小流域坡面产流汇流模拟研究

根据山区流域雨水坡面产流、汇流及侵蚀特点,采用单元子流域的概化方法,把小流域概化为若干子流域,考虑流域降雨及下垫面条件的空间变化,建立了流域坡面产流、汇流模型,并得到了不同降雨历时的坡面流运动波模型的近似解。通过对坡面产流方式的分析,得到了坡面水力侵蚀区以“蓄满产流”为主,而重力侵蚀区以“超渗产流”为主的重要结论,对扩展山区小流域雨水集流利用具有重要意义。     

Water transport under winter conditions

Winter as well as summer floods result in soil loss and sedimentation. Up to now the winter events cannot be adequately predicted. This paper focuses on the infiltration processes under frozen winter conditions in order to model soil erosion processes in winter by adapting the computer model EROSION 3D [Schmidt, J., Werner, M. v., 2000. Modeling Sediment and Heavy Metal Yields of Drinking Water Reservoirs in the Osterzgebirge Region of Saxony (Germany). In: Soil Erosion - Application of Physically Based Models, Schmidt, J.(Editor). Berlin, Heidelberg, New York., pp. 93-108.].A new snow accumulation and snow melt module has been implemented in order to estimate erosion rates during snowmelt events. Tests show that infiltration still occurs in frozen soils, however, infiltration rates are reduced compared to unfrozen soils [Weigert, A., Wenk, G., Ollesch, G., Fritz, H., 2003. Simulation of snowmelt erosion using the EROSION 3D model. Journal of Plant Nutrition and Soil Sciences, 1/2003.]. In order to improve the EROSION 3D model regarding partly frozen soils a physical based infiltration model extension has been developed and experimentally verified.Processes of infiltration into partly frozen soils are successfully quantified by a newly designed experimental set-up using a soil column (height 50 cm, diameter 21.5 cm). At the bottom of this column a negative pressure can be applied in order to establish unsaturated hydraulic conditions. The volume rate of the percolating water is constantly measured by an online balance. In addition the column is equipped with three TDR and temperature probes.The behaviour of two soil samples (sandy vs. loamy soil) are investigated under saturated, unsaturated and frozen conditions. The improved physical infiltration model based on the combination of Darcy's Law, Hagen-Poiseuille's Law, the capillary-rise equation and the van Genuchten θ(h) function determines with considerable accuracy both the unsaturated hydraulic conductivity and the effective saturated hydraulic conductivity of a partly frozen soil for rigid soil matrix conditions. This approach is compared with the Mualem concept for predicting unsaturated hydraulic conductivities. Fractures were observed due to freezing cracks in case of loamy material. For fractured soils the calibration with a skinfactor is found to be absolutely necessary to give reliable results.     

红松人工林水文效应的初步研究

为了探讨人工林生态系统的生态功能与效应，根据生态学理论，采用长期定位观测的方法，系统地研究了东北林业大学老山人工林实验站地产流的特点。结果表明：⑴红松人工林对降雨的分配具有特殊的规律性，平均林冠截雨率为１３．４％，树干径流率为５．３％；⑵林内各降雨分量与林外降雨量呈显著的线性关系；⑶与落叶松人工林相反，红松人工林平均截雪率为３３．３％，明显强于截水能力；⑷红松人工林内地表径流很少发生，其他表径流率     

A Summary of Literature References of Factors Affecting Moisture Content Determination with D.C. Resistance Measurements

The protective effect of ectomycorrhizae of Pinus patula Schlecht. et Cham against the root pathogen Phytophthora cinnamomi was investigated. Three methods were employed to evaluate this effect. Firstly, extracts were prepared from the root systems of mycorrhizal plants and tested for antibiotic activity against P. cinnamomi. Secondly, fungal antagonism between two mycobionts Amanita muscaria and Boletus edulis, and the pathogen was tested for in vitro; and thirdly, in situ studies were conducted to determine the protective effect afforded under natural conditions. No fungal antagonism was observed in vitro, but significant protection was obtained in situ and when the pathogen was exposed to the extracts. The mechanism involved could thus probably be attributed to the production of antibiotic substances by the macrobiont and mycobiont, and the formation of a physical barrier, the Hartig-net and the fungal mantle.     

