Changes in soil and vegetation following stabilisation of dunes in the southeastern fringe of the Tengger Desert, China

Abstract

Properties of the soil and sand-binding vegetation were measured at five sites plus a control on dunes of the Tengger Desert stabilized for periods of up to 50 years. In the topsoil, fine particles, total N, P, K and organic matter increased significantly with increasing site age. However, there were no significant changes in deeper soil profiles (>0.4 m depth). Soil pH, calcium carbonate content, and total salt content tended to increase with age. Soil water in the topsoil changed little with increasing age, but was closely related to rainfall during the 50-year period. For deeper soil layers (0.4-3.0 m) soil water decreased significantly with age. After revegetation, the number of herbaceous species increased up to 30 years and then levelled off to 12-14 species, whereas the number of shrub species decreased from the 10 initial sand-binding species to only 3 species. Shrub cover decreased from a highest average of about 33% to the current 9%, whereas cover and biomass of herbaceous species increased throughout succession from 1956 to 2006. The development of soil and cryptogamic crusts on the surface of stabilized dunes enhanced the colonization and establishment of herbaceous plants due to increasing water availability, clay and silt content and soil nutrients. We propose that changes in properties of the surface soil led to increased interception of water, favoring shallow rooted grasses and forbs over perennial shrubs.

Review of the ecohydrological processes and feedback mechanisms controlling sand-binding vegetation systems in sandy desert regions of China

“…However, the SWC spatial distribution of windward topsoils was determined mainly by environmental features such as wind [64]. When deep-rooted shrub coverage decreased to <10%, the SWC at the deeper soil depths (1.5-3.0 m) was stable and improved compared to shallower soil depths [7,46].…”

“…The dew on the sand, the physical crusts and the BSC surfaces amounted to 15.9%, 22.9% and 37.9%, respectively of the total precipitation over a given period [45]. BSCs in arid zones, especially those zones with annual precipitation of less than 200 mm, had an important ecohydrological influence on the shallow soil water content and led to profound changes in the original water balance in the desert area [46].…”

“…The ratio of transpiration to ET decreased as annual precipitation declined, while the ratio of evaporation to ET increased. Drought stress decreased transpiration and ET and increased precipitation loss due to evaporation, which, in turn, led to a large decrease in available water for plant growth [46]. After the re-establishment of vegetation in the desert, the soil water was used by plant growth and so no water percolation occurred [53], which meant that the original water balance in the dune was replaced by a new water balance [10,11,26,27,57,58].…”

Ecological restoration and recovery in the wind-blown sand hazard areas of northern China: relationship between soil water and carrying capacity for vegetation in the Tengger Desert

“…Ten 10 m×10 m plots were set up in each of the revegetated areas established in the years quoted above (each area contained vegetation of a different age and had a width of 100150 m and length of more than 10 km). The vegetation, soil water content and climatic factors have been monitored continuously for more than 50 years [14].…”

“…Spatiotemporal patterns for soil water directly affected the composition and community structure of sand-binding vegetation [14]. With increasing time after dune stabilization, the initial spatiotemporal patterns for soil water in mobile dunes significantly changed, including decreased replenishment by precipitation of deep soil water and increased water-holding capacity and water availability in the shallow soil layers.…”