【摘要】 <正> 钾是植物的重要养分之一。由于土壤中存在着不同的矿物,因而产生钾的释放和固定,但这一过程受到很多因素的影响,其中水分状况是重要因素之一。多年来水分状况对钾素释放、固定影响的问题,受到了土壤研究者的注意,但是,到目前为止仍无一致的结论,例如Omuetiand等认为。用风干土测定的交换性钾能很好反映土壤供钾状况,而Luebs等则认为,以用新鲜潮湿土测定为好。为了更好的反映土壤当季的供钾水平,合理使用钾肥,以及发挥土壤钾素的潜力,因此这一问题的研究是有实践意义的,现将研究结果报告如下。更多还原

【Abstract】 Experiment using 100 field moist soil samples showed that potassium release wss found in 96% of the samples after air-dried treatment. For the soils with higher release capacity of K, the correlation between uptake amount of K by wheat and rice and K content in moist soils was more significant than that between the uptake amount of K and K content in air-dried soils. It indicates that moist soil is suitable to be used for analysis of K in soils with higher release capacity of K and lower content of slowly available K.Only a little K could be released from the moist soil containing abundant K after submergence and incubation. Through alternation of wetting and drying, more K could be released from the soils richer in hydromicas or montmorillonite. However, it was difficult to increase available K in the soils with lower release capacity of K through submergence or alternation of wetting and drying.The amount of released K increased with the increase of drying temperature. When the temperature was lower than 200℃, the released K was mainly derived from slowly available K, while the temperature was up to 400℃, the released K was mostly derived from mineral K. Most of the released K under the temperature above 60℃, was not derived from adsorbed K. The increase of exchangeable K in moist soil after air drying was closely related to the saturation degree of K in the soil. More K could be released from the soils containing such minerals as hydromica. The fixation range of fertilizer K applied into moist soils was 18%—56%. Generally the fixation of K increased significantly width the increase of drying temperature. The fixation capacity of K was dependent on soil properties.更多还原