Evapotranspiration of Caragana korshinskii communities in a revegetated desert area:: Tengger Desert, China

More than 40 years of revegetation using mainly Caragana korshinskii at Shapotou Desert Experimental Research Station in China has established a dwarf-shrub and herbaceous cover on the stabilized sand dunes. The evapotranspiration (ET) of the dwarf-shrub C. korshinskii community and the evaporation (E) of the bare soil were measured by the auto-weighing lysimeter method during the growing seasons from 1990 to 1995. The average ET rate was 0.83 mm d(-1) which varied from 0.71 to 1.06 mm d(-1) during the 6-year period. Monthly ET ranged from 0.14 to 2.35 mm d(-1), with a monthly precipitation (P) range of 0 to 3.12 mm d(.)(-1) Monthly ET/P ratios varied from 0.94 to 1.28 and averaged 97.4% overall. Most of the precipitation in this area usually falls between June and September. The lowest precipitation was recorded in 1991, with most of it falling during April and May. This temporal anomaly in the precipitation resulted in the highest ET/P ratio (by 0.33) and soil moisture depletion (DeltaS = -31.5 mm) for the 6-year period. ET from the revegetated sand dunes around Shapotou under natural precipitation may account for 12.2% of the potential evaporation. Cumulative P and cumulative ET and E were highly correlated, with a well-defined linear relationship of ET = 0.80P + 10.0 and E = 0.55P + 5.89, with regression R 2 ranging from 0.953 to 0.985. In 1991, however, the regression equations for both ET and E were considerably different than the other years, with a steeper slope and a negative intercept resulting from the anomaly in the precipitation pattern. Copyright (C) 2004 John Wiley Sons, Ltd.