Emergy Analysis of the Agricultural Eco-economic System in Dongting Lake Area of Hunan Province

[ Objective] The reseamh aimed to discuss eco-efficiency of the agro-ecosystem in Dongting Lake area of Hunan. [ Method] By referring to emergy reseamh method, emergy structure, function and efficiency of the system were analyzed according to emergy input -output data of the system in 2009. [ Result] The system had developed economy, and mechanization and modernization degrees were higher. Emergy output of the system was unbalanced, and market pricing of the agricultural product was significantly lower, especially farming product. Seen from sustainable development index and environmental loading ratio of the system, the system was full of vitality and development potential. The pressure of natural resources and environment was not very great, but the system accommodated too many populations. [ Conclusion] Basic direction of the agricultur- al policy in the zone was further shortening industrial and agricultural price scissors, continuing to implement price protection of the farming product, adjusting agricultural and product structures and transferring surplus labor.

Eco-compensation effects of the wetland recovery in Dongting Lake area

Eco-compensation is an environmental economic instrument for internalization of external cost. Returning farmland to lake is one of the important parts of restoring wetland ecosystem function in the Yangtze River Valley of China. Whether the project of lake recovery can be successful depends on the compensation to the farmers who have lost their original benefits and contributed to the wetland ecosystem recovery by returning farmland to lake. Aiming at the wetland recovery of the Dongting Lake, the practical implementation of pro- grams of the lake recovery and flood control in this area has been challenged by the heavy task of population resettlement, so it is an ideal area for case studies to reach the academic objectives proposed as the above. Based on field survey and experimentation, this research evaluated the benefit losses of the resettled farmers and the increased values of ecosystem service functions caused by wetland recovery, and furthermore, the value of eco-compensation for relocated farmers was calculated by considering the combination of the farmers＇ compensation appeal. The value of eco-compensation for relocated farmers in the Dongting Lake area was 6084.5 yuan per household by synthetic analysis of the effects on wetland ecosystem restoration. Moreover, this article took Dongting Lake area as a case to study and explore the basic issues of the eco-compensation by returning farmland to lake, that was who should pay, who should be paid, how much the payment was and what the payment means was, which sought the mechanisms of wetland restoration eco-compensation and prompted the people＇s enthusiasms for ecological restoration.

Discussion on the Green Tax Stimulation Measure of Nitrogen Fertilizer Non-Point Source Pollution Control-Taking the Dongting Lake Area in China as a Case

A study on designing the tax of nitrogen fertilizer can provide a new method for controlling nitrogen fertilizer non-point source pollution. The tax design of nitrogen fertilizer was discussed by utilizing the external theory and the demand elasticity theory. The results indicated that the coefficient of price elasticity of nitrogen fertilizer demand is -0.21, which instructed that the market demand is in lack of elasticity in the short period and the impact of nitrogen fertilizer manufacturers is subtle. The 11 counties （cities and boroughs） in the Dongting Lake area in China, where the farmland nitrogen application surpassed the average ecological fertilization dosage, is listed to the taxation scope of nitrogen fertilizer tax. The environment loss will reduce 0.07 hundred million RMB yuan and the revenue will increase 0.89 hundred million RMB yuan in the country after levying on nitrogen fertilizer. The loss, which was brought by the decreasing food supplies production, will be 0.58 hundred million RMB yuan and the net social benefit will be 0.38 hundred million RMB yuan following revenue collection. The variation scope of the increasing expenditure of farmers will range from 0.95 to 1.49%. The variation scope of the income of farmers will range from -8.41 to 6.44%. The 5 areas, Yunxi Borough, Junshan Borough, Hanshou County, Jinshi City, and Ziyang Borough, had an increase in food supplies production after the revenue collection. The environment loss will reduce 0.01 hundred million RMB yuan and the revenue will increase 0.16 hundred million RMB yuan in the country after levying on nitrogen fertilizer. The economic benefits, which was brought by the increasing cereals production, will be 0.67 hundred million RMB yuan and the net social benefit will be 0.84 hundred million RMB yuan after revenue collection. The variation scope of the increasing expenditure of farmers will range from 0.95 to 1.06%. The variation scope of the increasing income of farmers will range from 0.69 to 6.44%. Considering the entire social welfare, taxation of nitrogen fertilizer will have more advantages than disadvantages in the Dongting Lake area.

