施氮和不同品种水稻对紫色水稻土钾素形态的影响

通过盆栽试验研究了施氮水平和不同品种水稻对四川盆地 3种典型紫色水稻土 5种钾形态的影响以及各种土壤钾形态对水稻钾素营养的贡献。结果表明 ,4个紫色水稻土供钾能力均属中下水平 ,全钾含量为 1.29%～2.62% ,其中矿物钾量平均占 96.82% ,速效钾和非交换性钾仅平均占 0.62%和 2.56% ,土壤供钾能力以中性紫色水稻土 石灰性紫色水稻土 酸性紫色水稻土。施氮 (N 0～ 150mg/kg)促进 4个紫色水稻土钾素的释放 ,提高水稻对非交换性钾和矿物钾的吸收利用 ,使矿物钾和非交换性钾的贡献占植株吸钾的 80.3% ,速效钾仅为 19.7%。中性紫色土供试 4个品种水稻的吸钾能力为开优 5号 汕优 63Ⅱ优 6078引佳 1号。施氮后4个品种水稻吸自非交换性钾和矿物钾量平均占植物吸钾量的 66.9% ,以施中氮 (N 150mg/kg)时植株吸钾量最高 ;而低氮或高氮水平都不利于植物对钾的吸收和土壤钾的释放

Effect of nitrogen application and rice cultivars on forms of potassium in different purple paddy soils

Pot experiment was adopted to study the effects of nitrogen supplying levels and rice cultivars on five forms of soil K in three purple paddy soils in Sichuan basin. Results indicated that the total K in the tested purple paddy soils was low to medium ranged from 1.29% to 2.62%, and mineral K accounted for 96.82% while quickly availble K and slowly available K only accounted for 0.62% and 2.56%, respectively on average. The potassium supplying power of the tested soils showed the following order neutral purple paddy soil>calcareous purple paddy soil>acid purple paddy soil. Nitrogen application(0～150mg/kg) increased the release of soil potassium and the utilization of non exchangeable K and mineral K. In accordance with the total amount of net K uptake by rice, the contribution of non exchangeable K and mineral K accounted for 80.3%. The capability of potassium uptake by four rice cultivars was Kaiyou 5>Shanyou 63>Eryou 6078>Ying jia 1 in neutral purple soil. Contibution of non exchangeable K and mineral K to K uptake by four rice cultivars accouted for 66.9% after the application of nitrogen fertilizer on average. The maximun of net K uptake by four rice cultivars were obtained at medium nitrogen level (N 150mg/kg). It was not beneficial to the K uptake by rice and the release of soil mineral K at low or high nitrogen level.