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31.
南洞庭湖湿地生态系统结构、功能与可持续研究   总被引:3,自引:0,他引:3  
洞庭湖是我国著名的淡水湖泊湿地,也是世界上唯一的由3个国际重要湿地组成的湖泊。文章分析了南洞庭湖湿地的形成原因及演替规律,研究了其生态系统结构特征,评价了动物栖息地、植物基因库、生态改善、湿地生产、科教基地、旅游度假等湿地功能,指出其面临的主要问题是湖泊面积缩小、湿地功能衰退、动物种群衰减、资源利用率低、环境污染加剧,提出扩大湖泊面积、重视湿地资源保护、加强自然保护区建设、发展湿地生态农业、加快湿地污染治理的南洞庭湖湿地生态系统可持续发展途径。  相似文献   
32.
The investigation was carried out on 10-year-old plantation of Fraxinus mandshurica in Mao‘er Mountain Experimental Station of Northeast Forest University.tree height(H),diameter at breast height(D1.3) and the increment of tree height in 5 years (H5),the thickness of humus layer,as well as the soil moisture were measured for the plantation and the growth indexes(H,D1.3,H5) for different site conditions were analyzed.The results showedthat main site factors influencing the growth of Fraxinus mandshurica were soil moisture,gradient and location of siope in order.The growth of Fraxinus mandshurica was better on the middle-or up-slope site than on the down-slope site.Soil moisture and late frost caused by terrain are the main reasons that limit the growth of Fraxinus mandshurica plantation.  相似文献   
33.
This paper describes the use of a geographical information system (GIS) to construct environmental models for land-based aquaculture development in the State of Sinaloa, Mexico. Based on the source data, submodels were created focusing on three different themes: general environmental issues, water resources and water quality. Models enabled multicriteria and multiobjective decision making concerning site selection and location. In assessing site considerations these general models identified wider resource management options and solved conflicts of land allocation and land use between aquaculture and agriculture. Smaller-scale, more specific models enabled more detailed studies on environmental issues.  相似文献   
34.
欧建德 《安徽农业科学》2014,(21):7057-7058
该研究应用数理化理论模型Ⅰ的方法,对福建明溪闽楠林窗更新培育基地进行样地调查与数据收集,分析探讨不同立地因子对林下闽楠生长效应的影响。结果表明,影响林窗更新闽楠生长的主要因素依次是坡位、坡向、坡度,且对闽楠生长影响均达到极显著。在闽楠林窗更新过程中,进行坡位、坡向和坡度选择十分必要。  相似文献   
35.
郭星  王会儒  陈国鹏 《安徽农业科学》2014,(14):4293-4295,4357
白龙江干旱河谷脆弱生态区是我国西南地区典型的地区.在外业调查和综合分析的基础上,将白龙江干旱河谷脆弱生态区划分为1个立地类型小区,2个立地类型组,10个立地类型,通过对植被资源的调查分析,筛选出适合该区生长的28种造林树种,并将其与不同立地类型进行合理配置,以期为白龙江干旱河谷脆弱生态区植被恢复和生态环境建设提供科学依据.  相似文献   
36.
冷库选址是为了实现最优的定位,按照一定的规则与方式,把需要设置的"设施"安排在科学合理的区位,实现可观的经济效益。冷库与普通仓库在选址方面考虑的影响因素存在一定的差异。运用AHP层次分析法可以对冷链企业的仓库选点和战略决策提供切实可行的分析方法。  相似文献   
37.
本文通过对四川盆地北部、东北部、中部、西部、南部和东部香椿资源和香椿芽无公害森林蔬菜的培育技术研究,划分出香椿的立地条件类型,得出优质红椿芽的产量高,并对优质红椿芽的综合质量进行了排名,以评价其生态效益、经济效益和社会效益。  相似文献   
38.
Enhancing dry matter production with higher partitioning to fruit bunches is important for sustainable intensification of oil palm. A series of best management practices including site-specific nutrient management, canopy management, and harvesting has been developed for oil palm plantations. However, the effects of these practices on dry matter production and partitioning, and how the effects vary with climatic and soil conditions of plantation sites, remain largely unknown. We established a four-year field trial including 30 paired commercial blocks across Sumatra and Kalimantan, Indonesia. The paired treatments included site-specific best management practices, and standard estate practices as the control. The annual production of aboveground dry matter was 30.0 ± 0.5 t ha−1 yr−1 (mean ± se) under best management practices, higher than 28.8 ± 0.5 t ha−1 yr−1 under standard estate practices. The bunch index, an indicator of the fruit production efficiency, increased by 12% under best management practices compared to standard estate practices. Partitioning of dry matter to the fronds decreased by 8% under best management practices, compared to standard estate practices. The positive effect of best management practices on the annual production of total aboveground dry matter was stronger in the plantation site with higher annual rainfall. These results are useful for optimizing management practices to improve sustainable intensification of oil palm.  相似文献   
39.
总结赵王城遗址公园的景观规划原则、规划布局,重点分析生态景观区域的布局及植物造景特点,可供遗址公园保护及其景观设计参考。  相似文献   
40.
The objectives of this study were: (1) to relate the height growth pattern to the GIS-derived site index, (2) to construct various types of polymorphic height curves, and (3) to select the most accurate height curve for Japanese larch (Larix kaempferi). A total of 14 dominant trees were felled for stem analysis. Richards' function was first fitted to the height/age dataset recorded from stem analyses of 14 trees, and its parameters (i.e., A, k, and m) were then estimated for each sample tree. The relationship between parameter A and the GIS-derived site index was significant, while that of parameters k and m were not significant. The 12 height curve equation forms developed from the Richards' function were then fitted to the dataset consisting of 563 observations of height, age, and GIS-derived site index derived from 14 trees. All height curves were unbiased and provided an equally good fit. The shape of the height curves differed among sites of different site indices. These results indicated that Richards' function was sufficiently flexible to represent the polymorphic height growth pattern of Japanese larch. Finally, the best-fit height curve was selected so that accurate height growth predictions would be possible at any given age and site.  相似文献   
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