In order to elucidate the variation rule of rainfall erosivity (R) in Huangfuchuan Watershed, R value was estimated from 1954 to 2004 based on the daily rainfall data of 15 precipitation stations in Huangfuchuan Watershed, and the spatial and temporal variation of R was analyzed by Mann Kendall nonparametric tests and Kriging space interpolation method. The results are shown as follows. 1) The characteristics of spatial and temporal variation of R value were generally consistent with those of total rainfall and erosive rainfall; spatially, R value decreased and the contour lines of R value thinned from southeast to northwest. 2) From the temporal point of view, R value was concentrated from May to September, R value during this period accounted for more than 96% of the total annual R value; especially from July and August, R value amounted to 72.4% of the total annual R value. 3) Annual R value at nine stations had an increasing trend, but only at two stations such trend was significant over 51 years, while it had a deceasing trend at the other six stations and also only at two stations this decreasing trend was significant over 51 years. For the whole Huangfuchuan Watershed, the change of R value was consistent with the variation of rainfall and erosive rainfall, and showed an insignificant trend of decreasing over 51 years.

Vegetation is a factor influencing soil erosion significantly, as in turn soil erosion has great impacts on vegetation restoration. Pinus massoniana forests in eroded red soil region of southern China are subject to scarce undergrowth and severe soil erosion. It is therefore of great importance to study the relationship between undergrowth features and soil erosion in order to reveal the soil erosion process and the vegetation restoration mechanism of P. massoniana undergrowth. This study selected five hilly P. massoniana forests in Datian Town of Ganxian County in the eroded red soil region developed from granite in southern China. Each hill was surveyed along one belt transect from the upper to lower slope. There were totally five belt transects and fifteen sample plots of 10 m ×10 m. The investigation and measurement of landform, soil, vegetation and erosion gully were carried out in each sample plot. The relationship between vegetation features and soil erosion was analyzed statistically based on the observed data. The results showed: 1) The canopy density of P. massoniana forest in the eroded red soil region developed from granite was at a low level; the growth of woods was in poor condition and the total vegetation coverage was only 36.9%. 2) The undergrowth biomass of shrubs and herbs were low, and the richness, diversity and homogeneity were limited as well. 3) The undergrowth vegetation is mainly herbs dominated by Dicranopteris dichotoma whose biomass amounted for over 75% of the total herbs. 4) Rill and shallow gully erosions were serious which had a soil loss of 71.2 mm thick per unit area. 5) The development of eroded gullies and slope position were significantly correlated. There was a marked difference in micro-environment between eroded gullies and slopes, especially in terms of soil density and moisture. 6) The soil erosion amount under P. massoniana forests has an inhibitory effect on the vegetation restoration, while the growth of gully density increases the richness, diversity and uniformity of shrub and herb species.

It is insufficient to reveal the morphological characteristics of rill development only by using fractal theory. Geomorphologic comentropy should also be introduced to reflect the developmental stages of rill. Combining the fractal theory with geomorphologic comentropy, we studied systematically the relationship between fractal structure of rill network, geomorphologic comentropy and the rill morphology evolution. Case analysis shows that the complexity of the rill network can be quantified accurately by rill fractal dimension, but its relationship with erosion amount is unsatisfactory. The geomorphologic comentropy is highly correlated with erosion amount, and can be used as an important parameter in the analysis of slope morphological system.

In order to study the relationship among different vegetation communities, soil structure and infiltration characteristics in loess hilly region, and to quantitatively explore the soil structure, fractal theory and methods were used to study the relationship between soil fractal dimension and soil texture, bulk density, porosity, moisture content and saturated hydraulic conductivity of seven vegetation communities, i. e. , Pinus tabuliformis pure forest, Robinia pseudoacacia pure forest, P. tabuliformis + R. pseudoacacia mixed forest, Platycladus orientalis pure forest, Rosa xanthina shrubbery pure forest, Caragana microphylla shrubbery pure forest, and wasteland in Loess Hilly Region, Western Shanxi Province. The results showed that: 1) All kinds of vegetation communities were beneficial to improving the structure of the soil particles. The improvement of coniferous and broad-leaved mixed forest (P. tabuliformis + R. pseudoacacia mixed forest) is the best, followed by broad-leaved forest ( R. pseudoacacia pure forest and Rosa xanthina shrubbery pure forest), and coniferous forest ( P. tabuliformis pure forest and Platycladus orientalis pure forest) is the lowest. 2) The soil fractal dimension in the study area was between 2.799 and 2.805, and the mass fraction of clay ( < 0.002 mm) was inhigh level. 3) The soil fractal dimension had a significantly positive correlation with the mass fraction of soil clay, while a significantly positive correlation with the mass fraction of soil sand, total soil porosity, moisture content, and saturated hydraulic conductivity. Therefore, the soil structure and infiltration characteristics can be characterized by the fractal dimension of soil particles. The improvement effects of different vegetation communities on soil varied, and the results could provide a reference for the afforestation in the study area.

