Research Of Water Use Efficiency Of Populus Euphratica In The Bank Area Of The Lower Reaches Of Tarim River And The Path Of Improving Water Use Efficiency

Water use efficiency(WUE) is an important index describing the relationship between plant yield and the depletion amount of water. Also is an ecosystem index evaluating suitable level of plant growth. The research of improving WUE is the center and potential of efficient use of water.This research with the advantaged and key Populus euphratica research object in the lower reaches of Tarim river, to research the characteristic of WUE in river bank region, the environment factor of affecting WUE of Populus euphratica and the effects of population structure on WUE. The research conclusion is as follows:1. The ground water level of Tarim river downstream takes a leading role in species diversity, with desert riparian forests as main, the Tarim river downstream plant has the characteristic of companio river growth, after the river broke, the growth condition of Populus euphraticain then closely contacts with underground water level changing. The ground water level of each simple plot raising as distance to river course increasing, presenting a high correlation, this indicate that it is the ground water level, affectingδ13C level of Populus euphratica. As the underground water level descends, Populus euphratica WUE appear an increased trend, while the underground water level blow 7m, WUE appears a descend trend. Research of habitat group of Populus euphratica found WUE was lower in higherly biological diversity than in lowerly ones.2. Results of orthogonal experiment said effective regulated deficit irrigation(RDI) consistent with the physiology characteristic of Populus euphratica. Results of orthogonal experiment said the WUE of Populus euphratica improved with the increment of fertilizer, this means the moderate fertilizer improving WUE of Populus euphratica.In the certain scope. The WUE of Populus euphratica improved with the increment of sprays density of FA,this means FA contribute to increasing WUE of Populus euphratica. The WUE of Populus euphratica improved with the increment of planting density, therefore in the Populus euphratica growth phase, the moderate close planting also a path of improving WUE.