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291.
H. HENRY JANZEN 《Conservation biology》2007,21(3):668-674
Abstract: Farmlands are expansive, diverse, and intensively managed ecosystems. These lands, so critical to human welfare, are threatened by growing stresses as demand for food escalates, fresh water wanes, cheap fuels deplete, and other uses jostle for space. With these coming pressures, how can we foster permanence on the lands that sustain us? In this essay I contemplate the hypothesis that the greenhouse gases, because they emanate from the interwoven flows of C, N, and energy in ecosystems, can help steer us toward permanence (sustainability). Alongside other indicators these emissions may detect the ecosystem's pulse, alerting us to inefficiencies and guiding us to better practices. To be effective signals, however, the greenhouse gases will need to be considered in their local settings, monitored longer and in more "listening places," and measured across boundaries of disciplines and biomes. This approach may help reduce greenhouse gas emissions from our farmlands. But we may find that, in the long run, the main beneficiaries of our inquiry have been, not just the atmosphere, but our fragile lands, perhaps in ways we cannot yet foresee. 相似文献
292.
Van Butsic Noelwah R. Netusil 《Journal of the American Water Resources Association》2007,43(3):622-629
Abstract: This paper uses the hedonic price method to estimate the value of an acre‐foot of irrigation water in Douglas County, Oregon. The analysis uses detailed information from 113 arms‐length transactions of farmland for 2000 and 2001. The estimated willingness‐to‐accept of $261 to sell an acre‐foot of irrigation water is consistent with other studies and recent transactions in the study area. Estimates for the value of leasing water are provided using a range of discount rates and leasing periods. 相似文献
293.
Poverty is rampant in the rural areas of Pakistan, where people are in a state of deprivation with regard to incomes, clothing, housing, healthcare, education, sanitary facilities and human rights. Agriculture generates nearly 20.9 percent of the country's GDP and provides employment for 43.4 percent of its workforce. Most importantly, 65.9 percent of the population living in rural areas is directly or indirectly dependent on agriculture for their livelihood. Rising population, shrinking agricultural land, increasing demand for water resources, widespread land degradation and inadequate infrastructure appear to be major concerns of the agriculture sector in Pakistan. An attempt has been made to examine the population growth–agriculture growth–poverty alleviation linkage. It is argued that agriculture will continue to be one of the most important sectors of Pakistan's economy for years to come. To alleviate poverty, it is suggested that Pakistan enhance the productivity of the agriculture sector through the provision of a series of inputs including provision of easy credit to the small farmer, availability of quality fertilizers and pesticides, tractor and harvester services, improvement in the effectiveness of the vast irrigation system and, finally, farmer education. It is concluded that the high rate of population growth needs to be curbed for increased agricultural productivity to have any significant effect on poverty in rural areas of Pakistan. 相似文献
294.
高风险社会及其对策研究 总被引:3,自引:8,他引:3
经济和技术不断发展的过程中伴随的副作用使人类社会逐渐处于“风险社会”乃至“高风险社会”之中。当前我国正处于结构调整和社会转型中,存在着自然灾害、事故灾难、公共卫生事件和社会安全事件等各种各样的风险。在对现代社会风险的特点进行归纳后,对其量化方法也进行了初步探讨,并结合我国实际情况从影响风险大小的各因素入手,拟定了若干风险管理对策,对如何面对“风险社会”和提高风险承受能力可起到积极的参考作用。 相似文献
295.
296.
297.
Kwang‐Sik Yoon Jae‐Young Cho Jin‐Kyu Choi Jae‐Gwon Son 《Journal of the American Water Resources Association》2006,42(5):1205-1216
ABSTRACT: Assessment and control of nutrient losses from paddy fields is important to protect water quality of lakes and streams in Korea. A four‐year field study was carried out to investigate water management practices and losses of nitrogen (N) and phosphorus (P) in rice paddy irrigation fields in southern Korea. The amount and water quality of rainfall, irrigation, surface drainage, and infiltration were measured and analyzed to estimate inputs and losses of N and P. The observed irrigation amount surpassed consumptive use, and approximately 52 to 69 percent of inflow (precipitation plus irrigation) was lost to surface drainage. Field data showed that significant amounts of irrigation water and rainfall were not effectively used for rice paddy culture. Water quality data indicated that drainage from paddy fields could degrade the recipient water environment. The nutrient balance indicated that significant amounts of nutrients (29.5 percent of total N and 8.6 percent of total P compared to input) were lost through surface drainage. Furthermore, up to half the nutrient losses occurred during nonstorm periods. The study results indicate that inadequate water management influences N and P losses during both storm and nonstorm periods. Proper water management is required to reduce nutrient losses through surface drainage from paddy fields; this includes such measures as minimum irrigation, effective use of rainfall, adoption of proper drainage outlet structures, and minimized forced surface drainage. 相似文献
298.
299.
Nancy Grudens-Schuck 《Journal of Agricultural and Environmental Ethics》2000,13(1-2):79-100
Stakeholder engagement is a crucial concept of extension education. Engagement expresses democratic values of the land-grant
mission by providing opportunities for stakeholders to influence program planning, including setting the agenda and negotiating
resource allocations. In practice, the concept of engagement guides the formation of partnerships among extension, communities,
industry, and government. In the area of sustainable agriculture, however, stakeholders may conflict, presenting challenges
to the engagement process. Results from a study of a Canadian sustainable agriculture program, produced using cultural anthropology
and participatory action research, detail challenges of the engagement process that led to reconstruction of a farmer-extension
partnership. Notable in the early phase of the reconstruction process were critical reflection, stakeholder forums, exclusion
through caucusing, and coalition building. An argument for a neopragmatist view provides a theoretical basis for understanding
counterintuitive dimensions of engagement revealed by the study. 相似文献
300.
推进环保产业结构调整的思考 总被引:2,自引:0,他引:2
文章对环保产业结构调整要解决的问题进行了分析,指出产业结构调整必须符合市场经济要求的布局和流通结构,只有建立现代化的企业制度,企业才能有活力。 相似文献