Distribution of root biomass in different diameter classes of root system is an important structural feature of root. By using digging method, composition and spatial distribution of Populus root biomass were studied in the Dawenhe Watershed. The results showed that: 1) there was a significant difference in the biomass among varied root diameters. Among them, the biomass of 10 -20 mm roots was the biggest, followed by that of roots less than 2 mm, and the biomass of roots >20 mm was the smallest. 2) Biomass spatial distribution pattern of the roots with different diameters were basically identical. On horizontal direction, the root biomass was significantly different among all layers. The farther from the trunk, the smaller the root biomass. The difference in distribution of root biomass along vertical direction was also very remarkable, but without evident order. 3) With soil depth increasing, soil bulk density, soil organic matter and available N, P, K contents decreased in an insignificant manner. The spatial distribution of Populus roots had a weakly positive correlation with soil nutrient.

Soil saturated hydraulic conductivity (K_s) is one of the most important hydraulic parameters, and its determination in the laboratory has been shown to be influenced largely by column size. This study estimates measurements of K_s in the lab using six different column sizes: 5, 10, 15, 18, 23 and 29.5 cm. Constant water head method was used, and disturbed Lou soil, a typical clay loam soil in Guanzhong region, was selected. Results showed that K_s decreased over time, and the range of descending changed greater at the initial stage than later. At the column size range of 5 -30 cm, K_s decreased with increasing column size. A linear regression analysis of two data sets of K_s and column size showed that the K_s data were linearly correlated with the size data following y =0.000 4x +0.003 7(R² =0.965 1). This study may serve as reference to choose reasonable time and size in measuring the K_s of disturbed soils.

To explore the water use efficiency of Rosa xanthina L. in Loess Hilly region, the light response process of photosynthetic parameters of R. xanthina was measured under eight soil moisture conditions with CIRAS-2 portable photosynthesis system to elucidate the quantitative relationship between water use efficiency of R. xanthina, soil moisture and light intensity. The results show that: 1) The photosynthetic rate (P_n ) of R. xanthina has a certain response to the change of relative water content (R_WC); The photosynthetic rate keeps at a high level when R_WC ranges from 44.5% -66.5% and peaks when R_WC is 66.5%. 2) R. xanthina leaf transpiration rate (T_r) is sensitive to R_WC changes, reaching the highest level when R_WC is 66.5%, and will significantly reduce as R_WC increases or decreases. 3) The water use efficiency of R. xanthina is at a high level when R_WC changes from 22.9% -54.5% and culminates when R_WC is 44.5%. The water use efficiency of R. xanthina is insensitive to light intensity, keeping always at high levels when the light intensity varies from 800 -2 000 μmol/ (m²·s).

Based on the 1956—2010 meteorological data of the Yanhe River Basin, the variation tendency and distribution feature of precipitation, runoff and sediment were studied. The relationship among the precipitation, runoff and sediment were also studied with ordinary least square regression (OLSR) and quantile regression (QR), respectively. The results showed that, from 1956 to 2010, the annual precipitation, runoff and sediment load exhibited a significant downward trend in the study area, the time data had fluctuations in different stages and some outliers existed. The OLSR could describe the average correlation among the precipitation, runoff and sediment. However, when the data are skewed, outliers or data changed greatly, and the OLSR analysis is restricted. QR is more suitable for actual meteorological and hydrological data, and particularly it could better express their relationships in high quantiles and accurately reflect more local information. According to our analysis, the quantile regression as a new method for river runoff and sediment dynamic analysis can reflect the relationship between water and sediment more accurately and objectively.

