Effects of combined application of slow-release nitrogen fertilizer and urea on nitrogen uptake, utilization and yield of maize under two tillage methods

Corn is one of the important food crops in the world, in order to pursue high yield and high efficiency, the input of chemical fertilizer has been continuously increased, which has led to the decline of fertilizer utilization rate, environmental pollution and other problems, and the slow-release fertilizer has attracted much attention because of its nutrient characteristics, but the high price limits its wide application;On the other hand, long-term rotary tillage will lead to the shallowness of the soil tillage layer and the increase of the bulk density of the deep soil, and subsoiling can effectively break the bottom layer of the soil plough and reduce the bulk density of the soil. Therefore, in this study, Qiangsheng 388 was used as the experimental material, and under rotary tillage (R) and rotary tillage + subsoiling (R+S), CK (no fertilization), U (100% nitrogen fertilizer), S (100% slow-release fertilizer) and different UNS ratios (nitrogen fertilizer and slow-release fertilizer) were used for two years in field experiments to explore the effects of slow-release fertilizer and urea on soil water use efficiency, dry matter accumulation, nitrogen uptake and utilization, operation and yield under the two tillage methods. The results showed that compared with CK, U and S, UNS significantly improved water use efficiency, dry matter accumulation, nitrogen uptake, operation and yield. Among them, UNS2 (the ratio of S and U was 7:3) was the best. In 2022, R UNS2 had the best water use efficiency, dry matter accumulation, nitrogen uptake, operation and yield, which were 5.05%, 2.0%, 3.88%, 6.18% and 4.06% higher than those of R + S UNS2, respectively. In 2023, R + S UNS2 had the best treatment, which was 1.98%, 2.52%, 1.85%, 2.60% and 2.20% higher than that of R UNS2, respectively. R + S tillage can effectively improve maize yield, nitrogen uptake and utilization, water use and dry matter accumulation; Nitrogen application treatment UNS2 treatment was the best. In summary, R + S UNS2 is the best coordination strategy.