Valentindowling1914

Overall, soil bacterial communities was more sensitive to the tea plantation age than fungal communities. With the increases of tea plantation age, the ratio of soil fungi to bacteria showed increasing trend. Soil microbial community in the tea plantation changed from a "bacterial type" with low fungi/bacteria ratio (F/B) to a "fungal type" with high F/B.To acquire a feasible method for a rapid comparison of the cadmium (Cd) accumulation capacities of different leafy vegetables, using substrate cultivation with different contents of Cd and cultivation time, we compared the observed Cd accumulation capacity with these obtained in the field. The results showed that the Cd content and bio-concentration factors (BCFs) value in the aboveground tissue of leafy vegetable varied significantly with Cd content and cultivation time. Multi-factor analysis of variance showed that vegetable variety, cultivation time, Cd content in substrate and their interaction had significant effects on BCFs of Cd in leafy vegetable. Leafy vegetable variety was the dominant factor affecting BCFs of Cd in leafy vegetable and controlled its absolute level. When Cd content in the substrate reached 1.0 mg·kg-1 with a cultivation of 10 days, the correlation coefficient of Cd BCFs between the substrate cultivation and field experiments was the highest, with a R2 value of 0.90. The results of cluster analysis and one-way ANOVA had the highest consistence with the field results. Comparatively, the substrate cultivation with Cd content of 1.0 mg·kg-1 and a cultivation of 10 days showed a good reproducibility and stability in reflecting the difference in Cd accumulation capacities of different leafy vegetable varieties. The Cd-rich substrate cultivation could be used to screen the vegetables with low Cd accumulation and also would promote the field application of the vegetables with low Cd accumulation in the Cd-contaminated area of China.Yellow River Basin is an important water conservation and ecological barrier area, the study of water supply service in which is of great significance to the high-quality development and ecological environment protection. Based on the Invest InVEST model and the method of scenario analysis, we analyzed the temporal and spatial patterns of water yield in the Yellow River Basin in recent 20 years (1995-2015) with land use and cover, meteorological and soil data as inputs. We examined the impacts of precipitation change and land use change on water yield and their impacts on water yield. The results showed that water yield depth had average growth of 24.34 mm from 1995 to 2015. The high water yield area located in the west and southwest, and the low water yield area located in the northwest. The change of deep spatial pattern was not evident. Among the three grade basins in the Yellow River Basin, the river basin above Longyangxia, with the highest water yield of about 11.7 billion m3·a-1, was the main water yield area of the Yellow River Basin. The river basin from Lanzhou to Hekou had the lowest water yield, with a value of 44 million m3·a-1. The average water yield depth of permanent glacier and snow land was the largest in the whole basin. Grassland was the main contributor to the total water yield of the whole basin, providing 62.6% of the total water yield. Land use/cover change had moderate effect on water yield.The objective evaluation of human settlement in cities helps find the problems exposed in urban development and make targeted adjustments to improve urban environment. VRT752271 Taking the downtown of Fuzhou as the research area, the residential area as the research unit, using multi-source data such as meteorological monitoring data, remote sensing imagery, map points of interest data (POI), and land planning data, we constructed monitoring system of urban human settlement from four aspects environmental health and comfort, traffic convenience, city safety, and life conve-nience. The TOPSIS method was used to conduct a comprehensive evaluation of human settlement. The results showed that the human settlement level of downtown Fuzhou was quite different, which was high in the central area and low in the peripheral areas. The human settlement index was high in the middle of the urban area, low in the eastern and southern areas, with mixed high and low values in the western and northern areas. In each index layer, the characteristics of high-high agglomeration and low-low agglomeration of traffic convenience and life convenience were consistent with the distribution of high and low value clusters of the human settlement. Convenient transportation and complete service facilities had a greater impact on human settlement. The environmental health and comfort were characterized by interior low and edge high of the city, while city safety was characterized by interior high and edge low.As the main source of soil moisture supply in desertified areas, rainfall has a profound impact on soil moisture changes and plays an important role in deep soil moisture replenishment. Based on the Hydrus-1D model with optimized parameters, we analyzed the dynamic change process of the leakage in the 200 cm deep layer of the semi-mobile dunes in Horqin Sandy Land and its response to the rainfall patterns. The results showed that the averaged leakage replenishment of semi-mobile dunes was 254.31 mm from April to October each year during 2016 to 2019, accoun-ting for 61.8% of the rainfall in the same period. Deep leakage mainly occurred from June to August, accounting for 72.8% of the total. The leakage rate was distributed between 0.03-2.70 mm·h-1, with the maximum leakage rate occurring under heavy rainfall and frequent rainfall events. The deep soil water supplied by rainfall infiltration was affected by the amount of rainfall, rainfall intensity, duration of precipitation and soil moisture content in the earlier period. Precipitation events with long duration and small rainfall intensity were more conducive to deep water lea-kage, with a significant positive correlation between the leakage and rainfall (R2=0.85). 