Controlled by weighing the soil and pots, one-year-old Koelreuteria elegans seedlings were potted under four levels of drought stress including optimal water content (CK), mild drought stress (LD), moderate drought stress ( MD) and severe drought stress ( SD) to study the growth and physiological and biochemical characteristics under drought stress. The mechanism of drought-tolerance in K. elegans was discussed. The results showed that the height and biomass of the seedlings decreased significantly but the root/ shoot biomass ratio increased obviously, and the contents of MDA, soluble sugar and proline added up; the contents of K⁺ and Ca²⁺ had a slight increase in the treatment of LD and then slowly decreased, while the content of Mg²⁺ in leaves had no obvious difference at four levels of drought stress, while the content of protein and activity of CAT, POD, SOD and APX, which were the biggest at the level of MD, increased firstly and then decreased with drought stress becoming more severe. The above results indicated that the drought stress leads to more serious peroxidation of membrane of K. elegans, which inhibited its growth. However, K. elegans could protect its membrane structure and keep normal physiological activities through improving the activity of antioxidant enzymes system and accumulating osmotic regulators such as soluble sugar, proline and soluble protein, which leads to the good performance of K. elegans to tolerate drought.

An investigation was conducted in a 1.5 hm² plot of Picea asperata-Abies nephrolepis forest to determine the tree species, DBH, treefalls direction, level of decay and microsites characteristics of pit and mound complex formed by 36 uprooted treefalls from June to July, 2013. The plant species, their height, abundance, cover on the sites were measured; their importance value and richness in the P. asperata-A. nephrolepis forest were calculated. The results showed that: 1) all uprooted treefalls are composed of four tree species. The frequency of tree species forming pit/ mound complex decreased in the order of A. nephrolepis (54.1%), P. asperata (27%), Betula platyphylla (13.5%), and Pinus koraiensis (5.4%). 2) Twenty-nine of the 36 uprooted treefalls were located in the north direction. 3) There was significant, positive correlations between pit volume and pit width, between pit volume and mound height, between pit depth and mound thickness; there were significant, positive correlations between mound volume and its superficial area, between pit volume and its superficial area. 4) At three microsites, species richness, Pielou evenness index, Simpson eco-dominance index, Shannon index decreased in the order of intact site, pit bottom, and mound top. 5) The importance value of Rubus sachalinensis was the biggest on mound. Pit bottom was beneficial to the growth of Urtica laetevirens and Impatiens nolitangere. 6) Species richness on mound top and on pit bottom was the biggest when level of decay of uprooted treefalls was level Ⅱand level Ⅴ, respectively. Average total coverage of plants and their average density were in the sequence of intact site > mound top > pit bottom.

Fractal features of micro aggregate and available nutrients in Chao soil were studied by mixing organic materials (bean stalk, corn stalk, chicken manure and pig manure) into the soil samples on low-yield fields in Henan Province. The results indicated that: 1) The mass fraction of 0.1 -0.053 mm soil particles was 7% -13% higher than the CK treatment with the increase of added organic materials, and reached the level of significant difference; correspondingly the mass fraction of soil particles less than 0.053 mm size was lower than the CK treatment. 2) Fractal dimension of soil particles ranged between 2.52 and 2.72 by the fractal model, and it had a very significantly negative correlation with the mass fraction of soil particles with 0.1 - 0.053 mm size (R = - 0.945) and a very significantly positive correlation with soil particles with the size less than 0.053 mm (R = 0.981). Distribution of micro aggregates was changed with the transition from the single application to the mixed treatment of stalk and manure, and the fractal dimension decreased. 3) Compared with the CK treatment, the mass fractions of the available nutrients in the different particle sizes and in the soil itself were significantly increased with the addition of organic materials. The mass fractions of available nitrogen, potassium and phosphorus increased by 168% - 528%, 141% - 1000% and 16% - 81% compared with the CK treatment in 0.1 -0.053 mm size soil particles, and 13.4% -44%, 17% -170% and 21% -66% compared with the CK treatment in soil particles less than 0.053 mm, respectively. The mass fractions of available nitrogen was in the order as the application of stalk (73.1 mg/ kg) > application of double mixture of stalk and manure (69.3 mg/ kg) > application of mixture of stalk and manure, application of pig manure(63.0 mg/ kg) > application of chicken manure (59 mg/ kg) > the CK treatment (49.9 mg/ kg), and that of available potassium was in the order of the application of the bean stalk (140 mg/ kg) > application of double mixture of stalk and manure, and corn stalk (120 mg/ kg) > application of mixture of stalk and manure (86.5 mg/ kg) > application of manure (76.8 mg/ kg ) > the CK treatment (56.5 mg/ kg), that of available phosphorus in the order of application of corn stalk (40.9 mg/ kg) > application of manure and application of mixture of stalk and manure (35.91 mg/ kg) > application of bean stalk (30 mg/ kg) > the CK treatment (26.8 mg/ kg ), and that of total soil nutrients was in the order of bean 32 treatment and corn 32 treatment(259 mg/ kg) > application of double mixture of stalk and manure and bean16 treatment (225 mg/ kg) > corn 16 treatment (210 mg/ kg) > application of mixture of stalk and manure and pig manure 8 treatment (191 mg/ kg) > chicken manure treatment (191 mg/ kg) > pig manure 4 treatment (161 mg/ kg) > the CK treatment (133 mg/ kg ). In brief, both the mass fractions of the nutrient of different sizes and the soil itself were increased by adding organic materials into sandy soil.

