Research On Water Source Of Reaumuria Soongorica Based On The Stable Isotope Technique

In this study,three typical Reaumuria soongorica communities in Ejinaqi desert area were selected as plots.By analyzing the physical and chemical properties of soil,moisture content of Reaumuria soongorica,water potential.At the same time,the oxygen and hydrogen stable isotopes(delta D and delta 18O)of stem water,precipitation,soil water and groundwater were measured,and this paper used the two or three compartment linear mixing model,multiple sources linear mixing model,coupling model and the model of mean depth of water uptake by plants to analysis the Reaumuria soongorica's water source respectively.The main water source of Reaumuria soongorica was determined.The conclusions were as follows:(1)In plot ? of Ulan tug Gacha,Reaumuria soongorica is the dominant species,the main type of soil texture was sandy soil,groundwater level in 220cm soil layer.In plot II of Swan Lake,Reaumuria soongorica is a single dominant species,the main type of soil texture was sandy soil.In plot ? of railway station,Reaumuria soongorica is the dominant species,the main types of soil texture were sandy loam and sandy soil.The soil type of three plot was mainly gray-brown desert soil.Soil bulk density was 1.46?1.76g/cm3.The soil environment of Reaumuria soongorica growth was alkaline(pH8.02-8.97),the soil electrical conductivity was 0.06-2.25ms/cm.The soil moisture content was 0.187%-20.23%,the soil moisture potential was-2.99?-12.09Mpa.(2)The moisture content of Reaumuria soongorica was 18.032%-38.063%.The mean values of root?stem and leaf water potential were 8.61Mpa?-8.89Mpa?-9.71Mpa.In plot ?,the water absorption roots of Reaumuria soongorica were distributed in the 90cm-170cm soil layer,In plot ?,the water absorption roots of Reaumuria soongorica were distributed in the 70?80cm soil layer,In plot ?,the water absorption roots of Reaumuria soongorica were distributed in the 50?90cm soil layer.(3)The water absorption layer of soil was different.In plot ?,the main absorption layer of soil was 130?220cm,the soil moisture content was 8.55%?20.23.In plot ?,the main absorption layer of soil was 70?100cm,the soil moisture content was 1.28%.In plot?,the main absorption layer of soil was 70?100cm,the soil moisture content was 2.08%.With the continuous growth of the rootsthe water absorption layer of Reaumuria soongorica gradually extends to deeper soil layer.(4)The model determined that the growth and development of Reaumuria soongorica depend on a relatively stable soil moisture.In plot ?,Reaumuria soongorica absorb the soil water at 130-160cm and the average water absorption depth was located at 100-13 0cm soil layer.In plot ?,Reaumuria soongorica mainly used the soil water at 70-100cm to survive.The average water absorption depth was located at 50?70cm soil layer.In plot ?,Reaumuria soongorica absorb the soil water at 70?100cm.The average water absorption depth was located at 70?100cm soil layer.