The spatial-temporal changes of the land use/cover in the Dongting Lake area during the last decade

The research on the land use/cover change is one of the frontiers and the hot spots in the global change research. Based on the Chinese resource and environment spatial-temporal database, and using the Landsat TM and ETM data of 1990 and 2000 respectively, we analyzed the spatial-temporal characteristics of land use/cover changes in the Dongting Lake area during the last decade. The result shows that during the last ten years there were three land-use types that had changed remarkably. The cultivated land decreased by 0.57% of the total cultivated land. The built-up land and water area expanded, with an increase of 8.97% and 0.43% respectively. The conversion between land use types mostly happened among these three land-use types, especially frequently between cultivated land and water area. The land-use change speed of land-use type is different. Three cities experienced the greatest degree of land-use change among all the administrative districts, which means that the land use in these cities changed much quickly. The following changed area was the west and south of the Dongting Lake area. The slowest changed area is the north and east area.

External Costs and Optimum Use of Nitrogen Fertilizer Based on the Balance of Economic and Ecological Benefits in the Paddy Field System of the Dongting Lake Area, China

The external costs and the optimum use of nitrogen fertilizer based on the balance of economic and ecological benefits was studied with the paddy field system of Dongting Lake area, one of the main food production regions in China. The environmental impact was economically evaluated using methods of the environmental impact economical evaluation. The optimum use of nitrogen fertilizer was calculated based on the exterior diseconomy theory and by using the production function model. Both ecological benefits and farmers＇ economic benefits were considered. It was calculated on the data from 2002 that the losses caused by inappropriate utilization of nitrogen fertilizer in the process of food production were fishery, 0.1 × 10^7 RMB yuan; water treatment, 1.02 × 10^8 RMB yuan; tour business, 0.11 ×10^8 RMB yuan, and habitation environment, 0.3 × 10^7 RMB yuan, totally equivalent to 0.41 RMB yuan kg^-1 N. The economically satisfactory and the ecological agronomic nitrogen fertilizer dose for current production was 138 and 137 kg ha^-1, respectively. The research showed that the actual nitrogen fertilizer application amount in the paddy field system of the Dongting Lake area already reached or exceeded the farmers＇ economic satisfaction and the ecological agronomic nitrogen fertilizer dose for current production. An environmental tax is suggested to impose on over-use of nitrogen fertilizer.

Effects of the dispatch modes of the Three Gorges Reservoir on the water regimes in the Dongting Lake area in typical years

Based on the field-survey prototype hydrology data in typical years, the effect during the running periods of different dispatch modes of the Three Gorges Reservoir on the water regimes in Dongting Lake area is comparatively analyzed. The results are shown as follows. （1） The influence periods are from 25 May to 10 June, from 1 July to 31 August, from 15 September to 31 October and from December to the next April, among which the influence of the water-supplement dispatch in the dry season is not very sensitive. （2） During the period under the pre-discharge dispatch, the runoff volume slightly increases as well as both the average water level and the highest water level rise in the usual year. While in the wet and dry years, the average increase in the runoff volume is 40.25×1 08 m3 and the average rises of the average water level and the highest water level are both 1.06 m. （3） As for the flood-storage dispatch, the flood volume increases slightly, in the dry and wet years, the flood volume, the average water level and the highest water level averagely reduce by 444.02×108 m3, 2.64 m and 1.42 m respectively. （4） Under the water-storage dispatch, the runoff volume slightly in- creases and the water level heightens in a sort in the usual year. And in the dry and wet years the average decreases in the runoff volume, the average water leve/and the highest water levels are respectively 185.27×108 m3, 3.13 m and 2.14 m. （5） During the period under the water-supplement dispatch, the runoff volume, the average water level and the highest water levels averagely decline by 337.7×108 m3, 1.89 m and 2.39 m respectively in the usual and wet years. However, in the dry year, the runoff volume increases as well as the average and highest water levels slightly go up.

