缓控释硒肥对水稻农艺性状和硒积累的研究OA

[Objective]To investigate the effects of application timing and dosage of controlled-release selenium fertilizer on rice growth,selenium accumulation,and rice grain quality,thereby providing technical support for the green and efficient production of selenium-enriched rice.[Method]Field experiments were conducted using the conventional rice cultivar'Huanghuazhan'as the experimental material.Two selenium application periods(Basal stage and tillering stage)and three selenium application rates(600,900,and 1 200 g/hm2)were set,with the application of compound fertilizer alone serving as the control(CK).[Result]Controlled-release selenium fertilizer significantly promoted rice plant height(increased by 6.1%-16.9%)and dry matter accumulation(increased by 18.6%-37.2%),with the tillering stage application showing markedly superior effects compared to the basal stage.All selenium treatments increased yield(by 6.1%-23.2%),with the most significant increase(23.2%)observed when 900 g/hm2 selenium fertilizer was applied during the tillering stage(T900).This was primarily attributed to synergistic increases in panicle number per unit area(up 10.3%),grain setting rate(up 7.8%),and 1000-grain weight(up 4.2%).Regarding selenium accumulation,selenium application during the tillering stage facilitated more efficient transport of selenium to grains.The T900 treatment significantly elevated grain selenium content by 967.5%,increased brown rice selenium content by 54.0-fold,and boosted organic selenium content by 46.2-fold.Concurrently,selenium application during tillering markedly improved rice mineral nutrition,with T900 treatment increasing potassium,magnesium,calcium,and manganese levels in brown rice by 20.7%,25.9%,25.4%,and 101.6%,respectively.It also significantly reduced accumulation of harmful heavy metals cadmium and chromium by 85.1%and 55.6%,respectively.Regarding fertilizer utilization efficiency,the T900 treatment exhibited the highest agronomic utilization rate(1.75 kg/g),with grain selenium utilization reaching 0.67%.[Conclusion]900 g/hm2 controlled-release selenium fertilizer during the tillering stage is thought to be the best fertilization mode,achieving both high rice yields and significantly enhancing selenium nutritional quality and mineral element safety in rice grains.