不同厚度砾石覆盖对土壤蒸发的影响

Effects of Different Thickness Gravel Covering on Daily Evaporation

[目的]为了探求宁夏中部干旱地区最适宜的硒砂瓜覆砂厚度。[方法]采用蒸发器整体称重法,以宁夏中卫南山台地区天然砂石为试材,研究了不同厚度砾石覆盖对土壤蒸发的影响。[结果]砾石覆盖处理的土壤日蒸发量的大小顺序为CK>H1(5 cm)>H2(8cm)>H3(10 cm)>H4(15 cm)。同时,随着试验天数的增加,H3(10 cm)和H4(15 cm)处理的累积蒸发量的差别逐渐减小。土壤总蒸发量随碎石覆盖厚度的增加呈现幂函数减少的变化趋势,拟合曲线的决定系数达到0.925 5。[结论]随着砂石覆盖厚度的增加,土壤日蒸发量逐渐减少,土壤含水量逐渐增加。覆盖可以有效减小蒸发,且覆盖厚度越厚,对蒸发的抑制效果越明显。在实施砾石覆盖处理时,应该适量增加覆盖厚度,阻止大量水分因蒸发而造成的水分损失。当砾石覆盖厚度达10 cm以上时,砾石抑制蒸发的效果差别不大,因此10 cm的砾石覆盖厚度最适宜当地区域的自然条件。幂函数方程Y=atb可以用来模拟土壤总蒸发量随碎石覆盖厚度的变化。

[ Objective] The research aimed to explore the most suitable gravel covering thickness for selenium sand melon. [ Method] The natural gravel, which was from Nanshantai Region in Zhongwei City, Ningxia, was acted as test materials to study the effects of different thickness gravel covering on daily evaporation using evaporator overall weighing method. [ Result] The daily evaporation capacity order of the gravel covering thickness were as follows： CK 〉 H1 （5 cm） 〉 H2（8 cm） 〉 H3（10 cm） 〉 H4（15 cm）. Meanwhile, with the increase of test days, the difference of cumulative evaporation capacity between H3 （10 cm） and H4 （15 cm） decreased gradually. Soil evaporation capacity reduced at the power function with the increase of gravel covering thickness, and the decision coefficient of the fitted curve reached to 0. 925 5. [ Conclusion ] With the increase of thickness of gravel covering, evaporation capacity of soil reduced gradually, and the soil water content increased gradually. Gravel covering could effectively reduce the evaporation. The thicker of covering, the more obvious inhibition effect on evaporation. The thickness of covering should increase moderately to prevent moisture loss from evaporation. Gravel inhibition effects on the evaporation wash＇ t obvious when the gravel covering thickness reached more than 10 cm. 10 cm gravel covering was the most appropriate thickness for local regional natural condition. The soil evaporation capacity along with the change of gravel covering could be simulated with power function equation Y = at^b.