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281.
人类活动对锡林郭勒盟草原净初级生产力的影响研究   总被引:3,自引:0,他引:3  
张珺  任鸿瑞 《自然资源学报》2017,32(7):1125-1133
净初级生产力是草地生态系统生产能力的体现,同时也是草地生态系统固碳能力的重要指标。论文利用MOD17A3净初级生产力数据(NPP)与气象资料,分析了2001—2010年人类活动对锡林郭勒盟草原净初级生产力的影响。研究表明:1)锡林郭勒盟草原实际净初级生产力(NPPA)介于41.32~362.27 g C·m-2·a-1,均值为150.78 g C·m-2·a-1,有较明显的水平地带性规律,由东向西逐渐减小,草甸草原最大,典型草原次之,荒漠草原最小;2)锡林郭勒盟草原人类活动影响的净初级生产力(NPPH)介于-185.07~153.92 g C·m-2·a-1,均值为-34.80 g C·m-2·a-1,人类活动负作用占草原总面积的93.4%,人类活动正作用仅占6.6%;3)人类活动对锡林郭勒盟草原净初级生产力的影响主要是由负作用向正作用转变,且空间分布有明显的南北界线,南部表现为负作用增强,北部为正作用增强。研究可为锡林郭勒盟草地资源的管理和可持续利用提供参考依据。  相似文献   
282.
Attachment of Scenedesmus sp. LX1 was tested on certain materials. A criterion for selection of materials was used to choose seven materials. The amount of S. sp. LX1 attached on polyurethane foam was 51.74 mg/L. Materials’ surface influenced the attachment of microalgae. Hydrophilic and hydrophobic properties also affected the attachment of S. sp. LX1. Attached cultivation systems in the literature do not present a methodology to screen materials for microalgal growth. Hence, a method is needed to find suitable materials for attached cultivation that may enhance attachment of microalgae. In this paper, we have tested seven materials culturing Scenedesmus sp. LX1 (S. sp. LX1) to evaluate the attachment of microalgae on the material surface, its growth in suspension phase and the properties of the materials. Two materials showed attachment of S. sp. LX1, polyurethane foam and loofah sponge, and allowed microalgae to grow both in the surface of the material and suspended phase. Polyurethane foam proved to be a good material for attachment of S. sp. LX1 and the amount of attached microalgae obtained was 51.73 mg/L when adding 100 pieces/L. SEM images showed that the surface and the pore size of the materials affected the attachment of the microalgae, increasing its attachment in scaffold-like materials. Furthermore, the hydrophilic and hydrophobic properties of the materials also affected the attachment of microalgae. This research can be used as a methodology to search for the assessment of a material suitable for attachment of microalgae.  相似文献   
283.
This article begins by summarizing the importance of the forestry sector in the Philippine economy It provides an overview of the multiplicity of Philippine governmental institutions involved in forestry in 1982 Then it discusses forestry laws in the country and concludes by examining fifteen critical forest policy issues: sustained yield management; area-specific logging bans; increased use of wood wastes; revision of forest charges; unprocessed log export ban; rationalization of the forest industry, acceleration of reforestation; protection of watersheds; recognition of the social dimensions of slash- and-burn agriculture; fuelwood supply; public land classification for forestry and agriculture, development of plantations for dendrothermal electricity; multiple-use management; preservation of mangrove areas, and improvements in administration and implementation.Research for this paper was supported by the East-West Center Environment and Policy Institute. The author would like to acknowledge the assistance of the Natural Resources Management Center of the Philippine Ministry of Natural Resources.  相似文献   
284.
This study compares community-based managed forests under different purposes of management, namely, state-driven conservation or community-designed utilization in two villages located in the Sopsai watershed, Nan Province, northern Thailand. The forest health under different intensity of uses is assessed in association with the collective behaviors and long-term purposes embedded in village social–cultural context. The study found no significant differences in forest succession and proportion in diameter at 1.3 m (dbh) class and height-class distribution of the forest under different use intensity. The forest for utilization also showed higher density and basal area of the local preferred species than the conservation forest. In the utilization forest, we also found a higher number of multipurpose and preferred species than in the conservation forest, which actually responded to the needs of the community in the long term to have more wood products (both firewood and timbers). The community-based forest management (CBFM) for utilization can also lead to natural regeneration and biodiversity similar to conservation forests. Through CBFM, forest resources can be managed to maintain the healthy condition under different intensities and respond to both community needs and external expectation. The findings also emphasize the importance of recognizing community needs and management objectives in watershed restoration and improving the productivity of forests under collective management.  相似文献   
285.
