Soil aggregation formation in relation to planting time, water salinity, and species in the Taklimakan Desert Highway shelterbelt
2018
Wang, Yongdong | Zhao, Ying | Li, Shengyu | Shen, Fangyu | Jia, Mengmeng | Zhang, Jianguo | Xu, Xinwen | Lei, Jiaqiang
PURPOSE: Soil formation and development can play an important role in the control of desertification in artificially forested desert areas. Here, we aimed to investigate soil aggregate formation in the Taklimakan Desert Highway shelterbelt (TDHS), China. MATERIALS AND METHODS: We evaluated the topsoil aggregate stability and its fractal characteristics in relation to time from planting and irrigation water salinity. RESULTS AND DISCUSSION: The results showed that (1) regardless of soils investigated, the soil dry aggregate (SDA) content was higher than the soil water-stable aggregate (WSA) content. The > 0.25-mm SDA content ranged from 3.35 to 28.04%, whereas the > 0.25-mm WSA content ranged from 0.02 to 7.25%; (2) the > 0.25-mm SDA content, as well as the mean weight diameter (MWD) and geometric mean diameter (GMD) of soil aggregates increased with increasing planting time, indicating that plant growth accelerated soil formation; (3) the > 2-mm SDA content was considered to better characterize the soil mechanical stability against wind erosion, whereas the > 1-mm WSA content to better indicate the soil aggregate ability against water dispersion; and (4) the fractal dimension (D) of soil aggregates significantly increased with the increasing of shelterbelt ages, the total N and organic matter contents, and decreased with the increasing bulk density. Therefore, the D value was viewed as an indicator for quantifying the degree of sandy soil development. CONCLUSIONS: We concluded that the artificial construction of TDHS prevents desertification by accelerating aggregate formation and consequently increasing soil stability.
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