密度与化学调控对洞庭湖区夏玉米产量形成的影响

为明确洞庭湖区机收夏玉米适宜的化学调控措施,完善机收夏玉米高产栽培技术体系,于2017~2018年以胺鲜·乙烯利为化控剂,在3个密度下(60000、75000、90000株/hm 2)研究了3种化控处理(拔节初期1次化控、拔节初期+大喇叭口期2次化控、不化控对照)对夏玉米湘农玉27号产量形成的影响。结果表明:2017年因天气条件不利,群体长势较弱;2018年天气正常,玉米长势较好。两年玉米叶面积指数均随密度增大而显著增大、随化控次数增加而下降。干物质积累量,2017年随化控次数增加而下降,2018年中低密度下表现为:对照>1次化控>2次化控;高密度下表现为:1次化控>对照>2次化控。两年玉米产量随密度增大而显著提高;2017年玉米产量因化控而降低,2018年玉米产量受化控及化控与密度互作的影响,中低密度下对照>1次化控>2次化控,高密度下1次化控>对照>2次化控,高密度+1次化控处理产量最高。可见化控对洞庭湖区夏玉米产量的影响与群体长势有关,群体长势较差情况下化控导致玉米减产,而群体长势较好情况下拔节初期1次化控结合高密度栽培(90000株/hm 2)可以获得理想产量。

Effect of Density and Chemical Regulation on Yield Formation of Summer Maize in Dongting Lake Area

In order to clarify the appropriate chemical regulation measures for summer maize in Dongting Lake area and improve the high-yield cultivation technique system for machine-harvesting summer maize,the effects of three chemical control treatments(one chemical control at early jointing stage,two chemical control at jointing and big trumpet stage and no chemical control)on the yield formation of summer maize variety Xiangnongyu 27 were studied with amines ethephon as chemical regulator under three densities(60000,75000,90000 plants/hm 2)in 2017-2018.The main results showed that:the weather conditions were unfavorable and the maize population growth vigor was weaker in 2017,while it was contrary in 2018.The leaf area index of maize was significantly increased with the increase of density,and decreased with the increase of chemical control times in the two years.Dry matter accumulation of maize population was decreased with the increase of chemical regulation times in 2017.In 2018,CK>one time chemical regulation>two times chemical regulation in middle and lower density,and one time chemical regulation>CK>two times chemical regulation in high density.The maize yield increased significantly with the increase of density in two years,decreased due to chemical regulation in 2017,and was significantly affected by chemical regulation and the interaction between chemical regulation and density in 2018.The yield was CK>one time chemical regulation>two times chemical regulation under middle and lower density,while which was one time chemical regulation>CK>two times chemical regulation under higher density,and the maximum yield was obtained under high density and one time chemical regulation treatment.These results indicated that the effect of chemical regulation on summer maize in Dongting Lake area was related to crop growth vigor.Chemical regulation could lead to yield reduction in the case of weaker crop growth vigor,while in the case of good population growth,the ideal yield could be obtained by one-time chemical control combined with high-density cultivation(90000 plants/hm 2)at the early jointing stage.