Study On Water-holding Performance And Forest Water Consumption Law Of Three Forest Lands In Sandstone Area

In order to explore the water?holding capacity of different plantations and the transpiration characteristics of tree species and their response to meteorological factors,(Hippophae rhamnoides Linn.),(Pinus tabulaeformis Carr.)and(Caragana korshinskii Kom.)plantation were studied in the sandstone area of Zhungeer Banner,Ordos City,Inner Mongolia Autonomous Region,the SF60 stem flow meter was used to monitor the transpiration rate of different plantations,and the related meteorological factors were monitored in combination with the HOBO small meteorological station,and the water holding capacity of the litter layer under the forest and the physical properties of the 0-50 cm soil layer and water capacity was studied.The results show:(1)The variation of litter layer thickness under different forest types ranged from 0.73 cm to 2.77 cm,and the total accumulation range varied from 1.47 t/hm2 to 7.93 t/hm2,and different forest litters were observed.The order of total volume was consistent with the thickness,and the order of size was Pinus tabulaeformis Carr.>Hippophae rhamnoides Linn.>Caragana korshinskii Kom forest>Abandoned land;compared with litter of two different forest types,the thickness of semi-decomposed layer of litter and its accumulation The amount is significantly smaller than that of the undecomposed layer.(2)The study on the water holding capacity of the litter layer under different forest types shows that the water holding capacity of the abandoned land is less than that of the other three kinds of forest litter,and the maximum water holding capacity of the litter under the pine forest.The value of the largest value is 267.32%;the maximum water holding capacity of the wasteland is 149.48%.(3)Regression fitting of data on water holding capacity,water absorption rate and soaking time of litter under different forest types,the water holding capacity and water absorption rate of the undecomposed and semi-decomposed layers and the soaking time are respectively logarithmic relationship of Q=klnt+b and V=ktn power function.(4)The soil bulk density under different forest types was not changed much.The soil bulk density of the abandoned land was 1.71 g/cm3,and the soil bulk density of Hippophae rhamnoides Linn forest and Pinus tabulaeformis Carr.forest was the smallest,1.49 g/cm3 and 1.48 g/cm3 respectively;The change trend of total porosity is Pinus tabulaeformis Carr.>Hippophae rhamnoides Linn.>Caragana korshinskii Kom.forest>Abandoned land;The order of non-capillary porosity is Hippophae rhamnoides Linn.forest>Pinus tabulaeformis Carr.forest>Abandoned land>Caragana korshinskii Kom.forest;The maximum water holding capacity of Pinus tabulaeformis Carr.forest was 17.43 mm,and the maximum water holding capacity of the abandoned soil was 10.87 mm.The soil non-capillary water holding capacity was consistent with the non-capillary porosity order.(5)There were obvious diurnal variations in the three tree species.The transpiration rate during the day was much higher than that at night.There was a weak and stable sap flow at night,and the single and double peaks were obvious.In typical weather,the sap flow rate curve of three tree species on sunny days changed more gently and the peak range was wider.The liquid flow started earlier and stopped later.On rainy days,the peak value was steeper and the range was narrower,and the liquid flow started later.,stop earlier;cloudy on the middle.(6)The transpiration rates of the three tree species are closely related to meteorological factors,and are positively correlated with solar radiation,air temperature,wind speed,10 cm ground temperature,and water vapor pressure deficit meteorological factors,but negatively correlated with air relative humidity.The research results are intended to provide a theoretical basis for the planting management of plantations in arid areas and the rational use of water resources.