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1.
HAN Wen-jun HOU Xiang-yang OLOKHNUUD Chun-liang Michael P Schellenberg 《中国农业科学(英文版)》2014,(6):1157-1164
The East Eurasian Steppe Transect （EEST） is the ifrst international transect across regions of middle and high latitudes in the eastern Eurasian steppe. The EEST is an ideal platform for researching the response of Eurasian temperate steppe to global change, because of its integrated gradients of temperature and human activities on a large-scale. In this study, basic characteristics of plant communities along the EEST across a latitudinal gradient was analyzed. According to the survey of 58 sampling sites, there are 140 species belonging to 34 families and 94 genera. Of particular note was the ifnding of Astragalus dalaiensis which has disappeared in the grasslands of China. On the whole, Gramineae plants are dominant with Liliaceae plants in the communities signiifcantly decreasing along the latitudinal gradient from south to north. The Shannon-Wiener index and biomass of communities all decreased along the latitudinal gradient with signiifcant negative linear regressions. The SDR2 （summed dominance ratio based on two factors） of dominant plants in the upper layers of communities, such as Stipa and Leymus chinensis, decreased along the latitudinal gradient from south to north. Especially, the SDR2 of L. chinensis decreased signiifcantly. The SDR2 of Cleistogenes squarrosa, Agropyron cristatum in the lower layers of communities and the indicator species for degradation were not affected. Potentilla acaulis was found mainly in the southern and northern areas. Stellera chamaejasme was found just in a few sites in the southern area of the EEST. In communities of Stipa grandis and Stipa krylovii, annual and biennial species are dominant. The ratio of annual and biennial species in the community is signiifcantly related to the latitudinal gradient. Perennial herbaceous plants and shrubs were not affected. According to the principal component analysis （PCA）, with the data from 58＆#215;140 dimensions, the ifrst and second components had the lowest proportion, thus indicating that the species compositions and community structures are homogeneous along the EEST. There is a certain degree of spatial differentiation along the EEST due to degradation’s differences resulting from the different land uses. 相似文献
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热带林业实验中心人工林区景观格局变化分析 总被引：2，自引：0，他引：2
以中国林业科学研究院热带林业实验中心（热林中心）1998年、2004年和2009年3期森林资源调查成果为主要信息源,在地理信息系统软件的支持下,通过分析景观指数,对热林中心3个时期的景观格局作了系统分析。研究表明：1998 － 2009年,有林地景观要素占所有景观要素面积的49%以上,呈现出面积大、斑块数目多、优势度高的特征,它对热林中心景观的结构功能起着主导作用。未成林造林地、非林地、无立木林地在1998 － 2009年期间面积分别减少283.83,538.84和1 507.11 hm2, 疏林地在2004年和2009年2期数据中都已经不存在,宜林地面积在不断增加,苗圃和辅助生产这些为营林造林服务的土地面积也略有上升趋势。这些变化与热林中心近年来重视森林培育,精细化经营林地,对林地利用方式进行调整有关。表3参26 相似文献
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This study aims at investigating the AIS （Agricultural Information System） in Hamedan province, Iran, benefiting from the list of criteria for well functioning AISs that were identified in earlier researches. For this purpose, a survey method with multi-stage stratified random sampling technique was used to select 31 agricultural researchers, and 62 extension workers in the province. The data were acquired by questionnaire and structured interviews. The instrument for data collection was subjected to pre-testing, validation and reliability tests. The results of the factor analysis revealed that the criteria could be categorized into four overarching groups based on their inter-correlation. The analysis of mentioned criteria in Hamedan province AIS showed less efficiency and effectiveness than studies conducted in other areas. But among these, two desirable criteria existed. It is recommended that the ecological knowledge system （EKS） should be integrated with AIS, and some ecological and sustainable development criteria should be added to the existing ones. 相似文献
