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71.
邓虹 《西南师范大学学报(自然科学版)》2013,38(9):123-127
在四川丘陵旱坡地上,研究了不同种植技术对节水保水和粮食产量、经济效益的影响,结果表明:①在秸秆覆盖、免耕种植基础上,合理安排种植模式,可收到节水保水,提高产出的效果,"麦、玉、花、苕"模式节水保水效果最好,经济效益最高,"麦、玉、苕、豆"模式节水保水效果较好,粮食产量最高.②节水保水的关键措施,除免耕种植外,一是秸秆还田和间种豆科以增加土壤有机质;二是恰当配置匍匐作物和矮株作物,构建良好的地表植被增强生物覆盖.③秸秆还田和间种豆科有良好的改土培肥作用,对土壤有机质、氮素的效果最为明显,对钾和磷也有较好的作用. 相似文献
72.
Microparticle record in the Guliya ice core and its comparison with polar records since the last interglacial 总被引:5,自引:0,他引:5
WUGuangjian YAOTandong L.G.Thompson LIZhongqin 《科学通报(英文版)》2004,49(6):607-611
Based on the study of oxygen isotope and microparticle in the Guliya ice core,atmospheric dust and environmental changes in the northwest Tibetan Plateau since the last interglacial were revealed.The microparticle record indicates that low dust load on the Plateau in the interglacial.Particle concentration increased rapidly when the climate turned into the last glacial and reached the maximum during the MIS 4.In the Last Glacial Maximum, however,the enhancement of microparticle concentration was slight,differing to those in the Antarctic and Greenland.On the orbital timescale,both the temperature on the Tibetan Plateau and summer solar insolation in the Northern Hemisphere had their impact on the microparticle record,but the difference in phase and amplitude also existed. Though having the same dust source, microparticle records in the ice cores on the Tibetan Plateau and the Greenland seem to have different significance. 相似文献
73.
ZHOU Huarong XIAO Duning ZHOU Kefa 《科学通报(英文版)》2006,51(A01):82-91
The river corridor areas in the middle and lower reaches of the Tarim River are dominated by the traditional green corridors along the river section from the Qara Reservoir in Yuli County to the Taitema Lake in Ruoqiang County, which plays an important role in the social and economic development in the Tarim River Wate'rshed with a extremely significant ecological functions. The buffer zones perpendicular to the watercourse were defined along both riversides at a 5-km interval beginning from the watercourse (10 km wider) using the method of the buffer zone analysis. The landscape pattern indexes of each buffer zone were calculated, and the indexes of the main landscape patterns were analyzed so as to reveal the radiative effect and the characteristics of the river corridors on landscape and patch levels. The results show that the radiative width is generally 30 km in the study area, and can be up to 50-70 km in subregion FG1 because the study area is located in two drainage basins, with an ecological interstitial zone between them. The landscapes of woodlands and wetlands are generally distributed within the 10 km buffer zone (it means that the buffer zone is 5 km away from the watercourse; the same hereafter) along both riversides. Moreover, the closer the buffer zone is to the watercourse, the higher the patch density and the largest patch index are. In the ecological and environmental regeneration for the study area, the extent of ecological effect of the river corridors must be fully considered, and the projects must be scientifically and rationally planned and designed. 相似文献
74.
The river corridor areas in the middle and lower reaches of the Tarim River are dominated by the traditional green corridors along the river section from the Qara Reservoir in Yuli County to the Taitema Lake in Ruoqiang County, which plays an important role in the social and economic development in the Tarim River Watershed with a extremely significant ecological functions. The buffer zones perpendicular to the watercourse were defined along both riversides at a 5-km interval beginning from the watercourse (10 km wider) using the method of the buffer zone analysis. The landscape pattern indexes of each buffer zone were calculated, and the indexes of the main landscape patterns were analyzed so as to reveal the radiative effect and the characteristics of the river corridors on landscape and patch levels. The results show that the radiative width is generally 30 km in the study area, and can be up to 50-70 km in sub- region FG1 because the study area is located in two drainage basins, with an ecological interstitial zone between them. The landscapes of woodlands and wetlands are generally distributed within the 10 km buffer zone (it means that the buffer zone is 5 km away from the watercourse; the same hereafter) along both riversides. Moreover, the closer the buffer zone is to the watercourse, the higher the patch density and the largest patch index are. In the ecological and environmental regeneration for the study area, the extent of ecological effect of the river corridors must be fully considered, and the projects must be scientifically and rationally planned and designed. 相似文献
75.
