Study on the Forest Vegetation and Its Water and Soil Conservation Value in Fuxian Lake Drainage Area in Yunnan Province

By using French SPOT5 satellite remote sensing image to contrast on the spot,the forest vegetation in Fuxian Lake basin was categorized into 23 forest types,6 vegetation subtypes,5 vegetation types,and the areas were respectively calculated.The tree species structure and the coverage degree of every kind of forest vegetation were investigated,and the characteristics of forest vegetation were analyzed.The results showed that the soil conservation amount of forest in Fuxian Lake basin was 137.50×106 t/a,and the soil conservation value was 622.30×106 yuan/a.Moreover,the water source conservation value was 506.84×106 yuan/a.

Evaluating agricultural water-use efficiency based on water footprint of crop values: a case study in Xinjiang of China

Efficient agricultural water use is crucial for food safety and water conservation on a global scale. To quantitatively investigate the agricultural water-use efficiency in regions exhibiting the complex agricultural structure, this study developed an indicator named water footprint of crop values(WFV) that is based on the water footprint of crop production. Defined as the water volume used to produce a unit price of crop(m^3/CNY), the new indicator makes it feasible to directly compare the water footprint of different crops from an economic perspective, so as to comprehensively evaluate the water-use efficiency under the complex planting structure. On the basis of WFV, the study further proposed an indicator of structural water-use coefficient(SWUC), which is represented by the ratio of water-use efficiency for a given planting structure to the water efficiency for a reference crop and can quantitatively describe the impact of planting structure on agricultural water efficiency. Then, a case study was implemented in Xinjiang Uygur Autonomous Region of China. The temporal and spatial variations of WFV were assessed for the planting industries in 14 prefectures and cities of Xinjiang between 1991 and 2015. In addition, contribution rate analysis of WFV for different prefectures and cities was conducted to evaluate the variations of WFV caused by different influencing factors: agricultural input, climatic factors, and planting structure. Results from these analyses indicated first that the average WFV of planting industries in Xinjiang significantly decreased from 0.293 m^3/CNY in 1991 to 0.153 m^3/CNY in 2015, corresponding to an average annual change rate of –3.532%. WFV in 13 prefectures and cities(with the exception of Karamay) has declined significantly during the period of 1991–2015, indicating that agricultural water-use efficient has effectively improved. Second, the average SWUC in Xinjiang decreased from 1.17 to 1.08 m^3/CNY in the 1990 s, and then declined to 1.00 m^3/CNY in 2011–2015. The value of SWUC was highly consistent with the relative value of WFV in most prefectures and cities, showing that planting structure is one of the primary factors affecting regional agricultural water-use efficiency. Third, the contribution rate of WFV variations from human factors including agricultural input and planting structure was much more significant than that from climatic factors. However, the distribution of agricultural input and the adjustment of planting structure significantly differed among prefectures and cities, suggesting regional imbalances of agricultural development. This study indicated the feasibility and effectiveness of controlling agricultural water use through increasing technical input and rational selection of crops in the face of impending climate change. Specifically, we concluded that, the rational application of chemical fertilizers, the development of the fruit industry, and the strict restriction of the cotton industry should be implemented to improve the agricultural water-use efficiency in Xinjiang.

Water Retention Value： A Study Model-based by Asperglillus awamori and Aspergillus oryzae Embrace Three Models of Solid Substrate

The goal of this study was to evaluate the water retention value （WRV） of a test solid substrate and a fungal cell in solid state fermentation （SSF）. WRV is the ratio of the weight of water retained after centrifugation under specific conditions by a wet sample to the oven dry weight of the same sample. SSF refers to the microbial fermentation, which takes place in the absence or near absence of free water, thus being close to the natural environment. Many factors are involved in a successful SSF process. In addition to biological parameters, the SSF process is also dependent on physical factors such as WRV. A centrifugal technique has been modified and applied to the evaluation of WRV. Wheat bran, soybean hulls and rapeseed meal were used as model substrate. Aspergillus awamori and Aspergillus oryzae were used as model microorganism. Results revealed that the ability of wheat bran to retain water in the solid substrate is 56% higher than that of soybean hulls and rapeseed meal. In the term of fungal cell, the ability of A. oryzae to retain water in the cells was higher （73% higher） than that ofA. awamori. In addition, through oven method moisture content loss from A. awamori is 46% higher than that from A. oryzae during drying process. Nevertheless, it can be seen that A. oryzae is able to retain water content about 5 times higher than A. awamori. Through this results, we found that WRV varies depending on solid substrates and microorganisms. This initial information can be beneficial in the SSF process to be carried out.

