Experimental Study of Soil Particle Size, Bulk Density, and Crop Straw on the Water Diffusivity of Sandy Loam

不同容重、粒徑和混摻比例條件下沙壤土水分擴散率的試驗研究

古萊姆拜爾．艾爾肯(Gulaimubaier．Aierken) ； Hudan Tumarbay

《台灣水利》 69卷3期 (2021/09) Pp. 36-45

https://doi.org/10.6937/TWC.202109/PP_69(3).0005

摘要

The soil particle size, bulk density, and proportion of straw are important parameters that affect the diffusion rate of water in soil. The influence of these factors on soil water diffusivity varies considerably, resulting in different sensitivities in various models. Therefore, the previous simulation results that are obtained based on a single model exhibit large errors. In this study, we consider the sandy loam from cotton fields with long-term sub-membrane drip irrigation as an example. The soil particle size, bulk density, and the proportion of straw were observed to be the control variables. We explored the sensitivity of these three variables on each model in RETC. We found that: (1) soils with large particles have a higher moisture diffusion rate. However, the water-retaining efficiency decreases as the particle size increases; (2) an increase in the soil bulk density inhibits water diffusion, lowers the infiltration rate, and increases the water retention per unit volume; (3) straw is beneficial to the water diffusion rate and infiltration efficiency. The results of the RETC simulation exhibit that the soil particle size was sensitive in the VGM model, while the soil bulk density and straw mixture were sensitive in the BCM model. This study is important as a reference for selecting a simulation model of soil hydrodynamics.

關鍵字

Different condition ； Soil water diffusivity ； Soil volumetric water content ； Mixing proportion

並列摘要

土壤粒度、容重及稈混摻比是影響土壤水分擴散率的重要參數，這些因子對土壤水分擴散率影響機制的差異較大，致使其對各種模型的敏感性不同。因此，以往基於單壹模型的模擬結果存在較大的誤差。本文以長期進行膜下滴灌的棉田沙壤土為例，以土壤粒徑、容重及稈混摻比為控制變量，探究了這三種變量對RETC軟件中各模型的敏感性。研究結果表明：（1）大粒徑土壤有利於土壤水分擴散率，但是其保水效率隨粒徑的增大而減小。（2）土壤容重的增大會抑制水分的擴散及入滲速率，增大單位體積的保水量。（3）稈混摻有利於土壤水分擴散率及入滲效率。RETC模擬結果顯示，粒徑對VGM模型的敏感性較高，而土壤容重和稈混摻比對BCM的敏感性更高。本研究對於模擬土壤水動力學過程中的模型選定具有重要的參考價值。

並列關鍵字

不同條件 ； 土壤水分擴散率 ； 土壤體積含水率 ； 混摻比例