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Stem Borer Species Composition on Maize and Two Non-Cereal Hosts in the Forest Zone of Kisangani,DRC
Onesime Mubenga Kankonda ;Dudu Akaibe ;Walangululu Massamba ;George Otieno Ong'amo ;Bruno-Pierre Le Ru 《农业科学与技术》2014,(10):822-829
Lepidopteran stem borers are the most damaging pests of maize in Sub-Saharan Africa. Despite the growing importance of maize in the forest zone of Democratic Republic of Congo, no data is available regarding stem borer pest species present and their relative importance. It is thus important to gather information likely to guide future research in this area. This study was undertaken to catalogue stem borer pest species identity and assess their relative infestation levels on maize. Surveys were carried out in wild and cultivated habitats in Kisangani. Five species were collected on maize, i.e., Sesamia calamistis Hampson （1910）, Eldana saccharina Walker （1865）, Busseola fusca Fuller （1901）, Chilo sp. Strand （1913）, and Mussidia nigrivenella Ragonot （1888）. In the wild habitats, Poenoma serrata Hampson, B. fusca and S. calamistis were collected on Pennisetum purpureum whereas Chilo sp. was collected on Panicum maximum. Our results suggest that P. maximum might affect the population dynamics of Chilo sp. whereas P. purpureum is expected not to influence the population dynamics of other stem borers owing to its scarcity in the interior of the forest. 相似文献
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Constraints and probable pathway towards increasing tree density and diversity within farmlands as a means of reducing human dependency on Mt. Marsabit forest for wood are addressed. The forest provides a carbon sink to counteract the risks and hazards associated with climate change. A structured questionnaire was administered to a sample of 205 respondents that were selected from a population of 3075 farming households using a systematic random sampling procedure. While majority of the farms （53%） had low tree density （1-10 trees）, only 8% of the farms had high density （≥ 20 trees）. About 50% and 15% farms had Grevelia robusta and Eucalyptus cammudelensis, which were grown for timber production, respectively. Broad leafed trees, like Croton megalocarpus and Moringa stenoptella had been established in 17% of the farmlands, respectively. With only 20% of the households having a fence around the crop fields, coupled by widely inter-household sharing of crop residues for grazing, tree browsing by livestock was a constraint to tree establishment. The challenges present an opportunity to establish governance structures and processes for communal responsibility and management of tree resources in the farms. A plausible approach entails the Adaptive Collaborative Management （ACM） as a process that facilitates to experiential learning and negotiation for probable actions and policies in management of natural resources. 相似文献
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网格技术在森林防火地理信息平台中的应用 总被引：2，自引：1，他引：1
从网格角度分析了森林防火地理信息平台中存在的资源共享受限、缺乏协同工作能力等问题,并针对当前森林防火系统中空间数据资源的特点和资源共享的迫切需要,将空间信息网格技术引入森林防火系统中搭建网格地理信息平台(GGIP),以改善空间数据共享和应用的环境,同时对节点统一管理、资源一体化管理和异构数据库统一访问等问题进行了分析和研究,研究表明:所搭建的GGIP克服了传统GIS系统无法解决的资源有限共享和协同工作能力差等问题,可以实现资源全面共享和一体化管理,提高系统内资源的协同工作能力. 相似文献
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用现代高新信息技术对森林资源信息进行科学、高效地管理,为森林资源可持续经营战略决策搭建先进的技术支撑平台,是森林资源可持续经营研究的重要内容。本研究以火地塘林场为例,对目前森林资源信息管理存在的问题和现状进行分析之后,探讨了地理信息系统、多源数据无缝集成、面向对象数据库建模和决策支持模型与方法等技术对森林资源数据获取、存储、管理、分析及可视化决策的关键作用和重要意义,在G IS的强大空间分析能力基础上依托森林资源相关的分析和评价模型,对森林资源实施科学管理和可持续经营。 相似文献
