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41.
Practices that minimize the rate of soil degradation, increase crop yields and raise farm income are key to sustaining agricultural productivity in the hills of Nepal. The use of farmland is undergoing rapid changes in response to increasing population pressure, deforestation and subsistence needs. Against this background, this study examined the impact of an agroforestry intervention project on farm income based on a sample of subsistence farm households in Dhadhing district. The project was implemented by Nepal Agroforestry Foundation in 1993/94 to increase fodder production through the promotion of agroforestry. A total of 223 households (82 with project and 141 without project) were interviewed during May–October 1998 to collect information on production and agroforestrys' impact on farm income. The benefit-cost analysis showed that the agricultural system including agroforestry was more profitable than the conventional one. The results also showed that the introduction of mulberry trees for sericulture could further enhance the profitability of an agroforestry-based system. Thus, agroforestry has great potential for enhancing food production and farmers' economic conditions in a sustainable manner through its positive contributions to household income.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
42.
Salix discolor Mühl. (Sd) and Salix viminalis L. (Sv) were planted under short-rotation intensive culture (SRIC) on three unirrigated abandoned farmland sites with different drainage conditions, one well-drained (S1) and the other two poorly-drained (S2, S3). One dose of dried and granulated sludge equivalent to 150 (T1) kg of “available” N ha−1 was applied to some plots in the spring of the second season while others were left unfertilized (T0). The aims of the experiment were (i) to investigate plant response (growth and productivity) to plantation site conditions and sludge application; (ii) study nutrient status by foliar analysis. Over three seasons, growth in height and aboveground biomass were greater for S. viminalis than for S. discolor on all sites. S. viminalis planted on poorly-drained site 2 had the highest biomass yield (45.28 t ha−1). Both species showed best height and diameter growth on poorly-drained sites. For both species, best performances were obtained on wastewater sludge fertilized plots. Comparative foliar analysis suggested that unfertilized sandy soil (S1) and low foliar nitrogen concentration and content were limiting factors in the performance of the two species. Soil nitrate concentration increased as a result of sludge application. Heavy metal accumulation from sludge does not represent a risk to the environment. It was concluded that S. viminalis had the best productivity on clay sites, and that a moderate dose of dried and pelleted sludge (150 kg of “available” N ha−1) may be a good fertilizer during the establishment of willows in SRIC, and may reduce nitrate leaching. 相似文献
43.
This paper attempts to contribute to the forestry valuation literature by providing a template for executing ex ante cost–benefit analyses of large-scale temperate plantation forestry programmes, taking the Irish Government's Forestry Plan as an example. An ex ante assessment of the social efficiency of the Plan is undertaken and, in doing so, a range of externalities is examined using, inter alia, contingent valuation and production function approaches. The appropriate magnitude of subvention of the Plan is also examined. The study demonstrates how large-scale forestry programmes and their external effects, both positive and negative, can be evaluated. In so doing, it provides insights into the methodological difficulties and solutions for assessing the social efficiency of large-scale environmental projects and the appropriate level of their subsidisation. 相似文献
44.
An analogue approach to analysing the traditional homegardens of Keralavis-à-vis natural climax ecosystems is adopted. The traditional homegarden is apparently a climax ecosystem, where ecological succession is consciously manipulated by human beings. High intensity of vertical and horizontal space use, the highly dynamic chronological structure and the capacity to perform essential ecological processes make this ecosystem relatively sustainable. Homegardens in Kerala effectively serve as human ecosystems with their low input demand, staggered supply of outputs, and enhancement of habitat quality. However, recent trends in agrarian structure and the high market orientation exert pressures on the homegarden, and its sustainability as a human ecosystem is in question.This joint paper is based on part of the research conducted by Darley Jose for the degree of M.Sc. (Natural Resource Management) at the Agricultural University of Norway under the guidance of N. Shanmugaratnam. 相似文献
45.
