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121.
SUMMARY

An assessment is made of various grassroots development initiatives in Latin America which show that agroecological technologies can bring significant environmental and economic benefits to small farmers and rural communities in the region. Examined initiatives offer new ways of enhancing the multifunctional attributes of traditional agriculture through greater per unit area productivity and environmental services obtained in complex, integrated agroecological systems that feature many crop varieties, together with animals and trees. If such experiences were to be scaled up, multiplied, extrapolated, and supported in alternative policy scenarios, the gains in food security and environmental conservation would be substantial. The challenge now is to mobilize science, institutions and the right policies to increase the productivity of smallholder farming systems, while preserving the resource base and at the same time empowering local communities.  相似文献   
122.
报废汽车的回收拆解处理在我国已经逐渐兴起,但由于该产业尚处于发展初期,环保技术手段和可持续性发展意识还不够,因此在回收拆解过程中会产生大量的废水和其他污液。针对某汽车回收拆解厂的废水特性进行实验研究,形成“电荷凝集过滤一活性炭吸附”组合工艺,对报废汽车回收拆解企业的废水处理提供了一定的参考价值。  相似文献   
123.
中国生态农业与绿色食品   总被引:8,自引:0,他引:8  
傅宪 《四川环境》1994,13(2):61-64
本文从农业环境问题和食品安全性出发,阐述了中国生态农业的兴起及特点,绿色食品生产的要求,生态农业与绿色食品的关系。介绍了几种可用于开发绿色食品的优化生态模式。  相似文献   
124.
Substantial conflict exists over water management and allocation in the Platte River Basin of Nebraska. An interdisciplinary computer simulation model, representing the water quantity, water quality, environmental, and economic dimensions of the conflict, was developed in order to analyze the tradeoffs among allocation scenarios. Most importantly, decisionmakers and interest groups were involved in model development. Simulation results for a base case and two scenarios are presented. One scenario favors protection of instream flow for wildlife; the other favors water diversions for agriculture. Impacts of the instream flow scenario, as measured by the amount of land irrigated, groundwater levels, the amount of wildlife habitat for cranes and catfish, and net agricultural benefits did not differ greatly from those of the base case. However, impacts of the diversion scenario were substantial. On the negative side, instream flows and wildlife habitat declined an average of 39 percent; while, on the positive side, groundwater levels and net agricultural benefits each increased 6 percent. The modeling process was successful insofar as it promoted an understanding among the highly diverse interest groups of the systems nature of the Basin. One agreement on a water diversion schedule among three of the parties has been reached, partly as a result of this process. More comprehensive compromises have not yet been forged. Our experience, however, indicates that modeling success at the policymaking level depends more on the extent to which the policymakers understand the model than it does on model sophistication.  相似文献   
125.
ABSTRACT: An index of residential water efficiency - a “W-Index” - can serve as a measure of effectiveness of water conservation features in the home. The index provides a calculated numerical value for each dwelling unit, derived from the number and kind of water-saving features present, including indoor and outdoor water savers and water harvesting or recycling systems. A W-Index worksheet, devised for on-site evaluation of single-family residences in the Tucson, Arizona, region shows that a nonconserving residence with all the water-using features would use 151,000 gallons per year or 148 gallons per capita per day (gpcpd), while the fully conserving model would use 35,300 gallons per year or 35 gpcpd and with water harvesting and graywater recycling systems would have a maximum W-Index of W-160. A Tucson water conservation demonstration home, Casa del Agua, received a rating of W-139, and field tests of about 30 homes in new Tucson subdivisions show values ranging from W-75 to W-100, indicating the incorporation of some water conservation in current new models. By adjustment of some climatic or water-use parameters, the W-Index format can be applied to various types of dwelling units or to other urban areas. The W-Index can be used by individual homeowners or builders to evaluate water efficiency of residential units, or by water providers or water management agencies as a device for promoting and achieving water conservation goals.  相似文献   
126.
Biotechnology increases commercialization of food production, which competes with food for home use. Most people in the world grow their own food, and are more secure without the mediation of the market. To the extent that biotechnology enhances market competitiveness, world food security will decrease. This instability will result in a greater gap between rich and poor, increasing poverty of women and children, less ability and incentive to protect the environment, and greater need for militarization to maintain order. Therefore, biotechnology should be discouraged. An active program to protect and strengthen local food production and to decrease reliance on industrial agriculture should be promoted.  相似文献   
127.
