PAA对不同土壤保水和蒸发性能的影响

Effects of PAA on Soil Preserving Water and Evaporation

采用土柱法研究了不同PAA施入量对3种黄土高原主要土壤类型(黄绵土、黑垆土和塿土)的持水性能、土壤饱和导水率和土壤蒸发量的影响,以进一步阐明PAA的保水和蒸发作用。结果表明,施入PAA提高了土壤的持水性能。在未加入PAA之前黑垆土的持水性能最低,塿土的最高,黄绵土的次之;加入PAA后,黑垆土的持水能力显著增加,几乎为对照的2倍,塿土和黄绵土也都比对照高。土壤的供水能力随PAA用量的增加而增强,不同土壤类型之间表现为:塿土>黑垆土>黄绵土。未加入PAA时,3种土壤饱和导水率大小为:塿土>黑垆土>黄绵土;加入PAA后,3种土壤的饱和导水率都降低,且基本随PAA用量的增加而降低。在一定水分条件下,PAA的施入提高了土壤的抗蒸发性能,随PAA用量的增加,塿土和黑垆土的土壤蒸发量增加,但都低于对照,而黄绵土的土壤蒸发量随PAA用量的增加而降低。其中施PAA54.5 mg/kg的塿土、黑垆土和施PAA225.8 mg/kg的黄绵土与对照相比,土壤蒸发量分别减少了44.0%,44.6%和30.6%。

In order to clarify the effect of water conservation of PAA on main soil, such as Lou soil, Loessal soil and Dark loessial soil, of loess plateau, a method of soil column was used to measure soil water retaining capability, soil saturated hydraulic conductivity and evaporation capacity in three kind of soil of loess plateau by labtest. The results indicate that soil moisture was increased after applying PAA to field. When the PAA was not applied, the capability of preserving water of dark Loessial soil was lowest, that of Lou soil is highest, and that of Loessal soil is middle. After applying the PAA, the capability of preserving water of Dark loessial soil increased significantly, almost two times compared with CK, and that of Lou soil and loessal soil were higher than CK. Soil water-supplying capability enhanced with the increase of PAA. Between the 3 soils, the soil water-supplying capability showed Lou soil〉Dark loessial soil〉Loessal soil. When the PAA was not applying, the soil saturated hydraulic conductivity indicated Lou soil〉 Dark loessial soil〉Loessal soil. However, the saturated hydraulic conductivity of 3 soils reduced with the increase of it when the PAA was applied. Under the soil moisture, soil anti-evaporation enhanced when the PAA was utilizing, and evaporation of Lou soil and Dark loessial soil improved with the increase of PAA, but lower than CK. Evaporation of Loessal soil decreased with the increase of PAA. For example, the evaporation of three soils（Lou soil： PAA54.5 mg/kg, Dark loessial soil and loessal soi1：225.8 mg/kg） reduced respectively by 40.0%, 44.6%, and 30.6% compared with CK.