基于农户视角的盐池县退牧还草政策可持续性分析   总被引：2，自引：2，他引：0  

路慧玲  周立华  陈勇  黄珊  马兵  魏轩 《中国沙漠》2015,35(4):1065-1071

退牧还草政策的可持续性是关系到政策目标的实现与巩固、关系到区域乃至国家生态安全及社会经济环境可持续发展的重大战略问题。本文基于农户视角,从农户对政策的满意度、支持度以及对当前政策有效性和稳定性的感知等方面出发,建立盐池县退牧还草政策可持续性的评价指标体系,采用TOPSIS分析法对盐池县退牧还草政策的可持续性进行定量评价,并对可持续性的阻碍因素进行诊断。结果显示:(1)当前盐池县退牧还草政策处于弱可持续性阶段,其中农户对政策的满意度、支持度以及政策有效性为中等水平,政策稳定性则较差;(2)盐池县退牧还草政策可持续性的主要障碍因子为政策实施后农户收入水平的变化、农户偷牧行为、农户对环境重要性的认知及其对退牧还草政策的接受态度等。在此基础上,提出提高盐池县退牧还草政策可持续性的建议。  相似文献   

牧压梯度下高寒杂草类草甸土壤持水能力及影响因素分析   总被引：2，自引：0，他引：2  

吴启华  毛绍娟  刘晓琴  李红琴  张法伟  李英年 《冰川冻土》2014,36(3):590-598

以祁连山南麓坡地夏季牧场高寒杂草类草甸为研究对象,进行了封育对照（CK,禁牧）、轻度放牧（LG）、中度放牧（MG）和重度放牧（HG）下土壤持水能力及影响因素的分析. 结果表明：牧压梯度下0～10 cm层土壤最大持水量和毛管持水量均在LG最大,土壤自然贮水量LG略小于HG;而在10～20 cm和20～40 cm持水量均在HG最大,说明放牧对表层土壤的持水能力影响比深层更明显. 0～10 cm层土壤容重随牧压强度增加而增大,较深层次土壤容重基本一致,表明放牧对较深层土壤容重造成的影响远小于表层. 牧压梯度下植被地上地下生物量、枯落物、地表半腐殖质随放牧强度增大而减少;0～10 cm土壤有机质含量在MG最大,CK最小,10～20 cm和20～40 cm层土壤的有机质含量CK最大,说明不同土层有机质含量对牧压梯度的响应有所不同. 土壤持水量与多种因素有关,主要受到地下生物量、有机质和容重等因素的影响,表明随放牧强度增大,践踏使土壤表面硬度增加,土壤空隙度减少,同时家畜过度采食使地面植被覆盖降低而增加土壤水分的蒸发. 这些综合作用下引起放牧地土壤持水能力降低.  相似文献   

一类新型疏水缔合聚合物的合成及成胶性能     

张新 《东北石油大学学报》2013,(2):124-128,12

以甲氧基聚乙二醇丙烯酸酯(MPEGA)和甲基丙烯酸二甲氨基乙酯(DMAEMA)为均聚单体,通过乳液聚合制备一类新型疏水缔合型聚合物P(MPEGA-DMAEMA),采用FT-IR和1HNMR表征新型聚合物的化学结构;利用主剂P(MPEGA-DMAEMA)和交联剂醋酸铬形成凝胶体系,考察主剂P(MPEGA-DMAEMA)和交联剂醋酸铬的质量分数、pH值、温度、矿化度对新型聚合物凝胶体系成胶性能的影响.结果表明:当主剂P(MPEGA-DMAEMA)质量分数为1.2%、交联剂醋酸铬质量分数为0.2%、pH值为7、温度为45e时,该新型聚合物凝胶体系具有最佳的成胶强度.将新型聚合物凝胶体系应用于岩心封堵,在最佳成胶条件下,堵水率高于90%,堵油率低于40%,具有较好的选择封堵性.  相似文献   

Copepod feeding in a coastal area of active tidal mixing: diel and monthly variations of grazing impacts on phytoplankton biomass   总被引：1，自引：0，他引：1  

Doo B. Lee  Hye Y. Song  Chul Park  Keun H. Choi 《Marine Ecology》2012,33(1):88-105

This study examined monthly feeding rates and grazing impact on phytoplankton biomass, as well as diel feeding rhythms of four key copepod species in a tidally well mixed estuary (Asan Bay, Korean Peninsula). Monthly ingestion rates estimated based on gut pigment analysis were closely associated with their peak densities, but not with phytoplankton biomass, implying high ingestion may be related to reproductive output for population growth. The three smaller copepods, Acartia hongi, Acartia pacifica and Paracalanus parvus, showed feeding preference for smaller phytoplankton (<20 μm) with higher clearance rates, whereas the larger Calanus sinicus preferred larger phytoplankton. Acartia pacifica and P. parvus showed distinct increased nocturnal feeding rates as measured with gut fluorescence, whereas A. hongi showed no significant day–night differences. Copepod diel feeding patterns were not associated with food quantity, and endogenous physiological rhythm might be hypothesized as responsible for the observed diel feeding patterns. Grazing impact on phytoplankton biomass by the four copepods in the estuary was on average 8% (range 0.2–29.8%) of the phytoplankton standing stock, similar to values reported in other coastal waters. Very high copepod abundances but low daily carbon ration (<20% for all copepods) provided by feeding on phytoplankton indicate that copepods also grazed on other non‐phytoplankton foods in Asan Bay.  相似文献   

