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集水型生态农业:西北半干旱区可持续农业发展的模式 总被引:1,自引:0,他引:1
西北地区是中国的主要农牧业区之一,中国农业、农村、农民问题,在很大程度上也是西北地区问题,西北地区的生态环境问题不是工业的污染,而农业生产活动的破坏,因此,在西部大开发过程中,必须将生态环境的重建与当地农民的脱贫、与农业和农村经济发展紧密结合起来,采适应地区特点的集水型生态农业发展模式,实现西北地区农业的可持续发展和生态环境的逐步恢复和重建。 相似文献
73.
D. T. Pederson 《Journal of the American Water Resources Association》2000,36(6):1367-1374
ABSTRACT: Interpretation of ground water level changes in a developed aquifer usually relies on reference to some benchmark such as “predevelopment” ground water levels, changes from fall to fall and/or spring to spring, or to determination of maximum stress during the pumping season. The assumption is that ground water levels measured in the monitoring well accurately reflect the state of the ground water resource in terms of quantity in storage and the effects of local pumping. This assumption is questionable based on the patterns shown in continuous hydrographs of water levels in monitoring wells in Nebraska, and wells installed to determine vertical gradients. These hydrographs show clear evidence for vertical ground water gradients and recharge from overlying parts of the aquifer system to deeper zones in which production wells are screened. The classical concept of semi‐perched ground water, as described by Meinzer, is demonstrated by these hydrographs. The presence of semi‐perched ground water (Meinzer definition, there is no intervening unsaturated zone) invalidates the use of measured ground water levels in regional observation programs for detailed numerical management of the resource. Failure to recognize the Meinzer effect has led to faulty management. The best use of data from the observation well network would be for detection of trends and education unless it is clearly understood what is being measured. 相似文献
74.
半干旱草原地-气温室气体交换速率测定 总被引:3,自引:1,他引:2
重点介绍采用静态箱 -气相色谱法测定低交换速率的半干旱草原地 -气间温室气体交换速率的采样分析系统的配置及操作 .将静态采样箱置于采样点 ,用 50 cm3或 100 cm3的塑料注射器现场取样 ,转存于气袋中并送到实验室分析 .用改进了的进样系统并装有 FID和 ECD的气相色谱仪 ( GC)分析其中的 CH4、CO2 和 N2O浓度 ,计算出地 -气痕量温室气体的交换速率 .对内蒙古羊草草原、草甸草原 N2O、CO2 和 CH4交换速率日变化规律实测结果分析表明 ,该方法简便易行、准确可靠 . 相似文献
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Although implementing conservation practices on private farms and forests can produce substantial environmental benefits, these practices are not being adopted widely enough to result in measurable improvements at regional scales. Researchers have investigated the production and program factors influencing producer choices to voluntarily adopt these practices. However, the findings of reviews are inconsistent, raising questions about review methods, including the omission of relevant variables. Further, applying lessons from past work to promote adoption is difficult because many reviews investigated dispositional or demographic variables that practitioners and policy makers cannot directly observe or influence. We conducted a new review of 146 empirical studies that tested the effects of different interventions (e.g., financial incentives, outreach events, and nudges) on increasing the likelihood of producers adopting conservation practices. We conducted a metaregression of quantitative studies from diverse disciplines that filtered studies by quality (i.e., use of randomization and clear analysis reporting). We synthesized these results with a thematic analysis of qualitative studies on producer perspectives about conservation practices. Financial incentives had the strongest evidence of increasing producers’ likelihood of adopting conservation practices (odds ratio 1.86, p < 0.05). However, this effect was only apparent after filtering by study quality, which also improved model fit and identified significant regional differences (odds ratio –1.69, p < 0.01). The thematic review of qualitative studies revealed that peer groups may be successful in reinforcing adoption behaviors due to homophily effects and that financial incentives not only offset implementation costs but also mitigated perceived risks of adoption. Given the problems we encountered in testing hypotheses about the magnitude of variability explained by intervention types and practice characteristics, we recommend additional experimental and longitudinal work that accounts for financial incentives and pairs qualitative and quantitative data to clarify relationships between program design and practice adoption rates. 相似文献
77.
Brooke A. Williams James E.M. Watson Hawthorne L. Beyer Carissa J. Klein Jamie Montgomery Rebecca K. Runting Leslie A. Roberson Benjamin S. Halpern Hedley S. Grantham Caitlin D. Kuempel Melanie Frazier Oscar Venter Amelia Wenger 《Conservation biology》2022,36(4):e13874
Management of the land–sea interface is essential for global conservation and sustainability objectives because coastal regions maintain natural processes that support biodiversity and the livelihood of billions of people. However, assessments of coastal regions have focused strictly on either the terrestrial or marine realm. Consequently, understanding of the overall state of Earth's coastal regions is poor. We integrated the terrestrial human footprint and marine cumulative human impact maps in a global assessment of the anthropogenic pressures affecting coastal regions. Of coastal regions globally, 15.5% had low anthropogenic pressure, mostly in Canada, Russia, and Greenland. Conversely, 47.9% of coastal regions were heavily affected by humanity, and in most countries (84.1%) >50% of their coastal regions were degraded. Nearly half (43.3%) of protected areas across coastal regions were exposed to high human pressures. To meet global sustainability objectives, all nations must undertake greater actions to preserve and restore the coastal regions within their borders. 相似文献