FLOOD SIMULATION IN DONGTING LAKE DRAINAGE AREA AND ITS FLOOD CONTROL

On the basis of water-balance equation in Dongting Lake and Xiang Zi Yuan-Li River drainage areas, a possib1e flood height relating to the rainfall precipitation in these areas has been inferred. According to the flood simulation, some synthetic maintenance strategies to prevent future catastrophic f1oods in Dongting Lake drainage area have been also presented.

Mathematical model for flood routing in Jingjiang River and Dongting Lake network

The main stream of the Yangtze River, Dongting Lake, and the river network in the Jingjiang reach of the Yangtze River constitute a complex water system. This paper develops a one-dimensional （l-D） mathematical model for flood routing in the river network Of the Jingjiang River and Dongting Lake using the explicit finite volume method. Based on observed data during the flood periods in 1996 and 1998, the model was calibrated and validated, and the results show that the model is effective and has high accuracy. In addition, the one-dimensional mathematical model for the river network and the horizontal two-dimensional （2-D） mathematical model for the Jingjiang flood diversion area were coupled to simulate the flood process in the Jingjiang River, Dongting Lake, and the Jingjiang flood diversion area. The calculated results of the coupled model are consistent with the practical processes. Meanwhile, the results show that the flood diversion has significant effects on the decrease of the peak water level at the Shashi and Chenjiawan hydrological stations near the flood diversion gates, and the effect is more obvious in the downstream than in the upstream.

Architectural Design Concept of Dongting Lake Museum

Architectural design of Dongting Lake Museum takes "River dolphin ripples in the Dongting Lake" as the theme, tries to integrate into the local wetland environment and ecological resources of the Dongting Lake, in order to realize the dream of "making a great museum for the most gorgeous lake". The overall layout follows the concept of "coexistence of real and virtual, integration of exterior and interior", and the architectural image symbolizes "the river dolphin ripples", which is extremely harmonious in the whole natural environment. The design integrates planning, building, landscape and interior spaces, adopts technical means and ecological green to integrate the building into the environment, and presents us a tremendous ecological wetland museum that floats on the lake like a fish, an islet, a sail or a hill.

基于LMDI模型的土地利用碳排放时空差异及影响因素研究——以洞庭湖区为例

运用碳排放系数法和对数平均迪氏指数(LMDI)模型,对1996—2020年洞庭湖区土地利用变化、土地利用碳排放时空差异及其影响因素进行分析。结果表明:(1)土地利用变化整体呈现出“三增三减”特征,建设用地和未利用地的变化程度较为显著,水域和草地次之,耕地和林地的变化程度最小。(2)总净碳排放量呈不断上升趋势,碳排放高值区由中部转向西、东、南部,土地利用碳足迹压力指数始终大于1,以0.54的年均增幅不断上升。(3)人均GDP、单位GDP用地面积和单位土地碳排放强度是影响土地利用碳排放的主要因子,人均GDP和单位GDP用地面积分别成为促进和减缓洞庭湖区碳排放量增长的主要因素。

国土空间规划视域下国家公园适宜范围识别研究——以拟建洞庭湖国家公园为例

国家公园范围边界是平衡社会经济发展和生态保护的重要界线,作为国家公园设立的基础,范围识别是关系国家公园规划和建设管理能否顺利实施的先决条件,是其保护对象和管理目标的最直接体现。为科学识别国家公园范围,提出一套基于对生态系统原真性、生态系统完整性和管理可操作多重考虑的范围识别方法,并以拟建洞庭湖国家公园为例进行实证分析。研究结果表明:(1)选取生态系统原真性、生态系统完整性和可操作性三方面指标构建评价指标体系,进行叠加分析,识别国家公园范围,弥补了国家公园范围识别生态保护导向单一的不足。(2)研究区内生态系统原真性区域面积不大,仅1 165.46 km~2;维持了较好的生态系统完整性,完整性指数平均值为0.45;可操作性评价结果显示国家权属且属保护地所在空间的可行性指数较高。(3)洞庭湖国家公园适宜划定范围为2 145.7 km~2,包括了东洞庭湖、西洞庭湖和南洞庭湖三大片区,其中核心保护区205.8 km~2。可尝试动态评估自然生态系统原真性和完整性,并将国家公园纳入更大的保护地网络,为国家公园的创建和管护提供理论及实践借鉴。

