Biochar impacts on phosphorus cycling in rice ecosystem

Area of Science:

• Agricultural Science
• Soil Science
• Environmental Science

Background:

• Biochar application is a potential strategy to manage phosphorus (P) in agricultural soils.
• Understanding biochar's impact on the phosphorus cycle in rice ecosystems is crucial for sustainable agriculture.

Purpose of the Study:

• To investigate the effects of maize straw-derived biochar (BM) on phosphorus contamination risk and P supply in rice cultivation.
• To determine how biochar influences soil P fractions, P availability, and microbial communities.

Main Methods:

• Pot experiments were conducted using low-P and high-P soils with varying levels of biochar and P fertilizer.
• Analysis included total phosphorus (TP), phosphorus activation coefficient (PAC), dithionite-citrate-bicarbonate (DCB) extractable P, and bacterial community composition.
• Redundancy analysis (RDA) was used to correlate soil properties and P uptake with microbial community structure.

Main Results:

• Biochar increased total phosphorus (TP) and DCB-extractable P concentrations, particularly near root surfaces, promoting rice growth.
• Biochar altered the phosphorus activation coefficient (PAC), acting as a P source in low-P soils and a sink in high-P soils.
• Biochar enhanced bacterial community richness and diversity, while P fertilization inhibited microbial growth, with soil P fractions and Fe-P significantly correlating with microbial composition.

Conclusions:

• Maize straw-derived biochar influences the phosphorus cycle in rice ecosystems by affecting P availability, soil properties, and microbial communities.
• Biochar can mitigate P contamination risks and enhance P supply, positively impacting rice growth through interactions with iron plaque and microbial processes.
• Biochar's role as a P source or sink is dependent on soil P levels, highlighting its complex interactions within the rice agroecosystem.