内蒙古牧区矿产开发模式选择的思路探讨     

佟宝全  阿荣 《地理科学进展》2012,31(12):1693-1699

内蒙古牧区能矿资源富集, 生态环境敏感脆弱。国家“能源安全”战略要求大规模开发利用煤炭资源的地域分工与国家“生态安全”战略要求保护生态环境保护之间存在尖锐的矛盾。解决好这一矛盾, 对我国西部生态敏感区的矿产资源合理开发利用和生态环境保护具有重要意义。对生态敏感的煤炭富集区应基于区域发展的空间均衡这一视角, 选择合理的开发模式。其分析思路为:首先, 选择典型煤炭资源开发区域, 对开发空间与生态空间的空间耦合关系进行分析, 通过比较空间耦合类型, 揭示空间失衡点, 并分析空间失衡原因。其次, 构建指标体系, 构造矩阵, 对区域空间供给能力进行分区。最后, 综合空间失衡原因、空间供给能力分区以及资源开发与生态保护的需求因素, 提出区域发展的空间均衡模式与对策。  相似文献   

Effects of spring–summer grazing on longitudinal dune surface in southern Gurbantunggut Desert     

Xueqin Wang  Yuanming Zhang  Jin Jiang  Weikang Yang  Hongxu Guo  Yongfeng Hu 《地理学报(英文版)》2009,19(3):299-308

Intensive grazing in spring–summer has been responsible for environmental degradation of the Gurbantunggut Desert in recent years. The coverage of plants and biological crusts, sand surface stability and physicochemical characteristics of soil on the dune surface were conducted in 2002 (winter grazing) and 2005 (spring–summer grazing). The results showed that over 80% of the total area of the dune surface was covered by well-developed biological crusts and plants in 2002, when the interdune and middle to lower part of dune slopes were stabilized and only the crest had 10–40 m wide mobile belt. Affected by spring–summer grazing in 2005, over 80% of the total cover of biological crust was destructed and the plant coverage only reached 1/5 of that in 2002, especially the ephemeral plant cover had a great change. The value of sand transport potential in 2005 only reached 1/3 of that in 2002, but the total surface activity in 2005 was 1.6 times stronger than that in 2002. Meanwhile the mobile area began to expand from the dune top to the whole dune surface following spring–summer grazing. Compared with 2002, medium sand content of the dune surface soil increased by 13.9%, while that of fine and very fine sands decreased by 7.4% and 8.0% respectively in 2005 and the soil organic matter in 2005 was only about 1/2 of that in 2002. It is obvious that the presence of snow cover and frozen soil in winter could avoid the surface structure destruction in winter, while spring–summer grazing made excessive damage to biologic crusts and ephemeral plants. Spring is the main windy season in Gurbantunggut Desert and therefore intensive activity of dune surface occurred following spring–summer grazing, which led to a great loss of fine sand and organic matter. It can be seen that grazing season have a significant influence on the sustainable development of the desert ecosystem in Northwest China. Foundation: National Basic Research Program of China, No.2009CB421303; National Natural Science Foundation of China, No.40771032; National Science Supporting Program, No.2007BAC17B03 Author: Wang Xueqin (1964–), Ph.D and Associate Professor, specialized in aeolian sand geomorphology, desertification and its control.  相似文献   

科尔沁沙地持续放牧和不同强度放牧后封育草场中生物结皮生物量和土壤因子的变化   总被引：7，自引：1，他引：6  

徐杰  宁远英 《中国沙漠》2010,30(4):824-830

通过对科尔沁沙地放牧后封育样地和放牧样地生物结皮生物量的研究,探讨了不同样地生物结皮生物量的变化规律及其与环境因子的相互关系。结果表明,封育样地藓类和藻类植物的生物量显著高于放牧样地;在封育样地内,轻度、中度放牧封育区显著高于重度放牧封育区（P＜0.05）。封育样地生物结皮的土壤微生物量碳、氮含量高于放牧样地,并且各样区藓结皮土壤微生物量碳、氮含量显著高于藻结皮（P＜0.05）。在封育样地内表现为轻度、中度放牧封育区土壤微生物量碳、氮含量较高,重度放牧封育区含量较低,体现出不同强度放牧封育停牧后对土壤微生物量碳、氮影响的滞后效应。藻类植物的生物量与结皮厚度、有机质含量和粉黏粒呈极显著正相关（P＜0.01）,与细沙呈显著正相关（P＜0.05）,与粗沙呈极显著负相关（P＜0.01）。藓类植物的生物量与结皮厚度、有机质含量、粉黏粒呈显著正相关（P＜0.05）,与粗沙呈负相关,但不显著。藻类植物的生物量与土壤因子之间的相关性更为密切。  相似文献   

