蓄水坑入渗表层土壤体积质量和饱和导水率的变化

表层土壤体积质量和导水率是影响土壤入渗及水分运动的重要物理参数。该文采用土壤切片技术和数字图像分析技术,分析了蓄水坑灌条件下入渗水头对砂壤土表层土壤体积质量的影响,进行了不同入渗水头、土壤体积质量对砂壤土表层土壤饱和导水率的试验研究,并对蓄水坑侧向水平入渗湿润锋变化的试验结果与数值模拟结果进行对比分析。结果表明：该研究试验条件下（土壤体积质量为1.345 g/cm3）,入渗水头对土壤体积质量和表层土壤饱和导水率有较明显的影响。随着入渗水头的增大,其作用下的表层土壤体积质量趋于增大,土壤结构趋于密实,表层土壤的饱和导水率趋于减小;表层土壤饱和导水率与入渗水头和土壤体积质量之间呈乘幂关系,且表层土壤饱和导水率对土壤体积质量的变化较为敏感,当土壤体积质量达到某一程度时（1.466 g/cm3）,入渗水头对表层土壤饱和导水率的影响甚微。研究成果揭示了入渗水头影响蓄水坑土壤入渗的微观机制,为进一步研究蓄水坑灌法提供了理论依据。     

夹砂层土壤Green-Ampt入渗模型的改进与验证

对于土层夹砂结构,湿润锋穿过砂层上界面时,入渗率变为稳渗率。为确定各因素下夹砂层土壤的稳渗率,在Green-Ampt入渗模型基础上,引入导水度系数(小于1)来量化上层土壤的导水程度,建立了改进的夹砂层土壤Green-Ampt入渗模型。采用HYDRUS-1D软件,模拟了不同土壤质地、初始含水率、压力水头、砂层埋深和砂层厚度条件下的稳渗过程,根据模拟结果分析了夹砂层土壤的入渗规律及其影响因素,稳渗率主要受土壤质地、压力水头和砂层埋深的影响。在相同压力水头、初始含水率和砂层厚度下模拟获得不同砂层埋深的稳渗率,并采用改进的Green-Ampt入渗模型拟合,求得导水度系数和进水吸力值。分析发现导水度系数变化较小,为简化计算,取其平均值0.95。在此基础上,提出了由土壤物理特性参数进气值倒数估算进水吸力的计算公式。利用秦王川地区的夹砂层土壤积水入渗试验及已有文献资料验证所建模型的有效性,结果表明所建模型待定参数少,计算误差基本在5%以内,且试验设计较简单,可为农田水分管理及工程防渗技术提供理论依据。     

应用土壤质地预测干旱区葡萄园土壤饱和导水率空间分布

田间表层土壤饱和导水率的空间变异性是影响灌溉水分入渗和土壤水分再分布的主要因素之一,研究土壤饱和导水率的空间变化规律,有助于定量估计土壤水分的空间分布和设计农田的精准灌溉管理制度。为了探究应用其他土壤性质如质地、容重、有机质预测土壤饱和导水率空间分布的可行性,试验在7.6 hm2的葡萄园内,采用均匀网格25 m×25 m与随机取样相结合的方式,测定了表层(0～10 cm)土壤饱和导水率、粘粒、粉粒、砂粒、容重和有机质含量,借助经典统计学和地统计学,分析了表层土壤饱和导水率的空间分布规律、与土壤属性的空间相关性,并对普通克里格法、回归法和回归克里格法预测土壤饱和导水率空间分布的结果进行了对比。结果表明:1)土壤饱和导水率具有较强的变异性,平均值为1.64 cm/d,变异系数为1.17;2)表层土壤饱和导水率60%的空间变化是由随机性或小于取样尺度的空间变异造成;3)土壤饱和导水率与粘粒、粉粒、砂粒和有机质含量具有一定空间相关性,而与土壤容重几乎没有空间相关性;4)在中值区以土壤属性辅助的回归克里格法对土壤饱和导水率的预测精度较好,在低值和高值区其与普通克里格法表现类似。研究结果将为更好地描述土壤饱和导水率空间变异结构及更准确地预测其空间分布提供参考。     

Regional pattern of the mobile water fraction in soils as determined by disc infiltrometer experiments

