玉米芯颗粒对风沙土毛管水运移和蒸发特性的影响

Effects of Corncob on Capillary Water Transport and Evaporation Characteristics of Sandy Soil

为探索玉米芯在干旱地区的有效利用方式、提高其利用率,通过土柱模拟的方法,将1.5~6.0 mm玉米芯颗粒与风沙土混合开展吸水与蒸发试验。以未添加玉米芯的土柱为对照,设置10种添加玉米芯处理,对不同处理土柱的吸水量、湿润锋、蒸发量、蒸发强度等进行测定,分析玉米芯及其用量对风沙土吸水、保水效果的影响。结果表明,混合土壤毛管水上升高度比对照低0.0%~76.3%,毛管水平均上升速率比对照低7.3%~78.7%,蒸发强度比对照低10.7%~64.2%。玉米芯添加量≤40%时,吸水量比对照高8.6%~16.2%;玉米芯添加量>40%时,吸水量比对照低1.1%~46.0%。毛管水上升高度与时间之间呈幂函数关系,水分补给量与时间之间呈幂函数关系,水分补给量与毛管水上升高度之间呈线性相关。吸水条件下的Green-Ampt模型调整后可用于模拟混合土壤的毛管水上升过程。Rose蒸发模型能很好地表达混合土壤累计蒸发量随时间的变化特征。研究结果为沙化土地治理、秸秆还田改良耕地等研究与实践提供理论依据。

In order to explore the effective utilization of corncob in arid areas and improve its utilization rate,the water absorption and evaporation experiments were carried out by mixing 1.5~6.0 mm corncob particles with aeolian sand by means of soil column simulation.The water absorption,wetting front,evaporation,evaporation rate et al.of the soil column with 10 kinds of corncob added were measured,and the soil column without corncob was used as the control.The effects of corncob and its dosage on water absorption and water retention in sandy soil were analyzed.The results showed that the rising height of capillary water in the mixed soil was 0.0%~76.3%lower than that of the control,the average rise rate of capillary level was 7.3%~78.7%lower than that of the control,and the evaporation intensity was 10.7%~64.2%lower than the control.When the addition amount of corncob≤40%,the water absorption was 8.6%~16.2%higher than the control;when the addition>40%,the water absorption was 1.1%~46.0%lower than the control.There was a power function relationship between capillary water rise height and time,a power function relationship between groundwater recharge and time,and a linear correlation between groundwater recharge and capillary water rise.After adjustment,the Green-Ampt model under water absorption could be used to simulate the capillary water rise process of mixed soils.The Rose evaporation models could express the variation characteristics of the cumulative evaporation of mixed soils with time.The results provided a theoretical basis for the corncob material in the practice of desertification land management and straw returning to the field to improve cultivated land.