16-18 mm rainfall was the threshold for the leakage of 200 cm soil depth. The high-frequency rainfall event usually reached peak after 17-38 hours, with the entire leakage process being more than 164 hours. Accurate estimation of deep leakage has theoretical and practical significance for water resource assessment and ecological construction in desertified areas.Qilian Mountains is the boundary of the first and second steps of China's terrain, with fragile ecological environment. There is great ecological significance to study land use change and driving force in transitional areas. In this study, we investigated the spatial and temporal characte-ristic of land use and its driving force in the south slope of Qilian Mountains, based on RS image data from 1980 to 2018, with the spatial autocorrelation method, ArcGIS spatial analysis method and principal component analysis. The results showed that, from 1980 to 2018, grassland was the main land use type, and the proportion of construction land was the smallest. Water area and grassland showed a declining trend, while unused land, construction land and farmland showed an increasing trend. There was smaller change for the woodland. The single dynamic degree of different land types decreased following an order of construction land, water, farmland, unused land, woodland and grassland. The comprehensive dynamic degree of land use was 0.9%. The spatial distribution of different land use types showed the characteristics of spatial agglomeration. The increased areas of farmland and the decreased areas of woodland and grassland were mainly distributed in the northwest of the Datong River valley of Menyuan County, while in the upper reaches of Datong River in the northeast of Tianjun County, grassland was occupied by construction land. The driving force of land use was population, science and technology, urbanization, level of economic development, and policies. Our results would support the government to reasonably plan and utilize land resources, which is of significance to the protection of ecological environment and the sustainable development of society and economy on the southern slope of Qilian Mountains.Green space ecological network is important for improving the fragmentation of regional ecological space, biodiversity loss, imbalance of supply and demand in ecosystem services, and ensuring regional ecology. With Dongting Lake region as an example, the ecological sources were evaluated and identified, and basic ecological resistance of grid element was calculated from the perspectives of comprehensive ecosystem service function evaluation, potential biodiversity comprehensive index evaluation and morphological spatial pattern analysis with the support of 3S technology. We corrected the basic ecological resistance by night light index, used the minimum cumulative resistance model to identify ecological corridors, and constructed a weighted evaluation model, eva-luated the degree of aggregation and dispersion of the sources, as well as the contribution of ecological connection of the corridors. Furthermore, we compared and evaluated the structural characteristic index of the integrated networks, the potential. Compared with the "source-sink" potential network, the α, β, γ and ρ index of the integrated network was increased by 123.1%, 25.8%, 26.2% and 74.6% respectively. Compared with the "source-sink" planning network, the α, β, γ and ρ index was increased by 190.0%, 31.1%, 32.5% and 114.6% respectively. The results could provide reference for the construction of green space ecological network and planning of land use in Dongting Lake region.Ecological vulnerability is a hot issue in the study of global change and sustainable development. Understanding the vulnerability of agro-ecological environment is conducive to rational utilization of regional agricultural resources, which could put forward effective measures for prote-cting agro-ecological environment. Given that the evaluation of agricultural eco-environment vulnerability generally does not consider the relationships among different indicators in different evaluation levels, we used the grey trigonometrically whitening weight set pair analysis (SPA) model to evaluate the vulnerability of agricultural eco-environment in Karst mountain by selecting 11 indicators such as population density, per capita arable land area and per capita afforestation area from the external vulnerability of ecological environment. The results showed that the vulnerability degree of agro-ecological environment in the study area was very high, mainly at the extreme, high and medium vulnerability grades. The proportion of extremely, highly, moderately, mildly and slightly vulnerable areas was 32.4%, 14.1%, 17.7%, 23.6% and 12.2% respectively. This result was consistent with the status of agricultural ecological environment vulnerability in the study area. It was feasible to evaluate the vulnerability of agro-ecosystem with the SPA Model of grey trigonometrically whitening weight, which provided a new method for evaluating agricultural ecological environment vulnerability.Firmiana danxiaensis is an endemic species of Danxia landform in China. Identifying the main driving factors of its distribution can provide scientific basis for the conservation of F. danxiaensis and related habitats. With GeoDetector, we analyzed the correlation (measured by q value) between the spatial distribution of F. danxiaens and its habitat factors in F. danxiaens Nature Reserve in Nanxiong City and the Guangdong Danxia Mountain Tourism Scenic Area (core scenic area). Factors measured in this study included geographical elements (geomorphological type, soil subtype, elevation, slope, aspect) and climatic elements (annual precipitation and annual sunshine hours, mean annual relative humidity and mean annual wind speed). Our results showed that the main habitat factors affecting the spatial distribution of F. danxiaensis were soil subtype, annual sunshine hours, and geomorphologic genesis type. The q values of those three factors were higher than the mean values of all factors. In the pairwise combination of habitat factors, the interaction between geomorphologic genesis types ∩ annual sunshine hours and soil subtypes ∩ annual sunshine hours was enhanced by two factors and the q value was greater than the mean value of all combinations, with a strong correlation.