In order to characterize the partitioning of solutes into the mobile and the immobile fraction of pore water at the soil surface, field measurements of infiltration in unsaturated loamy sands were carried out using a disc infiltrometer in a region of about 10 km² at the Lüneburger Heide, Germany. The aims of these measurements were to obtain the mobile water fraction and the hydraulic properties of the soil, to relate them to other measured soil properties like the soil texture, and to assess their spatial variability in the region. From the infiltration results we obtained the hydraulic conductivity K₀ and the sorptivity S₀ using a three-dimensional infiltration analysis and the two-term infiltration equation, respectively. The mobile water fraction θ_m/θ of the soil was estimated from the infiltration results of a second disc infiltrometer filled with bromide solution. The estimated values of K₀ and S₀ were in good agreement with those reported in the literature as typical for loamy sands. The average value of θ_m/θ was calculated to be 71 % under the experimental conditions. Neither the horizontal spatial distribution of water and bromide concentration beneath the disc infiltrometer nor the change of the infiltrometer during the experiment had a notable influence on the experimental results. The spatial variability of the data was analyzed by means of variograms. All variograms were spatially structured and indicated a high small scale variation of the variables. In conclusion, the technique applied is suitable for the estimation of the hydraulic and solute transport properties of soils, especially at larger scales.     

不同含盐土壤圆盘入渗特征试验

不同含盐土壤水分入渗特征是获得准确的土壤水力参数的基础。该文通过圆盘入渗试验,分析了4种土壤在5个（-1、-3、-6、-9和-12 cm）负水头下的入渗特征。结果表明,随着水头的减小,4种土壤的吸湿率线性减小,稳定入渗率和非饱和导水率呈不同程度减小。随土壤含盐量增加稳定入渗率和导水率呈增大规律。根据实测资料确定了不同负水头下非饱和导水率的Gardner指数模型参数,为盐渍化土壤水力参数的确定提供理论参考。     

双环入渗仪的缓冲指标对测定土壤饱和导水率的影响

双环入渗仪在测定田间土壤饱和导水率时被广泛采用。本文采用不同直径的双环入渗仪(内环直径分别为20 cm、40 cm、80 cm和120 cm)和不同的内外环直径比,即不同的缓冲指标(0.2、0.33、0.5和0.71),进行了16组定水头积水入渗试验,研究了双环入渗仪缓冲指标对土壤饱和导水率测定的影响。结果表明:内环直径较小的入渗仪,其累积入渗过程曲线的分布较分散;随着入渗环直径逐渐增大,分散范围逐渐缩小。另外,随着缓冲指标的逐渐增大,测定的土壤饱和导水率并没有明显的增大或减小趋势,但内环直径20 cm的入渗仪测定的土壤饱和导水率的波动最大,而80 cm和120 cm内径的双环入渗仪测定的土壤饱和导水率最稳定,并且始终非常接近。因此,相对于双环入渗仪内环大小或土壤非均质性的影响,双环入渗仪的缓冲指标对于土壤饱和导水率测定的影响要小。     

入渗水水质对土壤导水特性影响的试验研究

为探究不同入渗水水质对土壤导水特性的影响,采用圆盘负压入渗法进行试验研究,选取两种水质(蒸馏水和自来水)对黄壤和红壤进行4个压力水头(0,-3,-6,-9cm)下的圆盘入渗试验。结果表明,随着入渗水电导率的增大,土壤入渗率、吸渗率及导水率均随之增大,且红壤在不同电导率的入渗水作用下土壤吸渗率的变化差异显著(P0.05)。在低水头压力下,两种水质入渗条件下测得的土壤导水率差异显著(P0.05);在高水头压力下,两种水质入渗下测得土壤导水率差异不显著,表明入渗水水质对土壤导水率的影响主要发生在低压力水头下即在细孔隙下的导水特性上。两种土壤的大孔隙与中等孔隙对水流贡献率随入渗水电导率的增大而增大,而小孔隙对水流贡献率随入渗水电导率的增大而减小,入渗水水质对红壤土不同级别孔隙水流贡献率的影响显著(P0.05)。研究分析相关参数的变化有利于探讨野外试验时入渗水水质对试验结果的影响,对于正确认识农田水文过程、开发利用劣质水资源、提高农业灌溉灌水质量和灌水效率等具有重要意义。     

