Objectives  Optimum and sustainable nutrient supply is an important measure to improve crop yield and quality. The effects of different controlled release fertilizers on the yield and quality of sweet corn were studied for selecting suitable controlled-release fertilizer for high value crop production.

Methods Field trials were conducted in Qinhuangdao, Shijiazhuang and Baoding in Hebei Province in 2020. ‘Wantian 2000’ cultivar of sweet corn was used as the test material. Five treatments including controlled-release compound fertilizer (T1), controlled-release net compound fertilizer (T2), polyaspartic acid and slow-release compound fertilizer (T3), conventional urea fertilizer (T4) and no N fertilizer (CK) were set up. The plant dry weight and total N content were measured at the key growth stages, the fresh ear yield and grain nutritional quality were measured after harvest.

Results Compared with T4 treatment, three kinds of controlled release fertilizers significantly increased the ear length and ear diameter of sweet corn, increased the fresh weight of single ear and the number of effective ears per unit area, and ultimately improved the fresh ear yield. All the controlled release fertilizers in the three sites significantly improved the fresh ear yield by 15.4%, N use efficiency by 57.2%, N partial productivity by 15.4% and nitrogen agronomic efficiency of maize by 67.0%, compared with common urea, and the best effect was obtained in T3 treatment, with increase of the above items by 8.33%, 55.6%, 7.21% and 22.6% respectively, compared with T1 and T2. The taste score of T3-grown sweet corn was 6.41% higher than that of T4 treatment, and higher than that of T1 and T2 treatment, with marked improvement in odor, peel softness, sweetness and other indicators. Compared with T4 treatment, T1, T2 and T3 treatment improved the nutritional quality of sweet corn, and T3 treatment had the highest content of soluble sugar, vitamin C, and vitamin E. Correlation analysis showed that there was no significant correlation between grain N and P concentration and other indexes, grain K concentration was significantly and positively correlated with grain soluble sugar, vitamin C, vitamin E and taste score; and grain soluble sugar was significantly positively correlated with vitamin C, vitamin E, and taste score.

Conclusions Polyaspartic acid controlled-release compound fertilizer had the best yield-increasing effect on fresh ear yield of sweet corn, with the highest nitrogen use efficiency, partial nitrogen productivity and nitrogen agronomic efficiency, the sweet corn exhibited the highest taste quality and nutritional quality, and its quality evaluation attained Grade 1. Therefore, the application of polyaspartic acid controlled-release compound fertilizer can improve the fresh ear yield and quality of sweet corn.