【摘要】 研究祁连山苔藓层对流域水文的影响可以人为干扰和控制水文,还可以正确评价下垫面产水量和土壤水分状况。该层是森林生态系统独特的结构层次,不仅在森林土壤发育、生态系统物质循环和能量流动过程中起重要作用,而且水文生态效应显著。利用野外调查取样和室内分析结合的办法对祁连山苔藓的持水能力、截留能力、保水能力以及一个生长季节的含水动态进行分析,获取第一手数据100 880个。研究表明:(1)苔藓季节含水量变化较大,5月含水量最高,7月最低,海拔3 300 m最高,2 700 m最低。(2)平均降水量和平均截留量呈多项式关系,2006年6月降水量3.2 mm,截留量3.1 mm,5月和9月降水较高,分别为8.6 mm和7.4 mm,截留量为5.8 mm和4.6 mm。(3)有苔藓林地和无苔藓林地土壤水分差异明显,体现苔藓保水性,有苔藓林地土壤水分蒸发较小,林内土壤水分变化不大且稳定;无苔藓林地土壤水分蒸发大,变化明显且不稳定,随着气温的升高慢慢趋向递减。(4)苔藓层越厚,最大持水量越大,厚度达到3.0 cm的最大持水率为519.44%。更多还原

【Abstract】 The moss layer,a particular layer in the structure of Picea crassifolia forest of Qilian Mountains,has played an important role in hydrological processes.It affects not only surface runoff but also soil moisture status.In addition,it can affect forest soil development,material cycling and energy flowing of the ecological system.Even now there has been a lack of effective study on eco-hydrological functions of the moss layer in Qilian Mountains.The object of this paper is to study moss layer’s effect on water holding capacity,interception capacity,water retaining capacity and moisture dynamic.The study area was selected at Pailugou catchment of Xishui Natural Reserve in Qilian Mountain,which is located at 100°17′E,38°24′N with elevation 2 100-3 800 m.First,10 sampling plots in size 20 cm× 20 cm were selected in the study area in 2007.Then the samples of moss were soaked in water for 24 hours.And then the maximum water holding capacity and the maximum water holding ratio were measured in the laboratory.Five gauges with 20 cm diameter were designed to measured the rainfall interception of the moss layer.The moss layer was cut as a disk with the diameter of 20 cm.The disk was put into each gauge.Three rain gauges were located near the moss gauges.After one precipitation event,precipitation and throughfall were measured from rain gauges and moss gauge respectively.And then rainfall interception can be calculated.At the same time,evaporation was measured at plots with moss layer and no moss layer.Total 100 880 records including water holding capacity,water holding ratio,rainfall interception,evaporation were obtained in one growth season in 2007.By analyzing the records,the results show as follows:(1) moisture of moss changes greatly with season.The maximum appears in May and minimum in July.Generally the moss moisture decreases with increase of air temperature.It also changes with the variation of elevation.It increases with the increase of altitude reaching the maximum at altitude 3 300 m and then decreases,but the minimum at altitude 2 700 m.(2) Rainfall is less and interception also less in June.They are 3.2 mm and 3.1 mm respectively.Precipitation is higher in May(8.6 mm) and September(7.4 mm).The interception is also higher.They are 5.8 mm in May and 4.6 mm in September.(3) Soil moisture difference is obvious between plots covered by moss and none.That results from the difference of water retaining capacity and evaporation capacity.Soil with moss layer has higher water retaining capacity than that with no moss.The evaporation of soil with moss cover is weaker than that with no moss cover.The moisture of soil varies little and is stable with moss layer,however it is inverse with no moss covered.(4) The maximum water holding capacity increases with the increase of moss layer thickness.The maximum water holding ratio can reach 519.44% when thickness of moss layer is 3.0 cm.更多还原