Nitrogen accumulation and utilization characteristics of wheat cultivar Yangfumai 4 at different population yield levels

Objectives Nitrogen accumulation and nitrogen use efficiency of wheat Yangfumai 4 at different yield levels was studied for acquiring more than 7500 kg/hm² yield level included.

Methods From 2008-2010, field experiments were conducted using three levels of yield population，high yield level population (≥ 7500 kg/hm²), medium to high yield level population (7000 -7500 kg/hm²) and low to medium yield level population (≤ 7000 kg/hm²). The split-plot design three application rates of nitrogen (187.5, 225 and 262.5 kg/hm²), and three nitrogen allocation ratios of basis: tillering: elongation: booting (7:1:2:0, 5:1:2:2 and 3:1:3:3) in the rice-wheat rotation system. The nitrogen accumulation, nitrogen translocation after anthesis different growth stages and nitrogen fertilizer use efficiencies were analyzed.

Results Compared to the midium high and midium low populations, the N accumulation amounts (NAA) of the high yield population from sprouting to wintering, from wintering to elongation and from elongation to anthesis were suitable, and the NAA from anthesis to maturity was higher; The N uptake to produce 100 kg grain, N harvest index, agronomic efficiency, recovery efficiency and partial factor productivity of the high yield population were 2.87–3.01 kg, 0.71–0.80, 17.69–17.96 kg/kg, 44%–47% and 34.70–36.07 kg/kg, respectively.

Conclusions For the cultivar Yangfumai 4 under planting density of 150 × 10⁴/hm², nitrogen amount of 225 kg/hm², and nitrogen allocation ratios of 5:1:2:2 and 3:1:3:3 will achieve yields higher than 7500 kg/hm². The NAA after anthesis, nitrogen fertilizer use efficiency and nitrogen harvest index will be the highest and the nitrogen agronomic efficiency and nitrogen utilization efficiency will be high.