Plants water status of the shelterbelt along the Tarim Desert Highway

The plant water consumption and irrigation management are the core issue of the sustainable growing of the Tarim Desert Highway shelterbelt in the hyperaride Taklimakan Desert. The stem sap flow, water status and water consumption of shelterbelt plants were studied, then, the issue of the water save in the process of shelterbelt irrigation management was discussed by measuring the sap flow of shelterbelt plants with a stem sap flow gauge. The stem sap flow exhibited a distinct diurnal course with maximum values between 10:00 and 15:00, and minimum values between 00:00 and 03:00. Generally, sap flow was lower at night than during the day. The daily average stem sap flow of Calligonum arborescens, Tamarix ramosissima and Haloxylon ammodendron (diameter 1.9―2.0 cm) was 67.2 g·h-1, 77.05 g·h-1 and 61.54 g·h-1 respectively. The sap flow was influenced by environmental factors, and the solar radiation, wind velocity, temperature and relative humidity were significantly correlative with plant stem sap flow. The annual water consumption of 8-a Calligonum arborescens, Tamarix ramosissima and Haloxylon ammodendron was 1937.80 kg, 1253.39 kg and 1026.96 kg, while daily average water consumption was 9.69 kg, 6.27 kg and 5.13 kg respectively. Under drip irrigation, soil moisture content of the shelterbelt in different months indicated no obvious fluctuation, and soil moisture was adequate. The predawn and midday plant water potential reflected that the plant water status was in good conditions. There is still some water-saving space if optimizing the present water management, integrating water resources conservation and protection performance.