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Updated: Oct 28, 2026

Microplot Design and Plant and Soil Sample Preparation for 15Nitrogen Analysis
Published on: May 10, 2020
Nitrogen-transforming bio-organic fertilizer mitigates soil nitrogen leaching and improves nitrogen utilization
Ruiding Li1, Yudi Hou2, Wendong Liu3
1Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan, 610031, PR China; School of Material Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan, 610031, PR China.
Abstract:
Nitrate nitrogen (NO3--N) and dissolved organic nitrogen (DON) are key forms of soil nitrogen leaching. Developing green technologies to mitigate both is crucial for reducing agricultural pollution, yet research on bioregulation methods remains limited. This study developed a nitrogen-transforming bio-organic fertilizer (BF) using a nitrogen-fixing bacterium and a putative nitrifying bacterium. A greenhouse pot experiment was conducted to evaluate the effects of BF on tomato growth, nitrogen leaching, soil microbial communities, and nitrogen-cycling functional genes. The effects of BF, organic fertilizer, urea, and microbial-urea combinations on tomato growth and nitrogen leaching were comprehensively quantitative analyzed. BF obtained the highest integrated score, increasing tomato biomass by 41.71-130.56% and reducing NO3--N and DON leaching by 38.38-88.16% and 7.42-51.14%, respectively. BF enriched beneficial microorganisms associated with nitrogen transformation (e.g., Galbibacter, Salinimicrobium), decreased the abundances of denitrification- and nitrification-associated genes (nirK, amoA, nxrB), and increased the abundances of genes associated with nitrogen fixation, nitrate reduction, and the glutamate cycle (nifH, narG, nrfA, glnA, gltB, gdhA). It also showed gene-abundance changes consistent with increased genetic potential for dissimilatory nitrate reduction (DNRA) and microbial ammonia assimilation. These findings suggest that BF may promote temporary microbial N immobilization in soil, as reflected by increased microbial biomass nitrogen (MBN), and improves crop nitrogen use efficiency. This strategy provides a promising approach for agricultural nitrogen management by simultaneously mitigating nitrogen leaching and improving crop nitrogen utilization.
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