Deep soil moisture is a highly important source of water for vegetation in the semiarid Loess Plateau of China, vegetation restoration reduced the deep soil moisture, but how to better quantify the impact of vegetation restoration on deep soil moisture is lack of certain understanding. To explore the impact exerted by different types of vegetation on deep layers of the soil moisture, the 0-10 m soil moisture content profile was measured before and after the rainy season in Armeniaca sibirica, Robinia pseudoacacia, Populus simonii, Pinus tabuliformis, Hippophae rhamnoides and in natural grassland in Wuqi County in Shannxi Province. These results showed that the highest soil moisture in the shallow layers (0-200 cm) was exhibited in the P.
View Article and Find Full Text PDFIn this study, several novel blend membranes based on ligand-immobilized amphiphilic carbonaceous particles (ACPs) and matrix polymer polyvinylidene fluoride (PVDF) were prepared by an immersion phase inversion method. The effects of the ACP content on filtration performance of the membrane were investigated. Endotoxin removal with blend membranes at different pH values and ionic strengths was analyzed and discussed.
View Article and Find Full Text PDFPrecipitation plays an important and crucial role in processes in the water-wind erosion crisscross region of the Loess Plateau than in other parts of the region. We analyzed precipitation data and standardized precipitation index (SPI) at 14 representative synoptic stations from 1958 to 2015 used trend-free prewhitening, linear trend estimation, Spearman's rho test, the Mann-Kendall trend test, the Mann-Kendall abrupt change test and rescaled range analysis. The following conclusions were drawn.
View Article and Find Full Text PDFThe loess hilly-gully region is a focus region of the "Grain for Green" program in China. Drought is the main problem in the study region. Precipitation and temperature are two indicators that directly characterize climatic drought.
View Article and Find Full Text PDFThree soil property test data of microtopography in the semi-arid Loess Plateau were used to compare the following three soil quality evaluation methods: correlation coefficient method, factor analysis method and Nemoro index method. The results of these methods were analyzed and compared to determine the most suitable method for comprehensive evaluation of soil quality. While correlation coefficient method and factor analysis method produced similar results, Nemoro index method showed several differences from the othertwo methods and exhibited higher sensitivity in its assessment results.
View Article and Find Full Text PDFPrecipitation is the only water supply and most important factor affecting vegetation growth on the slopes of semi-arid Loess Plateau of China. Based on precipitation data from 7 synoptic stations in the study area over the period 1957-2012, the trends of precipitation and standardized precipitation index (SPI) were analyzed by using linear regression, Mann-Kendall, and Spearman's Rho tests at the 5% significance level. The results show that (1) the precipitation fluctuation of monthly precipitation was intense (coefficients of variation> 100%), and the drier years were recorded as 1965 and 1995 at all stations.
View Article and Find Full Text PDFSoil moisture is the primary factor limiting plant growth and vegetation rehabilitation in the loess region of northern Shaanxi, China. This 5-year (2008-2012) study investigated methods of selecting appropriate microsites for vegetation restoration based on efficient use of soil moisture; 5-year data were compared with 56 years of precipitation data using standardized precipitation index. In addition, the effects of microtopography on the spatiotemporal variations of soil moisture were analyzed at the Wuqi Ecological Station of Beijing Forestry University.
View Article and Find Full Text PDFBased on the investigation data of the vegetations in Hegou valley in Wuqi County of Shaanxi Province, this paper studied the vegetation characteristics on the five typical micro-topography categories including shallow gully, gully, collapse, platform, and scarp in the loess area of north Shaanxi, with the undisturbed slope as the control. There existed distinct differences in the species composition, quantitative characteristics, and species diversity of plant communities on the five typical micro-topography categories and the undisturbed slope. After twelve years of enclosure recovery, the study area formed herbaceous plant community, with Artemisia sacrorum and Artemisia giraldii as the dominant species.
View Article and Find Full Text PDFThe life of impoverished people can be damaged by adverse environmental conditions, but these people can also be harmed by environmental conservation programs, particularly when the guiding policy ignores their needs. To improve the social and economic effectiveness of environmental protection, governments must understand that the ultimate goal of environmental protection is to improve human livelihoods, not just restore vegetation. The elimination of poverty by the development of sustainable, long-term enterprises is a precondition for successful ecological restoration.
View Article and Find Full Text PDFYing Yong Sheng Tai Xue Bao
February 2009
Based on the vegetation survey on 18 sampling plots in Wuqi County of Shaanxi Province, and by using the methods of substituting space series for time series and of contrastive analysis, the dynamics of plant community species diversity in the process of ecological rehabilitation in the County was analyzed from the aspects of succession time, rehabilitation mode, and slope direction. The results showed that in the 25 years natural succession series, the natural restoration community on previous cropland experienced the sequence of Salsola collina, Artemisia scoparia, Lespedeza davurica, Artemisia sacrorum, and Bothriochloa ischcemum, with the dominant species tended to be changed from annual to perennial and from low-class to high-class. The variations of species number, Margalef index, Simpson index, Shannon-Wiener index, and Pielou index in the succession process could all be described by a quadratic function y = at2 + bt + c, suggesting that after the outside pressure removed, the degraded ecosystem in loess area could naturally restore to an advanced and steady state, but the restoration rate would be very slow.
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