Spatial management system framework of soil and water conservation in China
[Background] Soil and water loss and soil and water conservation are of remarkable regionality. Soil and water loss in different regions can be manifested in different types, intensities and characteristics due to the differences of natural conditions and environment. Soil and water conservation work needs to adopt different control measures and management means due to different economic levels, land use and social development conditions in different regions. The depths and requirements of top-down spatial management of water and soil conservation are also different. Therefore, the establishment of a scientific and rational form of spatial organization and management is the inevitable requirement and important foundation for the fine, efficient and modern management of soil and water conservation.[Methods] In this study, comprehensive analysis and cluster analysis were adopted to deeply analyze the technical connotation of different types of spatial management practices, to analyze their internal structure and logical relationship, and to cluster them according to their use, nature and characteristics as the criteria of hierarchical classification. Based on the system analysis method, taking the construction of spatial management system framework as the whole research object, taking the hierarchical classification and the related links of the system framework as the key points of the main contradictions and the need for coordination, the integration of the existing spatial management status and the extension of the content within the system framework were carried out to form a scientific, reasonable and feasible overall system framework of spatial management of soil and water conservation to meet the needs of practical management.[Results] The framework of spatial management system is constructed in two latitudes:vertical and horizontal. In the aspect of vertical dimension, according to the difference of spatial management demand between upper and lower levels of soil and water conservation, the three-level spatial scale pattern of macro, meso and micro is constructed. There is clear scale positioning in different scales. By formulating and applying corresponding management rules and means, the spatial cohesion and interconnection between upper and lower levels are achieved. In horizontal dimension, according to the different purposes and target elements of spatial management, the types of spatial management are divided into three types:natural management, business management and administrative management. The three forms of spatial management exist in the macro, meso and micro scales, mainly in the macro aspect. The main purpose of natural management is to reflect the current situation of natural evaluation and to carry out spatial management of regional division based on natural geographical elements. Business management refers to the form of spatial management which focuses on the management of soil and water conservation, ecological environment management, supervision and protection, etc. Administrative management refers to the administrative spatial management based on administrative division units.[Conclusions] On the basis of systematic analysis, this paper puts forward the theory, construction method and framework content of the spatial management system framework of soil and water conservation in China. The framework of the spatial management system is based on the existing achievements of spatial management of soil and water conservation. It is the full inheritance and absorption of the existing achievements of spatial management, reduces the duplication of work and reduces the difficulty of establishing the spatial framework.
BAO SAIHenna, MIAO Yanjun, GUO Yunlei, XU Yamei, WANG Mingtao, WANG Xiangtao, XIE Guoping, WANG Chuanqi
Application study on ecological bag technology of restoring slope in high-grade highways in Nyingchi, Tibet
[Background] The rapid development of highway construction in Tibet has produced a large number of highway slope engineering wounds, naturally the difficulty and investment for the restoration of slope vegetation is huge. Therefore, to explore a slope vegetation restoration measures with strong soil and water conservation for the long-term stability has important guiding significance for ecological protection and ecological restoration in highway construction in Tibet.[Methods] The vegetation restoration experiment using ecological bags were conducted on the slope and flat land in the starting section of Lin La high-grade highways. The plants were Lolium perenne, Festuca elata, Poa pratensis, and Elymus sibiricus, all are of high resistance, domesticated and screened from plateaus. The experiment incorporated 2 irrigation levels(W1=60 mL/kg and W2=85 mL/kg)and 4 nitrogen levels(N0=0 g/kg, N1=0.027 8 g/kg, N2=0.055 6 g/kg, and N3=0.083 3 g/kg)according to the saturated water content (85%-90%) of sandy loam used in the experiment and nitrogen supply level (0.05-0.10 g/kg) of local crops, for a total 8 treatments. By analyzing the change of vegetation growth and biomass under different water and fertilizer conditions for ecological bags, the effect of vegetation restoration(especially on a slope) and the best combination of water and fertilizer were obtained.[Results] The vegetation growth in ecological bags were affected by the coupling effect of water and nitrogen. When in full irrigation and low nitrogen, for example W2N1,the seedling emergence rate was 79%, plant height was 4.97-13.70 cm, coverage was 68.33%-81.67%, density was 13 600plants/m2 and aboveground biomass was 0.032 5 g/plant, slope vegetation reached the highest level. The seedling emergence rate, coverage, density of flat land vegetation were the highest with full irrigation, medium and high nitrogen (W2N2/W2N3). However, with low water and no nitrogen (W1N0), the seedling emergence rate, height and coverage of both slope and flat land vegetation were low in the later seedling emergence stage. In addition, the seedling emergence rate, height and coverage of slope vegetation were higher than those of the flat land with 2 levels of irrigation and low nitrogen (W1N1 and W2N1).[Conclusions] The vegetation growth needs a certain water and nitrogen content, but there is limited distribution in an environment with excessive or insufficient water or nutrients, which is closely related to their resistances. Ecological bags lead to a strong regulation performance of water and fertilizer and play a protective role on the slope. Under a certain water and nitrogen coupling condition, the growth of the vegetation on the slope is better than that of the flat land. Moreover, the optimal condition of water and fertilizer in slope vegetation restoration of ecological bags is that:W2N1;that in the flat land is:W2N2/W2N3. It can be concluded that this technology is suitable for the promotion and utilization of highway slope restoration in the tableland area.
