion of small aggregates in the soil, as well as the plant height and stem diameter of crops, while reducing soil bulk density, pH value and the proportion of micro aggregates. In addition, the addition of rotted rice husks obviously increased the relative abundance of soil microorganisms such as Proteobacteria, Bacteroidota and Basidiomycota, but had no significant effect on microbial diversity. Spearman heatmap analysis and redundancy analysis indicated that the application of rotted rice husks could directly affect soil environmental factors, among which, pH, salinity, organic matter, bulk density and field capacity were the main environmental factors affecting the bacterial community structure, while salinity and field capacity were the main factors affecting the fungal community structure.

Conclusion This study can provide theoretical basis and reference for the improvement of alkalized greenhouse soil, and technical support for the effective utilization of agricultural wastes such as rice husks.