Key technology optimization and application effect evaluation for dryland rice planting in hilly and mountainous areastaking Lihaozhai Township in Jianshui County of Yunnan Province as an example

To solve contradiction between water scarcity in red loam hilly and mountainous areas of southern Yunnan Province and water consumption associated with traditional rice planting, technology research was carried out to optimize coupling of sowing methods and water and fertilizer management．Dianheyou 615 was used as experimental material, targeting ecological characteristics of Xiaokuangye Village in Lihaozhai Township, Jianshui County, Yunnan Province, such as mountainous terrain and nutrient-poor red loam．Using a randomized block design, three sowing methods and three water and fertilizer management schemes were set up．Effects of different technical combinations on rice growth, yield, water use efficiency, and soil fertility were systematically analyzed．Results have shown that optimal technical combinations for dryland rice planting covered with plastic mulch（using permeable plastic mulch with a width of 1400 mm and a thickness of 0.006 mm, with ridge width of 1.7 m and ditch width of 30 cm）combined with a precision fertilization scheme of base fertilizer+seedling fertilizer+tillering fertilizer+foliar fertilizer at heading stage（N∶P∶K=15∶15∶15）, and supplemented with precise irrigation when soil relative humidity was less than 70% during key growth period, proved to be the optimal combination．Under this combination, average annual rice yield reached 12250.38 kg/hm², with an average annual increase of 92.4% compared to direct seeding dryland rice planting and 24.8% compared to traditional seedling based paddy field transplanting; water use efficiency was 6.69 kg/m³, saving irrigation water by over 83%; soil organic matter content increased by 11.6%．Dryland rice planting engineering technology system adapted to red loam area in southern Yunnan Province, developed through this research, has provided technical support for efficient utilization of marginal land and large-scale development of water-saving agriculture．