Nature Environment and Pollution Technology

Man Cheng ¹, Zhijing Xue ², Shaoshan An ¹

Affiliations
1 College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, CN
2 State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yang ling, Shaanxi 712100, CN

Abstract

Revegetation has been reported as one of the most effective measures for reducing soil erosion on the Loess Plateau in China. We evaluated the effect of natural revegetation restoration on soil chemical nutrient, microbial biomass and enzyme activities on the Loess Plateau of China. The vegetation types studied, in order from the shortest to the longest enclosure duration, were abandoned grazed grassland (Ab.G3, 3 years), Hierochloe odorata Beauv. (Hi.O7, 7 years) communities, Thymus mongolicus Ronnm (Th.M15, 15 years), Artemisia sacrorum Ledeb (At.S25, 25 years), Stipa bungeana Trin Ledeb (St.B36, 36 years), and Stipa grandis P. Smirn (St.G56, 56 years). The results showed that soil organic carbon (SOC) and total nitrogen (N) was 9.2-32.2 and 1.2-3.5 g/kg during vegetation restoration, respectively. Except from Th.M15, SOC and total N increased with restoration time. Also, soil microbial biomass carbon (Cmic), phosphorus (Pmic), invertase activities, and alkaline phosphatase activities increased with restoration time. Whereas, soil microbial biomass nitrogen (Nmic) and urease activity was the highest in the early succession period and lowest in the mid succession period (under Th.M15 and At.S25). Revegetation resulted in more abundant and stable soil ecological environment by enhancing soil nutrients and biological properties. Thus, this is a beneficial measure for the recovery of degraded soils on the Loess Plateau of China.

Keywords

Microbial Biomass, Enzyme Activities, Vegetation Restoration, Loess Plateau.

Full Text

   

Zhijing Xue ¹, Xuan Fang ², Wanzhong Wang ¹, Shaoshan An ¹

Affiliations
1 Northwest A&F University, State Key Laboratory of Soil Erosion and Dry Land Farming on Loess Plateau, Yangling 712100, CN
2 Suqian College, Jiangsu 233800, CN

Abstract

Soil organic carbon distribution and its storage were estimated in two classical small watersheds that based on 163 samples under different land uses and landscape positions. Land use conversion may alter land cover, which results in carbon stock changes in biomass as well as in the soil. After the project of Grain for Green, initiated in Loess Plateau, most area has been conducted vegetation restoration same as the comprehensive managed watershed (Shanghuang), with spread vegetation-covered region and lower slope farmland. However, it is not clear that how effective the newly initiated project will be. In this study, we found an original watershed (Sidigou) as the reference, which has not done any ecological restoration projects, and kept primitive cultivated management. The results show that soil organic carbon (SOC) in comprehensive managed watershed (Shanghuang) was higher than the untreated watershed (Sidigou). As the soil depth increases, the SOC content gradually decreases. Soil organic carbon concentration and distribution were significantly influenced by land uses and landscape positions. The SOC of the shrub land and natural grassland were significantly higher than for the other land uses. The SOC of the valley was greater than that for the top of mound crests and mound slope. The total SOC storage of untreated watershed and comprehensively managed watershed were 20099.42 t and 46527.12 t, respectively. The area proportion of land uses is the important reason for income gap of the two study areas. Land use conversion from farmland to shrub land and or artificial grassland was better for loess hilly area. It was found that the projects to restore vegetation, such as Grain for Green would be beneficial for the ecological restoration of Loess Plateau in China.

Keywords

Soil Organic Carbon Density, SOC Storage, Landscape Positions, Land Uses, Loess Plateau.

Full Text