Abstract:

【Objective】A field experiment was carried out to study the effects of N application on yield of spring wheat, fertilizer N recovery and N balance in spring wheat (Ning Chun 4) in high productivity field in Yellow river irrigation area of Ningxia province. 【Method】The experiment design was the randomized complete block with three replications, the area each plot was 32 m2 (8m×4m).Four N rates were employed (0, 120, 240 and 360 kg/hm2). 60% of N fertilizer and total P (P2O5 120 kg/hm2) and K (K2O 90 kg/hm2) was used as basal fertilizer, and 40% of N fertilizer used as top dressing fertilizer during the growth stage of jointing. 【Result】The result showed that N fertilizer expects over application significantly increased grain, protein content and total N uptake of shoot of spring wheat in maturity. The apparent N recovery of all N treatments was ranged from 18.2% to 27.2%, which decreased slightly with increasing of N application rates. The research on N balance showed that in spring wheat season, total N mineralization was 54.6 kg/hm2. The apparent N losses were 37.5, 102.4 and 187.7 N kg/hm2, or 31.2%, 42.6% and 52.1% of applied N in the treatment of N120, N240 and N360. 【Conclusion】The results of residual soil Nmin and apparent N losses showed that the amount of fertilizer N should be controlled within 120～240 kg/hm2 in middle or high fertile soil considering spring wheat yield, high efficient N use and low N losses.