滴灌水肥一体化下施氮量与频次对夏玉米光合特性、保护酶活性及产量的影响

Effects of Nitrogen Application Rate and Frequency on Photosynthetic Characteristics,Protective Enzyme Activities and Yield of Summer Maize under Drip Irrigation

为探究滴灌水肥一体化条件下施氮量和施氮时期组合对夏玉米穗位叶叶片光合特性、衰老特性、籽粒灌浆特性及产量的影响,选用夏玉米品种郑单958为试材,设置了210 kg/hm^(2)条件下,拔节期、大喇叭口期和开花期追肥处理(A1),拔节期、大喇叭口期追肥处理(A2),拔节期、开花期追肥处理(A3);180 kg/hm^(2)条件下,拔节期、大喇叭口期和开花期追肥处理(A4),拔节期、大喇叭口期追肥处理(A5),拔节期、开花期追肥处理(A6);并设置传统畦灌为对照(CK),总施氮量为240 kg/hm^(2),CK1在拔节期一次性追施氮肥,CK2在拔节期和大喇叭口期分别追施氮肥,共计8个处理。结果表明,A1、A4处理与CK1相比,在夏玉米生育后期维持了LAI、SPAD值的同时,亦显著提高了抗氧化酶(SOD、POD、CAT)的活性,且有效抑制了过氧化物MDA的含量,从而延缓了其叶片的衰老进程,保护了叶片细胞功能结构。因此,该处理下的夏玉米在其生育后期维持了高效的光合特性,促进了籽粒灌浆速率,进而增加了穗粒数和千粒质量,使得玉米产量得以显著提高。A1和A4处理产量差异不显著,但A4相比A1施氮量降低14.3%,减少了氮肥的投入,节约了投入成本,为试验的推荐处理。

In order to explore the effects of the combination of nitrogen application rate and nitrogen application period on the photosynthetic characteristics,senescence characteristics,grain filling characteristics and yield of leaves at ear position of summer maize under the integrated condition of drip irrigation,summer maize variety Zhengdan 958 was selected as the test material.Under the condition of 210 kg/ha,top dressing treatment at jointing stage,belling stage and flowering stage(A1),top dressing treatment at jointing stage and belling stage(A2),top dressing treatment at jointing stage and flowering stage(A3);under the condition of 180 kg/ha,top dressing treatment at jointing stage,belling stage and flowering stage(A4),top dressing treatment at jointing stage and belling stage(A5),top dressing treatment at jointing stage and flowering stage(A6);the traditional border irrigation was set as the control CK,and the total nitrogen application was 240 kg/ha,CK1 was topcoated with nitrogen fertilizer at jointing stage at one time,and CK2 was topcoated with nitrogen fertilizer at jointing stage and belling stage respectively,with a total of 8 treatments.The results showed that compared with CK1,A1 and A4 treatments not only maintained LAI and SPAD values in the late growth stage of summer maize,but also significantly increased the activity of antioxidant enzymes(SOD,POD and CAT),and effectively inhibited the content of peroxide MDA,so as to delay the aging process of its leaves and protect the functional structure of leaf cells.Therefore,the summer maize under this treatment maintained efficient photosynthetic characteristics in its later growth stage,promoted the grain filling rate,and then increased the number of grains per ear and 1000 grains weight,so that the maize yield was significantly improved.The yield difference between A1 and A4 treatments was not significant difference,but the nitrogen application rate of A4 was reduced by 14.3%compared with A1,which reduced the input of nitrogen fertilizer and saved the input cost.It was the recommended treatment in this experiment.