Effects of nitrogen application on nitrogen absorption，utilization in super-high-yielding wheat in Huaibei region

Field experiment was conducted to investigate the effects of different nitrogen (N) ratio between base fertilizer and dressing on plant nutrient content, absorption and utilization efficiency of fertilizer from 2006 to 2008 using strong gluten wheat Yannong 19 and medium-gluten wheat Wanmai 50 as the experimental materials. The results indicated，under the condition of high yield above 9000 kg/ha, the uptake of N, P and K were 259.25-315.00, 82.86-89.70 and 224.67-305.28 kg/ha, respectively. Meanwhile, the amount of N, P and K that 100 kg grain need were 2.93-3.19, 0.87-1.04 and 2.47-3.27 kg, respectively. The results of nutrient uptake and utilization showed that the N utilization efficiency in two wheat cultivars was significantly increased with the rate of jointing fertilization increasing. The N utilization efficiency in Yannong 19 was higher than that in Wanmai 50 when the basal∶topdressing ratio of N fertilizer ranged from 6∶4 to 4∶6 indicating that suitable N application ratio could improve N utilization efficiency. The relationship between the N utilization efficiency, N harvest index and yield were significantly positive correlated. With the rate of jointing fertilization increasing, the N use efficiency was decreased, which was showed that the increase amplitude of grain yield was declined with the N uptake increasing. When the basal∶topdressing rate of N fertilization ranged from 5∶5 to 4∶6, the super high yield cultivation could be reached in Huaibei area.