Controlled‐Release Urea Combined With Urea Sustains Yield and Improves Soil Organic Carbon Storage Under Reduced Nitrogen in Rice–Wheat Rotation

Summary

This 3-year field trial in a rice-wheat rotation demonstrates that blending 70% controlled-release urea with 30% conventional urea as basal fertiliser maintains or improves annual yields (8.32–15.37% higher than urea alone) whilst increasing soil organic carbon storage and lability, even under reduced nitrogen input. The treatment significantly elevated labile organic carbon fractions and showed positive correlations between crop yields, soil carbon status, and plant carbon input, suggesting that controlled-release formulations can support resource-efficient production. The findings identify a practical nitrogen-management strategy for sustaining intensive cereal production with lower environmental impact.

Regional applicability

This study was conducted in China's intensive rice-wheat systems, which differ from United Kingdom cereal production in climate, crop type, and farming intensity. However, the principle of blending controlled-release with conventional nitrogen fertilisers to improve soil carbon whilst reducing total nitrogen input is transferable to UK arable systems, particularly for winter cereals and potentially reduced-input organic transitions. UK farmers and agronomists should evaluate the approach's cost-benefit and soil carbon benefits in temperate conditions.

Key measures

Annual yields (tonnes/hectare), soil organic carbon (SOC) content, labile organic carbon fractions (resistant organic carbon, dissolved organic carbon, microbial biomass carbon), plant carbon content, available alkaline hydrolyzable nitrogen, carbon pool management index

Outcomes reported

The study measured annual crop yields, soil organic carbon (SOC) storage, labile organic carbon fractions, and plant carbon content across nine fertiliser treatments in a 3-year rice-wheat rotation. It evaluated whether blending controlled-release urea with conventional urea could maintain productivity whilst improving soil carbon status under both conventional and reduced nitrogen levels.

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