The land use is very complex in hilly and gully regions of northeastern China. There is an interesting phenomenon that the runoff of uphill melts firstly, which results in different erosion processes. This study was designed to investigate the influence of snowmelt runoff, slope gradient, slope length and snow density on snow melting rate via simulating snowmelt experiment. The results are shown as follows. 1) The snow melting rate was mainly controlled by the snowmelt runoff and significantly increased with the increasing snow-melt runoff. When the volume of snowmelt water was 0.1 L/ s, the snow melting rate was 591 g/ min; when the volume of snowmelt water was 0-5 L/ s, the snow melting rate was 1 121 g/ min. 2) Snow melting rate was significantly positively correlated with slope gradient. When slope gradient was 2°, the snow melting rate was 766 g/ min; when it was 14°, the snow melting rate was 1 002 g/ min. 3) The snow melting rate showed a positive correlation with slope length. 4) There was no obvious linear relationship between snow density and snow melting rate. Our findings would provide reference for the research of water erosion prediction project (WEPP).

In order to reduce the subjective influence imposed by indicator selection and weight determination, the method coupling rough set and catastrophe progression has been proposed for the comprehensive sustainable utilization evaluation of regional water resources. Taking nine cities of Fujian Province as basic research units, an evaluation index system consisting of four criteria and twenty indicators is constructed to evaluate the sustainability of water resources. The results show that the method of coupling rough set with catastrophe progression is feasible in evaluating the sustainability of water resources, due to its superiority of screening redundant information and reducing the subjective influence imposed by human intervention. The sustainability of water resources utilization in Fujian Province is in a descending order as follows: Longyan, Sanming, Ningde, Nanping, Zhangzhou, Fuzhou, Quanzhou, Putian and Xiamen, showing a declining trend from the northwest toward the southeast. Based on the evaluation results, nine districts and cities can be divided into four partitions, providing a theoretical basis for the exploration, utilization and protection of water resources in Fujian Province.

In order to study the spatial distribution characteristics of soil salinity in mixed forest of Yellow River Delta saline land, a new mixed plantation composed of 11 species in Yellow River Delta was taken as the object. The spatial variation of soil electrical conductivity in different seasons and different soil layers (0 -15 cm and 15 -30 cm) was measured and analyzed by traditional statistics and geostatistics. The spatial distribution maps and semi-variograms charts could explicitly explain the random and structural variations of soil electrical conductivity. Results showed that: 1) The mean value of soil electrical conductivity in spring and autumn had a significant difference, and the mean value, either in the upper layer (0 -15 cm) or in the lower layer (15 -30 cm), was larger in spring than in autumn. In spring, the range of soil electrical conductivity in the upper layer was 1.12 - 5.18 mS/ cm with an amplitude of 4.08 mS/ cm, and that in the lower layer was 0.83 -3.72 mS/ cm with an amplitude of 2.89mS/ cm. In autumn, the range of soil electrical conductivity in the upper layer was 0.85 -2.91 mS/ cm with an amplitude of 2.06 mS/ cm, and that in the lower layer was 0.62 -3.05 mS/ cm with an amplitude of 2.43 mS/ cm. The coefficient of variation in spring was larger than that in autumn. 2)In spring, soil electrical conductivity in both the upper and the lower layers had a strong autocorrelation. In autumn, there was no autocorrelation for the soil electrical conductivity neither in the upper layer nor in the lower layer, with an amplitude of 213 m and 71 m, respectively, both exceeding the sampling area. 3)Kriging interpolation indicated that the patchiness of soil electrical conductivity in spring was more serious in comparison to that in autumn.

