GRAZED STUBBLE HEIGHT AS A CRITERION FOR CONTROLLING SEDIMENT PRODUCTION FROM GRAZING LANDS1

ABSTRACT: Efforts by state and federal agencies to develop standards and guidelines for protecting and enhancing water quality on grazing lands have led to suggestions that grazed stubble height criteria could be used to determine when cattle should be removed from a specific pasture or grazing area. Until recently only indirect scientific evidence from agronomy and laboratory studies gave support to the stubble height concept. Consequently, a grazing study was initiated on a Montana ranch in 1997 to determine the reduction in overland sediment achieved by grazing a pasture to a predetermined stubble height. Treatments consisted of 7 cm (3 in) grazed, 7 cm (3 in) clipped or mowed, 15 cm (6 in) grazed; 15 cm (6 in) clipped and untreated or natural forage plant height. The five treatments were used in a two‐year trial spanning 1997 to 1999. At the conclusion of this study the magnitude of sediment production was related to the number of intense rain events during the March through June period rather than total precipitation. There was a significant year effect in terms of sediment accumulation (P < 0.01) but no year by treatment effect (P = 0.11). Even though a significant difference in sediment accumulation was detected between the shorter and taller stubble heights (P = 0.04) in both 1998 and 1999, the difference could not be explained by grazed stubble height alone. Close grazing (7 cm stubble) consistently ranked lowest in sediment production (P < 0.01) among all treatments, including the ungrazed control. These results suggest that changes in plant community structure and microtopographic caused by grazing influence sediment entrapment (retention) on hillslopes more than those caused by plant height.     

浅谈环保行政执法证据的收集、制作

在环境案件调查处理过程中,证据具有重要作用.收集、制作有效的执法证据是环保部门作出具体行政行为的基础.只有掌握充分确凿的证据,才能保证正确认定案件事实,也才能正确适用法律,避免出现行政复议变更或行政诉讼败论情况的发生.在此,根据环境案件的执法的特征和特点阐述了收集、制作证据的方法和要求.     

综合预防的环境策略—清洁生产

从综合预防的角度出发，探讨环境保护的战略决策清洁生产的内涵，清洁生产审计以及建立清洁生产实施机制。     

搞好噪声治理改善环境质量

石化企业是噪声大户，由压缩机、鼓风机、机泵等声源设备及其它背景噪声构成了各种各样的噪声源，不但单源声级峰值高，而且面源辐射面积广，治理难度非常大，辽化公司采取自难而易的原则，对纤维生产中重点噪声源进行了治理，收到了明显的成效。     

On developing cleaner organic unit processes

Organic waste products, potentially harmful to the human health and the environment, are primarily produced in the synthesis stage of manufacturing processes. Many such synthetic unit processes, such as halogenation, oxidation, alkylation, nitration, and sulfonation are common to a large number of organic chemical manufacture in several different industry sectors. The environmental impact of organic chemical syntheses can be significantly reduced by incorporating cleaner unit processes. A review of research and development activities shows that progress is already being made along these lines worldwide, and commercialization of cleaner organic technologies is also proceeding.     

环境影响评价中清洁生产分析存在的问题及改进建议

论述了清洁生产分析已成为建设项目环境影响评价的重要内容，但尚存在三个主要问题，提出做好清洁生产分析的建议。     

Copper in India: Present and future outlook

The availability of mineral resources plays an important role in India's national economy. Copper, one of the important non-ferrous metals, has various industrial uses and demand for it is increasing in India where the inventory and production of copper, though not comparable with developed countries, shows an impressive growth rate, particularly during the last decade. With an increasing rate of industrial production envisaged in future plans copper consumption is expected to rise. Logistic curves have been used to study the potential long-term production capability under the dynamic concept of reserves and resources, with curves drawn for various estimates of total available resources. The production figures shown are not final and are subject to change due to a number of factors. This approach merely provides a method for projecting trends in future production.     

漫湾库区生产恢复障碍及其原因

在对漫湾库区调查的基础上，总结了库区生产恢复现状，认为农业生产相应条件恢复不到位，影响土地的持续利用：土地生产力降低，单一的种植业结构和产业结构，经济林与畜牧养殖业因土地被淹没带来萎缩，渔业、旅游业等缺乏规划和移民的参与，表现出库区移民生活水平相对于远迁移民、全县(省)平均下降了。分析了漫湾库区生产恢复的障碍及其原因，并就生产恢复提出一些建议：(1)提升澜沧江梯级开发水电工程中对移民问题的重视，将漫湾电站纳人中央直属电站范畴，统筹安排移民遗留问题，给予资金支持；(2)重新整体规划漫湾库区的移民安置，控制库区土地人口压力；(3)调整产业结构，促成传统种植业人口向林、牧业，向第二、三产业转移；(4)理顺和明确移民方面的责、权、利关系，将生产恢复问题与安置区地方经济发展问题结合起来考虑；(5)建立公众积极参与的决策体制与决策执行机制。     

液氯的清洁生产工艺

对氨盐法、氟利昂法和高温高压法生产液氯的3种生产工艺流程、工艺特点进行了具体分析，指出了高温高压清洁生产工艺不仅经济而且环保，是企业生产液氯产品的必由之路。     

旅游景区清洁生产与可持续发展研究——以扬州凤凰岛景区为例

本文就清洁生产及清洁生产在旅游景区的应用进行了阐述 ,着重分析了旅游景区清洁生产的主要内容 ,并以扬州凤凰岛景区为例 ,就该景区实施旅游清洁生产提出了具体方法和建议。