关键词: 贮存温度, 贮存时间, 土壤钾, 测定值

Abstract: In order to correctly evaluate the timeliness of soil potassium (K) test value, this paper studied the dynamic changes of potassium test value in soil samples dried by different forms through culture experiment under 4 types of storage temperature (room temperature, 4℃ low temperature, 25℃ constant temperature, 60℃ dry incubator). The results showed that: Storage temperature and time could significantly affect the test values of different K forms. Under different storage temperature, along with the extension of storage time, the test value of water soluble K was different from that of before culture (the initial value). Under room temperature, the variation relatively to the initial value was smaller, and it was greater under 4℃ low temperature and 60℃ dry incubator. The test value of exchangeable potassium under 60℃ dry incubator had larger variation relatively to the initial value; while the variation under room temperature and 25℃ constant temperature were smaller. The test value of nonexchangeable K had smaller variation under 4℃ low temperature, and it had a larger variation than the initial value under room temperature, 25℃ constant temperature and 60℃ dry incubator. The transformation of different K forms was significantly affected by storage temperature and time. The water soluble K, exchangeable K values were increased under 4℃ low temperature; and there was a dynamic balance between water soluble K and exchangeable K when the soil samples stored at room temperature and 25℃ constant temperature conditions; with the extension of storage time, the nonexchangeable K was converted into exchangeable potassium under 60℃ dry incubator for long period of time. In conclusion, storage temperature and time significantly affected air-dried soil K test value, and K test value had timeliness.

Key words: storage temperature, storage time, soil potassium, test value