长江流域麦(油)后直播棉增效缩节胺化学封顶技术研究

【目的】明确长江流域麦(油)后直播棉应用增效缩节胺(25%DPC水剂,简称DPC+)进行化学封顶的可行性。【方法】于2015―2017年在江苏大丰、安徽宿松和湖北武汉开展田间试验,采用随机区组设计,以人工打顶为对照,研究化学封顶时期(人工打顶同期、人工打顶后5 d)和封顶剂DPC+剂量(750,1 125,1 500 m L·hm^-2)对麦(油)后直播棉农艺性状及经济性状的影响。【结果】与人工打顶相比,DPC+化学封顶处理的株高和果枝数增加(最多分别增加21.6 cm和4.8个),中部和上部果枝(尤其是上部果枝)缩短,除个别点次外果节数不受影响。在不同环境条件下,化学封顶处理的产量多与人工打顶相当,低剂量DPC+处理的产量在降水量大的年份有一定程度下降,化学封顶时期对产量影响较小。【结论】应用DPC+对长江流域麦(油)后直播棉进行化学封顶有较好的可行性,未来需进一步优化技术参数、建立稳发稳长的配套栽培技术体系。

Research of chemical topping with fortified mepiquat chloride on direct-seeded cotton after wheat/rape harvest in the Yangtze River valley

Objective]The purpose of this study is to explore the feasibility of chemical topping with fortified mepiquat chloride(DPC+,a type of aqueous formulation containing 25%1,1-dimethyl piperidinium chloride)on direct-seeded cotton after wheat/rape in the Yangtze River valley.Method]Field experiments were conducted in Dafeng,Jiangsu province,Susong,Anhui province and Wuhan,Hubei province during growing seasons of 2015-2017.The randomized block design with three replicates was adopted.There were two chemical topping time(same time with local manual topping,and five days after local manual topping)and three DPC+dosages(750,1125,1500 mL·hm-2),with manual topping as the control.Result]Compared with manual topping,chemical topping with DPC+increased plant height and the number of fruiting branches at most by 21.6 cm and 4.8 per plant,respectively;shortened the length of middle and upper fruiting branches(especially the upper ones),but did not influence the number of fruiting sites except few sites.Chemical topping with DPC+showed similar yield with manual topping under most environmental conditions.However,the treatments with low DPC+dosages reduced yield to some extent during growing seasons with high precipitation(more than 1000 mm).The time of chemical topping had slight effects on cottonyield.Conclusion]For direct-seeded cotton after wheat/rape harvest in the Yangtze River valley,manual topping could be substituted by chemical topping with DPC+.Future work will focus on optimizing the time and dosage of DPC+application,and using agricultural practices for steady growth and development of cotton plants.