Changes of soil potassium pool in paddy area of the coastal plain，eastern Hebei
通过对大面积土壤各形态钾的定位监测，研究了 1982～ 2016年 30余年间冀东滨海平原稻区土壤钾库的现状、变化及其影响因素，分析了成土母质、耕种施肥等对该区域土壤钾库的影响。主要结果:(1)冀东滨海平原稻区土壤全钾、缓效钾、速效钾平均含量分别为 23.04g/kg、1 615.94mg/kg、247.37mg/kg。种稻 40～ 70余年间，各年限土壤全钾、速效钾分别维持在 23.96 g/kg、257.41 mg/kg左右。与种稻 40年相比，缓效钾年均减少20.19 mg/kg。(2)不同母质土壤全钾、缓效钾、速效钾含量大小顺序为:海相沉积物、泻湖沉积物 >河流冲积物；土壤缓效钾 /全钾和速效钾 /全钾均为海相沉积物、泻湖沉积物 >河流冲积物，3种母质发育的土壤速效钾 /缓效钾差异不显著；海相沉积物、泻湖沉积物二者之间的各形态钾含量及比值均无显著差异。(3)土壤速效钾与土壤盐分、有机质均呈显著正相关关系；土壤速效钾与有效磷无显著相关关系。主要结论:随种植年限增加，土壤全钾、速效钾无显著变化，缓效钾显著下降。海相沉积物、泻湖沉积物发育的土壤全钾、缓效钾、速效钾的含量均显著高于河流冲积物，土壤速效钾与盐分呈显著正相关关系。稻区土壤钾输入量小于水稻钾的输出量，随着种稻年限的增加，逐渐消耗土壤缓效钾。
Based on in situ monitoring of various soil potassium forms，we investigated how parent material and long -termrice planting(from 1982 tO2016)changed soil potassium content in the coastal plain，eastern Hebei province.Resultsshowed that:(1)Average contents of the total potassium，slowly available potassium and rapidly available potassium ofthe paddy soil were 23.04g/kg，1 615.94 mg/kg and 247.37mg/kg，respectively.For the paddy soil with 40～ 70-yearsrice planting，the annual rate of the slowly available potassium pool was reduced by 20.19mg/kg.(2)Soils developed frommarine and lagoon sediments had similar potassium pools with respect to the totalpotassium，slowly available potassium andthe rapidly available potassium，and also had similar proportions of the slowly available potassium to total potassium andthe rapidly available potassium to totalpotassium，which were all greater than the respective ones of the alluvialsediments.In addition，for all three sediments no significant differences in the rapidly available potassium to the slowly availablepotassium proportion werefound.(3)The soil salinity and organic matter were both positively correlated to the soil rapidlyavailable potassium，and no significant correlations between the rapidly available potassium and the available phosphoruswere observed.The conclusions showedthat:With the increase of planting years，contents of the total potassium andrapidly available potassium of the paddy soil did not changesignificantly，slowly available potassium decreasedsignificantly.The total potassium，slowly available potassium and the rapidly available potassium in marine and lagoon sediments weresignificantly higher than those in the alluvialsediments，and there was a significant positive correlation between the rapidlyavailable potassium and the soilsalinity.The potassium input in rice area was less than the potassiumoutput，and the slowly available potassium was gradually consumed with the increase of growing years.