化学调控和氮肥对高密度下春玉米光热水利用效率和产量的影响

【目的】探讨高密度下化学调控和氮肥对玉米光合特性、籽粒灌浆及光热水利用效率的影响,为玉米密植抗逆高产高效栽培提供依据。【方法】于2017—2018年哈尔滨区域玉米生长季,在大田高密度种植下（90 000株/hm²）,设置3个不同氮肥水平N100（100 kg·hm^-2）、N200（200 kg·hm^-2）和N300（300 kg·hm^-2）,7叶期喷施化控剂（玉黄金,30%胺鲜酯·乙烯利水剂）,研究化控和氮肥对高密度种植下玉米生长发育和光热水利用效率的影响。【结果】随氮肥施用量的增加,玉米叶片净光合速率（P_n）、最大光化学效率（F_v/F_m）、籽粒内源激素含量、灌浆速率、光热水利用效率（RUE、HUE和WUE）及产量均呈先升高后降低趋势,在施氮量200 kg·hm^-2下达到最大。与单施氮肥处理相比,化控和氮肥共同作用显著提高了叶片P_n和F_v/F_m,提高了籽粒内源激素含量和灌浆速率,RUE、HUE和WUE显著提高,使产量得到进一步增加。相关分析表明,灌浆速率与籽粒内源激素生长素（IAA）、细胞分裂素（CTK）、赤霉素（GA）和脱落酸（ABA）含量极显著正相关,产量与RUE、HUE和WUE显著正相关。【结论】高种植密度下,200 kg·hm^-2施氮量和化控显著改善玉米的光合特性,促进了籽粒灌浆进程,提高了光热水利用效率,显著提高了产量。

Effects of Chemical Regulation and Nitrogen Fertilizer on Radiation,Heat and Water Utilization Efficiency and Yield of Spring Maize Under Dense Planting Condition

【Objective】 This experiment was conducted to study the effects of chemical regulation and nitrogen fertilizer on photosynthesis, grain filling characteristics and radiation, heat and water utilization efficiency of maize under high planting density, so as to provide a theoretical basis for stress resistance, high yield and high efficiency of maize under high planting density. 【Method】 The experiment was performed with three nitrogen rates, N100 (100 kg·hm^-2), N200 (200 kg·hm^-2) and N300 (300 kg·hm^-2) under high planting density (90 000 plants/hm²) during the maize growth season from 2017 to 2018. Chemical control (Yuhuangjin, 30% amine fresh ester·ethyl hydroxide) was sprayed at the seventh leaf stage. The effects of chemical control and nitrogen application on maize growth and development and radiation (RUE), heat utilization efficiency (HUE) and water utilization efficiency (WUE) under high density were studied. 【Result】 With the nitrogen application increasing, the 8 indexes, including net photosynthetic rate (P_n), max photochemical efficiency (F_v/F_m) of maize leaves, the content of grain endogenous hormones, grain filling rate, radiation utilization efficiency, heat utilization efficiency, water utilization efficiency and yield, first increased and then decreased, and all reached the maximum at 200 kg·hm^-2 nitrogen rate. Compared with the single application of nitrogen fertilizer, the combination of chemical control and nitrogen fertilizer significantly increased P_n and F_v/F_m in leaves, endogenous hormone content in grains, grain filling rate, RUE, HUE, and WUE, which further increased grain yield. The correlation analysis showed that the grain filling rate was positively correlated with indole-3-acetic acid (IAA), cytokinin (CTK), gibberellin (GA) and abscisic acid (ABA), while the yield was positively correlated with RUE, HUE and WUE.【Conclusion】 Under high planting density, 200 kg·hm^-2 nitrogen application and chemical control significantly improved the photosynthetic characteristics, promoted the grain filling process, improved radiation, heat and water utilization efficiency, and significantly increased the yield.