腐殖酸对浑河流域草甸土钾素固定与释放的影响研究

Meadow soil is the one of major agrotype in Liaoning province, there are a large amount of 2:1 clay minerals in them, which have stronger capacity for potassium fixation. So meadow soils also have stronger capacity to fix potassium, that make the utilization rate of potassium would be lower. The miscible displacement technique was used to investigate the effect of humus acids on fixation and release of potassium in this study. The results showed that the application of humus acids reduced potassium fixation from the meadow soils, and potassium fixation rate was depended on the order of humus acids into the soils. When the humus acids was added before potassium, the potassium in soil solution increased markedly than no humus acids, about 41.8% increased by humic acids and about 56.3％ by fulvic acids. When the humus acids and the potassium were added in the same time, which could also caused the increase of potassium soil solution, but the degree was lower than before. About 7.3％ increased by humic acids and 26.2％ increased by fulvic acids. And when the humus acids was added after the potassium, the growth on the potassium in soil solution was not strong, about 5.5％ by humic acids and 9.8％ by fulvic acids. Rate of K fixation was in the following order：no humic acids>adding humic acids after K> humic acids and K added at same time>adding humic acids before K. Three orders had no significant impact on the exchangeable potassium.?????