Water Consumption And Scaling-up Of Artificial Populus Forest In The Dunes-meadow Ecotone Of Horqin Sandy Land

The study chose artificial Populus forest as experimental material in the dunes-meadow ecotone of Horqin sandy land, and the sap flow of the Populus and environmental factor were measured for long-term using the thermal dissipation sap flow probe and the automatic weather station, combined with Li-6400 measuring light response process and CO2 response process of Populus in multiple scenarios.Expecting to provide theoretical basis for the construction of sand-fixing species and the rational use of water resources. The main conclusions were as follows:(1)The potential for photosynthesis of leaves at the initial and late stage of growth, tender leaves, and leaves in the afternoon, as well as leaves in the low light intensity and low CO2 concentration environment was inhibited; non-rectangular hyperbola model had the best fitting effect to light response curve and photosynthetic physiological parameters in every month.(2)The diurnal variation of sap flow velocity was single peak and wide peak curve for different DBH Populus in the typical sunny day, and daily accumulated sap flow flux was S-shaped curve. Sap flow velocity and tree diameter had no significant relationship, and sap flow flux of large diameter tree was higher than small diameter tree.(3)Sap flow velocity and meteorological factors were in good agreement in different time scales, and artificial Populus forest had no water stress in the stand condition of study area, and the key influencing factors of transpiration for Poplus were weather conditions; Tree water consumption could be predicted by single tree water consumption model in different time scales.(4)Computing stand water use in 2014 using DBH as scalar, in 2015 using DBH, leaf area and comprehensive index as scalar respectively, and compared to the result of the revised P-M formula, and found the calculation result of the revised P-M formula is higher than scaling up; Stand transpiration water consumption was higher than the same period effective rainfall in the growing seasons, and artificial Poplulus forest need to consume part of groundwater to maintain growth.