喀斯特森林近地表层覆盖对碳酸盐岩红土蒸发过程的影响

蒸发是西南喀斯特地区薄层土壤水分损失的主要途径,浅层土壤水分的存蓄对喀斯特地区农业生产和生态恢复至关重要。以西南喀斯特森林碳酸盐岩红土为研究对象,基于室内蒸渗试验设置4个苔藓生物量(0,0.32,0.64,0.95 kg/m~2)和3个松针生物量(0,0.32,0.64 kg/m~2)共12种处理,分析森林近地表层覆盖对碳酸盐岩红土蒸发过程及表层温度时空分布的影响规律,并对比3种蒸发模型(Black、Rose、空气动力学蒸发模型)在喀斯特森林碳酸盐岩红土的适用性。结果表明:苔藓和松针覆盖显著降低累积蒸发量和蒸发速率(P0.05),接种苔藓0.95 kg/m~2和覆盖松针0.64 kg/m~2处理比裸土累积蒸发量小36.9%;苔藓和松针导致土壤含水量显著增加(P0.05);苔藓和松针增加了表层土壤的平均温度,松针对土壤温度的提升作用强于苔藓;Black、Rose和空气动力学模型均能较好地模拟碳酸盐岩红土蒸发过程,Black蒸发模型的拟合精度高于Rose和空气动力学蒸发模型。研究结果能为西南喀斯特地区的水量平衡分析提供理论支撑并加强对喀斯特森林地表水文过程的认知。

Effect of Surface Cover on Evaporation Process of Carbonate Laterite in Karst Forest

Evaporation is one of the most important ways for soil water loss of shallow layer from karst areas in Southwest China. The storage of soil water in shallow layer is very important for agricultural production and ecological restoration in these regions. Based on a series of indoor evaporation experiments, four moss crust biomass levels (0, 0.32, 0.64 and 0.95 kg/m²) and three pine needle biomass levels (0, 0.32 and 0.64 kg/m²) were used to estimate the influences of moss crusts and pine needles on the evaporation losses and the temporal and spatial distribution of soil surface temperature. The performances of three different evaporation models (Black, Rose and Bulk) to simulate the evaporation process of carbonate laterite in karst forest were compared. The results showed that the cumulative evaporation and evaporation rate of moss and pine needle coverage were significantly reduced (P<0.05), and the cumulative evaporation of soil treated with moss inoculation (0.95 kg/m²) and pine needle coverage (0.64 kg/m²) was reduced by 36.9% compared with that of bare soil. Soil water content was significantly increased by moss crusts and pine needles (P<0.05). Moss crusts and pine needles increased the average temperature of the topsoil, and the effect of pine needles on soil temperature was stronger than that of moss crusts. Black, Rose, and Bulk models could well simulate the evaporation process of carbonate derived laterite, but Black model had better performance than Rose and Bulk models. Our results can provide theoretical support for the analysis of water balance and strengthen the understanding of surface hydrologic process in karst forests.