耕作土壤非交换性钾有效性的研究

采用２种化学连续提取法及连续耗钾实验。研究了几种耕作土壤非交换性钾释放特性及有效性。结果表明，供试土壤非交换性钾释放特性和有效性与粘土矿物密切相关。富含伊利石的土壤非交换性钾的释放量大，速率快，有效性高；黑麦草吸收该土壤的非交换性钾量及总吸钾量高，生物量大。而富含高岭石或蒙脱石的土壤非交换性钾有效性明显较低；非交换性钾的释放量和速率、黑麦草吸收该土壤的非交换性钾量、总吸钾量及生物量的均值分别仅为富含伊利石上壤的４６．９６％、４５．５０％、４１．６５％、４３．９０％和６７．５２％。供试土壤耗竭前期非交换性钾有效性高，供钾量大；黑麦草生长良好，生物量大。

Study on the Availability of Nonexchangeable Potassium in Cultivated Soils

The releasing characteristics and availability of nonexchangeable K in cultivated soils were studied by two chemicalsuccessive extraction and pot exhaustion. The results showed that the releasing characteristics and availability ofnonexchangeable K related remarkably to clay minerals. The releasing capacity, rate and availability ofnonexchangeable K in soils with rich illite were much higher than those in others with rich kaolinite or montmorillonite,so that the amounts of nonexchangeable and total K absorbed by ryegrass and dry biomass in the soils were higher thanthose in others. The averages of release capacity and rate, amounts of nonexchangeable and total K absorbed by ryegrassand dry biomass in kaolinitic and montmorillonitic soils were 46.96%. 45.50%. 41.65%. 43.90% and 67.52% ofthose in illitic soils. The availability of nonexchangeable K in the soils was much higher so that soil K suppliedsufficiently, ryegrass grew well and the dry biomass were much higher during the earlier stage of exhaustion.