不同残膜量对土壤水分运移的影响及模拟

为解决绿洲区残膜污染,结合已有研究,根据农田残膜量与覆膜年限的关系,设计了9种残膜量处理(0、50、80、132、160、264、396、792、1 320 kg·hm~(-2)),利用室内土柱模拟试验,对不同处理的土壤水分湿润锋运移距离、运移速率、累积蒸发量、蒸发速率、土壤含水率进行监测分析并进行模型模拟,探究残膜量对土壤入渗和蒸发的影响以及模型模拟精度。结果表明:随着残膜量增加,湿润峰运移距离呈减小趋势,较CK减少2.76%～8.66%(P0.05),0～5 h内的平均运移速率较CK减少0.4%～19.5%(P0.05),总体呈幂函数降低趋势;随残膜量增加,累积蒸发量逐渐减小,较CK减少5.04%～38.92%(P0.05),蒸发速率呈降低趋势,而随着蒸发时间增长,蒸发速率也呈幂函数降低趋势;各残膜处理0～10 cm土层土壤平均含水率比10～20 cm土层降低1.51%～3.08%(P0.05),残膜破坏了土壤水分分布的均衡性。通过评价模型的结果显示,各处理拟合结果的决定系数R~2均大于0.988。随着残膜量的增加,RRMSE值出现差异,CRM值趋近0,CE值出现波动变化,模型拟合的结果呈现先变好后变差。

Effects of different residual film quantity on soil moisture movement and simulation

In order to solve the residual film pollution in the oasis area, combined with existing research and based on the relationship between the amount of residual film in the farmland and the year of film coating, an experiment with nine kinds of residual film treatments (0, 50, 80, 132, 160, 264, 396, 792 kg·hm^-2, and 1 320 kg·hm^-2) was designed. Using the indoor soil column simulation test, we monitored and analyzed the migration distance, migration rate, cumulative evaporation, evaporation rate, and water content of the wet front under different treatments and simulated the model, also explored the influence of residual film amount on soil infiltration and evaporation, as well as the advantages and disadvantages of model simulation. The results showed that with increasing the residual film amount, the migration distance of the wet peak showed a decreasing trend, which was 2.76%~8.66% less than CK (P<0.05), the average migration rate within 0~5 h was 0.4%~19.5% less than CK (P<0.05), the overall trend was decreasing power function. As the amount of residual film increased, the cumulative evaporation gradually decreased between 5.04%~38.92% (P<0.05) compared with CK. The evaporation rate showed a decreasing trend, and with the evaporation time, the rate also decreased with a power function. The average water content of 0~10 cm was lower 1.51%~3.08% (P<0.05) than that of layers 10~20 cm, and the residual film destroyed the balance of soil water distribution. The results of evaluation model showed that the R² of fitting results of each treatment was greater than 0.988. With the increase of residual film amount, the RRMSE value is different, the CRM value is close to 0, the CE value fluctuates, and the model fitting results show that the first change is better and then worse.