掺砂对土壤水分入渗和蒸发影响的室内试验

通过掺砂调控农田土壤水分入渗和蒸发，对新疆干旱绿洲农田抑盐、保水及合理的掺砂制度制定具有重要意义。该研究以不同的掺砂率为影响因子进行土柱模拟试验，设置了4个掺砂率水平，分别是0（对照）、25%、50%、75%。结果表明：不同掺砂率条件下湿润锋和累积入渗量与入渗历时有显著地乘幂关系，影响顺序为75%＞50%＞25%＞0，且在掺砂率≥25%影响幅度较大；不同掺砂处理对土壤水分蒸发过程同样也有显著地影响，随着掺砂率的增加，土壤蒸发显著减弱，随着掺砂率的增加，抑制土壤蒸发越强，且在掺砂率≥75%时有较大幅度影响。土壤在连续20 d蒸发过程中，各个处理的土壤累积蒸发量随时间的关系和Rose经验公式拟合度高; 不同掺砂处理能显著提高土壤掺砂层以下的土壤含水率，随着掺砂率的增加而增加，其中掺砂75%时最高。

Effects of surface soil mixed with sand on water infiltration and evaporation in laboratory

Employing sand mixed with surface soil is very conventional way in agriculture, it plays a significant role in control soil water infiltration, evaporation as well as inhibition soil salt accumulation in arid region in Xinjiang area. In present research, simulating experiments were conducted to investigate the effects of different sand mixed rate on soil water infiltration and soil evaporation. The soil cylinder incubation treatments were setup including 0 (Control), 25%, 50%, 75% of sand mixing rate, respectively. There were extremely significant power relationships among wetting front distance, accumulated infiltration quantity and infiltration time under different mixing rate of sand treatments. The more sand mixed, the more soil water infiltration capacity observed, i. e., the infiltration capacity order was 75%>50%>25%>0. Moreover, by means of sand mixed with soil exerted obvious positive effects on inhibition of soil evaporation, namely, the more sand mixed, the remarkable less soil water evaporated, especially when sand mixed rate increased above 75%. The relationship between cumulative evaporation and time could be described by the Rose experience formula under different mixing rate of sand, and had closely fitting accuracy during the successive evaporation of 20 days. The soil moisture at deep layers which under sand mixed layer could also be remarkably enhanced by means of soil surface mixed with sand. The more mixing rate of sand, the remarkable higher soil water content obtained.