水土流失监测是国家水土保持规划和部署的基础.目前我国已建立起较为完善的水土流失监测网络.针对我国水土流失监测中遇到的普适性问题,以河北崇陵观测站为代表,提出相应对策.1)径流小区:径流泥沙自动观测仪量程有限制,建议布设水沙观测复合设备;自动设备精密度高,受野外环境影响大,建议安装报警装置,人工及时处理设备故障;自动设备专业性强,后期自主维护难,探索设备模块化组装,便于后期自主维护;自动设备数据量大,整编数据任务重,管理部门可统一要求,规范厂家数据库,减小数据整理量.2)小流域:控制站观测设施单一、量程范围窄,建议结合实际,布设复合堰;观测设施依据标准不统一、建设不规范,管理部门可统一设计标准、建设规范;控制站水沙自动观测协同难,建议多点观测,增设多探头自动监测设备.

[目的]通过划分小流域类型,对太行山中低山石灰岩区典型小流域提出治理措施,分析治理效果,为建立小流域综合治理优化模式体系奠定基础.[方法]通过野外调查和查阅资料,根据岩石类型和小流域所处的地理位置划分小流域类型,在对小流域分类和分区的基础上,考虑物种的生态适宜性、小流域经济特征,兼顾社会、经济、生态效益,从而形成规模经营,发挥区域资源优势小流域治理模式.[结果]太行山中低山石灰岩区选取的典型小流域有东井小流域、翟庄小流域、继城小流域、安河小流域、册井小流域、上岳各庄小流域.各小流域主要治理措施有栽植水保林,主要树种有油松、侧柏、小叶杨、垂柳、黄连木、刺槐、紫穗槐等,鱼鳞坑整地;栽植经济林主要树种有胡桃、柿子、枣、花椒、杏、板栗,反坡梯田整地;各小流域的治理措施还包括封禁治理、建设水平梯田、河滩人工垫地、谷坊坝、水池、扬水站、道路、蓄水池、水窖.[结论]通过治理,太行山中低山石灰岩区典型小流域提高了生态效益和经济效益,减少了地表径流和土壤流失量,减轻了各种自然灾害可能造成的损失.使土地资源得到了合理的开发利用,提高了土地资源利用率和商品产出率,为发展优质、高效、绿色产业奠定了基础;同时水土保持治理措施的实施,有效地防治了洪水、泥石流的危害,增强了抗御自然灾害的能力.

[目的]揭示库姆塔格沙漠东南部柽柳的水分传输过程,探究柽柳的耗水特性,为该地区柽柳生长及生理研究提供数据支撑,对该区域柽柳经营管理具有一定理论意义.[方法]利用PS-TDP8树木茎流监测系统对库姆塔格沙漠东南部柽柳的液流变化进行测定,采用相关分析及逐步回归法分析气象因子对柽柳液流的影响.[结果]柽柳茎干液流速率整体为"宽峰型".夏季,液流速率最早启动,峰值最大,持续时间最长,日树干液流量最大.秋季,液流速率有最晚的启动时间.不同季节夜间有低值液流.液流速率均值夏季最大,秋季最小.春季,空气温度能单独解释73.1％的液流速率变化,三者共同解释78.3％的液流速率变化;夏季,太阳辐射能单独解释63.0％的液流速率变化,4个因子共同解释69.8％的液流速率变化;秋季,空气温度能单独解释73.3％的液流速率变化,2个因子共同解释液流速率变化的73.8％.春秋季液流主要受气温影响,太阳辐射是影响夏季柽柳液流速率的主导因子.[结论]柽柳液流速率可以通过回归方程估算.本研究结果为摸清干旱沙漠地区柽柳水分利用特性提供基础数据.