喷洒部件及喷雾助剂对担架式喷雾机在桃园喷雾中的雾滴沉积分布的影响

采用诱惑红为指示剂研究测定了喷洒部件以及喷雾助剂Silwet408对电动担架式喷雾机在桃园喷雾中的雾滴沉积分布的影响,试验结果表明：采用喷枪大容量喷雾,当施药液量为250 L/667 m2时,有35.2%的药液流失到地面,喷雾雾滴在桃树冠层内膛和外膛的上/下层沉积比分别为0.59和0.62;当在喷雾液添加0.1%的Silwet408并把施药液量降低到125 L/667 m2时,药液在地面的流失率减少到21.2%,喷雾雾滴在桃树冠层内膛和外膛的上/下层沉积比分别为1.28和1.19,沉积分布均匀性明显提高。采用装配小喷片的组合喷头喷雾,当施药液量为250 L/667 m2时,有28.4%的药液流失到地面,当在喷雾液添加0.1% 的Silwet408并把施药液量降低到185 L/667m2时,喷雾压力分别为0.25 Mpa和0.35 Mpa时,药液在地面的流失率分别减少到18.5%和8.6%。研究测定结果表明,通过更换喷洒部件、增加喷雾压力、减少施药液量、添加喷雾助剂等措施可以显著减少果园喷雾中的药液流失率、提高喷雾雾滴在桃树冠层的沉积分布均匀性。     

田间药液用量影响农药单位剂量防治效果的原因分析

【目的】分析药液用量与水稻植株持液量的关系,探索稻田药液用量影响农药单位剂量防治效果的机制,为科学使用农药提供依据。【方法】在喷雾状态下计量水稻单位面积的持液量变化,明确液体在水稻叶片上的流失点和稳定持液量。依照国家标准GB/T 5549-2010测定液体表面张力,利用表面活性溶液的表面张力随表面活性剂浓度变化的规律,测定表面活性剂溶液的临界胶束浓度;用Zisman的方法测定水稻叶片的临界表面张力,分析影响水稻叶片持液量的关键因子。在喷雾塔内模拟用氯虫苯甲酰胺防治稻纵卷叶螟、用吡蚜酮和毒死蜱防治褐飞虱的试验,分析药液用量与雾滴密度的关系及农药单位剂量对防治效果的影响。【结果】随着喷液量的增加,水稻叶片的持液量经历增加、达到最大值后开始流失、随之下降到稳定值并不再随喷液量而变化,与最大值比,稳定值减少持液量约50%。供试水稻的临界表面张力为29.90-31.22 mN·m^-1,为低能表面,清水的表面张力为71.8 mN·m^-1,大于水稻的临界表面张力,限制了水稻叶片的持液量;助剂TX-10和Silwet-408可使液体的表面张力小于水稻临界表面张力,增加水稻叶片的持液量,当助剂达到临界胶束浓度时,增加持液量的效果最好;喷液量影响雾滴密度,从而影响农药单位剂量的防治效果。雾滴体积中径为200 μm时,药液量150 L·hm^-2的雾滴少于10滴/cm²,20、25和30 g 3个有效剂量的氯虫苯甲酰胺对稻纵卷叶螟的防治效果不足60%;药液量450 L·hm^-2的雾滴少于40滴/cm²,氯虫苯甲酰胺3个有效剂量对稻纵卷叶螟的防治效果分别为56.92%、62.86%和65.07%;药液量900 L·hm^-2的雾滴为82滴/cm²,氯虫苯甲酰胺3个有效剂量对水稻纵卷叶螟的防治效果最好,达到70%以上。减小雾滴体积中径,增加单位体积液体的雾滴数量,可以适量减少喷液量。雾滴体积中径为75 μm、药液量450 L·hm^-2时,雾滴为140滴/cm²,氯虫苯甲酰胺防治稻纵卷叶螟的效果与雾滴体积中径为200 μm、药液量900 L·hm^-2的防治效果无显著差异。由于水稻冠层的阻挡,叶面喷雾时冠层下的雾滴极少,雾滴体积中径200 μm喷药液量900 L·hm^-2和雾滴体积中径75 μm喷药液量450 L·hm^-2,冠层下的雾滴不足20滴/cm²,农药对褐飞虱防治效果差。冠层下喷雾,直接将农药喷洒到褐飞虱栖息危害的部位,显著提高了吡蚜酮和毒死蜱单位剂量对褐飞虱的防治效果。【结论】药液用量影响农药在水稻植株上的沉积量和水稻单位面积上的雾滴密度,从而影响农药单位剂量对害虫的防治效果。当稻田药液用量在450 L·hm^-2（雾滴体积中径75 μm）或900 L·hm^-2（雾滴体积中径200 μm）,冠层上下喷雾均匀,能确保药液在水稻最大持液量范围内并使植株表面有足够的雾滴密度,可取得良好的防治效果。     