多因素作用下浑水入渗对土壤导水特性的影响

浑水土壤入渗具有复杂的上边界变化过程,其上边界导水能力的变化规律是研究浑水土壤入渗特性的重要基础。为研究浑水入渗形成致密层过程中导水率的变化情况,该研究进行了17组(9组正交试验处理,8组用于模型验证)浑水饱和土柱入渗试验,通过对试验结果进行多元回归构建多因素(浑水含沙率、黏粒含量及入渗时间)影响下砂土导水率动态模型;并结合浑水饱和土柱入渗特性进行合理假设,分别建立浑水砂壤土和粉壤土饱和土柱导水率动态模型并进行验证。结果表明:浑水含沙率、黏粒含量及入渗时间对砂土导水率影响极显著(P<0.01),入渗时间为砂土影响导水率变化的主要因素,其次为含沙率和黏粒含量;建立的砂土导水率动态模型决定系数为0.853,均方根误差为0.004 cm/min,表明该模型可客观反映各因素与导水率之间的关系;模型验证试验结果中均方根误差小于0.01 cm/min,相对误差绝对值均值小于7%,说明该导水率动态模型可靠性较高;砂壤土和粉壤土导水率动态模型决定系数分别为0.912和0.930,均方根误差分别为2×10^-3和5×10^-5 cm/min;模型验证中均方根...     

砂层在黄土中发生指流条件的试验研究

根据层状结构土壤在积水入渗过程中存在发生指流的现象,该文针对黄土地区"垆盖砂"的土壤条件,在室内以西安黄土为主体,对6种不同粒径的砂质双层结构土壤进行积水入渗试验,以观测研究发生指流的现象、机理与条件.研究表明:决定砂质双层结构能否发生指流现象的重要因素,一是入渗水流进入砂层后的稳渗率;二是表征砂层物理特性的饱和导水率;并以二者的比值做为判断发生指流现象的一个重要量化指标.根据试验分析,可将该比值＜0.02作为砂层发生指流现象的临界值.该指标也表明,当进入砂层的稳渗率小于砂层饱和导水率1/50时,即可发生明显的指流现象.     

六盘山华北落叶松坡面土壤饱和导水率空间异质性及其影响因素

为深入理解森林坡面土壤饱和导水率的空间变异,利用经典统计学和地统计学的方法研究六盘山华北落叶松人工林坡面不同土层土壤饱和导水率的空间异质性,并基于相关性分析揭示其空间变异的主要因素。结果表明:(1)随土层的加深,土壤饱和导水率逐渐增加,不同土层土壤饱和导水率的空间变异程度存在差异,表现为40—60 cm土层土壤饱和导水率为强变异,其他土层均为中等变异。(2)不同土层土壤饱和导水率的空间结构也存在差异,20—40,40—60,60—80 cm土层土壤饱和导水率表现为强烈的空间自相关性,0—20,80—100 cm土层土壤饱和导水率表现为中等空间自相关性。(3)坡面土壤饱和导水率与石砾含量、非毛管孔隙度、毛管持水量、田间持水量和毛管孔隙度显著相关。综上,研究坡面土壤饱和导水率具有较强的空间变异,石砾含量和土壤物理性质是影响研究坡面土壤饱和导水率空间分布的主要因素。     

盘式入渗仪法测定喀斯特洼地土壤透水性研究

研究土壤水入渗有助于了解喀斯特地区表层岩溶带对降水资源的调蓄作用。该文利用盘式负压入渗仪(盘径d=20 cm,负压h0=-20 mm)研究了桂西北喀斯特洼地典型剖面各层次土壤透水性。结果表明:各层土壤透水性能差异较大,具有随土层深度增加而减小的趋势,但菜地50-80 cm层大于20-50 cm层;菜地剖面0-10 cm层土壤近似饱和导水率(1.85×10-3cm/s)是20-50 cm层的5.2倍,玉米地剖面0-16 cm层土壤近似饱和导水率(2.21×10-3cm/s)是55-70 cm层的3.1倍;土壤比重、初始含水率同土壤入渗性能关系密切,与近似饱和导水率的相关系数分别为-0.676*和-0.841**。     

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.     

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.     

