湘南丘陵地区油后直播棉花栽培技术OA

Based on the characteristics of the hilly areas in Southern Hunan Province,the high yield cultivation techniques for direct-seeded cotton after rapeseed harvest from the aspects of variety selection,sowing,and water and fertilizer management were summarized.In terms of variety selection,early to mid-maturing,dense-planting-tolerant,and stress-resistant cotton varieties such as Xiang FZ031 and Xiang K28 were chosen.Regarding sowing,pre-sowing weeding was carried out,and after full-rate return of rapeseed straw to the field,fine land preparation was conducted.Early sowing was carried out within the optimal period from mid-May to May 25th.Depending on soil fertility and variety,the planting density was controlled at 3 000-4 000 plants/667 m2.After sowing,timely closed weeding was performed,followed by seedling checking and gap filling.For fertilizer and water management,the principles of controlling nitrogen,stabilizing phosphorus,and increasing potassium,with light application at the early stage,heavy application at the middle stage,and supplementary application at the late stage,were followed.The core of water management was waterlogging prevention at the early stage and drought resistance at the late stage.For disease and pest control,agricultural measures were adopted as the foundation,combined with the installation of trap plants and insecticidal lamps,supplemented scientifically by chemical agents.During the seedling stage,control damping-off diseases and thrips;during the bud stage,prevent wilt disease and blind stink bug infestation;during the flowering and boll stage,manage red bollworms and cotton leaf mites.For chemical regulation and topping,mepiquat chloride was applied in stages at the seedling,budding,early flowering,and post-topping periods to control plant height at approximately 1 m.Topping was completed before August 15th,following the principle of"topping when branches reach the standard,regardless of time;topping when time arrives,regardless of branches".For harvesting,when the natural opening rate reaches 40%,defoliant ripening agent should be sprayed to accelerate the maturation and opening process of cotton bolls.Mechanical harvesting was completed before October 15th to ensure sufficient time for the subsequent rapeseed crop,while guaranteeing dry cotton lint and good quality.This study provides a reference for efficient cotton production in the region.