Evaluation of water resources conserved by forests in the Hani rice terraces system of Honghe County,Yunnan,China：an application of the fuzzy comprehensive evaluation model

The Hani Rice Terraces System, based on gravity-flow irrigation, is one of the Globally Important Agricultural Heritage Systems(GIAHS) pilot sites selected by FAO in 2010. The water resource plays an important role in the sustainable development of this system. The value of water conserved by the forest is influenced by natural, economic and social factors. In this paper, the water quality, per capita water resources, per capita GDP and population density are chosen as indices to construct an index system for a comprehensive evaluation of water resources value. The weights of these indices are 0.443, 0.31, 0.141 and 0.106 respectively, which are determined by the analytic hierarchy process(AHP) method. The water resources value has been assessed by the fuzzy comprehensive evaluation model. The results show that the water resources value in the Hani Rice Terraces System is 4.25 RMB/m^3. Evaluating the value of water resources in the Hani Rice Terraces System can provide a reference for ecological compensation, for raising public awareness of the importance of protecting the system, and ultimately achieving its sustainable development.

Correlation Analysis of Two Hydrochemical Factors Affecting the Distribution of Ceratopteris thalictroides in China

[ Objective] This study was to analyze the two hydrochemical factors affecting the distribution of Ceratopteris thalictroides, further to provide basis for its habitat protection and population restoration. [ Method ] Twenty two hydrochemical parameters of 22 sampling sites in China＇s tropical and subtropical zones were respectively averaged for calculating their variation coefficients, of which the two showing significant differences were used for multiple comparisons and correlation analyses via least significant difference and correlation coefficient. E Result ] The correlation coefficients of all the 22 tested hydrochemical parameters varied hugely, but only pH value and conductivity showed significantly differences in two water body （type A and type B）. Analysis of correlation presented that pH value were positively correlated with conductivity; further the multiple comparisons showed that the significant difference of pH value was higher than that of conductivity. [Conclusion] With regard to the two hydrochemical parameters showing significant differences, pH value influences the distribution of C. thalictroides more.

Economic Value of Water Resources of the Upper Reaches of the Xin’an River Basin, China

Estimating the value of water resources not only forms the basis of water rights transactions between upstream and downstream and eco-compensation standards, but also provides scientific data for the reasonable establishment of local water prices and promotes sustainable use and efficient management. Here, we estimate the economic value of the water resources of the upper reaches of the Xin’an River basin. Our purpose is to establish theoretical support for eco-compensation standardization and provide data for the protection of water resources and water price reform.

Diurnal and seasonal variations of soil respiration rate under different row-spacing in a Panicum virgatum L. field on semi-arid Loess Plateau of China

Soil respiration（SR） in crop field is affected by environmental factors, agronomic practices and crop types. To clarify how planting density affects the SR dynamics in switchgrass（Panicum virgatum L.） field on the semi-arid Loess Plateau, this research investigated diurnal and seasonal changes of soil respiration rate（RS） under three different row-spacing treatments（20, 40 and 60 cm） in the fourth growing year of switchgrass. Results showed that RS presented a pronounced seasonality under all row-spacing treatments. The highest daily average RS values appeared in August, while the lowest（P〉 0.05） among the row-spacing treatments, and similar results were found for soil temperature in 0–15 cm soil depth. Soil respiration temperature sensitivity（Q_（10）） values were 1.0–3.7 during the growing months, which were strongly correlated with air temperature in May and June and the soil temperature at 15 cm depth in August. Higher aboveground biomass production and lower RS in most growth months indicated that 20 cm row-spacing treatment was beneficial for increasing the carbon fixation in switchgrass field. Results also implied that it is necessary to take into account the influence of phenology and root growth of switchgrass on soil respiration for accurately evaluating the carbon cycle in the region.

STUDY ON ACRYLAMIDE-SODIUM ACRYLATE COPOLYMER GELS

Acrylamide-sodium acrylate copolymer hydrogels have been obtained by radiation techniques. Two different methods have been used to introduce—COONa groups into polymer chains of the gels: (1) by partial hydrolysis of acrylamide homopolymer gel; (2) by direct copolymerization and crosslinking of acrylamide and sodium acrylate in aqueous solutions. It was found that the gels obtained in different ways had different properties, the swelling character of the gels obtained by partial hydrolysis were more sensitive to pH of swelling aqueous media, in order to explain these differences, ^(13)C-NMR techniques were used to investigate the sequence distribution of monomer units of both gels.

