Agronomic evaluation of control-release urea (CRU) in maize and rice in Heilongjiang

The objective of this study was to explore the right rate of CRU and the right blending ratio of CRU to regular urea

IPNI-2013-CHN-HL

25 Mar 2015

2014 Annual Interpretive Summary


The purpose of this project was to study the rate of control release urea (CRU) and blending of CRU with regular urea (RU) on yield and N use efficiency in maize and rice in Heilongjiang.

Compared with RU application alone, various combinations of CRU (40 to 75%) plus RU (25 to 60%) produced 7 to 18% more grain yield, and 3.8 to 11.1 kg/kg higher agronomic efficiency (AE). Grain yield increased as the proportion of CRU rose from 40 to 75%, and the highest yielding fertilizer combination was 75% CRU with 25% RU. When RU was added at only 80% of the N recommendation, yield decreased compared with the full N recommendation. However, grain fertilized with CRU at a rate of only 80% of the full recommendation had no loss of yield. This indicates that CRU can maintain grain yield with 20% less N when compared to RU.

Very similar results were obtained in rice. Various combinations of CRU (40 to 75%) plus RU (25 to 60%) produced 4 to 27% more grain yield, and 1.7 to 10.6 kg/kg higher AE than RU alone. The grain yield increased as the ratio of CRU rose from 40 to 75%, with the best yields achieved at a combination of 75% CRU plus 25% RU.

Results from both maize and rice indicate that the right blend of CRU with RU can improve grain yield and N use efficiency, and that CRU can have comparable yield with 20% less N as compared to RU application.