Abstract: Abstract: In order to provide theoretical basis for the sustainable utilization of desert sand gravel soil, we studied the effects of straw mulching on the nutrients and salt in the soil under the condition of deep trench planting and assessed the capabilities of straw mulching such as soil nutrients accumulation, inhibiting soil evaporation and soil salt accumulation in surface soils. Field experiments were conducted in Laofengkou ecological zone located in the Tacheng basin of Xinjiang. The total experimental area was 10 000 hm2, where grooves were excavated parallelly by using mini excavators according to contour lines. The spacing between grooves was 3.0 m and the length, width and depth of each groove were 50 m, 50 cm and 70 cm respectively. Wheat straw with a thickness of about 20 cm was mulched to the grooves and the quantity for each groove was 5 m3. And the length of wheat straw was in accord with the crush degree of the wheat harvester. The biennial plant Popolus Russkii was selected as the experimental plants, and the planting spacing was 2.0 m. Three treatments were designed as follows: 1) straw coverage for 70 cm groove; 2) no straw for 70 cm groove; and 3) conventional planting without straw. Soil samples were collected in July, 2008 (before experiment) and in September, 2012 in 3 depths of soil layers including 0-20, >20-40 and >40-70 cm. Nine sampling points were chosen randomly as replications for each treatment, and finally 108 soil samples were collected. Then we used the cutting ring weighing method, the contamination of water saturation method and conventional methods, such as capacity of potassium dichromate method to analyze characteristics of soil nutrient and salt. The results of the study were as follows: the soil bulk density under the straw coverage for 70 cm groove treatment decreased by 9.7%-24.9% compared with the conventional planting treatment, whereas the soil porosity and the soil saturated water capacity increased by 11.2%-20.2% and 13.0%-24.6%, respectively. Soil organic matter increased 24.48% under straw mulching, and nitrogen also increased significantly. The soil bulk density was in such order: straw mulching for 70 cm groove > no coverage for 70 cm groove > conventional planting without straw. The soil porosity, soil saturated water capacity and soil organic matter were in the same order. As the age of the straw mulching in groove increased, straw coverage had obvious effects of inhibiting surface accumulation of soluble salt, and the salt rejection and pH value and total salt content in the soil of forest belts showed a decreasing trend. The salt content of the soil with straw mulching in deep groove decreased by 35.7% in surface layer and 2.9% in basement soil, but the salt content of the soil with no coverage in 70 cm groove decreased indistinctively. After afforestation for 4 years, the growth amount of trees in the straw coverage in 70 cm groove treatment was 1.61 times that in the treatment without straw coverage in 70 cm groove and 1.76 times that of the conventional treatment without straw mulch. In summary, straw mulching in groove planting can optimize the soil structure, improve the soil nutrient and inhibit soil water evaporation, and provide favorable conditions for the growth of trees.