11.
应用3S技术进行了拉萨市森林资源调查,并对拉萨市森林资源现状进行了分析.结果表明:拉萨市现有森林面积352 637 1 hm2,森林覆盖率为7 3%,以天然灌木林为主占林业用地总面积的74 9%.拉萨市森林植被处在西藏森林分布的北界,呈沿河谷坡地零星的间断分布,森林少,而且分布极不均匀.作者提出把"保护性林业"作为拉萨市林业建设的指导思想,确实保护好现有天然灌木林;实行多层次、多林种、多形式的绿化造林,不断扩大森林面积,提高森林覆盖率.建立复合生态系统,依靠科技兴林,走可持续发展的道路. 相似文献
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以越南同奈天然文化自然保护区的不同胖大海优势度林分林隙内胖大海更新为研究对象,对不同优势度林分林隙下胖大海更新种群的生命表、空间分布格局以及更新密度分布特征进行研究。结果表明：在3个优势度等级林分中胖大海SL1的个体株数最大,其中SL1到SL5的个体数量单调递减, SL4至SL5呈较为稳定状态;在优势度3级林分胖大海SL1的死亡率为0.358,均小于优势度2级林分的0.480和1级林分的0.413,而胖大海SL2至SL4的死亡率均大于优势度2级和1级林分;在不同林隙大小等级中胖大海幼树幼苗的空间分布型均呈聚集型;在优势度1级林分中,胖大海随着林隙面积增加,更新平均密度单调增加,林隙面积<80 m2时,胖大海幼树幼苗的平均密度均较小,林隙面积401-500 m2时,胖大海幼树幼苗平均密度达到峰值,在优势度1级和3级林分中胖大海幼树幼苗生长发育最适林隙面积为401-500 m2,但优势度2级林分中林隙面积为201-300 m2最适于胖大海幼树幼苗生长。虽然,胖大海幼树幼苗耐荫,需要光照强度不高,但林隙面积过小,光照强度过弱也不利于胖大海幼树幼苗生长。 相似文献
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森林防火工作是森林资源保护中的重要方面,在网络环境下,充分运用3S及其集成技术是提高森林防火工作效率的一个重要途径.该文整合了北京市房山区多年的信息资源,建立了包括航拍影像、林业小班等信息在内的空间数据库,使用Java技术,建立了一个基于3S集成技术的分布式计算平台,实现了火险等级预报、火点定位、火行为预测、位置服务、扑救指挥、损失评估等功能,为房山区林业局的林火档案管理、火险信息发布、林火扑救提供信息化管理手段和决策支持. 相似文献
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为了研究害鼠对四川南部山区农业生产及森林的危害,于2008年12月至2009年3月,采用样方法对地处该地区的雅安市郊区周边农区的农田、人工林、河滩湿地和人口聚居区4种生境的害鼠多样性进行了研究。本次调查共捕获鼠类107只,隶属于2目2科6种。调查结果显示,在不同自然环境中,主要害鼠的多样性水平呈现明显差异。人工林中害鼠多样性最高(H=1.7493),农村聚居点的害鼠多样性最低(H=0.9994)。计算了各生境中害鼠的均匀度和优势度,结果显示,农村聚居点均匀度最高(E=0.9994),农田中均匀度最低(E=0.6507),农田的优势度最高(D=0.5057),人工林的优势度最低(D=0.3924)。 相似文献
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通过对比各类油松林分类型水平空间结构指数的差异，为应用结构指数调控林分抚育提供依据。以黄龙山林区的57块油松林固定样地为研究对象，基于角尺度（W）、胸径大小比（U）、混交度（M）和密集度（C）探讨油松天然林和人工林空间、不同坡向油松林的空间结构和不同林龄油松林空间结构的差异。结果表明，在角尺度方面，天然林显著高于人工林（P=0.028<0.05），且极显著高于人工成熟林（P=0.004 7<0.01），阴坡人工成熟林（AMC）显著低于其余不同林分类型（P<0.05）；胸径大小比数（U）方面，不同林分类型中均无显著差异，但是在径阶分布上天然林的胸径大小比数分布呈双峰，而人工林的呈单峰；在混交度（M）方面，阴坡油松林显著高于阳坡油松林（P=0.002 7<0.05），中龄林极显著低于成熟林（P=0.009 4<0.01）；在密集度（C）方面，天然林的密集度显著低于人工林的密集度（P=0.000 3<0.05），阴坡油松林显著高于阳坡油松林（P=0.53>0.05），成熟林显著高于近熟林（P=0.018<0.05），天然林极显著低于人工近熟林（P=0.001 2<0.01）。在水平格局分布上，起源影响了油松林分布的均匀与聚集程度；在林木大小分化方面，坡向影响了林木的竞争强度；林分的树冠拥挤程度上，起源影响了油松林的树冠竞争；在林分混交上，坡向和林龄都会影响林分的混交程度，阳坡天然近熟林（NSS）和阳坡人工近熟林（ASS)显示了一个极低的混交度，表明短期单纯抚育或者封育较难提升阳坡油松林的混交度。 相似文献
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The objective of this study was to evaluate the effects of elemental sulphur （S） and farmyard manure on soil pH, EC and N, S, P concentrations of tomato grown in a calcareous sandy loam soil. For this purpose, a pot experiment was conducted in greenhouse conditions. Sulphur was applied at 0, 50, 100, 150, 200, 400 mg kg~ and farmyard manure at 0, 3 ton da^-1 to the soil. Three weeks after applications, tomato seedlings were planted and 8 weeks later, the plants were harvested to determine N, S, P concentrations and dry matter yield. Soil pH and EC were determined in the soil samples taken at 3 different periods. Effects of sulphur and farmyard manure applications were not significant on N, P concentrations and dry matter yield of tomato plant. S concentration of tomato plant was increased by sulphur alone. Soil pH was decreased and soil EC was increased in both 2^nd and 3^rd soil sampling period by the sulphur applications. As a result of farmyard manure application, soil pH decreased in the 2^nd soil sampling period but increased in the 3^rd soil sampling period. Also, soil EC was significantly increased in 1^st and 3^rd soil sampling period. Farmyard manure had no significant effect on S supply to tomato plant. The N：S ratio of tomato plant was decreased by sulphur alone. However, the sulphur with farmyard manure applications decreased N：S ratio in lesser extend compared to the S applications. 相似文献
17.
