不同施钾方式对甘薯钾素吸收及产量的影响

【目的】钾素是调控块根类作物生长和产量的关键因子,特别是对淀粉型甘薯后期块根膨大及产量形成尤为重要。本试验选择胶州(砂姜黑土)和即墨(风沙土)两个不同土壤质地类型的试验点布置田间试验,探究不同施钾方式在两种不同类型土壤条件下对甘薯钾素吸收、 钾肥利用率以及产量形成的影响,以期对甘薯生产提供理论指导。【方法】借助水肥一体化技术能够实现甘薯钾营养的精细化调控,提高钾肥利用率和促进甘薯生长。试验共设置4个处理: K0(不施钾肥,CK)、 K1(钾肥基施)、 K2(钾肥1/2基施+1/2封垄期追施)和K3(钾肥全部封垄期追施)。【结果】与CK相比,三种不同施钾方式均显著提高了甘薯生物量、 养分吸收量及产量(P0.05)。与K3和 K1处理相比,砂姜黑土条件下K2分别增产18.7%和10.4%,但K3和 K1处理之间的产量差异不显著; 风沙土条件下K2增产幅度分别为35.3%和17.3%,其中K1处理的产量显著高于 K3处理(P0.05)。与K1处理相比,K2处理显著提高了甘薯生长中后期(115天~150天)钾素积累量和地下部生长速率,同时提高了钾收获指数、 钾肥偏生产力、 钾效率、 钾肥农学利用率。与K1 和K3相比,砂姜黑土条件下K2处理的钾肥表观利用率分别提高了12.5%和8.8%,风沙土条件下K2处理的钾肥表观利用率分别提高了13.9%和13.2%。不同土壤类型条件下同一施钾方式相比较,砂姜黑土条件下氮钾积累量、 生物量和产量均高于风沙土,但K2处理的钾素日积累速率、 钾素利用率与增产效应均表现为风沙土高于砂姜黑土。【结论】在供钾量较低的风沙土上采用分期施钾(1/2基施+1/2封垄期追施)能显著提高钾肥利用率和增加甘薯产量,是甘薯合适的施钾方式。

Effect of K application method on K absorption and yield of sweet potato

Objectives] Potassium is particularly important for starch tuber yield of sweet potatoes.In this research, different potassium application methods were tested in sweet potato in Jiaozhou City and Jimo City.Methods] Two kinds of soils, Shajiang black soil in Jiaozhou City and aeolian sandy in Jimo City, were used in the experiment, and four treatments were designed: K0 ( CK, no potassium fertilizer ) , K1 ( all potassium basal applied) ,K2 ( half potassium fertilizer as basal and half as top dressing at the ridged covered stage ) and K3 ( all potassium fertilizer top dressed at ridge covered stage ) .Results] Three potassium applications significantly increased the biomass, nutrient uptake and yield of sweet potatos.Compared with K3 and K1 in Shajiang black soil, the yield of K2 was increased by 18.7% and 10.4%.The yields differences between K3 and K1 were not significant.In aeolian sandy soil, the yield of K2 was increased by 35.3%and 17.3%compared with K3 and K1 , The yield in K1 was significantly higher than that in K3 .The highest yield achieved in K2 was significantly higher than in K1 and K3 in both the two tested soil types.Compared with K1 , K2 significantly improved the tuber growth rate, accumulation of potassium at late growing stages(115 days to 150 days) , potassium harvest index, potassium day accumulation rate, partial productivity, potassium efficiency and potassium agronomic efficiency.Compared with K3 and K1 , the potassium apparent use efficiency in K2 was increased by 12.5%and 8.8%in Shajiang black soil, 13.9%and 13.2% in aeolian sandy soil, respectively.Under the same way of potassium application, the accumulation of nitrogen and potassium, the biomass and yield of sweet potatoes in shajiang black soil were higher than in aeolian sandy soil, but the potassium day accumulation rate and potassium use efficiency in aeolian sandy soil were higher than in shajiang black soil.Conclusions] Half potassium as basal dressing and half as top dressing at the ridge covered stage is an appropriate method in aeolian sandy soil.