黄瓜温室土壤溶液中钾的动态变化及其淋失特征

为探讨黄瓜温室土壤溶液中钾含量的变化特征,以河北永清县黄瓜主产区的黄瓜温室为研究对象,研究了黄瓜温室整个生育期根层(35~40 cm)和非根层(95~100 cm)不同深度土壤溶液中钾的动态变化规律及土壤中钾的淋失特征。结果表明,根层(35~40 cm)各处理土壤溶液钾含量为47.7~114.0 mg/L,呈现升高-降低-升高的趋势;在非根层(95~100 cm)土壤溶液中,常规施钾处理(施钾量为3 022 kg/hm~2)的钾含量(40.3~105.0 mg/L)动态变化规律与根层相似,而对照处理(不施钾)的钾含量(49.6~66.5 mg/L)和推荐施钾处理(施钾量为600 kg/hm~2)的钾含量(30.6~42.8 mg/L)随时期无明显变化。土壤淋溶液中钾的浓度随施钾量的增加呈不同程度的升高趋势,其浓度为27.9~65.1 mg/L,黄瓜整个生育期土壤钾的总淋失量为154 kg/hm~2。综上所述,该试验区黄瓜温室存在一定程度的钾淋失风险,推荐600 kg/hm~2在保证产量的基础上可以降低钾素的淋失,可有效增加经济效益和环境效益。

Dynamics of Potassium Concentrations in Soil Solution and Characteristics of Potassium Leaching from Soil in Greenhouses with Cucumber

In order to probe into variation characteristics of leaching of potassium from soil,a study was conduc-ted in cucumber greenhouse in Yongqing of Hebei Province to investigate dynamics of potassium concentrations in soil solution and leaching of potassium from soils during the whole cucumber growth period by the different fertilizer application.The results showed that dynamics of potassium concentrations in soil solution collected in the depths at 35 -40 cm and 95 -100 cm soil layers.Potassium concentration (47.7 -1 14.0 mg /L)for all the treatments in-creased at first,decreased subsequently and then increased again in soil solution at 35 -40 cm for greenhouse. Meanwhile potassium concentrations in soil solution at 95 -100 cm (40.3 -105.0 mg /L)kept the similar dynamic trend to that at 95 -100 cm for conventional potassium rate treatment.However,potassium concentrations in soil so-lution of CK (49.6 -66.5 mg /L)and the treatment of recommended potassium rate (30.6 -42.8 mg /L)kept stable during different periods at 95 -100 cm.Potassium levels of leaching solution increased with increase of potas-sium application rate and ranged at 27.9 -65.1 mg /L for the cucumber greenhouse.Total amounts of potassium leaching from soil layer (0 -100 cm)of the greenhouse was 154 kg /ha.Therefore,the application rates at 600 kg /ha could not only keep the high yields of cucumber and reduce soil potassium leaching loss,but also increase the economic benefit and environment benefit effectively.