Work

Chitosan oligosaccharide co-applied with urease and nitrification inhibitors improves fertilizer nitrogen allocation in maize: Evidence from a 15N microplot study

Year: 2026

Type: article

Abstract: Urease inhibitors (UIs) and nitrification inhibitors (NIs) can slow fertilizer nitrogen (N) transformation and reduce N losses, but conserved fertilizer N is not always recovered by crops. Chitosan oligosaccharide (COS) may provide an approach for improving fertilizer-derived N uptake by regulating the soil N supply and crop growth. We conducted a field microplot experiment with 15 N-labeled urea in a maize cropping system to quantify the fertilizer-derived mineral N supply intensity and measured fertilizer N allocation under inhibitors, COS and their co-application. The measured fertilizer N fates included crop uptake, retention in the 0–40 cm soil layer, NH 3 -N volatilization and N 2 O-N emissions. The inhibitors increased the fertilizer-derived mineral N supply and reduced fertilizer-derived NH 3 -N and N 2 O-N losses, but did not significantly increase the fertilizer-derived N uptake by maize or fertilizer-derived N retention in the soil ( P >0.05). COS increased fertilizer and soil-derived mineral N supply, fertilizer-derived N uptake by maize, and soil-derived N 2 O-N emissions and reduced fertilizer-derived N retention in the surface soil. Co-application of COS and inhibitors enhanced the fertilizer-derived mineral N supply and increased fertilizer-derived N uptake by maize and fertilizer-derived N retention in the 0–40 cm soil layer. Correlation analysis showed that fertilizer N transfer to the crop and soil under co-application was significantly associated with improved fertilizer-derived mineral N supply ( P <0.05). Overall, the co-application of COS with UIs and NIs increased fertilizer N recovery from 78.5 to 95.8% by enhancing the fertilizer-derived mineral N supply and its linkage with crop uptake and soil retention.

Source: Journal of Integrative Agriculture

DOI: 10.1016/j.jia.2026.10.022