LAUSR

The effects of polyaspartic acid and different controlled-release fertilizers with urea on dry matter accumulation and distribution, nitrogen absorption and accumulation, and the activities of enzymes involved nitrogen metabolism and yield of corn were studied by using xianyu (XY688), a maize nitrogen efficient cultivar, and Jifeng NO.2 (JF2), a maize nitrogen-inefficient cultivar, as experimental materials and through random blocks experimental design in 2019. For XY688, polyaspartic acid chelated nitrogen fertilizer (PASPN) had the highest yield, which was 21.34% higher than N0 treatment. For JF2, it also had the highest yield under PASPN combined urea treatment, which was 23.44% higher than N0 (no nitrogen fertilizer), and JF2 had a 9.7% lower yield under XY688 treatment. For XY688, PASPN treatment had the largest nitrogen uptake in grain, up to 3.14 kg/hm2, and PASPN treatment increased 17.4% compared with N0. For JF2, grain nitrogen uptake was also the highest under PASPN treatment, which was significantly different from other treatments. Nitrogen uptake was 3.16 kg/hm2, which increased 37.4% compared with N0. Compared with JF2, XY688 showed higher nitrogen uptake efficiency, nitrogen utilization efficiency, and partial nitrogen productivity. For XY688, the highest nitrogen absorption efficiency was SU3 (slow-release urea and ordinary urea) treatment (0.36 kg/kg). The partial nitrogen productivity and harvest index of PASPN treatment were the highest and significantly different from other treatments. The partial nitrogen productivity of PASPN treatment was 57.02 kg/kg. These results can provide help for the further researches of the rational utilization and absorption of nitrogen fertilizer.