炭添加物对基于粒径分析的砂性基质饱和导水率的影响(英文)

Estimatingwater conductivityof sand-based root zone materials from particle size distribution: effects of peat amendments

泥炭/砂混合物是一种广泛应用于高尔夫果岭坪床,运动场草坪,园艺盆栽,及滤水系统中的基质。然而,对于泥炭/砂混合基质水力特性的直接测量耗时较长。试验的目的为：（1）测试符合美国高尔夫协会（USGA）推荐标准的砂与高比例泥炭混合基质的饱和导水率（Ksat ）是否为层流并遵循达西法则。（2）研究泥炭类别和有机物含量对之前建立的预测饱和导水率的多重线性回归模型的准确性的影响。试验采用3种泥炭类别即木本泥炭藓（Peat,Inc.Minnesota,USA）,苔藓泥炭（Sun Gro Horticul-ture,Maryland,USA）和苇苔泥炭（Dakota Peat,North Dakota,USA）,并分别按照泥炭占0%,0.2%,0.4%,0.8%,1.6%,4%,8%和10%的重量配比与纯砂混合。试验评估的模型如下：Log10（Ksat）=5.3407-0.5286ρb-1.2846 CP-0.0442c＋0.0612φ5-0。6095φ95,其中ρb为容重（g/cm3）,CP 为毛管孔隙度（%）,c为粉粒含量（%）,φ5,φ10,φ16,φ84,φ95为土壤粒径分布曲线分析中以 phi （φ）为单位的粒径参数,其中φx=-log （2,d）,x代表筛析法测定下直径小于 d 的颗粒所占重量百分比。结果表明：在液压压力梯度小于3的范围内,混合基质饱和导水率为层流并遵循达西法则。结果也表明：除了含有配比超过4%的腐殖化程度低的苔藓泥炭混合基质外,对于有机物含量在0%~10%的泥炭/砂混合基质,该模型对饱和导水率的预测结果与实际测定结果符合度较好（R2=0.74）。

Sand and peat mixtures are widely used in constructed root zones of golf course putting greens and sports fields,containerized horticulture,and water filtering systems.Direct measurement of hydraulic properties often is time consuming.One of the objectives of this study was to test if saturated water flow is laminar and o-beys Darcy＇s law when a large amount of peat is mixed with sand that conform to the USGA specifications.An-other objective was to evaluate a previously developed multiple linear regression （MLR）model for predictingsat-urated water conductivity （Ksat）as affected by peat types and organic matter （OM）content.Woody sphagnum peat （Peat,Inc.Minnesota,USA）,sphagnum peat moss （Sun Gro Horticulture,Maryland,USA）,and reed sedge peat （Dakota Peat,North Dakota,USA）were mixed with sand at 0%,0 .2%,0 .4%,0 .8%,1 .6%, 4%,8%,and 10% （w/w）in the final mixtures.The model tested wasLog10（Ksat）=5.340 7-0.528 6ρb-1. 2846CP-0.044 2c＋0.0612φ5-0.6095φ95,withρb as bulk density （g/cm3）,CP as capillary porosity （%）,c as silt content （%）,andφ5 ,φ10 ,φ16 ,φ84 ,φ95 values from the particle size distribution curve representing grain size in phi （φ）unit.Briefly,φx= -log （2 ,d）,with x representing the percentage of sand mass smaller than d in size in a traditional particle size distribution curve.Results showed that Darcy＇s law prevailed at hydraulic pressure gradients up to 3 .Results also showed that,with exception of less humified sphagnum peat moss at 〉4%,the model provided fair predictions of Ksat （R2=0 .7 4 ）for OM content up to 1 0%.