中文摘要：

研究蔬菜保护地18个长期定位施肥处理的土壤钾素Q/I曲线特性，结果表明，不同长期定位施肥蔬菜保护地土壤供钾容量（-△K0即QK）、供钾强度（AReK即IK）和缓冲能力PBCK差异明显，土壤基本理化性质的差异是其存在差异的根本原因；土壤CEC、速效钾、粘粒、有机质含量越高，土壤-△K0、AReK值越大，PBCK值越小．影响各处理鲫曲线特性的主要原因各异，施有机肥的各处理主要因为CEC和速效钾含量高，从而-△K0和AReK值较高，PBCK值较低；施钾肥的各处理主要因为速效钾含量高，具有较高的-△K0和AReK值和较低的PBCK值；施高量氮肥的处理有较低的-△K0值和PBCK值和较高的AReK值，这或许与NH4^＋浓度大有关．

英文摘要：

Effects of 18 long-term located fertilizations on the quantity-intensity characteristics of potassium in sheltered vegetable field soil were investigated. The results showed that there were great differentiations between the quantity factor（-△K0）, intensity factor （AReK） and potential buffering capacity of K^＋ （PBCK） in different treatments, and the changes of basic physical-chemical properties contributed to this. When the contents of soil CEC, fast-available potassium, clay and organic matter were increased, the value of -△K0 and AReK increased but the value of PBCK decreased. The main reasons for changes in quantity-intensity characteristics of each treatment were different. The treatments using organic fertilizer presented a high value of -△K0, AReK but a low value of PBCK, primarily owing to the higher content CEC and fast-available potassium; the treatments using potassium also presented a high value of -AK0, AReKand a low value of PBCK, while the main reason may be the higher content of fast-available potassium; the treatments using great amount of urea produced a high value of AReK only but a low value of PBCK, -△K0, properly owing to the higher amount of NH4^＋.