地质统计学储量估算中块尺寸的合理选择     

张延凯  李克庆  杨诗海  李迪  宫明山 《吉林大学学报(地球科学版)》2017,47(1)

在矿产勘查、矿山设计、生产及管理等各阶段都需要进行资源储量估算的工作。地质统计学方法相对于传统储量估算方法具有明显优势,在资源储量估算中获得了广泛的应用。估值过程中单元块尺寸的合理选择对储量估算结果至关重要,然而,在以往实践中块尺寸通常根据经验或主观判断进行选择,缺乏科学依据。本文在总结前人工作及地质统计学资源储量估算经验的基础上,将块尺寸的选取问题明确地划分为勘探阶段和生产阶段。针对不同阶段的特点,重点讨论了块尺寸与品位、储量、估计精度、选别开采单元的关系,为块尺寸的合理选择提供参考。并以某特大型钼矿为工程背景,进行了深度解析及数据实验,得出了块尺寸不仅影响资源品位分布、矿石量而且影响开采技术经济指标的结论,综合考虑估计精度和选别开采单元,推荐该矿床选择15m×15m×15m的单元块尺寸进行储量估算。  相似文献   

关于提高金刚石钻头胎体工作能力的试验研究          下载免费PDF全文

汤凤林  沈中华  段隆臣  柳少青  孙环平  Чихоткин В.Ф. 《探矿工程》2017,44(10):55-60

在地质勘探中,金刚石钻进是一种主要的方法。在金刚石钻探生产中,钻探设备、钻头、钻探工艺、钻探生产操作技术和生产管理都是非常重要的。钻探技术经济指标与钻头胎体的工作能力关系更为密切,因此成了人们关心的问题。俄罗斯Кубасов В.В.博士等在提高钻头胎体工作能力方面做了大量的工作,取得了很好的技术经济效果。本文介绍了他们在低品级金刚石的选择性破碎处理、金刚石的热处理、金刚石钻头的低温处理和胎体性能的控制技术等方面的研究内容及取得的成果。  相似文献   

BOOK REVIEWS     

《The Professional geographer》1986,38(4):430-457

Book Reviewed in this article: Latin America: Case Studies . Richard G. Boehm and Sent Visser Locality and Rurality: Economy and Society in Rural Regions . Tony Bradley And Philip Lowe The City and the Grassroots . Manuel Castells Geopolitics and Conflict in South America. Quarrels among Neighbors . Jack Child Post-Industrial America: A Geographical Perspective . David Clark Coastal Research: UK Perspectives . Malcolm W. Clark A Rural Policy for the EEC? Hugh Clout Peasant Agriculture in Assam: A Structural Analysis . M. M. Das . Environmental Change and Tropical Geomorphology . I. Douglas and T. Spencer Advances in Abandoned Settlement Analysis: Application to Prehistoric Anthrosols in Colombia, South America . Robert C. Eidt Measuring Culture . Jonathan L. Gross and Steve Rayner North America: A Human Geography . Paul Guinness and Michael Bradshaw A Geographical Bibliography for American Libraries . Chauncy D. Harris et al. Geography and the Urban Environment: Progress in Research and Applications, Vol. VI . D. T. Herbert and R. J. Johnston Changes in Global Climate: A Study of the Effect of Radiation and Other Factors During the Present Century . K. Ya . Kondrat'ev . Rural Development and the State: Contradictions and Dilemmas in Developing Countries . David A. M. Lea and D. P. Chaudhri The Martial Metropolis: U.S. Cities in War and Peace . Roger W. Lotchin The Climate of the Earth . Paul E. Lydolph . Weather and Climate . Paul E. Lydolph . Spatial Divisions of Labor: Social Structures and the Geography of Production . Doreen Massey . Panorama of the Soviet Union . N. Mikhailov . Soviet Armenia . K. S. Demirchian . USSR: Geography of the Eleventh Five-Year Plan Period . K. Spidchenko . Planung und Verwirklichung der Wiener Ringstrassenzone (Planning and Materialization of the Ringstrasse-Zone of Vienna). Kurt Mollik , Hermann Reining , Rudolf Wurzer . The American West Transformed: The Impact of the Second World War Gerald D. Nash . An Overview of the Survey of Income and Program Participation . Dawn Nelson , David Mc Millen, and Daniel Kasprzyk . Phenomenology, Science and Geography: Spatiality and the Human Sciences . John Pickles . Biological Diversification in the Tropics . Ghillean T. Prance Die Wanderviehwirtschaft im gebirgigen Westen der U.S.A. und ihre Auswirkungen im Naturraum . Gisbert Rinschede . Social and Economic Aspects of Radioactive Waste Disposal: Considerations for Institutional Management . World-Wide Weather . K. Takahashi Coastal Geomorphology in Australia . B. G. Thom Settlement System in Rural India: A Case Study of the Lower Ganga-Yamuna Doab . Ram Chandra Tiwari . Computer Programming for Geographers . David J. Unwin and John A. Dawson . Late Quaternary Environments of the Soviet Union . A. A. Velichko, ed . H. E. Wright , Jr. and C. W. Barnosky Ethics in Planning . Martin Wachs  相似文献