【摘要】 本试验选用8种有效钾测定法对花岗岩、玄武岩水稻土及珠江三角洲沉积水稻土进行测定,以第一造水稻吸钾量、稻谷产量及连续种植四造的总吸钾量、稻谷总产量作为参比项进行校验,结果表明:对玄武岩水稻土,各方法测定值与各参比项都有很好的相关性,其中以1N HNO₃法的相关性较好;对花岗岩水稻土及珠江三角洲沉积水稻土,1N HNO₃法测定值与第一造的参比项相关性不好,与连续四造总吸钾量相关性较好,但仍较其他方法差,0.01M CaCl₂法与参比项的相关性也较差,其他方法测定值与第一造吸钾量或连续四造总吸钾量都有很好的相关性,其中以6N冷H₂SO₄法最好。对上述三种类型土壤若只测定有效钾时,可选用1N中性NH₄OAc法或6N冷H₂SO₄法,若同时测定有效磷和有效钾,可选用Olsen法联合提取,然后分别测定。更多还原

【Abstract】 Available potassium of the Paddy Soils developed from granite,basalt and sediments of the Pear River Delta was tested by 8 methods and the results were compared with the amount of absorbed potassium, the yield of the first crop of rice, the total amount of absorbed potassium and the total yield of four crops of rice. For paddy soil developed from basalt, the abstraction values of each method had a rather good correlation with the parameters. Among the methods tested 1 N HNO3 method was better. For the paddy soils developed from granite and sed diments of the Pear River Delta, the abstraction value of 1 N HNO3 had poor correlation with the parameters of the first crop, a better one to the total amount of absorbed potassium of the four successive crops, but the correlation was still inferior as compared to that with other methods. The 0.01M CaCl, method had poor correlation with the parameter too. The abstraction values of the rest methods had a very good correlation with the potassium absorbed by the first crop and the four successive crops. Among the methods cold 6N H2SO4 method was the best. For the three kinds of soils tested if only the avilable potassium should be determined it was better to use the NH4OAc or SN H2SO4 method. But if available phosphorus and potassium were to be determined it would be better to use the Olten method.更多还原