有机物质类型与含量对土壤持水性能的影响

Effect of organic compounds content and types on soil water retention capacity

【目的】研究灌溉水中不同类型有机物质及其含量对土壤持水性能的影响。【方法】分别以不同含量的亲水性有机物质乙醇（0．0001％，0．001％，0．1％，1％，42．27％，100％）与疏水性有机物质苯酚（0．0001％，0．001％，0．003％，0．006％）水溶液为供试材料，用离心机法测定供试溶液饱和土壤的水分特征曲线，用VanGenu—chten模型（V—G）进行数学拟合，分析模型的相关参数以及土壤水分常数。【结果】pF为0～4．1时，乙醇对土壤水分特征曲线有不同程度的影响，其中乙醇含量高于0．1％时影响明显，且随乙醇含量增加土壤持水量和有效水的含量均呈递减趋势。乙醇对水分特征曲线VanGenuchten模型中土壤饱和含水量只的影响呈现凸峰特征，而对进气值倒数α影响呈现凹形特征。pF为O～1．5时，苯酚对于土壤持水性能有明显影响；随苯酚含量增加，θ1和α均呈递增趋势。乙醇对土壤水分常数与水分有效性的影响比苯酚明显。【结论】有机物质的类型和含量均不同程度地影响着土壤的持水能力，水中含有一定量的有机物质可以提高土壤的持水能力，其中亲水性有机物质乙醇的影响大于疏水性有机物质苯酚。

[Objective] The effect of different types of organic compounds content in water on soil water retention was studied in this paper. [Method] Ethanol and phenol presented hydrophilic matters and hydrophobic matters. Centrifugation was used to determinate soil water characteristic curve after soil satu- rated by ethanol and phenol solutions of different concentrations （ethanol, 0. 000 1%, 0. 001 %,0.1%, 1%, 42.27% and 100% ,phenol,0. 000 1% ,0. 001%,0. 003% and 0. 006%）. Van Genuehten Model was fitted to experimental data, and the influence of water quality on curve parameters and soil moisture constants was analyzed. [Result] Ethanol influenced soil characteristic curve differently when pF was from 0 to 4. 1. When the ethanol content was greater than or equal to 0. 1%, the effect was significant, and soil water- holding capacity and available water content decreased with the increase of ethanol content. Ethanol content had greater effect on θs, than other V-G model parameters. The effect tendency separately presented protuberance and concave. Phenol influenced soil characteristic curve only in low soil suction range （pF〈1. 5）.θs and increased as phenol content increased. Ethanol content has greater effect on a soil water parameters and soil water availability than phenol content. [Conclusion] The types of organic compounds affect soil water-holding capacity differently. A certain content of organic compound in solution improves soil water holding capacity,and ethanol,hydrophilic matter,has greater effect than hydrophobic matter phenol.