Abstract:In order to study the effects of basal/topdressing nitrogen fertilizer on nitrogen utilization and soil nitrogen apparent loss under water saving cultivation, this study took the cultivar Jimai 22 as the experimental material, and set up five treatments with different basal/topdressing nitrogen (0:10(N1), 3:7(N2), 5:5(N3), 7:3(N4) and 10:0(N5)). And the preconditions of the experiment were that the total nitrogen application rate was 240 kg/hm2, and the relative water content of the 0-40 cm soil layer was maintained up to 70% at the joining and anthesis stages. The results showed that the nitrogen accumulation amounts and nitrogen accumulation in grain of the N3 treatment were significantly higher than those of other treatments, while the nitrogen accumulation in vegetative organs, loss of mineral nitrogen, apparent residual rate of nitrogen fertilizer and apparent loss rate of nitrogen fertilizer were significantly lower than those of other treatments. Compared with N1, N2, N4 and N5 treatments, in the N3 treatments, the nitrogen utilization ratio increased by 33.22%, 12.60%, 11.54% and 98.14%, respectively, and grain nitrogen recovery efficiency increased by 148.65%, 56.48%, 59.63% and 229.29%, respectively, nitrogen agronomic efficiency increased by 96.52%, 34.86%, 37.64% and 204.98%, respectively, apparent budget of nitrogen decreased by 35.04%, 13.82%, 30.36% and 29.30%, respectively. According to the correlation coefficient analysis of different basal/topdressing nitrogen fertilizer, nitrogen accumulation amounts, nitrogen accumulation in grain, nitrogen utilization ratio, grain nitrogen recovery efficiency, nitrogen agronomic were significantly negatively correlated with NO3-N content and total amount of residual mineral nitrogen in the 0-200 cm soil layer of mature period. In conclusion, the treatment with base/topdressing nitrogen fertilizer of 5:5 was the best treatment under the experimental conditions.