广东不同母质水稻土供钾特性的评价

Evaluation of K-supplying Characteristics of Paddy Soils Derived from Different Parent Materials in Guangdong Province

应用生物耗竭法并结合模拟试验综合评价了广东5种主要母质发育水稻土的供钾特性。研究结果表明:(1)2mol/L冷HNO3法提取的有效钾与水稻吸钾量间的相关性最好,建议用2mol/L冷HNO3法提取的钾来评价土壤的供钾状况。(2)1mol/L沸HNO3法提取的非交换性钾含量在耗竭后高于耗竭前的水平,与水稻吸钾量相关性很小或呈负相关,不适宜用来评价耗竭土壤。(3)广东5种主要母质发育的水稻土供钾能力大小顺序为:三角洲沉积物发育水稻土>花岗岩发育水稻土>砂页岩发育水稻土>石灰岩发育水稻土>玄武岩发育水稻土。该试验结果可供水稻合理施用钾肥作参考。

The soil potassium supplying characteristics of 5 representative paddy soil samples from Guangdong Province were studied by simulation experiment and pot experiments under exhaustive cropping with rice. The results showed as following:(1)There have better correlation between the effective potassium extracted by 2 mol/L HNO_3 and the amount K uptake by rice than by other methods. It is suggested that the available K extracted by 2 mol/L HNO_3 was a suitable index for evaluating the K supplying capacity. (2) The amount of 1 mol/L HNO_3-extractable K was unsuitable to evaluate soils exhausted as it was higher than that pre-exhausting and had no correlation or negative correlation with the amount K uptake by rice.(3) The K supplying capacity of five different soils were followed the order: soil derived from Pearl River Delta deposits>soil derived from granite>soil derived from sandstone>soil derived from limestone>soil derived from basalt.