秸秆颗粒形态对沟灌入渗特征影响的试验研究

为了探明秸秆粉碎颗粒形态对沟灌土壤水分运移特征和土壤质量含水率分布状况的的影响,采用具有不同秸秆粉碎形态的玉米叶(片状)和玉米芯(颗粒状),进行了室内试验研究,并采用HYDRUS-2D软件对不同处理湿润锋运移情况进行了模拟.结果表明:具有片状形态的玉米叶各处理,随混掺比例及埋深的不同,均能降低土壤的入渗率,而具有颗粒形态的玉米芯处理显著增加了土壤入渗率;玉米芯混掺处理表明在埋深(10,15］ cm设置混掺层能增大土壤的垂向运移距离,18%土壤质量含水率等值线垂向距离明显大于埋深(5,10］ cm处理的;玉米叶不同埋深处理表明埋深(10,15］ cm比(5,10］ cm更能增加18%土壤质量含水率等值线的水平距离;3%Y10~15(混掺比例3%,玉米叶,埋深(10,15］ cm)处理最大土壤质量含水率值达到21%,而其垂向运移距离最短,说明该处理能够有效地阻滞水分的垂向入渗,增强植物混掺层上部土壤质量含水率;采用HYDRUS-2D软件模拟的湿润锋运移值与实测值误差在3%以内,说明其能够准确描述植物混掺条件下沟灌入渗过程中的湿润锋运移特征.

Experimental investigation into effects of maize leaf and straw fragments on soil water infiltration characteristics in furrow irrigation

To clarify effects of straw fragments on soil water infiltration characteristics and water content distribution in the soil in furrow irrigation, a series of experiments are carried out in laboratory by using maize leaf and straw fragments with different sizes, proportions and depths buried. In addition, the wetting front movement of soil water in different treatments is simulated with the software of HYDRUS-2D. The results show that soil water infiltration rate is decreased in the cases with maize leaf fragments, but increased in the cases with maize straw fragments significantly. For the cases with maize straw fragments, the soil vertical infiltration distance is increased if the fragments are buried in a depth of 10-15 cm, and the vertical distance of 18% soil water content contours is greater than that if the fragments are buried in 5-10 cm depth. In the cases with maize leaf fragments, the horizontal distance of 18% soil water content contours is increased when the fragments are buried in 10-15 cm depth compared with 5-10 cm depth. In the case that the soil is blended with 3% maize leaves in 10-15 cm depth, the maximum soil water content can be as high as 21%, and the vertical infiltration distance is the shortest. This implies that in this treatment the water movement in the vertical direction has been obstructed effectively and the water content in the soil above the buried layer is increased simultaneously. Meanwhile, the error of wetting front movement between experiment and simulation of HYDRUS-2D is less than 3%, suggesting the software demonstrate the behavior of wetting front movement accurately.