Abstract:

Wind activity and its material transportation are the key terrestrial progresses， which have significant impact on sandy land ecosystem. In this study， the artificial Haloxylon.ammodendron plantations in Minqin County at the lower reaches of Shiyang River were selected as research objects， we evaluated effects of sand fixation afforestation on soil carbon and nitrogen at 0-1 m depth， and change characteristics of carbon and nitrogen caused by wind erosion and dustfall. Our aim was to explore the effects of wind activity on soil organic carbon （SOC） and total nitrogen （TN） storages in artificial plantations. The results showed that SOC storages in 0-1 m and 0-5 cm increased by 2.5 and 4.6 times， and TN storages in 0-1 m and 0-5 cm increased 3.3 and 5.3 times in 35-year-old H. ammodendron plantations compared to mobile sand dunes， respectively. The 5-year averaged carbon and nitrogen input rates caused by near-surface wind-blown intercepted by artificial H. ammodendron plantations were 1.12 g?m²?a^-1 and 0.15 g?m²?a^-1， accounting for 2.2% and 1.8% of SOC and TN fixed rates in 0-1 m， and 21.5% and 24.9% of SOC and TN fixed rates in 0-5 cm in 35-year-old H.ammodendron plantations， respectively. The 5-year averaged carbon and nitrogen input rates caused by dustfall intercepted by artificial H. ammodendron plantations were 2.47 g?m²?a^-1 and 0.29 g?m²?a^-1， accounting for 4.7% and 3.5% of SOC and TN fixed rates in 0-1 m， and 45.7% and 48.1% of SOC and TN fixed rates in 0-5 cm in 35-year-old H. ammodendron plantations， respectively. The carbon and nitrogen fixed by dustfall activity was is nearly twice that of near-surface wind-blown. Our results conclude that the reduction of artificial H.ammodendron plantations on sand blown activity activity can significantly promote SOC and TN accumulation in 0-1 m soil layer in sandy land， which was more obvious in 0-5 cm soil layer.

Key words: wind erosion, dustfall, artificial Haloxylon ammodendron, soil organic carbon, total nitrogen