黄瓜叶片喷雾药液持留量试

为研究喷雾药液在靶标植株黄瓜叶片上的流失点与最大稳定持留量,以炮塔式压力雾化轴流风送高压静电喷雾系统为试验平台,采用微称量法对其进行了测量.引用润湿方程的基本理论,对影响持留量的因素(喷雾距离、雾滴叶面接触角及施药量)进行了分析,探讨各因素对药液持留量的影响规律.试验结果表明:随着喷雾距离的增加,药液在黄瓜叶片上的流失点和最大稳定持留量先上升后下降,最大值均出现在距离喷头125cm处;药液雾滴在黄瓜叶片上的接触角θ、粘附张力β、粘附功W_a和临界表面张力γ_0的稳定值分别为85.07°、6.17mN/m、77.97mJ/m~2、61.23mN/m;黄瓜叶片持留量在施药量为1.26～3.36kL/hm~2范围内出现峰值,超过该范围后持留量随着施药量的增加而减少并逐渐趋于稳定.     

桥山油松天然林水文效应的研究

探讨了３０年生油松天然林的水文效应。林冠截留量占大气降雨量２０．０２％,林内降雨量占７７．１５％,树干径流量占１．８０％;凋落物层的饱和持水量４．４７ｍｍ,有效持水量２．６１ｍｍ;年地表径流量６．６４１～１０．９９１ｍｍ,径流率１．２２％～１．４１％。     

卧龙巴郎山流域大气降水与河水关系的研究

根据四川卧龙自然保护区巴朗山流域皮条河河水的氢氧同位素组成分析,并与同期降水中氢氧同位素进行比较,研究了河水和降水氢氧同位素的变化规律.结果表明:(1)卧龙地区皮条河河水(δD～δ18O线性关系为:(δD = 3.888δ18O-45.614(R2= 0.494,p＜0.05,n=61).河水δD、δ18O变化幅度远小于降水δD、δ18O值的变化幅度.河水氘过量参数(d)与大气降水的氘过量参数(d)的季节变化趋势基本一致,冬春季氘过量参数(d)值较高,而夏秋季较低.(2)不同的季节,雪水和冰雪融水补给河水不同,雪水和冰雪融水补给河水主要发生在11月至翌年6月.(3)当降水量在0～10 mm时,降水δD、δ18O 的升高(或降低)引起河水δD、δ18O升高(或降低),这种影响在降水后第3天滞后发生.当降水量在10～20 mm时,降水δD、δ18O的升高或降低引起河水δD、δ18O升高或降低,这种影响在降水后第2天滞后发生.降水量在20～30 mm时,这种影响在降水后第1～2天发生.这表明河水δD、δ18O的响应时间与降水强度紧密相关,显示出发育良好的亚高山暗针叶林植被结构有利于土壤对降水的吸收、渗透和运移,从而调节和补充河川径流.     

试论森林水文效应趋向

总结了过去一段时间国内外森林水文效应的研究情况，在森林能增加水平降水、森林枯落物和林下土壤的涵养水源功能以及改良水质等方面达成共识，认为这些方面的效应为正效应，但森林对垂直降水的影响、对径流和洪水的影响等方面还存在分歧，其主要是由研究方法的差异、试验区域差异的不可比性、研究尺度的差异性和森林本身的异质性引起的。并提出今后森林水文生态效应的研究要结合水文过程的研究，对森林在水文循环中所起的作用和作用机理进行分析，建立具有不同下垫面特征的标准地尺度上的土壤——植被——所连续体模型，并与中尺度大气环流模式相嵌套，再分析流域、区域的森林水文生态效应。