干湿交替对植烟土壤钾素有效形态变化的影响

Effect of Dry and Wet Alternation on Change of Potassium Effective Form in Tobacco-planting Soil

研究旨在探究水分条件变化对植烟土壤中钾素有效形态的影响,以期为准确评估植烟土壤的钾素供应状况及合理施用钾肥提供科学依据。选取位于湿润季风气候区的会东和高原季风气候区的德昌两个生态区的主要植烟土壤类型(紫色土、红壤),进行分层土壤样品采集(0~20、20~40、40~60 cm)。通过室内培养设置不同水分条件(恒湿、干湿交替、湿润),研究干湿交替对土壤速效钾、有效性钾和缓效钾含量变化的影响。结果表明:恒湿、干湿交替和湿润处理增加会东地区紫色土、会东地区红壤和德昌地区红壤各土层速效钾含量,增加值最大达85.96 mg/kg,降低了德昌地区紫色土速效钾含量。土壤缓效钾含量与速效钾含量变化趋势相反。会东地区紫色土和红壤的有效性钾含量随培养时间增加而增大,德昌地区紫色土和红壤有效性钾含量变化则相反。水分条件和黏土矿物类型可能是影响德昌紫色土、红壤的钾素有效形态变化的重要因素;在烤烟生产中,尤其需注重雨季期间对德昌地区紫色土供应适量钾肥。

The aims were to study the effects of water conditions on the potassium availability,to clarify the response of soil potassium available to dry or wet alternation and provide scientific basis for accurate understanding of the potassium supply in tobacco planting soil and rational application of potassium fertilizer.Two ecological regions,Huidong(humid monsoon climate zone)and Dechang(plateau monsoon climate zone),were selected as the main types of tobacco soil(purple soil and red soil).Soil samples were collected in different layers(0-20,20-40 and 40-60 cm),and different moisture conditions(constant humidity,alternating dry and wet,wet)were set up in culture experiment.The effects of dry and wet alternation on the content of available potassium,effective potassium and slowly available potassium in soil were studied.The results showed that constant water,dry and wet alternation,and wet treatments increased the available potassium content in each soil layer of purple soil(Huidong county)and red soil(Huidong county,Dechang county),with the maximum increase value of 85.96 mg/kg,and decreased the available potassium content of purple soil in Dechang county.Soil slow available potassium content showed an opposite trend to that in available potassium content.The effective potassium content of purple soil and red soil in Huidong area increased with the culture time along,but the change of effective potassium content in purple soil and red soil in Dechang area was opposite.Water condition and clay mineral type might be the important factors affecting the change of potassium available form in Dechang purple soil and red soil.In the production of flue-cured tobacco,it was necessary to pay attention to the supply of appropriate potassium fertilizer to purple soil in Dechang area especially in rainy season.