BAO Yuhai, YIN Yanli, QIN Wei, CHEN Shangshu, HE Xiubin
Planning and design of a science & technology demonstration park for soil and water conservation: A case of the Nanchongyan Demonstration Park in Jianyang, Sichuan
[Background] The establishment of science & technology demonstration park for soil and water conservation (DPSWC) in China is currently still in the exploratory stage, and has not yet formed perfect planning theory and norms. In order to provide theoretical and practical basis for the planning of DPSWC, the key points and methods that should be noted in the planning of the DPSWC were discussed here.[Methods] Combining the planning practice of typical DPSWC in Sichuan province and according to the literature, national laws and regulations, and relevant documents of departments, the ideas and relevant technical points for the planning of the science and technology demonstration park were analyzed.[Results] The main content of collecting data, confirming boundary zoning, designing layout, planning investment schedule in DPSWC planning were put forward, and the working requirements of maps drafting and documents outline during the planning were also defined. Based on the above mentioned design ideas, the planning results of basic condition analysis, construction objectives, planning scope and functional zoning, construction content and schedule arrangement for Nanchongyan DPSWC were introduced. The planning achievements fully considered the characteristics of the park and determined the reasonable construction objectives. Meanwhile, the planning results also efficient integrated soil and water conservation with ecological orchards, industrial development and tourism. Furthermore, the planning achievement perfected soil and water conservation measures in Nanchongyan DPSWC and improved the effects of demonstration and science popularization.[Conclusions] Overall, the construction planning is an important basis for the pre-construction work of the DPSWC. The planning compilation should meet the basic requirements during the feasibility study stage at the pre-construction work of soil and water conservation project. It should be followed the steps of selecting site, collecting data, determining target, confirming boundary zoning, designing content layout, planning investment schedule, proposing safeguard measures and so on.
Review on spatio-temporal variation of extreme precipitation events in China in the past 50 years
[Background] Extreme precipitation events occurred frequently in China due to the climate change and global warming, resulting in severe soil erosion events and huge property and personnel losses, such as the torrential rains in Wudinghe Basin in 2017. Thus, studies on the extreme precipitation events and their spatial-temporal variations are of great importance for soil and water conservation planning and management. Currently, there are abundant researches on this issue across China, however, the results of these studies have not been fully and comprehensively analyzed, which limited us for better understanding the extreme precipitation events in China.[Methods] In this study, s researches on extreme precipitation in China have been collected, important information such as the extreme precipitation indices, diagnostic methods for trend analysis, interpolation methods for spatial interpolation, and the results on spatial-temporal variations were extracted from literatures according to different regions of China and then, summarized and compared with each other with carefulness.[Results] After the comprehensively review of published literature, it is found that the spatial-temporal trends were mainly analyzed based on daily precipitation from meteorological stations and a nonsignificant increasing trend for extreme precipitation was reported on the national scale, of which, the increasing trends were mainly in South China and Southwest China, while the decreasing trends in North China, Northwest China and Northwest China. However, there are still some deficiencies which may limit the further researches:first, currently the densities of rain gauges in many studies are usually sparse; second, the effects of topographical factors on extreme precipitation are usually not taken consideration, probably due to the rain gauges are sited preferably in the flatland; third, the spatial-temporal trends may be greatly affected by the inter-decadal quasi-periodic oscillations in rainfall since the study period in many studies are relatively short. These deficiencies may have lower down the reliability of current studies and then make different studies less comparable. Under this circumstance, some advices aiming to improve the further studies have been proposed in this study:first, more meteorological station should be established quickly to get more available precipitation data; second, studies on the effects of topographic factors on extreme precipitation should be strengthened, which can be initiated from small scale watershed with plenty rainfall and hydrological data and then extend to wider regions; third, the precipitation data from meteorological stations should be used combinedly with spatial coverage data, such as TRMM to improve the station based data.[Conclusions] The researches on extreme precipitation events in China have been reviewed from published literature in this study, it can bee seen that many valuable results have been reported while there are still some deficiencies. Some advices were proposed in this study for future researches and it is expected more valuable results can be acquired in the future, which are also important for practical works, such as flood control, soil conservation, etc..
