Spatial Distribution Characteyistics Of Root System Of Populus Euphratica Along The Argan Section In The Lower Reaches Of Tarim River

Populus euphratica Oliv is one of the typical plants for emergency water conveyance and ecological restoration in lower beach of Tarim River. Research on plant roots has been an important aspect of ecological research. However, many difficulties seriously affect the study progress. The same is true to the study of Populus euphratica. People have done a lot of research about Populus except the part of underground, root. On the condition of dry environment, the study of root distribution of Populus euphratica can reflect the utilization of Populus euphratica, so it has more special ecological significance. In addition, research on root distribution of Populus euphratica can provide a reference to improve the ecological environment.In order to get Populus euphratica′s roots, I took the measure of digging and classifying the roots system in different directions and at different distances from the river. At the same time of digging, I collected soil moisture samples. Then, according to mass, density and acreage of the roots system, analyzed the correlation between root system and soil moisture,roots and ground water level. The results are: (1)The percentage of composition of the root system: The proportion of dead roots gradually decreasing from surface to deeper soil and majority of dead roots are fine roots. The fine roots that maintain the basic function, take the largest proportion of the frequency distribution. (2)With the increase of the horizontal distance, the length of fine roots shows the characteristics that the far from the bole, the roots will be shorter and the spread of the roots will show that the far the lighter. Root system will automatically adjust the distribution. As the environment changes, root system changes accordingly, showing some plasticity. (3)The vertical of roots in the soil have characteristics of stratification. However, between 0~30cm of soil there is no fine-root distribution and between 30~120cm the acreage of the roots will increase. The quantity of the roots shows two small, the middle pattern. Weakening factor of Populus euphratica is large, so it illustrates that root distribution of Populus euphratica in Alagan was deep. Under the condition of drought, the fine roots have to expand into deeper soil and this leads to more fine roots in deeper soil. (4) Among characteristics of Populus euphratica′s fine roots, eigenvalue of surface area dovetails the spread of water on various vertical soil profiles. In the scope of 30～120cm, the distribution of surface area and soil moisture'content was spatial autocorrelation. (5)Root length density from the river to the ladder on both sides of the river was diminishing. Max at the 50m. Within the scope of 200m is the main distribution of the root system. In the vertical direction of the river, it has relevance between root length density and groundwater level.