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1.
Small-scale forestry in Serbia is characterized by high fragmentation of properties, a large number of parcels and forest owners. Numerous activities for private forest owners in Serbia supported by the State, FAO and CEPF have resulted in an increased interest of owners in forming private forest owners’ associations (PFOA). The goal of this paper is to explore preconditions that are necessary for organizing private forest owners in Serbia into effective associations. In order to reach this goal, results of PRIFORT project were used. The over-arching research questions of this paper are: “What is the level of interest among forest owners in forming owners’ associations?”; “Why has forest owner interest in organizing developed so slowly?” and “What are the necessary preconditions for the development of private forest owners’ organizations in the country?” In order to answer these questions, quantitative survey with 42 close, open and Likert scale questions was conducted. Sample size was determined following Malhotra’s proportion method and, in total, 350 private forest owners, from nine municipalities were interviewed. Results of this paper show that majority of respondents are very little or not at all aware of existing legislation. Almost half of respondents consider that their interests are not represented well. Although about 50% of interviewed forest owners miss interest organization, only 0,3% are members of PFOA. More than 70% are ready to join association, if it would provide some economic advantages.  相似文献   
2.

Objectives

We examined canopy gap structure and regeneration patterns at the landscape scale using a combination of remote sensing and field-based surveys.

Methods

The study was carried out in the forest reserve of Lom, an old-growth Fagus-Abies-Picea forest located within the Dinaric Alps in the north-western part of Bosnia and Herzegovina. A high-resolution (1-m panchromatic and 4-m multispectral) Kompsat-2 satellite image was orthorectified and classified through an unsupervised pixel-based classification using an artificial neural network method.

