以位于晋北风沙区右玉县贾家窑6种人工林地(11a油松林、21a油松林、23 a华北落叶松林、17 a油松+柠条混交林、柠条林和沙棘林)为研究对象,通过测定土壤含水量及粒度、计算粒度参数等分析比较不同林地土壤水分和粒度的变化及分布.结果表明:1)在0 ～ 100 cm深度,6种林地平均土壤含水量由大到小依次为:沙棘林＞11a油松林＞柠条林＞17a油松+柠条混交林＞23 a华北落叶松林＞21 a油松林;0～ 20 cm土层土壤含水量相对较低,较深土层土壤水分受植物蒸腾耗水、根系分布深度及密度等因素影响;2)6种林地的粒度组成以极细砂和粉粒为主.7个粒级中,柠条林和沙棘林粉粒占比最大,其他林地极细砂含量占比最大;3)在0～ 100 cm深度,6种林地土壤平均粒径大小依次为:23 a华北落叶松林＞11a油松林＞21 a油松林＞17a油松+柠条混交林＞沙棘林＞柠条林;4)沙棘林和柠条林有较强的水土保持能力,在晋北风沙区植被恢复过程中可以优先选择沙棘和柠条进行造林;5)研究区经过多年植被恢复,人工林耗水量增加.认为有必要根据土壤水分状况结合植被耗水特性和生长阶段开展人工林的科学管护,如适当调整植被盖度,加强林下草本和枯落物保护.%[Background] Windy and sandy region of North Shanxi where the severe water erosion and wind erosion happened is the most extremely frail eco-environment of Shanxi province.In the past few decades,large areas of plantations have been planted here for windbreaks and sand fixation.However,at the same time as it works,plantations can also absorb lots of water from soil and lead to soil desiccation.Jiajiayao catchment,located in Youyu County,is one of the most typical ecological fragile areas in windy and sandy region of North Shanxi province.[Methods] Due to soil moisture and grain size are the limiting factors for ecosystem restoration in this area,based on the field investigation,sampling and measurement,the characteristics of soil moisture and grain size of 6 different plantation types (11-year Pinus tabulaeformis,21-year P.tabulaeformis,23-year Larix principis-rupprechtii,17-year P.tabulaeformis and Caragana korshinskii,C.korshinskii and Hippophae rhamnoides) in Jiajiayao catchment was analyzed in order to provide useful references for vegetation restoration.[Results] 1)There were considerably differences in characteristics of average soil moisture content in 0-100 cm soil profile among different plantation types.Mean soil moisture content of individual plantation type was about 4.62％-8.30％,and showed following sequence:Hippophae rhamnoides ＞ 11-year P.tabulaeformis ＞ C.korshinskii ＞ 17-year P.tabulaeformis and C.korshinskii ＞ 23-year L.principis-rupprechtii ＞ 21-year P.tabulaeformis.Mean soil moisture content in the topsoil (0-20 cm) among 6 plantation types was relatively low.Thereafter the pattern of variation began to be inconstant with the increase of depth.This may be explained by that the antecedent precipitation was in the uniform condition,while affected by plant transpiration,depth and density of root distribution,soil moisture content became complicated in deeper soil layers.2) The grain size characteristic of all 6 plantation types was similar that silt and very fine sand content was the highest.However,silt content was the highest at C.korshinskii and H.rhamnoides,very fine sand content was the highest at the other plantation types.3) The variation tendency of the grain size of different plantation types was not consistent in 0-100 cm soil profile.For the average grain size,the order was:23-year L.principis-rupprechtii ＞ 11-year P.tabulaeformis ＞ 21-year P.tabulaeformis ＞ 17-year P.tabulaeformis and C.korshinskii ＞ H.rhamnoides ＞C.korshinskii.[Conclusions] The water-holding capacity of H.rhamnoides and C.korshinskii was much better than the other plantation types.H.rhamnoides and C.korshinskii should be given priority in the process of vegetation restoration in windy and sandy region of North Shanxi.After years of vegetation restoration,the water consumption of plantations had increased in the study area.It was necessary to carry out the scientific management according to the soil water status,water consumption characteristics,and growth stages of plantations,such as adjusting the vegetation coverage and strengthening the protection of the undergrowth herb layer and litter layer.
展开▼
