With the implement of the Three Gorges Dam project in 2008, the water level of the reservoir fluctuates, resulting in formation of the water level fluctuation zone (WFLZ) in the Reservoir. Plants in the water level fluctuation zone of the Three Gorges Reservoir Region disappeared due to winter-flooding and prolonged inundation. Revegetation (plantation and natural recovery) has been promoted to restore and protect the riparian ecosystem in recent years. Revegetation may affect soil qualities and have broad important implications both for ecological services and soil recovery.  

Dr. YE Chen under the supervision of Prof. ZHANG Quanfa from Wuhan Botanical Garden investigated the effects of two recovery measures (plantation and natural recovery) on soil quality.  

They investigated soil properties including soil pH values, bulk density, soil organic matter (SOM), soil nutrients and heavy metals, soil microbial community structure, microbial biomass, and soil quality index (SQI) under plantation and natural recovery in the Three Gorges Reservoir Region. 

Soil properties showed  significant temporal and spatial variations in both the plantation and natural recovery areas. Higher contents of SOM and NO₃-N were found in plantation area, while higher contents of soil pH values, bulk density, and total potassium were observed in the natural recovery area. However, there were no significant differences in plant richness and diversity and soil microbial community structure between the two restoration approaches.  

The present study suggests that natural recovery could be effective for soil restoration in areas with natural recovery capacity in WLFZ. Plantation should be carried out only in areas with seriously degraded habitats or where seed sources are absent. 

This research is supported by the National Natural Science Foundation of China, Q-CAS Biotechnology Fund of the Chinese Academy of Sciences, and the Executive Office of the State Council Three Gorges Construction Committee. Results were published in Environmental Science and Pollution Research (10.1007/s11356-013-2128-5) entitled “Recovery approach affects soil quality in the water level fluctuation zone of the Three Gorges Reservoir, China: implications for revegetation”. 

Spatial variations (a) and temporal variations (b) of soil quality index (Image by WBG)