定位施肥紫色菜园土壤钾素效应研究

基于紫色菜园土壤3年12季连续蔬菜(莴笋-白菜轮作)定位施肥试验,研究不同施肥条件对土壤钾素形态和供钾水平的影响。采用田间试验和室内化学分析结合的方法测定不同施肥处理土壤钾素形态的变化和蔬菜产量的关系。结果表明:紫色菜园土壤钾素主要以矿物钾为主,占全钾的95.11%~97.33%,土壤缓效钾和速效钾分别占土壤全钾的2.22%~3.38%和0.44%~1.52%。连续施用钾肥显著提高土壤速效钾和缓效钾含量,以增钾处理作用最优。定位施肥显著提高土壤水溶性钾、非特殊吸附钾、特殊吸附钾含量,以有机无机肥料配施作用优于单施化学肥料。土壤水溶性钾、非交换性钾与土壤有效磷含量呈显著或极显著正相关,莴笋和白菜产量与紫色菜园土壤速效钾、缓效钾含量呈显著正相关。定位施肥协调紫色菜园土壤钾形态,改善土壤供钾能力,以有机无机肥料配施作用为优。

EFFECT OF SITE-SPECIFIC FERTILIZATION ON THE STATUS OF SOIL POTASSIUM IN PURPLE VEGETABLE SOIL

A three-year (12 seasons) field experiment was conducted on a purple vegetable soil under a lettuce-cabbage rotation to investigate the effects of site-specific fertilization on forms and supply capacity of soil potassium. Field experiment and chemical analyses were used to determinate the change of soil potassium form and its relation with vegetable yields. The results showed that the main forms of potassium in the purple vegetable soil was structural potassium which accounted for 95.11%~97.33% of the total potassium, slow-release potassium and available potassium accounted for 2.22%~3.38% and 0.44%~1.52% of the total potassium, respectively. Long-term application of potash significantly improved the contents of soil available potassium and slow-release potassium, the addition of potassium fertilizers achieved the highest increasing rate. Located fertilization significantly improved the contents of water soluble potassium, non-specifically absorbed potassium and specifically absorbed potassium, and the increasing rate in organic fertilizers treatments was better than in only inorganic fertilizer treatments. Water soluble K and non-exchangeable K had positive significant correlations with available P. Available K and slowly available K also had the positive significant correlations with lettuce and cabbage yields. Site-specific fertilization coordinated potassium forms of purple vegetable soil improved the supply capacity of soil potassium and the best was in combined application of organic and inorganic fertilizers.