Effects of a one-time application of controlled-release nitrogen fertilizer on quality and yield of rice

Limited information is available on the influence of a one-time application of controlled-release nitrogen fertilizer (CRNF) in improving both yield and quality of rice. In this study, two rice cultivars, Jia58 (158) and Jia67(J67), were used to study the effects of six combinations of short-acting (40-60-day release periods) and a long-acting (80-120-day release periods) CRNF. The six combinations were as follows: A1, 40-day + 80-day CRNFs; A2, 40-day + 100-day CRNFs; A3, 40-day + 120-day CRNFs; B1, 60-day + 80-day CRNFs; B2, 60-day + 100-day CRNFs; and B3, 60-day + 120-day CRNFs. Each combination of CRNFs was mixed with common urea (CU) to apply as basal fertilizer to rice crops to assess grain yield and quality. In addition, CU without CRNFs was applied as the control (CK). The results showed that the release of nitrogen from A2 and B2 were most matched with nitrogen accumulation by rice resulting in a higher yield (132 treatment) or the same yield (A2 treatment) as CK. The average yield of 2 years of J58 in B2 was 7.38% higher than that of the CK. Similarly, the average yield of 167 in B2 was 6.46% higher than CK for both years. Milling quality, appearance quality, milled rice starch content, and taste value of rice in CRNF treatments were significantly higher than CK. In contrast, protein, gliadin, and glutenin contents and hardness of rice in the CRNF treatments were lower than CK. The higher protein content of rice in the CK resulted in higher gelatinization temperature and harder rice, which may explain why the eating and cooking qualities of rice in the CK were lower than those of rice in the CRNF treatment. These results demonstrate that the A2 and B2 treatments can produce improvements in both yield and quality of rice.