Results

This approach allowed the identification of 650 canopy gaps, ranging in size from 32 to 1,776?m2. Only 20 intermediate to large gaps (>250?m2) were identified, and they were mainly present near the perimeter of the reserve. The origin of these large openings was associated with past human-caused disturbances or topographic conditions. The species composition of regeneration within large, human-caused gaps differed markedly from small gaps and non-gap sites in the core area of the reserve. Shade-intolerant species dominated the seedling and sapling layers in large openings. The landscape approach employed in this study confirmed the hypothesis that small gaps predominate at Lom, especially within the core area of the reserve.  相似文献   
3.
Journal of Plant Diseases and Protection - In autumn 2018, daffodil (narcissus) plants with basal bulb rot were noticed in a plantation in locality Jasika, Serbia. Morphological characterization...  相似文献   
4.
Journal of Plant Diseases and Protection - During a survey from 2004 to 2016, symptoms of grapevine dieback were observed in six vineyards in Serbia. Symptoms initially appeared as small,...  相似文献   
5.
Improving the sluggish kinetics for the electrochemical reduction of water to molecular hydrogen in alkaline environments is one key to reducing the high overpotentials and associated energy losses in water-alkali and chlor-alkali electrolyzers. We found that a controlled arrangement of nanometer-scale Ni(OH)(2) clusters on platinum electrode surfaces manifests a factor of 8 activity increase in catalyzing the hydrogen evolution reaction relative to state-of-the-art metal and metal-oxide catalysts. In a bifunctional effect, the edges of the Ni(OH)(2) clusters promoted the dissociation of water and the production of hydrogen intermediates that then adsorbed on the nearby Pt surfaces and recombined into molecular hydrogen. The generation of these hydrogen intermediates could be further enhanced via Li(+)-induced destabilization of the HO-H bond, resulting in a factor of 10 total increase in activity.  相似文献   
6.
Red–yellow (Pisum fulvum Sibth. et Sm.) and Ethiopian (Pisum abyssinicum A. Br.) peas have become of increasing interest to breeders in the last decade, as they have been found to be partially or completely tolerant to various biotic stresses, such as to attack by pea weevil, mildew blight or rust. A trial was carried out at the Institute of Field and Vegetable Crops at Rimski ?an?evi from 2005 to 2007, with 13 accessions each of red–yellow and Ethiopian peas sown at 100 viable seeds m?2, in plots of 0.5 m2. Seed yield per plant in red–yellow pea was significantly and positively correlated with seed number per plant (r = 0.881**), pod number per plant (r = 0.839**) and number of fertile nodes (r = 0.820**). The highest positive correlation among the agronomic characteristics in Ethiopian pea was between number of fertile nodes and number of pods (r = 0.937**). Seed yield in Ethiopian pea was highly significantly correlated with number of seeds (r = 0.807**), pods (r = 0.692*), and fertile nodes (r = 0.638*). The results suggest that plant morphology of the progenies between red–yellow or Ethiopian peas and grain-type common pea could not differ significantly from that of individual parents. That means that it could be possible to develop hybrid lines that could keep the desirable morphological traits of grain-type common pea, such as lodging-tolerance and high seed yields, and to make an introgression of a specific resistance from wild pea taxa, especially by back-crosses with the former. However, one must always be aware of unpredicted outcomes as a result of rather different genetic basis of individual seed yield components.  相似文献   
7.
The slow rate of the oxygen reduction reaction (ORR) in the polymer electrolyte membrane fuel cell (PEMFC) is the main limitation for automotive applications. We demonstrated that the Pt3Ni(111) surface is 10-fold more active for the ORR than the corresponding Pt(111) surface and 90-fold more active than the current state-of-the-art Pt/C catalysts for PEMFC. The Pt3Ni(111) surface has an unusual electronic structure (d-band center position) and arrangement of surface atoms in the near-surface region. Under operating conditions relevant to fuel cells, its near-surface layer exhibits a highly structured compositional oscillation in the outermost and third layers, which are Pt-rich, and in the second atomic layer, which is Ni-rich. The weak interaction between the Pt surface atoms and nonreactive oxygenated species increases the number of active sites for O2 adsorption.  相似文献   
8.
Large-flowered vetch (Vicia grandiflora Scop.) is widely present in many Eurasian wild floras, where it has significance in improving grassland communities and environment-friendly uses as a cover crop and green manure. The main goal of this study was to assess the possibility of transforming large-flowered vetch into a field crop and assess the basics for its breeding. A small-plot trial was carried out in three consecutive growing seasons 2005–2008 in Novi Sad, including twelve large-flowered wild populations collected at various sites in Serbia and France from 2002 to 2004 and multiplied ex situ during subsequent years. The population MM 02/01 of Serbian origin had the highest three-year average proportion of plants surviving winter (0.96). The smallest average number of days from sowing to first flower was in the population MM 03/10 (199 days). The population MM 03/08 produced the highest forage dry matter (8.0 Mg ha?1) yield stage between full flowering and forming first pods. The highest seed yield was in the population MM 03/10 (2,084 kg ha?1). Forage dry matter yield was significantly correlated to main stem length (r = 0.932), number of fertile nodes (r = 0.710), number of internodes (r = 0.640) and number of leaves (r = 0.604). Seed yield was significantly correlated to number of pods (r = 0.930), number of seeds (r = 0.883), number of stems (r = 0.882) and number of fertile nodes (r = 0.768). Our study confirmed that large-flowered vetch may represent a stable and quality source of forage in temperate regions such as the Balkans, as well as that it may have its place in various crop rotations and farming systems. At the same time, the existing phenotypic variability offers a solid basis for further improvement of this species.  相似文献   
9.
针对当前生物质固体成型燃料抗结渣剂成本高、抗结渣效果差等实际问题,该研究采用凹土作为天然复合添加剂,制备了凹土添加量为0~7%的生物质固体成型燃料,并对其进行了工业分析及高位热值测定。燃烧生物质固体成型燃料获得灰样,采用高速相机采集灰样宏观形貌,采用扫描电镜(Scanning Electron Microscope,SEM)对灰样微观形貌进行分析。最后借助X荧光(X-ray Fluorescence,XRF)、X射线衍射(X-ray Diffraction,XRD)对生物质灰成分进行确定,以分析凹土抗结渣机理。结果表明,凹土添加量为3%以下时,热值下降速度较小,但灰分随凹土添加量增大而增加较快。由宏观形貌和微观形貌谱图发现,凹土可以极好地提升生物质固体成型燃料抗结渣性,这主要是因为添加凹土后,凹土改变了K的迁移途径,生成了更多KAlSiO4、KAlSi2O6、Ca2Mg(Si2O7)等高熔点的复盐。该研究可为解决生物质固体成型燃料行业缺乏高效低成本抗结渣剂问题提供良好解决方案。  相似文献   
10.
为了研究添加物对混合原料恒温厌氧和好氧发酵过程的影响,实现生物质向沼气和沼肥的快速转化,先在3个分别无添加、添加质量浓度1 g/L尿素和1 g/L草木灰的0.56 m3恒温发酵装置中进行了牛粪和番茄茎叶VS(Volatile Solid)比例1:1、TS(Total Solid)为8%、发酵温度(26±2)℃、为期54 d的恒温批式厌氧发酵,并将剩余沼液进行(30±1)℃、12 L/min、为期8 h的好氧曝气处理,对比分析不同添加物的厌氧发酵及沼液好氧处理组合对装置产气和产肥性能的影响。结果表明:厌氧发酵阶段,反应前28 d各添加物对系统产沼气及合成甲烷的促进作用显著,且尿素组效果最好,累计产气量、累计产甲烷量分别为4 917、1 746.4 L,较空白组提高91%、128.7%,较草木灰组提高12.6%、69.4%,同时尿素组甲烷体积分数达到50%以及达到系统总产气量80%即5 346 L的时间均较空白组提前了5 d,但全周期空白组累计产气量和累计产甲烷量均高于其它2组;好氧处理阶段,空白组、草木灰组和尿素组沼液完全腐熟的最快时间分别为第1小时、第4小时、第1小时,此时GI(Germination Index)分别为98%、124.5%、100.4%,TDS(Total Dissolved Solid)分别为5 670、5 350、7 010 mg/L,NH+ 4-N分别为734.4、538.1、862.1 mg/L,尿素组沼液生物有效性最好。综上,尿素组系统中前期的产气效率最佳、产肥品质最优,但与复混液体肥料标准相比仍需补充养分,或浓缩处理。该研究为提高沼气产气效率、沼肥品质提供参考。  相似文献   
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