Study On Soil Water Characteristics Of Different Plant Communities In Subalpine Meadows Of Wugong Mountain

Jiangxi Wugong Mountain meadow has the characteristics of wide area and low distribution standard,which is typical and special in the vertical vegetation of southern China.However,in recent years,due to the continuous development of tourism resources,the number of tourists has increased.Ecosystems have caused great influence and destruction,exacerbating the contradiction between people's production,living needs with meadow resources.Soil water is one of the important links to maintain the operation of meadow ecosystem,and it is also the main limiting factor of vegetation restoration and growth in meadow.Therefore,this paper studied the soil water,soil water supply and water availability of different plant communities and under different elevations,and analyzed the effects of soil physical and chemical factors on soil water characteristics.The relationship between vegetation and soil moisture is explored from the soil moisture,which provides a theoretical basis for the water conservation,soil water quality assessment and rational monitoring,vegetation restoration and sustainable development of meadow resources in Wugong Mountain meadow soil.The main conclusions are as follows:(1)The difference of natural water-holding capacity,maximum water-holding capacity and capillary water-holding capacity among different plant communities in Wugong Mountain Meadow reaches the significance level(p<0.05).The order of water-holding capacity of each vegetation community was: Sinarundinaria nitida>Miacanthus floridulus>Fimberistylis wukungshanensis>Carex chinensis,indicating that the ability of water storage and water conservation of Sinarundinaria nitida and Miacanthus floridulus is stronger than Fimberistylis wukungshanensis and Carex chinensis in subalpine meadow vegetation species of Wugong Mountain.The difference of Soil depth has a significant effect on soil water-holding capacity,surface soil(0~20cm)is greater than deep soil(20~40cm).Altitude has no significant effect on the soil water content and water-holding capacity,but the highest of the soil water content and water-holding capacity is in the soil layer of 0~20cm at an altitude of 1700 m.There are significant differences between surface soil with deep soil under different altitudinal gradients.Soil water-holding capacity is closely related to soil physical and chemical properties,influenced mainly by bulk density,organic matter and porosity.(2)The soil water characteristic curve of the study area is fitted by the power function equation proposed by Gardner,and the good fitting effect is obtained.The regression coefficient R2 is above 0.9542.There is a critical value of the soil water characteristic curve,0.1MPa.The range of parameter a in between plant community and soil layer is 43.264~74.345,and the variation range of parameter b is 0.0919~0.1339.The order of water-holding capacity of each plant community judged by a value was: Sinarundinaria nitida>Chrysanthemum indicum>Miacanthus floridulus>Fimberistylis wukungshanensis> Carex chinensis.The surface soil is larger than deep soil in the water-holding capacity.The difference of parameter b between the surface soil with the deep soil is small,which indicates that the trend of soil water characteristic curve is basically the same among different soil layers.(3)By comparing the specific water capacity parameters between the plant communities,the specific water capacity at the suction value of 0.1MPa,and the range of soil available water content,we obtain the result about the differences in the water supply capacity between the plant communities and the soil layers.In general,the water supply capacity of surface soil(0~20cm)is greater than deep soil(20~40cm),indicating that vegetation absorb less water with the increase of soil depth,and water supply capacity and drought resistance gradually is weakened as surface to the lower of soil.The specific water capacity and available water content of the Sinarundinaria nitida is the largest in the plant community,followed by the Miacanthus floridulus and the Chrysanthemum indicum,and the Fimberistylis wukungshanensis and the Carex chinensis are in the last row.