Water Consumption Of Three Typical Irrigated Plants For Wind Sheltering And Sand Fixation In The Shi Yang River Basin

In the Shiyang River Basin, the deterioration of ecological environment has accelerated in recent decades. Due to the depletion of water resources, areas with sand dune plants have been shrinking and planted forests for wind sheltering and sand fixation have degraded. More sand dunes have become mobile and large areas have desertified. Dust storm has happened more frequently in recent years. Such environmental problems have severely affected people's life in this region, so as to the whole Gansu Province, northwest and north China. It has become an urgent issue to manage the ecological environment in the Shiyang River Basin. Apart from natural sand dune plants, irrigated plants for wind sheltering and sand fixation have been used to cope with environmental deterioration over the years.In the Experimental Station of Shiyang River Basin for Water-Saving Agriculture and Ecology, experiments were carried out in the fields on three irrigated plants for wind sheltering and sand fixation, including Populus alba var. Pyramidalis Bge, Tamarix elongata Ledeb. and Caragana Karshiskii Kom.. By means of advanced technology such as Tube-type time domain reflectometry, Li-Cor ultra compact photosynthesis system and Heat pulse sap flow sensors, systematic research efforts were made to investigate the dynamic trends of soil water content around the root zones throughout the growing season, the water ecophysiological characteristics, sap flow and corresponding influential factors and evapotranspiration of these three irrigated plants. The main results are:(1)The change patterns of trunk sap flow of irrigated Populus alba var. Pyramidalis Bge In spite of some fluctuations, the daily average sap velocities at 5mm and 10mm from cambium presented a consistent trend throughout the whole growing periods, with a correlation coefficient of R2=0.9407. In the early stage of development, the sap velocity at 5mm from cambium was greater than that of 10mm. However, only slight differences could be observed in metaphase and telophase of growth. The leaf transpiration rates and water potentials were significantly positively and negatively correlated with sap velocities at the corresponding time, respectively. The daily sap flux in the trunk of Populus alba var. correlated quadratic parabolically with the days after bud burst (DAB), with a correlation...