[目的]探讨玉米种植制度对红壤土壤钾形态及其有效性的影响,为该区域合理安排种植制度和玉米地土壤钾素管理提供依据.[方法]于春播前采集红壤区撂荒(CK)、玉米连作(CY)、豌豆-玉米轮作(RWY)和西葫芦-玉米轮作(RXY)4个种植制度下耕层(0~20 cm)和亚耕层(20~40 cm)土壤,测定其土壤理化性质和各形态钾含量,并分析其相关性.[结果]4个玉米种植制度下土壤各形态钾分布规律不同,耕层土壤水溶性钾、非特殊吸附钾、特殊吸附钾和非交换性钾含量均高于亚耕层,矿物钾含量未表现出典型规律,种植制度对耕层土壤钾素含量影响更大.耕层和亚耕层土壤的水溶性钾、特殊吸附钾和非特殊吸附钾均与速效钾含量呈极显著正相关,特殊吸附钾是该区有效钾的最大供应源.与玉米轮作相比,玉米连作导致土壤酸化程度增加,尽管其速效钾含量显著高于其他土壤(P<0.05),但长期采用玉米连作不利于维持土壤钾素平衡.轮作可降低土壤酸化程度,防止速效钾过度累积,其中西葫芦-玉米轮作可使土壤供钾能力处于较高水平并保持稳定.[结论]玉米种植制度对红壤耕层钾形态及其有效性影响较大,其中西葫芦-玉米轮作是该区钾素可持续利用的玉米最佳种植制度.
[Objective]This paper explored the effects of maize based cropping systems on the forms and availability of potassium(K)in red soil to provide basis for rational cropping system designing and soil K management in the red soil areas.[Method]Before spring sowing,soil samples were collected from the cultivated layer(0-20 cm)and sub-cultivated layer(20-40 cm)under four cropping systems,including abandoned land(CK),maize continuous cropping(CY),pea-maize rotation(RWY)and zucchini-maize ro-tation(RXY).Soil properties and contents of different K forms were determined,and analyze its correla-tion.[Result]The distribution patterns of soil K forms were different under the four cropping systems.The contents of water-soluble K,non-specially adsorbed K,specially adsorbed K and non-exchangeable K in the cultivated layer were higher than those in the sub-cultivated layer.The mineral K contents did not show the typical pattern.Planting systems had greater effects on soil K contents in the cultivated layer than sub-cultivated layer.The contents of water-soluble K,specially adsorbed K and non-specially adsorbed K had significantly positive correlation with the available K,and the specially adsorbed K was the largest source of available K supply in this area.Compared to corn rotation,continuous maize cropping increased soil acid-ification.Although its available K content was significantly higher than that of other soils(P<0.05),long-term continuous cropping of maize was not conducive to maintaining soil K balance.Maize rotation could reduce soil acidification and prevent excessive accumulation of available K,especially zucchini-maize rota-tion could keep soil K supply capacity at high and stable levels.[Conclusion]Maize cropping system had great influences on the forms and availabili-ty of K in the cultivated layer of red soil.The zucchini-maize ro-tation was the best maize cropping system for sustainable utilization of K in this area.