A study of some tillage practices for sustainable crop production in India

Soil tilth has been defined in terms of a ‘Physical Index’ based on the product of the ratings of eight physical properties — soil depth, bulk density, available water storage capacity, cumulative infiltration or apparent hydraulic conductivity, aggregation or organic matter, non-capillary pore space, water table depth and slope. The Physical Index and a tillage guide were used to identify the tillage requirements of different soils varying in texture from loamy sand to clay in the semi-arid tropics. The physical index was 0.389 for a loamy sand, 0.518 for a black clay loam and 0.540 for a red sandy loam soil and the cumulative rating indices in summer and winter seasons were 45 and 44 for loamy sand, 52 and 51 for red sandy loam and 54 and 52 for black clay loam soils, respectively. The compaction of the loamy sand by eight passes of a 490 kg tractor-driven roller (0.75 m diameter and 1.00 m length) increased the physical index to 0.658 and chiselling of the red sandy loam and black clay loam increased the physical indices to 0.686 and 0.729, respectively. The grain yields of rainfed pearl millet and guar and irrigated pearl millet, wheat and barley increased significantly over the control (no compaction) yields by compaction.

The chiselling of the soils varying in texture from loamy sand to clay at 50 to 120-cm intervals up to 30–40 cm depth, depending upon the row spacing of seedlines and depth of the high mechanical impedance layer, increased the grain yields of rainfed and irrigated maize on alluvial loamy sand, rainfed maize on alluvial sandy loam and red sandy loam, rainfed sorghum on red sandy loam and black clay loam, irrigated sorghum on black clay loam and rainfed black gram on red sandy loam, pod yield of rainfed groundnut, tuber yield of irrigated tapioca and fresh fruit yield of rainfed tomato on red sandy loam and sugarcane yield on black clay soil, significantly over the yields of no-chiselling systems of tillage such as disc harrow and country plough.     

坡面尺度土壤特性的空间变异性

通过对20m长坡面土壤特性空间变异性的经典统计学分析,结果表明:(1)在同一土壤剖面内,各级粒径含量呈弱变异性,而有机质含量随土层深度的增大而逐渐降低,呈中等变异性;(2)土壤干容重的空间变异性较小,呈弱变异性,但土壤饱和导水率的空间变异性较大,呈中等变异性;(3)水分特征曲线具有一定的空间变异性,比水容量空间变异性较大,呈中等变异性。坡面土壤饱和导水率和干容重的等值线图表明,土壤饱和导水率的变化趋势并不仅仅取决于土壤干容重的相对大小,可能与有机质含量、黏粒含量以及根系分布情况等也有一定的关系。     

黄土高原生态工程区土壤容重及饱和导水率的分布特征

土壤水力性质是影响水分运动、溶质运移以及流域水文模型模拟的重要参数。近年来,黄土高原实施的退耕还林(草)工程、治沟造地工程等重大生态工程,影响了该区域的地形地貌、土壤水力性质等。深入研究流域尺度土壤容重(Bulk Density,BD)与饱和导水率(Ks)的动态变化特征,对于理解重大生态工程影响下的水文过程演变规律具有重要意义。本研究以黄土高原重大生态工程影响的典型小流域为对象,采用80m×80m的网格布点(89个样点),分别于2016年9月(夏末)、11月(初冬)和2017年3月(初春)采集土壤表层(0～5 cm)环刀样品,分析BD和Ks的动态分布特征及其影响因素。结果表明:BD在0.93～1.61 g/cm3之间变动,Ks介于0.01～7.30 cm/min;BD呈弱变异性,变异系数(Coefficient of Variation,CV)为10%,而Ks呈强变异性(CV=166%)。坡面BD显著小于沟底(P0.05),而Ks则显著大于沟底(P0.05)。坡面林地和草地BD表现出显著的季节性差异(P0.05),而Ks在林地、灌木和草地之间均表现出显著的季节性差异(P0.05)。地形对流域内的土壤水力参数分布有显著影响,外界环境(温度)变化是决定BD和Ks呈季节性动态变化的重要因素。多因素方差分析表明土地利用类型对BD与Ks均有显著影响;采样时间对Ks有显著影响,对BD无显著影响。相关结果可为揭示重大生态工程区小流域土壤水力参数的动态变化规律及其主控因素提供数据支撑和理论参考,有助于小流域水文过程的模型模拟研究与精细调控。     

Spatial variability of Southeastern U.S. Coastal Plain soil physical properties: Implications for site-specific management