基于数字足迹的洞庭湖区游客感知研究

洞庭湖区是湖南省旅游战略发展要地,探究该区游客感知有利于提升目的地旅游形象.以洞庭湖区数字足迹为原始数据,运用文本分析法探究游客对洞庭湖区旅游的整体感知.研究发现,洞庭湖区旅游目的地整体形象较好;洞庭湖区游客多集中于岳阳市,常德市、益阳市等游客到访量较少.游客对洞庭湖区旅游发展的感知以积极情绪为主,整体满意度较高,也有游客认为旅游发展没有达到预期效果,体验感差.基于上述研究结果,提出丰富旅游产品业态、优化目的地旅游环境、深度开发旅游产品等建议,以期为洞庭湖区旅游发展提供新思路.

洞庭湖区旅游产业与生态环境适应性时空演变及影响因素

【目的】诊断旅游产业与生态环境适应性,为旅游产业高质量发展和生态环境可持续承载提供参考依据。【方法】从旅游产业和生态环境2个子系统,压力、状态和响应3个维度构建旅游产业与生态环境适应性评价指标体系,运用熵权Topsis法、适应性评价模型、标准差椭圆及地理探测器,分析洞庭湖区2012—2021年旅游产业与生态环境适应性时空演变及影响因素。【结果】1)旅游产业指数呈现升—降—升变化趋势,生态环境指数呈现波动上升趋势,旅游产业与生态环境适应性指数时空差异显著,呈现中部地区较低、四周地区较高的“盆地型”空间分布格局。2)近10年来适应性时空迁移趋势以东西方向为主导,空间离散程度呈现出先扩大后缩小的变化趋势,重心位于洞庭湖中部地区,集聚特征明显。3)旅游产业与生态环境适应性类型以低度适应为主,县域占比达41.18%,空间格局表现边缘地区>外围地区>中部地区的分布特征。4)旅游资源禀赋、政府调控力度、经济发展水平和环境治理能力是驱动旅游产业与生态环境适应性时空演变的重要因素。【结论】洞庭湖区旅游产业与生态环境适应性较低,县域发展不平衡、不充分问题较突出。未来洞庭湖区旅游产业发展,应立足生态环境承载能力,科学开发旅游资源,加强区域旅游合作,提高旅游产业与生态环境的适应能力。

洞庭湖区生态经济系统时空耦合演变及驱动因素

统筹生态环境与经济发展是促进生态经济可持续发展的内在要求,对推动我国经济高质量发展具有重要的现实意义。本文分别从压力、状态和响应,以及水平、结构和效益3个维度构建生态环境与经济发展评价指标体系,运用耦合协调度模型、探索性空间数据分析法、标准差椭圆和地理探测器等方法,分析洞庭湖区生态经济系统时空耦合演变特征及驱动因素。结果表明:(1)2013—2022年生态经济系统耦合协调度呈现出稳定上升趋势,由0.3798增长到0.6348,空间差异显著,呈现出中部低、四周高的“盆地型”空间分布格局。(2)耦合协调度呈现出显著的正向全局空间自相关,且集聚性不断增强;局部自相关存在低—低和高—高2种集聚类型。耦合协调度的重心位置位于洞庭湖中部地区,并逐渐向西北方向移动。(3)生态弹性、经济发展、科学技术和政府调控是生态经济系统耦合协调度时空演变的主要驱动因素。

湖南省“一湖三水”岸线保护与利用规划研究

岸线的有效保护和合理利用对沿岸地区生态文明建设和经济社会发展具有重要的作用。分析了湖南省“一湖三水”岸线保护与利用现状,综合评价现状岸线资源,明确“一湖三水”临水边界线和外缘边界线划定方法,科学合理地划分岸线功能区,严格把握岸线保护与利用控制条件。结果表明:湖南省“一湖三水”岸线保护存在的主要问题包括管理体制机制不够完善、利用方式不合理、集约节约利用程度不高等。洞庭湖、资水、沅江、澧水河湖岸线长5567.1 km,共划定岸线功能区1038个,其中岸线保护区、岸线保留区的总体比例达78.1%,充分体现了大保护的要求。河湖临水边界线和外缘边界线划定方法、岸线功能分区及管控措施等研究成果可为湖南省及类似地区岸线规划提供参考。

