The relationship between vegetation and soil moisture reveals the vegetation carrying capacity threshold—A case study of a Haloxylon ammodendron plantation in the Alxa desert, China

Afforestation is an important and effective way to curb wind-sand hazards in the Alxa Desert. However, over-afforestation makes soil drying occur frequently. The formation of a layer seriously restricting effectiveness vegetation construction regional ecological stability. To clarify process desiccation Haloxylon ammodendron plantations determine suitable planting years, typical H. plantation this area was selected as research object, moisture variation characteristics sand-fixing region with age were analyzed. analysis results on water supply, consumption, balance showed that storage 0–400 cm varies significantly different ages. 0–11 years old largest, supply greater than consumption. profile increased increase precipitation, at 11–22 first then decreased inflexion existed 16.5 old. consumption 22–46 supplement, appeared negative continuously. Therefore, prevent further deterioration environment promote sustainable development afforestation desert areas, thinning measures are suggested when growth period reaches years. could provide scientific basis for dry regulation desert.