Yihunie Hibstie Asres ;Ashok Kumar Chaubey ;Awoke Taddesse Hailu ;Dilbetigle Assefa Mamo 《农业科学与技术》2014,(4):342-352
Farmers may not be conscious for their farmland＇s nutrients, soil organic matter, water and air because they simply concerned only for their labor availability and soil fertility losses. The composition and proportion of these components greatly influence soil physical properties, including texture, structure and porosity, the fraction of pore space in a soil. The soil of this farmland must be able to supply adequate amount of plant nutrients, in forms which can be absorbed by the crop, within its lifespan. Deficiencies or imbalances in the supply of any of essential elements can compromise growth, affecting root development, cell division, crop quality, crop yield and resistance to disease and drought. This study was conducted to fill this knowledge gap in order to develop economically vital and environmentally accepted nutrient management strategies for the use of soils in agricultural lands. The objective of this study is to assess the elemental contents and concentration of soil samples collected from farmlands of ＂Yebrage＂ using neutron activation analysis （NAA） techniques regardless of oxidation state, chemical form or physical locations. NAA is used to determine the elemental composition and concentrations present in a soil. The macro/micronutrient and organic matter deficiencies have been verified in agricultural soils through increased use of soil testing and plant analysis. The challenge for agriculture over the coming decades will meet the world＇s increasing demands for food in a sustainable way. Current issues and future challenges point out that as long as agriculture remains a soil based industry, major decreases in productivity likely to be attained ensuring that plants do not have adequate and balanced supply of nutrients. 相似文献
18.
F. Perveen 《农业科学与技术》2011,(1):73-80
Identification of lxodid tick species on livestock in two districts, viz., D.I. Khan and Lakki Marwat of Northern Pakistan were made during the period from March to November 2009 through animals＇ survey and questionnaire. The main tick species were Amblyomma （14.3%）, Boophilus microplus （l 8.5%） and Hyalomma anatolicum and H. dromedarii （67.2%）. Out of 3009 collected ticks, the highest number of female （88.7%） and the lowest of males （ l 1.3%） belong to Boophilus; the lowest number of female （92.4%） and the highest of males （77.5%） belong to Amblyomma. However, cows were more susceptible than buffaloes and camels ranked third to ticks infestation. Moreover, cows, buffalos, goats and sheep harbored mixed infestation （had more than one type of ticks）, however, camels and donkey harbored single infestation （had only one type of tick）. An emerging ethno-veterinary or traditional remedy is poultry keeping for ticks＇ elimination in Lakki Marwat. The results of this research will be helped in taking appropriate measures to reduce tick infestation and to improve management practices. Hence, it will help to increase farm productivity and farmers income. 相似文献
19.
Impacts of Climate Change on Rice Yield in China From 1961 to 2010 Based on Provincial Data 总被引：3，自引：0，他引：3
The impacts of climate change on rice yield in China from 1961 to 2010 were studied in this paper, based on the provincial data, in order to develop scientiifc countermeasures. The results indicated that increase of average temperature improved single cropping rice production on national level by up to 11%relative to the average over the study period, however, it resulted in an overall loss of double cropping rice by up to 1.9%. The decrease of diurnal temperature range （DTR） in the major producing regions caused the decrease by up to 3.0%for single cropping rice production and 2.0%for double cropping rice production. Moreover, the contribution of precipitation change reached about 6.2%for single cropping rice production, but no signiifcant effect for double cropping rice production in recent 50 years. 相似文献
20.
Rinat Ismagilovich Ibragimov ;Ildar Salimyanovich Mardanshin ;Galina Vasilyevna Benkovskaya ;Maksim Borisovich Udalov ;Irina Andreevna Shpirnaya ;Vyacheslav Olegovich Tsvetkov 《农业科学与技术》2014,(4):331-341
In field and laboratory conditions the reproductive potential （survival at different stages of development） of the Colorado potato beetle has been measured, the dependence of the parameters of insects fertility on varietal features of the feed has been investigated, the food activity of the representatives of insects from four areas of the Southern Urals has been measured, the intensity and time of hypersensitivity reactions on potato leaves has been defined. In laboratory experiments, the level of activity of hydrolytic enzymes in insects and the level of activity of these enzymes inhibitors in the leaves of three potato varieties differing in their resistance to the Colorado potato beetle have been determined. The results show that the insects-representatives of different samples have different food activity in relation to different potato varieties. High mortality rates were revealed at feeding with leaves of potato of the Bashkir variety characterized by a high level of hydrolases inhibitors and relatively rapid development of necrotic reactions after the appearance of eggs laying on the leaves. We suppose that the neerogenetic barrier appearing in the form of necrosis is the major cause of the fetal mortality of insects. The level of the content of inhibitors inactivating larvae digestive enzymes affects the survival of insects at postembryonic stages. The speed of the necrosis emergence, the level of activity of digestive enzymes inhibitors in potato can be considered as criteria for the selection of breeding material for resistance to the Colorado potato beetle. 相似文献