研究人工模拟降雨对坡耕地土壤侵蚀特征的影响,旨为北方土石山区坡改梯建设提供科学依据.以北方土石山区典型砂质壤土为研究对象,采用人工模拟降雨试验的方法,在室内模拟不同坡度(10°、15°、20°和25°)、不同降雨强度(40、90、120和180 mm/h)下的坡面产流和产沙过程,研究不同坡度和降雨强度对坡面土壤侵蚀过程的调控机制.结果表明:(1)坡面开始产流所需的时间不受坡度的影响,随着降雨强度的增大,坡面产流所需的时间明显缩短;(2)在降雨强度一定的条件下,随着坡度的增大,坡面产沙量逐渐增加,本试验坡面最高产沙量的临界坡度约为22°;(3)产流量随坡度变化并非单调的递增或递减趋势,而是随着坡面由缓变陡呈先增加后降低的变化;(4)在降雨量相等的前提下,大降雨强度能够带来较大的单位时间产流量,但并不能保证总产流量也最大;在其他条件一致时,坡面侵蚀随着降雨强度的增大而增加.在降雨强度一定的条件下,坡面产沙量存在临界坡度,不同土质、不同降雨强度下的临界坡度尚需进一步研究.

为评价河北省太行山区经济林水源涵养功能,选择梯田栽植的苹果、核桃、樱桃、板栗、杏5种经济林,采用室内浸水法和环刀法等研究其林下枯落物和土壤的持水特性和持水效益,分析其水文效应.结果 表明:枯落物蓄积量表现为杏(3.42 t/hm2)＜樱桃(3.69 t/hm2)＜苹果(4.07 t/hm2)＜板栗(7.11 t/hm2)＜核桃(8.28 t/hm2);板栗林下枯落物最大持水量(17.07 t/hm2)最大,枯落物的持水量与持水时间正相关呈对数函数关系,持水速率与持水时间呈幂函数关系;至于林下枯落物有效拦蓄量,板栗林最大(14.37 t/hm2).5种经济林林下土壤容重均值在1.40～1.52 g/cm3,随深度增加而增大;土壤的最大持水量均值在856.01～946.41 t/hm2,其排序与总孔隙度一致,依次为苹果＜核桃＜樱桃＜板栗＜杏;有效持水量均值在185.82～329.03 t/hm2,排序与非毛管孔隙度一致,依次为樱桃＜苹果＜核桃＜板栗＜杏.

[目的]探索河北省太行山区4种经济林林冠层的水文效应,揭示其水源涵养功能.[方法]选取位于石家庄市西南部山区的核桃、苹果、杏、樱桃成林,雨量筒测定穿透雨量,树干缠绕法测定树干径流量,分析林冠层水文效应.[结果]4种经济林的林内穿透雨量、树干径流量均随林外降雨量增加而增大;林外降雨量达到45.1 mm之前,林冠截留量随之增加而增大,之后增大趋势减缓;次降雨量在14.3～29.5 mm时,4种经济林的林冠截留作用最大,截留量占比均在20％以上;林外降雨量一定的情况下,4种经济林林冠层对降雨的截留量有较大差异,其排序为:樱桃＞苹果＞核桃＞杏,与郁闭度大小排序一致,林内穿透雨量与截留量排序相反;树干径流量排序为:樱桃＞杏＞核桃＞苹果,与平均地径大小排序基本一致.[结论]4种经济林林冠层对降雨的再分配作用明显,林冠截留作用主要与林外降雨量有关,受林分类型、树冠结构特征如郁闭度、树木地径等的影响.

Objective] The differences in litter water‐holding characteristics of different plantation types were investigated to provide scientific basis for understanding the forest hydrological cycles and its management in study area .[Methods] Larix principis‐rupprechtii and Betula platyphylla plantations in Chongli mountain of Zhangjiakou City were chosen in this study .We established standard plots under the two forest types . The depth and storage of the litter layer were measured and water‐holding characteristics of litter were meas‐ured using immersion method .[Results] The litter was as thick as 4 .2 cm and 3 .4 cm and the total litter vol‐ume was 10 .90 t/hm2and 4 .92 t/hm2 in the L .principis‐rupprechtii and B .platyphylla plantations ,re‐spectively .The maximum water holding capacity (measured after 24 h immersion) of litter layer in L .princi‐pis‐rupprechtii and B .platyphylla were 4 228 .5 g/kg and 5 208 .6 g/kg ,and the corresponding effective water holding capacity were 14 .06 t/hm2 and 8 .85 t/hm2 ,respectively .During the whole water holding process ,the water holding capacity ,absorption and the immersed time change with same trend ,they were superior to the rest of time in the first 4 hours and the water holding capacity reached saturation after 10 h immersion .In addition ,the relationship between litter water holding capacity and immersed time followed a logarithmic curve ,and that between the water absorption rate and immersed time was fitted well with a power function .[Conclusion ] Hydrological function of forest litter is regulated by both litter storage and water‐holding capacity .Some factors ,such as species composition and stand density ,should be considered in forest management .