利用煮茧废水培养钝顶螺旋藻的初步研究   总被引:4,自引:0,他引:4  
本文对缫丝厂煮茧废水和Zarrrouk培养基的主要营养成份进行了分析比较,筛选出了适合钝顶螺旋藻(Spirulinaplatensis)在煮茧废水中生长繁殖的培养基和与之相适应的驯化藻种。经室外150升煮茧废水扩大培养,干藻生物量可达16.03克/米 ̄2·天,粗蛋白含量达58.6%,含有17种氨基酸。比用Zarrouk培养基培养的螺旋藻产量提高15.78%,成本减少80%以上。培养后的煮茧废水COD和BOD_5浓度低于我国污水综合排放标准。研究结果表明:采用本实验室筛选的煮茧废水培养基和驯化藻种,在煮茧废水中大量培养螺旋藻,实现废水资源化是可行的,具有明显的经济效益和环境效益。  相似文献   
128.
Recycling wastewater seems to have become a highly useful technique for meeting the shortage of fresh water in all parts of the world. It seems all the more important for Muslim countries because a large number of these countries face acute fresh water shortage. This paper views the problem from an Islamic viewpoint, that is, in the light of the Qur'n, theSunnah, andFiqh works.In Islamic law, water is classified into three categories oftahr,thir, andmutanajjis. The last two categories can be transmuted intotahr water and thus may be used for all mundane as well as religious purposes if they are assimilated into the overall supply oftahr water. This would be lawful from the Islamic viewpoint even without treating the water. To make use of modern technology in order to recycle wastewater effluents after treatment seems quite in keeping with the spirit and letter of the Islamic teachings.  相似文献   
129.
我国农业水旱灾害的时间分布及重灾年景趋势预测   总被引:21,自引:4,他引:21  
分析了我国 1970~ 1999年农业水旱灾害的时间分布特征。分析结果表明 :在研究时段内 ,我国农业自然灾害总体上呈增长态势。该时段可划分为两个明显的阶段 :80年代中期以前 ,总灾、水灾及旱灾对农业生产的危害较轻 ;80年代中期之后 ,呈现出影响范围广、损失增大的趋势 ,重灾年份明显增加。旱灾和水灾是威胁我国农业生产最为严重的自然灾害 ,尤以旱灾为甚。我国农业遭受旱灾威胁的范围多年基本不变 ,而旱灾受灾率波动明显 ,成灾率逐年增长 ,这与近几年农田水利设施建设缓慢、灌溉能力降低有关 ;水灾受灾率和成灾率具有特别显著的同步特点 ,表明水灾致灾能力强 ,一旦发生 ,极易成灾 ,水灾危害加剧与防洪、抗洪能力低下及生态环境恶化有关。各灾种的受灾率和成灾率呈正相关关系 ,表明我国农业生产系统的抗灾能力总体上较弱。  本文还用灰色系统理论的建模方法 ,建立了农业总受灾率 -总成灾率、水灾受灾率 -成灾率、旱灾受灾率 -成灾率的重灾年景灰色灾变GM(1,1)预测模型 ,对未来 10年我国农业灾害趋势进行了预测分析。灰色预测结果表明 ,2 0 10年之前 ,除 2 0 0 3,2 0 0 6年水旱灾害危害较小外 ,其它年份均为灾情严重年份 ,其受灾率和成灾率均高于近 30年的平均水平。其中 ,2 0 0 4 ,2 0 0 7年将为水灾重  相似文献   
130.
The article discusses agricultural practices in sub-Saharan Africa, especially in terms of maintaining soil fertility. It disagrees with alarmist tendencies in the current debate, exaggerating the state of soil impoverishment in the African region. Nor does it subscribe to the idea that the remedy lies primarily in a massive influx of chemical fertilisers, especially phosphorus.
Instead, the article advocates a more balanced approach, where soil nutrient replenishment, as an improvement in natural capital, is but one part of the investment African agriculture needs. To achieve sustainable rural livelihoods, other forms of capital are also required, such as physical capital, i.e. infrastructure (roads, means of communication); financial capital in the form of credit and savings schemes; and human- and social capital, especially improved access to information and knowledge for farmers as well as improved local organisation and empowerment.
The article reviews nine case studies, taken from different climate zones in the region and representing different soil conditions. All case studies were projects using the participatory learning and action research (PLAR) method, which is discussed in detail.  相似文献   
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