黄河三角洲引黄灌区不同植被类型的降盐改土功能

Function of Reducing Soil Salinity and Soil Improvement of Different Vegetation Types in Yellow River Irrigation Area of the Yellow River Delta

以裸地为对照,对黄河三角洲小开河引黄灌区输沙干渠两侧的白蜡林、棉田及杂草地3种植被类型改良土壤盐碱程度、土壤容重和孔隙度状况、土壤养分含量及土壤呼吸速率等参数进行比较分析。结果表明:①植被建设具有降盐效应,棉田、白蜡林、杂草地含盐量均值分别比裸地下降66.7%,52.4%,16.7%,表层低于20-40cm土层。②植被建设使土壤容重减小、孔隙度增大,土壤容重均值表现为白蜡林<杂草地<棉田<裸地,总孔隙度则与之相反,对土壤表层的改良效果好于20-40cm土层。③不同植被类型土壤有机质及速效养分含量均有提高,白蜡林、棉田、杂草地土壤有机质含量均值分别是裸地的2.72,2.03,1.75倍,土壤表层高于20-40cm土层。④白蜡林、杂草地、棉田的土壤呼吸速率日动态呈现单峰曲线,土壤呼吸速率日均值及日变幅均表现为白蜡林>棉田>杂草地>裸地,其中白蜡林、棉田、杂草地土壤呼吸速率日均值分别是裸地的8.01,6.47,3.36倍。

Compared with bare land,characteristics of soil pH value,soil salt content,soil density and porosity,soil nutrients and soil respiration of forest of Fraxinus chinensis,cotton field and grassland vegetations were researched in Xiaokaihe Yellow River diversion irrigation district of the Yellow River delta.Results indicated that： ①Different vegetation types had obvious function of controlling soil salinity content beside the channel.Compared with bare land,the soil salinity content of cotton field,forest of F.chinensis and grassland decreased by 66.7%,52.4%,16.7%,respectively,and the index of 0-20 cm was less than that of 20-40 cm.②Soil density decreased,and soil total porosity increased with different vegetation types.Soil density showed this order： F.chinensis forest 〈grassland 〈cotton field 〈bare land.However,soil total porosity showed a contrary tendency,and these indexes of 0-20 cm were better than that of 20-40 cm.③Soil organic matter and available N,P,K were mostly increased in different type of vegetations.Soil organic matter of F.chinensis,cotton field,and grassland was 2.72,2.03,1.75 times respectively,larger than that of bare land,and these indexes of 0-20 cm were higher than that of 20-40 cm.④There was a significant increase for diurnal soil respiration rate after vegetation restoration in bare land.The significant diurnal variation of soil respiration in different types of vegetations and bare land showed a single-peaked curve,and the average and daily variation amplitude of soil respiration rate showed this order： F.chinensis forest 〉cotton field 〉grassland 〉bare land.The average soil respiration rate of F.chinensis forest,cotton field,grassland was 8.01,6.47,3.36 times respectively,larger than that of bare land.