Effect of coated compound fertilizer on yield,nitrogen use efficiency and soil available nitrogen in summer maize

This experiment was conducted to comparatively study the effects of compound fertilizer(CF) and coated compound fertilizer(CCF) on yield,nitrogen use efficiency(NUE),soil available N content(SANC) and apparent budget of soil N(ABSN) in summer maize in north China plain.The main results were as follows: 1) Yield increased with the increment of N application rate,and yield of CCF was higher than that of CF under N 180 kg/ha but it was contrary under N 90 kg/ha.2) Compared to CF treatment,under N 180 kg/ha,NUE of CCF treatment was higher nearly 5.3 percentage point,but it was lower 2.4 percentage point under N 90 kg/ha.3) SANC increased with the increment of N application rate generally.In all stages,SANC of CCF treatment was higher than that of CF in the top soil layer commonly,but it was contrary in middle and lower soil layers.Before 12-leaf stage,SANC of middle and lower soil layers were higher than those of upper layers(020 cm or 040 cm) in CF treatments,but in CCF180 treatments,those of 060 cm soil layers were higher than those of 60120 cm soil layers.4) After summer maize season,soil N deficit(SND) appeared in all stages in zero N treatment,and about 80% of the amount of SND appeared after silking.Two types of fertilizer showed the same trend that amount of SND was decreased with the increment of N application rate,and amount of SND of CCF was lower than that of CF under the same N application rate.These results showed N release speed of CCF was slower and steadier than that of CF, and CCF was beneficial to control the downward movement of soil available N and decrease the amount of potential leaching N.Considering comprehensively yield, NUE and loss of N,CCF N 180 kg/ha is the more ideal choice for summer maize in Wuqiao experimental station.