Soil Microbial Co-Occurrence Patterns under Controlled-Release Urea and Fulvic Acid Applications

Area of Science:

• Soil Science
• Agricultural Microbiology
• Environmental Science

Background:

• Controlled-release urea (CRU) and fulvic acids (FA) are increasingly used in agriculture.
• Understanding the impact of FA on microbially mediated nitrogen (N) cycling with CRU is crucial for optimizing fertilizer use and soil health.

Purpose of the Study:

• To investigate the effects of CRU with and without FA on soil microbial N-cycling processes and soil fertility.
• To elucidate the mechanisms by which CRU+FA influences soil nutrient supply and microbial community structure.

Main Methods:

• Laboratory experiment (0-60 days) and consecutive pot experiment (2016-2018).
• Assessment of soil nutrient content, including leached nitrate nitrogen (NO₃⁻-N).
• Analysis of soil microbial community structure and function using molecular techniques and network analysis.

Main Results:

• CRU+FA treatment increased wheat yield by 22.1% compared to CRU alone.
• CRU+FA significantly reduced leached NO₃⁻-N by 12.7-84.2% in the top 20 cm of soil.
• CRU+FA altered microbial community composition, increasing beneficial N-fixing bacteria (e.g., Ensifer, Blastococcus) and decreasing bacteria involved in nitrification and denitrification.

Conclusions:

• The synergistic effects of CRU and FA enhance soil microbial communities involved in the nitrogen cycle.
• CRU+FA application effectively reduces nutrient loss, improves soil nutrient supply, and increases crop yield.
• This combined application offers a promising strategy for sustainable agriculture and improved soil fertility.