我国北方主要土壤非交换性钾释放速率的研究

RELEASE RATES OF NON-EXCHANGEABLE POTASSIUM IN SELECTED SOILS FROM NORTHERN CHINA

采用连续流动交换技术研究了我国北方25个供试土壤非交换性钾的释放速率、结果表明，土壤非交换性钾释放缓慢，而持续时间长；最大释放速率变幅为0．195～2．30mg／（kg·min），600分钟平均释放速率变幅为0．066～1．12lmg／（kg·min），释放持续时间一般在600分钟以上。在600分钟释放时间内非交换性钾释放百分率变幅在5．4％～39．6％之间。土壤非交换性钾释放速率与盆栽耗钾试验中玉米吸钾量之间有极显著的相关性，可以用它作为土壤供钾能力的评价指标。

Release rates of non-exchangeable potassium (NE-K) in 25 selected soils of 12 primary soil types from northern China were studied using a continuous flow apparatus and 0.10mol/L HCl as extracting solution. Results indicated that NE-K was released slowly for a long time. Maximum release rate of NE-K varied from 0.195 to 2.30mg/(kg·min), average release rate of NE-K in 600 minutes ranged from 0.066 to 1.121mg / (kg·min), and the NE-K release lasted for more than 600 minutes in most soils. The NE-K released in 600 minutes accounted for 5.4% to 39.6% of the total NE-K in the soils. Generally speaking, the release rare and percentage of soil NE-K gradually increased from the east to the west of China, the release parameters of NE-K were the highest in northwest soils and the lowest in the northeast soils, on average. The release rate of NE-K was very closely and positively correlated with the potassium uptake by corn seedlings in the potassitum depletion experiment in greenhouse.Therefore, it could be used as a reliable index of potassium-supplying power in soil.