In order to study the effect of Salix psammophila checkerboard sand barrier on the composition and characteristics of particle size quantitatively,the drifting sand dune(LS),the sand dune with sand barrier of two years(TS) and the sand dune with sand barrier of six years(SS) were studied.Samples were taken on different parts of sand dunes and in different layers of sand and on different positions of checkerboard sand barrier,and composition and characteristics of particle size were studied.The results can be seen as follows:(1) with the sand barrier setting time increases,the content of silt and clay increases and the content of fine sand deceases.The content of silt and clay of SS shows significant difference with the content of silt and clay of TS and LS,when there is no significant difference between TS and LS;There is no significant difference in the content of each particle size in the three sand layers of LS and TS,but the volume content of silt,clay and fine sand of 0-5cm of SS is different from the two other layers.(2),The rangeability of frequency distribution curve of SS is smaller than the rangeability of TS and LS.The order of average particle MZ,sorting coefficient δ,skewness SK and kurtosis KG of each sand dunes is SSTSLS,each particle parameters of SS are significant different from the two other sand dunes,and there is no significant difference between TS and LS,and the order of each particle parameters of each layers of SS and TS is 0-5cm5-10cm10-15cm,but the particle parameters of each layers of LS have no significant difference.(3) The content of silt and clay of SS and TS on the northwest and southeast corner of the checkerboard sand barrier is bigger than the content in the center of the checkerboard sand barrier,and each particle parameters in the center of the checkerboard sand barrier are smaller than the ones on the northwest and southeast corner.

With mobile dune as control,the Salix psammophilacheckerboard sand barrier which specification was 1.5m×1.5m,with period of 2a,4aand 7awas studied.The wind velocity,sediment discharge and the erosion-deposition status at seven locations(the low land,the lower part of windward slope,the middle part of windward slope,the upper part of windward slope,the top part,the middle part of leeward slope,the lower part of leeward slope)of dune were analyzed.The result showed that:The effect of the Salix psammophila checkerboard sand barrier on reducing the wind velocity tended better along with the period longer.As to the height of 2m,that of 0.2mhad a significant decrease on wind velocity.Relation to the effect of the windbreak,the 4-year sand barrier was the best while the 2-year was the worst.The windbreak effect of dune with the sand barrier at different locations,that was the effect decreased from foots of slope to the top,and that of windward was better than leeward.The low land had the best effect of windbreak.Barrier could increase surface roughness,reduce sediment discharge and weaken the intensity of the corrosion product.The sediment discharge and wind erosion intensity was inversely proportional with the barrier period tends longer.With the period of the barrier longer,sediment discharge and erosion intensity reduced in different degrees.The period of barrier year was unary quadratic equation of wind erosion depth at center of checkerboard sand barrier.The sediment discharge and the intensity of the wind erosion showed a trend of increase from foots of slope to the top.

Enclosure is one of the effective measures for ecological restoration of degraded grassland.On the basis of existing research,the effect of enclosure on plant diversity,biomass,vegetation succession,soil physical and chemical property were summarized and six contents and directions were proposed about degraded grassland enclosure research in future.Conclusion: As a result of different geographical area,climatic conditions and degradation degree before enclosure,vegetation diversity under enclosure appeared three results,significant increase,stability and dramatic decline.Biomass increased in the early period of enclosure,and for long time enclosure biomass could not keep the increasing tendency.In addition,enclosure could increase population colonizing ability and community resources redundancy,prompt the improvement of soil seed bank structure,increases of density and positive succession of prairie which may appear three succession modes.Enclosure improved the physics properties of soil,since at soil surface "tight layer" was eliminate,but conclusions of enclosure effect on soil nutrients were not too consistent.