|其他摘要||In present study, field experiments were carried out in Cele desert-oasis ecotone in the south edge of Taklimakan Desert.Through transplant the seeding of Haloxylon ammodendron and take different protection (litter shield,fixing agent shield,biological protect,composite protect) on the mobile sandy land of oasis-desert ecotone, studying the effect of different Protection Treatment on the Soil Moisture and Salt and Haloxylon ammodendron Growth,drawing the following conclusions.
(1)Different protection treatment had obvious effect on sandy soil moisture content.The moisture content of surface 0-30cm soil was increased under litter shield and fixing agent shield. But this difference gradually disappeared with the increase of soil depth.The soil moisture content is low under biological protect and composite protect. With the irrigation in the early spring, the soil moisture content of May was the highest (about 10%-11%). The soil water content of different protection decreased in different degrees over time. The decline in soil moisture rate is greater from May to July, and it tends to be gentle from July to October.In the end of the experiment(October), the 1m soil moisture content of the litter shield was the maximum,which has reached 2.9%.The fixing agent shield 1m soil moisture content has reached 2.45%.While the biological protect and composite protect both in about 1.6%.
(2)From the spatial scale, the environment factors have a greater influence on surface soil moisture, in particular, the strong evaporation of the study area. The surface soil moisture fluctuation range is large, and it decreases with the increase of soil depth.The soil moisture content of each layer was more evenly after the irrigation in the early spring. As time passed, the soil moisture gradually transits to deeper soils, and each sample plots soil moisture mainly concentrated in the 60-100cm soil layer by October. The soil moisture in this layer under different protection treatment in descending order is: litter shield plot 6.04%, fixing agent shield 4.47%, biological protect plot and composite protect plot both in 2%-3%.
(3)On the mobile sandy land of desert-oasis ecotone,the one-time irrigation about 135L·m-2 in early spring has a certain effect on soil salt distribution.The soil electrical conductivity of the soil in 0-60cm is lower after the irrigation, which was about 0.7ms/cm in each layer. Below 60cm soil, the soil electrical conductivity increased rapidly, and its value of 70-100cm is much higher than that of 0-70cm. In the end of the experiment(October), the soil salt is gathered in the surface soil layer by the water evaporation. The 0-20cm soil salt content has high yield increase. The 0-10cm soil salt content of the control was 2.61ms/cm.Which is 3.2 times of litter shield and 2.5 times of fixing agent shield. The 0-10cm soil salt content of the Biological shrub area was about 1.5ms/cm. The content of soil organic matter shows different protection treatment higher than the control in 0-30cm soil layer. The average value of soil organic matter under litter shield is 1.65 times that of control.With the increase of soil depth,This difference is gradually disappearing.The pH value of soil showed the fixing agent shield is significantly lower than that of control in 0-30cm and 30-60cm soil layer.The litter shield and composite protect is lower than that of control only in 0-30cm.
(4)On the desert-oasis ecotone,the one-time irrigation about 135L·m-2 in early spring can ensure the annual growth of Haloxylon ammodendron seeding. It`s different from the irrigation system of farmland protection forest, which need repeated irrigation in one year. There is of great significance to the construction of ecological protection on the desert-oasis ecotone. The plant height, the crown width and the diameter of Haloxylon ammodendron seeding reach maximum value under the litter shield and fixing agent shield,higher than the control 17.8cm、44.1dm2、4.5mm and 10.2cm、25.5dm2、4.14mm respectively. The max growth rate of the height, the crown width, the diameter and new shoots length of Haloxylon ammodendron seeding appeared in June to August. By September the growth rate of Haloxylon ammodendron seeding became slow down.The crown width and new shoots length even negative growth. While the Haloxylon ammodendron seeding crown and the diameter of the biological protect and composite protect were significantly lower than the control.|