喀斯特峡谷区不同经济林地土壤水分变化特征——以贵州花江示范区为例

Study on soil moisture variation characteristics of different economic forest lands in karst gorge area:A case study of Huajiang demonstration area in Guizhou Province

选择喀斯特高原峡谷关岭—贞丰花江示范区为研究对象,在2018年5-9月采用土壤水分传感器对0~40 cm土层的土壤含水率进行监测,以分析花椒地、金银花地、火龙果地3种不同经济林地土壤储水量的季节变化特征及土壤含水量的剖面变化特征。结果表明:(1)3种经济林地土壤储水量随着降雨的季节变化明显,与降水随时间的变化趋势一致,但在时间上滞后于降水量。在观测期内不同经济林地0~40 cm土层土壤储水量表现为火龙果地(478.97 mm)>金银花地(372.64 mm)>花椒地(322.15 mm);(2)随着土层的加深,含水率总体呈增加趋势,观测期火龙果地、金银花地、花椒地的土壤含水率分别为35.97%、27.36%、23.55%,整体变异系数分别为9.64%、19.53%、24.27%,火龙果地为弱变异,花椒地和金银花地为中等变异。火龙果地的持水效果最好,金银花地和花椒地次之,因此在贵州省花江喀斯特高原峡谷区的石漠化治理过程中可适量种植火龙果以达到生态恢复效果,并推动当地产业发展。

The study area is located in the Guanling-Zhenfeng Huajiang demonstration area in the southwestern Gui⁃zhou Province.The total area of the study area is 51.62 km2,with the karst area of 45.39 km2,and the altitude is 500-1,200 m.It is a typical karst plateau gorge area in Guizhou with exposed and broken surface and undulating terrain.Hylocereus undulatus Britt,Zanthoxylum bungeanum and Lonicera japonica Thunb are typical economic plants in this area.In this study,this three economic forest lands were selected as the sampling plots to conduct a long-term monitor⁃ing on soil moisture and rainfall and to reveal the dynamic characteristics of the soil moisture and the influence of dif⁃ferent economic plants on the dynamics of soil moistures along soil profile.This research is also to provide scientific basis for vegetation restoration and sustainable development of the ecological environment in karst rocky desertifica⁃tion area.Three observation points are equidistantly arranged in each plot with three probes installed in an observation point.A soil moisture sensor(EM 50,Meter Corporation,USA)was used to continuously monitor the volumetric soil water content.At each observation point,the probes were installed at the depth of 10 cm,25 cm and 40 cm to the soil surface,respectively,which monitored the soil water content 24 hours a day and the monitoring was conducted in five month time from May to September,2018.During the monitoring process,the soil moisture content was recorded at a 10-minute interval.In the meantime,the rainfall data is monitored by a small meteorological observatory(ATMOS,Me⁃ter Corporation,USA).Based on the monitoring data,the coefficient of variation of soil water storage and soil water con⁃tent were calculated.SPSS 20.0 was used for statistical analysis of the data,and Origin 8.5 was used for mapping.The result showed that the variation of soil water storage in the three economic forest lands was consistent with rainfall in both quantity and time.The soil water content reached a maximum value in August and its fluctuation slightly lagged behind the precipitation.During the observation period,the soil water contents in the 40 cm deep soil layer showed a difference in the three types of land,which were Hylocereus undulatus Britt field(478.97 mm)>Lonicera japonica Thunb field(372.64 mm)>Zanthoxylum bungeanum field(322.15 mm),respectively,with the water contents of 35.97%,27.36%,and 23.55%.In a conclusion,the Hylocereus undulatus Britt field has the best water holding effect,followed by Lonicera japonica Thunb field,and Zanthoxylum bungeanum field,which plays an important role in im⁃proving the water and soil conservation function of the area.Therefore,in the process of rocky desertification control in Huajiang karst plateau gorge of Guizhou Province,Hylocereus undulatus Britt will be helpful to be planted in an appro⁃priate amount to achieve the effect of ecological restoration and promote the development of local industries.