在充分考虑草地土壤水分亏缺和生产力水平的基础上,构造了草地缺水指数和旱灾评判系数。通过对旱灾评判系数与灾情历史序列的对比分析,确定了旱灾等级指标,并提出了大面积监测草地旱灾的方法,为客观准确地监测草地旱灾提供了科学依据。  相似文献   
286.
塔里木河上游及源流区草原荒漠化及其防治研究   总被引:3,自引:0,他引:3  
加强生态环境保护和建设是西部大开发的战略重点。针对塔里木河流域环境恶化、草地开发利用失衡、草原荒漠化日趋严重的问题,提出具体规划和综合治理方案。  相似文献   
287.
通过对黄山药(Dioscorea Panthaica)在四川德昌县的田间栽培试验,其生物学特性及栽培性状表现为:全生育期290天左右,明显地分为萌动期、营养期、孕蕾开花期、果期、根茎生长期、枯萎期和休眠期;具有根茎分枝多、繁殖系数高的优良栽培性状。栽后8个月的新根茎重是种根茎重的0.65倍,20个月则达3.06倍;单位面积产量随栽培9~18万株/ha 的密度增加,最高达15493.9kg/ha,平植法优于垄植法。皂素含量以盛花期最高,休眠期最低。  相似文献   
288.
若尔盖草地沙化及防治对策   总被引:15,自引:0,他引:15  
赵仁昌 《四川环境》1995,14(2):15-20
草地沙化是国内外关注的重大环境生态问题,本文主要报道了若尔盖草地沙化的成因,分布及其特征,沙化对草地土壤,植被的危害,同时提出了防止草地沙化的对策。  相似文献   
289.
The atmospheric deposition of reactive nitrogen on turf grassland in Tsukuba, central Japan, was investigated from July 2003 to December 2004. The target components were ammonium, nitrate, and nitrite ions for wet deposition and gaseous ammonia, nitric and nitrous acids, and particulate ammonium, nitrate, and nitrite for dry deposition. Organic nitrogen was also evaluated by subtracting the amount of inorganic nitrogen from total nitrogen. A wet-only sampler and filter holders were used to collect precipitation and the atmospheric components, respectively. An inferential method was applied to calculate the dry deposition velocity of gases and particles, which involved the effects of surface wetness and ammonia volatilization through stomata on the dry deposition velocity. The mean fraction of the monthly wet to total deposition was different among chemical species; 37, 77, and 1% for ammoniacal, nitrate-, and nitrite-nitrogen, respectively. The annual deposition of inorganic nitrogen in 2004 was 47 and 48 mmol m−2 yr−1 for wet and dry deposition, respectively; 51% of atmospheric deposition was contributed by dry deposition. The annual wet deposition in 2004 was 20, 27, and 0.07 mmol m−2 yr−1, and the annual dry deposition in 2004 was 35, 7.4, and 5.4 mmol m−2 yr−1 for ammoniacal, nitrate-, and nitrite-nitrogen, respectively. Ammoniacal nitrogen was the most important reactive nitrogen because of its remarkable contribution to both wet and dry deposition. The median ratio of the organic nitrogen concentration to total nitrogen was 9.8, 17, and 15% for precipitation, gases, and particles, respectively.  相似文献   
290.
分析心理契约与安全感内涵,进一步探讨煤矿企业员工心理契约形成过程及其与安全感之间的关系模型,指出心理契约是影响员工安全感的重要因素。根据心理契约的动态发展特性,提出煤矿企业员工安全感3阶段培育策略。指出通过生产设备本质安全化、健全安全管理制度,安全行为矫正与安全心理培训等手段建立良性互动的心理契约,是培养煤炭企业员工安全感的重要途径。研究表明:在煤炭企业内部建立有效的沟通平台可以强化企业与员工之间的心理约束,提高员工的心理承受能力和风险干预能力,进而增强煤炭企业员工的安全感。研究的思路和方法为煤炭企业的安全管理提供了一种全新的视角,对遏止煤矿重大事故具有重要意义。  相似文献   
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