This study examined effects of vegetation restoration on the plant diversity and community composition in the abandoned farmland ecosystem of Poyang Lake Eco-economic Zone. The results are shown as follows. 1) There were totally 42 plant species, 42 genera and 22 families in the farmland ecosystem. For the natural regeneration community (NRC), 20 genera and 10 families were found; while for the artificial regeneration community (ARC), 34 genera and 19 families were found. 2) The numbers of families, genera, species and coverage were higher in the ARC than in the NRC, but the differences were not statistically significant. The plant species abundance and diversity between two communities were not statistically significant but had an increasing trend for both ARC and NRC. 3) The species similarity coefficient between two communities was 0.44. Twelve common plant species that were dominated by annual herbaceous species coexisted in both communities. 4) Results of detrendedcorrespondence analysis (DCA) showed obvious grads from NRC to ARC. Since perennial herbaceous, perennial herbaceous vine and shrub species (Rubus idaeus) were found in the ARC. Our study suggests that planting tree species would mitigate the loss rate of abandoned farmland biodiversity under the urbanization process.

Based on investigation, the riparian section in the upper stream of Chaobai River in Beijing is classified as V-shaped, U-shaped and floodplain types. According to the gradient and height of bank slope, the corresponding measures of ecological revetment are proposed. Three types of revetment design, i. e. , willow piles, gabions, and rock filling, are proposed for providing reference in practical construction.

Integrated land carrying potential and carrying capacity of urban agglomeration are important indexes for measuring urban population concentration, economic development, ecological environment and the space of future development. This paper chooses indexes from three aspects, i. e. , carrying capacity of cultivated land, construction land carrying capacity and ecological land bearing capacity, constructs the evaluation index systems of integrated land carrying potential and realistic capacity, and carries out a case study of “3 +5”urban agglomeration of Hunan Province. The results show that Loudi City is overloaded in that its integrated land carrying capacity exceeds its carrying potential with a ratio of 1.383 4. Yiyang, Changsha, Zhuzhou and Hengyang cities are fully loaded regions in that their integrated land carrying capacity are very close to their carrying potential with ratios of 1.022 9,0.951 0, 0.923 8,0.920 4, respectively. Yueyang and Changde cities are areas which can still carry some people and activities, and their ratio of integrated land carrying capacity to carrying potential is 0.867 6 and 0.854 7, respectively. Xiangtan City is an area that carries not enough in that its integrated land carrying capacity is the lowest compared to its carrying potential with a ratio of 0.685 5. The paper also analyzes the causes of overloading or bearing and proposes specific measures for enhancing land carrying potential or reducing carrying capacity according to different bearing conditions.

The idea and principle of ecological civilization must be insisted during urbanization process. The central government has demanded to strengthen the system building for ecological civilization, and protect ecological environment relying on a complete legal system. Rapid process of urbanization and social development urgently requires legislation in urban soil and water conservation. The government should focus on the implementation of goals and responsibilities formulated in soil and water conservation laws in each functional urban area, and establish coordination mechanisms for soil and water conservation in relevant plans. The government should determine the key prevention and control areas based on the characteristics of cities, and implement the strictest soil and water conservation management process in all construction projects. Controlling urban rain flood and earthwork construction should be reinforced, in order to speed up the governance and ecological restoration of soil and water loss. Besides, a monitoring, announcing, reporting, and public supervising system should be established with clear legal responsibilities and precise penalty clauses.

With the rapid development of social economy, the agricultural non-point source pollution has become one of the main contributors to the deterioration of water quality and eutrophication of water bodies. The riparian buffers play an important role in purifying water quality, which are considered as one of best management practices (BMPs). The main results of research on the purification mechanism of the riparian buffers, as well as on the influencing factors for the effectiveness of purification, are systematically summarized in this paper. Based on the defects of previous studies, some suggestions are proposed, including broadening the range of research on purification mechanism of the riparian buffers, not limited to the nutrients and surface runoff. Besides, not merely natural factors, but also human factors should be taken into account when it turns to the influencing factors for the effectiveness of purification.