Our objectives were to describe the field-scale horizontal and vertical spatial variability of soil physical properties and their relations to soil map units in typical southeastern USA coastal plain soils, and to identify the soil properties, or clusters of properties, that defined most of the variability within the field. The study was conducted on a 12-ha field in Kinston, NC. A 1:2400 scale soil survey had delineated three soil map units in the field: Norfolk loamy sand, Goldsboro loamy sand, and Lynchburg sandy loam. These are representative of millions of hectares of farmland in the Coastal Plain of the southeastern USA. Sixty soil cores were taken to ∼ 1-m depth, sectioned into five depth increments, and analyzed for: soil texture as percentage sand, silt, and clay; soil water content (SWC) at − 33 and − 1500 kPa; plant available water (PAW); saturated hydraulic conductivity (Ksat); bulk density (BD); and total porosity. A penetrometer was used to measure cone index (CI) at each sample location. Variography, two mixed-model analyses, and principal components analysis were conducted. Results indicated that soil physical properties could be divided into two categories. The first category described the majority of the within-field variability and included particle size distribution (soil texture), SWC, PAW, and CI. These characteristics showed horizontal spatial structure that was captured by soil map units and especially by the division between sandy loams and finer loam soils. The second class of variables included BD, total porosity, and Ksat. These properties were not spatially correlated in the field and were unrelated to soil map unit. These findings support the hypothesis that coastal plain soil map units that delineate boundaries between sandy loams versus finer loam soils may be useful for developing management zones for site-specific crop management.     

Pedotransfer Functions for the Estimation of Saturated Hydraulic Conductivity for Some Indian Sandy Soils

Determination of the saturated hydraulic conductivity (k_s) is needed in many studies and applications related to irrigation, drainage, water movement and solute transport in the soil. Although many advances are made for direct measurements of k_s, they are usually time consuming and costly. Some attempts have been made to indirectly predict the saturated hydraulic conductivity from the more easily or readily available basic soil properties. The objective of this study was to develop and validate Pedotransfer Functions (PTFs) for estimation of saturated hydraulic conductivity using multiple non-linear regression technique. One hundred and one soil samples were collected from agricultural and forest soils at different depths, at different locations in the Pavanje River basin that lies in the southern coastal region of Karnataka, India. Saturated hydraulic conductivity was measured, by variable falling head method through Permeameter in the laboratory. Prediction accuracies were evaluated using coefficient of determination, root mean square error, mean error, geometric mean error ratio and geometric standard deviation of the error ratio between measured and predicted values. The results show that, the PTFs for the estimation of saturated hydraulic conductivity could be used appropriately for the soils with loamy sand and sandy loam textures falling in this area of the coastal region of southern India.     

祁连山区不同尺寸双环入渗仪对比试验

设计7组不同内外径的双环入渗仪,在位于祁连山区的黑河上游平坦草地开展多次野外土壤入渗试验,对比分析双环入渗仪内外环尺寸对土壤入渗率和饱和导水率的影响。结果表明,双环入渗仪内径相同时,外径越大则稳定入渗率和饱和导水率越小;外径相同时,内径越小则稳定入渗率和饱和导水率越小。初始入渗率与双环入渗仪尺寸关系不显著,但稳定入渗率和饱和导水率与入渗仪缓冲指数呈显著负相关。综合考虑安装简便,用水条件,试验可靠等多方面因素,推荐山区使用内径20cm,外径40cm的双环入渗仪。     

土壤质地和灌水器材料对负压灌溉出水流量及土壤水运移的影响

负压灌溉法是一种新近提出的节水灌溉技术,灌溉时供水水头为“负值”,即灌溉水源高程低于灌水器高程。不同材料灌水器和土壤质地是影响灌溉系统出水流量及土壤水运移的重要因素。该文研究了在高程差H为-0.5 m情况下两种灌水器及两种质地土壤对两者的影响。结果表明：灌水器相同时,累计入渗量、水平和垂直最大湿润距离随时间呈幂函数关系变化;在历时相同时黏壤土较砂壤土大;湿润体近似为六分之一的竖直椭球体,但黏壤土水平与垂直最大湿润距离之比大于砂壤土。土壤质地相同时,纤维灌水器较陶土灌水器出水流量高。试验结果进一步证明了负压灌溉的可行性,并为确定负压灌溉系统应用范围及规划设计过程中灌水器选择提供了依据。