地下水埋深和施氮量对夏玉米灌浆特性及水氮利用效率的影响

Effects of groundwater depth and nitrogen application rate on grain filling characteristics and water and nitrogen use efficiency of summer maize

为揭示不同地下水埋深和施氮量对夏玉米灌浆过程和水氮利用效率影响,以夏玉米‘怀玉208’为试验材料,基于大型地中渗透仪,采用随机区组的试验方法,研究了地下水埋深(GW,2、3、4 m)和施氮量(N,300、240 kg·hm^(-2))对夏玉米籽粒灌浆过程和水氮利用效率的影响。结果表明:(1)各处理玉米百粒质量随花后天数呈“S”型曲线变化趋势。施氮量和地下水埋深均极显著影响玉米收获时的百粒质量,但二者交互作用不显著;地下水埋深相同时,施氮量为300 kg·hm^(-2)玉米的百粒质量均显著高于施氮量为240 kg·hm^(-2)玉米的百粒质量。(2)灌浆期各处理玉米籽粒灌浆速率均呈“抛物线”型变化趋势。Logistic方程能很好地拟合各处理玉米籽粒灌浆过程。收获期玉米籽粒百粒质量与最大灌浆速率时的籽粒质量、玉米平均灌浆速率极显著正相关。地下水埋深和施氮量对玉米灌浆参数的影响具有显著交互作用。(3)施氮量和地下水埋深极显著影响玉米产量,其中N300GW4处理玉米产量最高,N240GW3处理的产量最低。玉米产量与穗长、穗粗、百粒质量、穗行数、行粒数、穗粒数极显著正相关。(4)施氮量、地下水埋深及二者交互作用均极显著影响玉米氮肥偏生产力;施氮量极显著影响玉米水分利用效率,地下水埋深及二者交互作用对玉米水分利用效率影响不显著。N240GW4处理玉米氮肥利用效率及水分利用效率均最高。综上可知,地下水埋深和施氮量对玉米水氮利用效率及灌浆过程交互作用显著,N240GW4处理是本研究推荐的农业绿色高产生产模式。

The purpose of this experiment was to investigate the effects of groundwater depth and nitrogen application rate on grain-filling process and water and nitrogen use efficiency of summer maize.‘Huaiyu 208’was used as the experimental material.A two-factor experiment of groundwater depth and nitrogen application rate with randomized block test method was adopted based on a large-scale lysimeter.The experiment was conducted with groundwater depth(GW)of 2 m,3 m and 4 m and nitrogen application rate(N)of 300 kg·hm^(-2) and 240 kg·hm^(-2).Results showed that:(1)The 100-grain weight of summer maize under all treatments showed an S-shaped curve with the days after flowering.Both nitrogen application rate and groundwater depth significantly affected the 100-grain weight of summer maize,but the interaction between them was not significant.Under the same groundwater depth,the 100-grain weight of summer maize with nitrogen application rate of 300 kg·hm^(-2) was significantly higher than that with nitrogen application rate of 240 kg·hm^(-2).(2)The grain filling rate of summer maize under different treatments showed a“parabolic”trend.Logistic equation fitted the grain filling process of each treatment well.The 100-grain weight of summer maize at harvest stage was significantly positively correlated with the grain weight at the maximum grain filling rate,and the average grain filling rate of summer maize.Groundwater depth and nitrogen application rate had a significant interaction effects on summer maize filling parameters.(3)Groundwater depth and nitrogen application rate had a significant interaction on summer maize yield,and N300GW4 treatment had the highest yield,while N240GW3 treatment had the lowest yield.The yield of summer maize was positively correlated with ear length,ear diameter,100-grain weight,ear rows,grain numbers per row and grain numbers per spike.(4)Nitrogen application rate,groundwater depth and their interaction significantly affected the partial nitrogen productivity of summer maize.Nitrogen application rate significantly affected summer maize WUE,but groundwater depth and their interaction had no significant effect.Both the nitrogen use efficiency and WUE of summer maize under N240GW4 treatment were the highest.In conclusion,groundwater depth and nitrogen application rate had significant interaction on water and nitrogen use efficiency and grain filling process of summer maize.The N240GW4 treatment is the recommended agricultural green and high-yield production mode.