《国际水土保持研究(英文)》2020,8(2):164-172
Watershed development programmes carried out in different agroclimatic conditions in India resulted in beneficial impact in terms of productivity enhancement and natural resources conservation, but less attention paid to institutional and participatory aspects. This paper explored the performance of various institutions regarding execution of watershed development programmes in semi-arid region of India. Recorded observations from documents maintained at watershed level and information collected through primary survey as well as focus group discussion with different types of stakeholders were used for analysis. The results indicated lacunae in participatory aspects during programme implementation process like monitoring activities, management of common property resources and equity. Gap in linkages and differential level of performance of various watershed level functionaries indicates the necessity for corrections in the structures and linkages pattern for sustainability of the infrastructure and institutions. The study also showed unequal priorities by the implementing agencies towards institutions, land and water resources development, production enhancement activities and fodder resources development as well as rationalities of technical, economic, financial, political and social aspects among the watersheds. 相似文献
46.
W. Li Z.-H. Yan Y.-M. Wei X.-J. Lan Y.-L. Zheng 《Journal of Agronomy and Crop Science》2006,192(3):221-227
An understanding of the characteristics of crop varieties and advanced lines could help improve their cultivation and to further enhance their potential. The objectives of this study were to estimate the genotype (G), environment (E) and genotype × environment (GE) interactions on the grain yield of Chinese spring wheat genotypes in 2000 and 2001 by the additive main effects and multiplicative interaction (AMMI) model, and to evaluate the relationships between yield and its components by correlation and path analysis. Grain yield varied from 3.9 to 5.2 t ha?1, among which SW8188 had the highest yield performance, followed by 58769‐6 and Chuannong 16. Three interaction principal components (IPC) accounted for a total of 79.99 % and 72.96 % of the interactions with 41.05 % and 52.08 % for the corresponding degrees of freedom in 2000 and 2001, respectively. When IPC3 was significant, the stability coefficient Di was more useful in the evaluation of the stability of each genotype. The estimates of Di in the 2 years indicated that the Di values varied between genotypes and years. The Di values ranged from 1.804 to 14.665 and 2.497 to 12.481 in 2000 and 2001 respectively. The suitable locations (environments) for all genotypes were characterized. These results would be useful for improving the Chinese spring wheat cultivation and improvement. 相似文献
47.
为了进一步改善履带式拖拉机的传动性能,利用有限元分析技术展开设计.根据履带式拖拉机的变速箱体内部各轴系的位置关系与承受载荷程度,结合履带式拖拉机田间作业环境特点,充分将组成部件离散化,利用ANSYS进行分析,得到变速箱体压力分布云图,达到预期优化目标并进行性能试验.试验表明:变速箱内部组合结构局部优化后,固有频率试验值... 相似文献
48.
49.
从经济角度而言,森林旅游的可持续发展就是要实现森林旅游经济效益的持续增长.通过对影响森林旅游经济效益增长的主要因素的分析,指出：努力保持森林旅游供需在数量上和结构上的均衡,制订合理的森林旅游产品价格,积极拓展森林旅游市场,并努力降低森林旅游业的经营成本,是提高森林旅游经济效益的关键和实现森林旅游可持续发展的有效途径. 相似文献
50.
This article discusses the determinants of profitability expressed as return on capital among Japanese pulp and paper companies. Return on capital is measured as income before tax related to stockholders’ equity. Return on capital has been divided into profit margin and asset utilization rate. The hypothesis is that return on capital can be explained by mill size, productivity, product line, financial situation, and use of wood resources. The dataset consists of 13 larger Japanese pulp and paper companies listed in Pulp &; Paper Statistics. Data on financial performance, production, and use of wood fibers were collected for the period 1991–2001. The average return on equity for the studied companies is 4.2%. Labor productivity has increased quite significantly, from about 600 to 1,000 kg/employee and year. An econometric analysis indicates that the best model fit is found when the asset utilization rate is used as the dependent variable. Significant variables are, among others, asset utilization rate lagged one time period (?), labor productivity (+), capital productivity (?), paper production as a share of total paper and board production (?), total value of assets on the books (?) and solidity (+). This may indicate that the total value of assets on the books is large in relation to the total production of paper, paperboard and pulp. 相似文献