Interaction between nitrogen fertilizer and plant density on nutrient absorption, translocation and yield of spring maize under drip irrigation in Northeast China

Objectives An optimum interaction between nitrogen fertilizer and plant density is pertinent to increasing the growth and productivity of maize in Northeast China. This study aimed to investigate the influence of nitrogen application rate, plant density and their interaction on maize yield, nutrient absorption, translocation and utilization efficiency under drip irrigation and plastic mulching condition. The research could provide theoretical basis for high yield and high efficiency cultivation of spring maize in semi-arid region of Northeast China.

Methods The field experiment was conducted using compact ‘Nonghua101’maize cultivar in Qian’an County of western Jilin Province in 2016 and 2017. The nitrogen rates included 0, 140, 210, 280 and 350 kg/hm² (N0, N140, N210, N280 and N350, respectively) and plant densities were 6.0 × 10⁴, 7.5 × 10⁴ and 9.0 × 10⁴ plants/hm² (D1, D2 and D3 respectively). The dynamics of aboveground nutrient accumulation, the characteristics of translocation and distribution, yield and nitrogen utilization efficiency under different treatrments were analyzed.

Results The results showed that maize yield firstly increased and later decreased with increasing N- application rate and plant density. The highest yield was obtained from D2 under nitrogen rate of N210. Under the same plant density, the accumulation of N, P and K increased from seedling stage to flowering stage, however, it increased initially and then declined from filling to mature stage with increasing nitrogen application rate. Accumulated N, P and K of maize were highest in D2 × N210. Compared with no nitrogen treatment, maize N, P and K proportion after flowering stage was increased first, however they later decreased with increasing N-rate, but there was no significant differences in the trends under different plant density. Nutrient translocation amount of maize firstly increased but later decreased with increasing N application rate and plant density, and it was highest in D2 × N210. There was no significant difference in nutrient translocation rate, contribution rate of translocated nutrient and contribution rate of accumulated nutrient after flowering stage under different plant density. The N-utilization efficiency, agronomic efficiency and partial factor productivity decreased with increased rate of applied nitrogen at varied plant density, with the highest values obtained under D2. Correlation analysis showed that the relationship between yield and the amounts of N, P and K accumulated was significant or highly significant (r = 0.6250−0.9224) around flowering stage, whereas the values after flowering stage were higher than those before the flowering stage.

Conclusions The reasonable plant density and nitrogen application level enhance the proportions of nutrient accumulation and distribution after flowering stage of maize, promote nutrient translocation amount and contribution rate of accumulation nutrients after flowering stage synergistically, improve yield and nitrogen utilization efficiency of maize. Considering maize yield, nutrient accumulation and translocation, and nitrogen utilization efficiency under drip irrigation system and mulching condition, the plant density of 75000 plants/hm² and nitrogen application rate of 210 kg/hm² are optimum in semi-arid region of Northeast China.