Extracting the interference components of normal modes in shallow water waveguide using singular value decomposition method

The normal mode interference characteristic in shallow water waveguide is a valu- able topic in the fields of underwater acoustic. A method for extracting the interference components of normal modes from broadband acoustic propagation data recorded by a single hy- drophone without any prior information is present in this paper. First, a Hermitian matrix is formed by the power spectral density. Second, a singular value decomposition （SVD） is performed on the Hermitian matrix to obtain the orthonormal eigenvectors, which are proportional to the interference components of normal modes. The fundamental equations of the new extracting method are derived based on normal mode and waveguide invariant theory. And the validity of the present method is verified by the numerical simulation and experimental results. In addition, the extracted results of normal-mode interference components are intended to be used for passive ranging of broadband sources.

An Alternative Method to Study Wave Scattering by Semi-infinite Inertial Surfaces

A new method to solve the boundary value problem arising in the study of scattering of two-dimensional surface water waves by a discontinuity in the surface boundary conditions is presented in this paper. The discontinuity arises due to the floating of two semi-infinite inertial surfaces of different surface densities. Applying Green＇s second identity to the potential functions and appropriate Green＇s functions, this problem is reduced to solving two coupled Fredholm integral equations with regular kernels. The solutions to these integral equations are used to determine the reflection and the transmission coefficients. The results for the reflection coefficient are presented graphically and are compared to those obtained earlier using other research methods. It is observed from the graphs that the results computed from the present analysis match exactly with the previous results.

Altitudinal effect of soil n-alkane δD values on the eastern Tibetan Plateau and their increasing isotopic fractionation with altitude

Stable isotope paleoaltimetry has provided unprecedented insights into the topographic histories of many of the world's highest mountain ranges. However, on the Tibetan Plateau(TP), stable isotopes from paleosols generally yield much higher paleoaltitudes than those based on fossils. It is therefore essential when attempting to interpret accurately this region's paleoaltitudes that the empirical calibrations of local stable isotopes and the relations between them are established. Additionally,it is vital that careful estimations be made when estimate how different isotopes sourced from different areas may have been influenced by different controls. We present here 29 hydrogen isotopic values for leaf wax-derived n-alkanes(i.e., δD_(wax) values,and abundance-weighted average δD values of C_(29) and C_(31)) in surface soils, as well as the δD values of soil water(δD_(sw)) samples(totaling 22) from Mount Longmen(LM), on the eastern TP(altitude ~0.8–4.0 km above sea level(asl), a region climatically affected by the East Asian Monsoon(EAM). We compared our results with published data from Mount Gongga(GG). In addition,47 river water samples, 55 spring water samples, and the daily and monthly summer precipitation records(from May to October,2015) from two precipitation observation stations were collected along the GG transect for δD analysis. LM soil δD_(wax) values showed regional differences and responded strongly to altitude, varying from.160‰ to.219‰, with an altitudinal lapse rate(ALR) of.18‰ km^(-1)(R^2=0.83; p<0.0001; n=29). These δD_(wax) values appeared more enriched than those from the GG transect by ~40‰. We found that both the climate and moisture sources led to the differences observed in soil δD_(wax) values between the LM and GG transects. We found that, as a general rule, ε_(wax/rw), ε_(wax/p) and εwax/sw values(i.e., the isotopic fractionation of δD_(wax) corresponding to δD_(rw), δD_p and δD_(sw)) increased with increasing altitude along both the LM and GG transects(up to 34‰ and 50‰, respectively). Basing its research on a comparative study of δD_(wax), δD_p, δD_(rw)(δD_(springw)) and δD_(sw), this paper discusses the effects of moisture recycling, glacier-fed meltwater, relative humidity(RH), evapotranspiration(ET), vegetation cover, latitude,topography and/or other factors on ε_(wax/p) values. Clearly, if ε_(wax-p) values at higher altitudes are calculated using smaller ε_(wax-p) values from lower altitudes, the calculated paleowaterδD_p values are going to be more depleted than the actual δD values, and any paleoaltitude would therefore be overestimated.