洞庭湖区油菜—豌豆间作栽培技术

油菜—豌豆间作可丰富农田生物多样性,提高土地及光热资源利用率,实现资源利用最大化,是有机农作模式的理想组成作物。本文阐述了洞庭湖区油菜—豌豆间作栽培技术,包括品种选择、间作模式确定、整地施肥、播种间苗、苗期管理、大田管理、采收等方面内容,以期更新油菜现有栽培模式,为该模式种植户提供参考。

2022特枯年洞庭湖区洲滩面积变化特性分析

2022年洞庭湖出现了“汛期反枯”的罕见现象,湖区水文情势发生较大改变,直接导致汛期洞庭湖区洲滩大面积提前出露,从而对洲滩湿地环境产生不利的影响。基于此,根据最新实测资料研究了2022年湖区洲滩面积变化特征,初步分析了其变化对湿地环境的影响,并取得了以下主要认识:(1)2022年1~6月城陵矶站水位一般高于2003~2021年同期水位值,7月份开始城陵矶站水位持续走低,水位由7月初的30.40 m下降至9月30日的19.43 m;(2)除10月上旬城陵矶站水位抬高外,其他月份该站水位基本变化不大;(3)与2013~2021年相比,2022年7~11月份湖区洲滩面积分别增加了340,680,860,660 km^(2)及510 km^(2);(4)湖区洲滩面积不断增大引起苔草类和芦苇群落生物量不断向水深区域增加,导致沉水植被的生存空间急剧缩小,不利于耐旱能力较差的植物生长繁殖与以鱼类、沉水类植物为食的鸟类捕食,同时一旦来年汛期水量较大,将有可能导致东方田鼠暴发。

基于土壤侵蚀方程的大通湖流域吸附态氮磷负荷估算

【目的】大通湖的水质长期处于Ⅲ类及以下,其主要超标污染物为总氮和总磷,通过估算大通湖流域吸附态氮、磷污染负荷,为大通湖地区水污染治理和水环境保护提供科学依据。【方法】该研究采用修正通用土壤侵蚀方程,耦合吸附态氮、磷污染负荷模型估算研究区的吸附态氮、磷污染负荷,重点分析大通湖流域吸附态氮、磷污染的空间分布特征。【结果】模型计算结果表明:2020年,大通湖流域土壤侵蚀总量为4804.8 t,平均土壤侵蚀模数为5.20 t/(km^(2)·a),吸附态氮、磷的负荷量分别为4.943、2.098 t,对流域内各土地利用类型按吸附态氮、磷污染负荷模数由大到小排序依次为:林地、耕地、建设用地;按行政区域划分,茅草街、青树嘴、乌嘴乡、明山头和河坝镇吸附态氮、磷污染较为严重;按流域划分,五七运河流域、苏河流域、大新河流域、大通湖西入湖区以及草阳渠片区氮、磷污染负荷较大。【结论】大通湖流域土壤侵蚀强度以微度侵蚀为主,耕地是吸附态氮、磷的主要流失来源,对于吸附态氮、磷流失较大的区域,可以按照源头减量、过程拦截、末端治理的思路进行治理。同时适当调整农业种植结构、改进耕作方式、完善水土保持措施,减少土壤流失量,降低吸附态氮、磷污染物对水体的直接影响。

基于三阶段超效率SBM-Malmquist指数分解的洞庭湖区农业水资源绿色效率研究

近年来,洞庭湖区农业用水供求矛盾日益凸显,提升农业水资源绿色效率对实现洞庭湖生态经济区高质量发展具有重要意义。基于2011—2019年农业水资源投入与产出数据,运用三阶段超效率SBM-Malmquist指数模型对洞庭湖区农业水资源绿色效率进行测度。结果表明:剔除外部环境和随机误差项影响,2011—2019年洞庭湖区农业水资源绿色效率均值为0.5832,农业水资源绿色效率存在较大的提升空间;人均GDP和政府农林水事务支出增加可以促进农业水资源绿色效率的提升,人均水资源量增加会降低农业水资源绿色效率;洞庭湖区农业水资源全要素生产率指数经历上升—下降—上升三个主要阶段,农业水资源全要素生产率指数与技术进步变化指数基本同步。最后提出了洞庭湖区农业用水绿色效率的相关对策建议。