Subsoiling-Induced Shifts in Nitrogen Dynamics and Microbial Community Structure in Semi-Arid Rainfed Maize...

Area of Science:

• Agricultural Science
• Soil Science
• Microbiology

Background:

• Agricultural intensification leads to soil compaction and nitrogen inefficiency, threatening crop production.
• Sub-soiling, a tillage method, can improve soil physical properties and nitrogen cycling.
• Optimizing sub-soiling depth is crucial for sustainable agriculture in semi-arid regions.

Purpose of the Study:

• To investigate the impact of different sub-soiling depths on soil microbial communities and nitrogen transformations.
• To understand how sub-soiling affects soil physical properties and nutrient retention in maize systems.
• To identify the optimal sub-soiling depth for enhancing nitrogen use efficiency and crop yield.

Main Methods:

• Field experiment with three sub-soiling depths (0, 20, 40 cm) in a semi-arid maize system.
• Analysis of soil physical properties (porosity) and nitrogen content (nitrate-N, ammonium-N).
• High-throughput 16S rDNA sequencing for microbial community analysis and functional gene analysis (nosZ).

Main Results:

• Sub-soiling at 40 cm (D2) significantly increased nitrate-N and ammonium-N retention, linked to improved porosity and microbial activity.
• D2 altered microbial communities, increasing Proteobacteria and ammonia-oxidizing archaea while decreasing denitrifiers.
• Microbial interaction networks showed increased complexity under sub-soiling, influenced by aeration and carbon redistribution.

Conclusions:

• Sub-soiling depth is a key factor in modulating soil microbiome assembly and nitrogen retention.
• A 40 cm sub-soiling depth promotes a shift from denitrification to nitrification-mineralization, enhancing nitrogen availability.
• Optimized sub-soiling practices provide a mechanistic basis for improving maize yield and sustainability in semi-arid agroecosystems.