Ecological capital is the summation of the direct value of biological resources and the ecological service function value of ecosystems. Under the support of RS, GPS and GIS, in this paper the RS-based quantitative measurement model of assessing ecological capital is developed based on the traditional ecology theory and the research on the value of ecological capital per unit area by using the ecological parameters including Landsat TM data, CBERS satellite data, meteorological data, MODIS satellite data, land cover data and field-measured data. A case study on the spatiotemporal distribution of ecological capital in Changji Hui Autonomous Prefecture in 1990, 1995 and 2003 is carried out, and the dynamic change of ecological capital in the prefecture is measured and compared with GDP. The maps of the spatial distribution of ecological capital in the study area are charted, and the characteristics of spatial distribution of ecological capital are analyzed. The results show that the values of ecological capital in the prefecture in 1990, 1995 and 2003 were 1.47368×1011, 1.66160×1011 and 1.77895×1011 yuan RMB (hereafter referred to as yuan) respec-tively, and that in spatial distribution, the ecological capital decreases from the alpine zones to the plains and from the oases to the deserts, which accords with the zonal distribution of vegetation in arid areas. The measured results can more objectively reflect the ecological capital and its spatial distribution in arid areas, provide an ideal foundation for further study in the future, and can also be combined with the study on service functions of ecosystems and the regional planning as an important basis of regional planning. 相似文献
76.
宁夏中部干旱带生态环境现状与发展策略研究 总被引:3,自引:0,他引:3
在实地考察调研的基础上,结合宁夏中部干旱带生态现状,阐述了其人口分布特征、人口素质对乡村农业、经济结构的影响,对不同影响因素的作用进行了分析.结果表明,相关因素对退耕还林工程生态环境效益的发挥有很大作用.应进一步改善区域生态环境,加强环境保护,加快培养特色林业产业,有效促进农民增收,在建立生态效益补偿机制的基础上加快发展劳务产业。促进退耕工程理智进行和生态环境效益的长期发挥. 相似文献
77.
Ecosystem degradation is a common and cardinal environmental problem in arid zones. The change in the eco-hydrological processes is the basic cause responsible for such a problem. The study on the eco-hydrological processes in arid zones has become a forefront and focus of the eco-environmental research. Recent studies on eco-hydrological processes in arid zones show that the primary vegetation pattern and its eco-hydrological effect are of the most stable state of the ecosystem in arid zones. Special water absorption ways of plants in arid zones and the hydraulic lift and reverse hydraulic lift functions of some plants are the key mechanisms to maintain the stability of the ecosystem in arid zones. In the case of water shortage, ensuring ecological water requirement and maintaining proper ecological ground- water table are the prerequisite to keep healthful operation of the ecosystem in arid zones. The paper reviews some advances in the study of eco-hydrological processes in arid zones. It puts forward the concepts of critical ecological water requirement, optimal ecological water requirement and saturated ecological water requirement, and discusses their determination methods. It also emphasizes that the studies on natural vegetation pattern and eco-hydrological effect, on plants with hydraulic lift function, on water sources for plant absorption, on ecological water requirement and ecological groundwater table for different plant species should be strengthened to determine the species composition and pattern suitable for the restoration and reestablishment of vegetation in different arid zones in China. 相似文献
78.
西北干旱区农业灌溉水资源优化分配的DDP模型 总被引:2,自引:0,他引:2
西北干旱区水资源短缺,实行农业节水灌溉和水资源最优分配至关重要。在作物生长季节,灌区内多种作物并存,并且不同类作物有其各自的生长规律和需水要求,以水量分配和经济效益为决策目标,建立多种作物间灌溉水资源最优化分配的双层动态规划(DDP)模型。第一层为单项作物在生长季节的水量分配;第二层为多种作物间水量的分配。以甘肃省景泰川一期灌区为实例,对模型进行模拟和较正。 相似文献
79.
马应贤 《新疆师范大学学报(自然科学版)》1995,(2)
新疆旅游资源具有独特的地域环境。本文主要论述了深居欧亚大陆腹地的区位环境,干旱荒漠区的自然环境,资源丰富且待开发的经济环境和多民族风土习俗的人文环境。并对今后旅游资源的开发方向提出若干建设性意见。 相似文献
80.
本文讨论了我国北方干旱平原地区如何发展现代化农业经济,提出了机井变台经济模式,论述了机井变台经济特征及对促进社会主义大农业发展的意义,还总结了初步实践的结果。 相似文献