施钾对茶园土壤钾素及平衡的影响

盆栽选取四川、重庆典型的砂岩黄壤、灰岩黄壤、酸性紫色土为供试土壤,田间选取在砂岩黄壤上生长了25年的茶园,连续5年研究了施用钾肥(硫酸钾)对茶园土壤钾库及钾素平衡的影响。结果表明:施用钾肥能显著提高土壤钾库的各类钾素,但其绝对含量都呈逐年下降的趋势。土壤中各类钾素的变化因土壤类型而异,土壤各类钾素的增量均为灰岩黄壤砂岩黄壤酸性紫色土。不施钾肥(CK)的盆栽茶树、田间茶树分别每年从土壤取走钾素0.10.g/kg。盆栽三种土壤的钾素年平均流失量分则别为0.18.g/kg(灰岩黄壤)、0.09.g/kg(砂岩黄壤)、0.07g/kg(酸性紫色土),可见种植茶树施用K肥很有必要。

Effect of potassium fertilizer application on the potassium and its equilibrium in tea-grown soils

5-year successive field and pot experiments were carried out to study the effect of potassium fertilizer application on the potassium pools and equilibriums in tea-grown soils. The soils adopted in pot experiment were yellow sandy soil, yellow lime stone soil and purple acidic soil, and the soil in field experiment was a yellow sandy soil under 25 years tea cultivation. The result indicated potassium fertilizer application increased significantly potassium pools in soils. However, the absolute contents of the soil potassium trend to decrease year by year. The changes of potassium varied by potassium fertilizer in different soils, and the increment changed in the sequence: yellow lime stone soil > yellow sandy soil > purple acidic soil. The amount of potassium removed by tea from soils without potassium application were both 0.10g/kg in pot experiment and field experiment. Annal quantities of potassium leached out from soils every year were 0.18 g/kg (yellow lime stone soil), 0.09 g/kg (yellow sandy soil) and 0.07 g/kg (purple acidic soil) in pot experiment, respectively, thus potassium fertilizer should be applied to meet the K equilibrium in soil under tea planting.