密度和施氮量互作对全膜双垄沟播玉米产量、氮素和水分利用效率的影响

【目的】本研究旨在探讨旱地全膜双垄沟播玉米产量、氮素和水分利用效率对种植密度和施氮量的响应。【方法】选择甘肃省定西市安定区农业部西北黄土高原地区作物栽培科学观测试验站，作物一年一熟，无灌溉，为典型旱地雨养农业区。2016和2017年，以耐密品种‘先玉335’为试验材料进行了大田试验。设置了3个种植密度 (45000、60000、75000 株/hm2) 和4个施氮量 (N0、138、207、276 kg/hm2，分别表示为N0、N138、N207、N276)。收获期调查分析了玉米籽粒产量、氮素和水分利用效率。【结果】种植密度和施氮量均显著影响玉米籽粒产量、氮素和水分利用效率，且两者互作效应显著。在中密度 (60000 株/hm2) 条件下，玉米籽粒产量较低密度 (45000 株/hm2) 和高密度 (75000 株/hm2) 分别增加了24.86%～26.91%和25.83%～34.34%，氮素利用效率分别提高了41.07%和41.63%，水分利用效率分别提高了9.87%～18.09%和17.81%～32.89%，且差异性均达到了显著水平。施氮量在138～276 kg/hm2范围内的玉米籽粒产量和水分利用效率均显著高于无氮处理，各施氮处理表现为N276 > N207 > N138 > N0，且N276、N207与N138、N0处理间差异显著。随着施氮量的增加，氮肥偏生产力呈下降趋势，氮肥利用率呈先升高后降低趋势，以施氮量为207 kg/hm2时玉米氮肥吸收利用率最大，较N276和N138处理分别提高了4.23%和27.37%。玉米产量提高引起了氮肥吸收利用率和水分利用效率的协同提高。【结论】综合考虑产量、氮素利用率和水分利用效率等因素，在本试验条件下，旱地全膜双垄沟播玉米栽培以种植密度为60000 株/hm2，施氮量为207 kg/hm2较为适宜。

Effect of plant density and nitrogen application rate on yield,nitrogen and water use efficiencies of spring maize under whole plastic-film mulching and double-furrow sowing

【Objectives】The suitable plant density and nitrogen application rate were studied for efficient spring maize production and nitrogen and water use efficiencies under the technique of whole plastic-film mulching and double-furrow sowing in rain-fed cropland area.【Methods】The field experiment was conducted in the Northwest Loess Plateau Observation Station of Crop Production of Ministry of Agriculture, Dingxi City, Gansu Province, where is typical rain-fed area with one crop a year. The field experiment was carried out in 2016 and 2017 with a density-tolerant cultivar of maize ‘Xianyu335’ as tested material. Three plant densities of 45000, 60000 and 75000 plant/hm2, and four nitrogen application rates of 0, 138, 207 and 276 kg/hm2 were designed (expressed as N0, N138, N207, N276, respectively). The yield, nitrogen and water use efficiencies of spring maize were investigated.【Results】Both the plant density and nitrogen application rate had significant effects on yield, nitrogen and water use efficiencies of spring maize, and the interaction between them was significant as well．Compared to low plant density (45000 plant/hm2) and high plant density (75000 plant/hm2), the grain yields under plant density of 60000 plant/hm2 were significantly increased by 24.86%?26.91% and 25.83%?34.34%, respectively. The nitrogen use efficiencies were significantly increased by 41.07% and 41.63%, and the water use efficiencies were significantly increased by 9.87%?18.09% and 17.81%?32.89%. When the nitrogen application rate was increased from 138 to 276 kg/hm2, the grain yields and water use efficiencies of maize were significantly increased and all were significantly higher than that of the N0 treatment. Both the grain yields and water use efficiencies were in order of N276 > N207 > N138 > N0, and the maize yields and water use efficiencies in the N276 and N207 treatments were significantly higher than in the N138 and N0 treatments, and there was no significant change between the N276 and N207 treatments. The nitrogen use efficiency of maize was firstly increased with nitrogen application rate and decreased when continue to increase amount of nitrogen fertilizer. With the increasing of nitrogen application rate, the nitrogen partial factor productivity was decreased, and the nitrogen use efficiency reached the highest in N207, which was 4.23% and 27.37% higher than those in N276 and N138 treatments. The increase of maize yield caused synergistic improvement of nitrogen utilization rate and water use efficiency.【Conclusions】Under this experimental field condition, comprehensively considering the nitrogen fertilizer and water use efficiency, the appropriate plant density is 60000 plant/hm2 and the nitrogen application rate is 207 kg/hm2.