【作者】 周宏民；

【导师】 康绍忠；

【作者基本信息】 西北农林科技大学 ， 农业水土工程， 2012， 硕士

【摘要】 研究土壤水分特性的空间分布特征对研究土壤中物质与能量的交换，推动土壤与水科学等的发展具有重要的意义。在干旱地区土壤盐渍化现象十分普遍，土壤盐渍化不仅会影响作物生长，而且还间接造成生态环境恶化，因此有必要对土壤中的盐分状态进行研究。本文以西北旱区一葡萄园为研究对象，采用理论分析与室内外试验相结合的方法研究了葡萄园内土壤水分特征参数的空间特征，不同生育期灌水后不同时间不同深度处土壤水分的变异性，灌水后不同时间不同深度土壤盐分的空间变异性以及葡萄整个生育期蒸发蒸腾量的空间变异性。以期通过研究为葡萄园的精准灌溉和土壤盐渍化防治提供依据。取得了以下结果：（1）用Van Genuchten模型对葡萄园内实测的土壤水分特征曲线进行拟合，并对模型参数的空间变异性进行探讨。结果表明，饱和含水量θs和形状参数n具有中等偏弱的变异性，并且饱和含水量θs和形状参数n的变异性随着深度的增加具有增大的趋势；形状参数a具有中等的变异性，其变异性明显比饱和含水量θs和形状参数n大。（2）葡萄不同生育期灌水后不同时间土壤水分的平均值随深度增加而增加，各层土壤含水量的最小值、最大值也随着深度的增加而增加；不同生育期灌水后不同时间不同深度土壤水分具有中等变异强度，并且表层和根区土壤含水量的变异系数随时间增长而增大，深层的波动较小；试验设计的土壤水分采样数目满足置信度水平为95%，精度为10%时的合理取样数目。（3）指数模型和球状模型是适用于该葡萄园不同生育期灌水后不同时间各层土壤水分的最佳半方差模型；各个生育期灌水后不同时间表层和深层处土壤水分具有强的空间相关性，不同生育期灌水后不同时间根区处土壤水分具有中等的空间相关性；以新梢生长期灌水后不同时间的土壤水分为例，做出了土壤水分的空间分布图。（4）不同时间各深度土壤电导率的平均值随着深度的增加而增大；不同时间各土层的电导率具有中等强度的变异性，表层电导率的变异系数变化幅度最大，根区和深层电导率的变异系数比较稳定。（5）葡萄园内灌水后不同时间各层土壤电导率的半方差函数适用模型为球状模型和指数模型；表层和根区土壤电导率具有较强的空间相关性，深层土壤具有中等的空间相关性；表层土壤电导率的自相关系数变化幅度比根区和深层的变化幅度大；各层土壤电导率的正相关性均随着滞后距离的增大而减小。从绘制的土壤电导率的克里金插值图中可以看出，不同时间各层土壤电导率呈斑状分布的格局。（6）采用水量平衡法计算出葡萄全生育期各个测点处的蒸发蒸腾量。葡萄全生育期的蒸发蒸腾量在285.27mm-495.85mm之间，具有中等强度的变异。葡萄全生育期蒸发蒸腾量的克里金插值图呈斑块状分布，通过葡萄全生育期蒸发蒸腾量空间分布图可以为葡萄的精准灌溉提供参考。更多还原

【Abstract】 The studies of spatial variability characteristics of soil properties had great significanceon matter and energy exchange of soil and promote the soil and water science development.In arid region, the soil salinization was very common. Soil salinization would not only affectcrop growth, but also indirectly lead to the deterioration of ecological environment, so, it wasnecessary to study the status of the salt in the soil. In this paper, the research was carried outat a vineyard in the Northwest Arid. Based on the method of theoretical analysis andlaboratory and field test, this paper studied the spatial variability of soil water retention curve,the spatial variability of soil moisture in different depth and time after irrigation at differentgrowth stages, the spatial variability of soil salinity in different time after irrigation and thespatial variability of grape’s evapotranspiration in the whole growth stage. Through the studycould provide certain scientific directions for precision irrigation scheme and soil salinizationprevention and treatment in this vineyard. The main conclusions were showed as follows:(1)The soil water retention curve of soil samples was simulated by Van Genuchtenmodel, and then the spatial variability of parameter of fitted model was studied. The variationcoefficient of saturated water content θsand shape parameter n belonged to moderate weakdegree of variation. The variance of θsand n became strength with the increasing of soil depth.The shape parameter (a) belonged to moderate degree of variation, and the variance of shapeparameter (a) higher than the variance of θsand n.(2)The mean value of soil moisture became strength with the increasing of soil depth indifferent time after irrigation at different growth stages, and the minimum soil moisture andthe maximum soil moisture at different soil depth became strength with the increasing of soildepth. The soil moisture in different time after irrigation at different growth stages belongedto moderate degree of variation. The variation coefficient of surface and root zone layerincreased with time, and the deep layer had small variation. The soil moisture samplingnumber in this trial fulfilled the reasonable sampling number which the Confidence level was95%and the accuracy was10% (3)The best semivariogram models of soil moisture were exponential model andspherical model in different time after irrigation at different growth stages in this vineyard.Surface and deep soil moisture showed strong spatial correlation. The root zone soil moistureshowed moderate spatial correlation. The spatial distribution maps of soil moisture weredrawn in different time after irrigation at shoots growth stage. The spatial distribution mapscould supply reference for precision irrigation in vineyard.(4)The average of soil electrical conductivity increased with the soil depth. The soilelectrical conductivity presented moderate variability. In different time after irrigation, theelectrical conductivity variation coefficient of surface layer fluctuated wildly, but theelectrical conductivity variation coefficient of root zone and deep layer kept stably.(5)The best semivariogram models of soil electrical conductivity were exponential modeland spherical model in different time after irrigation in this vineyard. Surface and root zonesoil electrical conductivity performed strong spatial correlation, and deep layer soil electricalconductivity performed moderate spatial correlation. The autocorrelation coefficient ofsurface soil layer fluctuated wilder than root zone and deep layer. Positive correlation of soilelectrical conductivity decreased with the lag distance. The spatial distribution maps of soilelectrical conductivity showed patch distribution in different layer after irrigation.(6)The evapotranspiration of wine grapes at each sampling location were calculated bywater balance method in the whole growth stage. Evapotranspiration of the grapes in thewhole growth stage were between285.27mm and495.85mm, and showed moderatevariability. The map of evapotranspiration performed patch distribution in the whole growthstage, and it could supply reference for precision irrigation in vineyard.更多还原