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排序方式: 共有6555条查询结果,搜索用时 15 毫秒
961.
962.
对焦作市中马村矿矸石山周围土壤中5种重金属(Cu、Cr、Pb、Zn、Mn)的含量、分布特征及其污染状况进行了调查与评价。结果表明,矿区土壤不同程度地受到5种重金属的污染,依次为Zn>Pb>Cu>Cr>Mn;土壤综合污染指数为1. 74,属轻污染; 5种重金属元素中Zn、Pb相关性显著,其余均为低度相关。 相似文献
963.
Gregory C. Luther Joko Mariyono Raden M. Purnagunawan Ben Satriatna Martin Siyaranamual 《Natural resources forum》2018,42(2):71-82
This study assesses the impact of farmer field schools (FFS) on the productivity of vegetable farming in vegetable‐producing areas of East Java and Bali, Indonesia. The FFS have equipped over 3,000 vegetable farmers with integrated crop management knowledge applicable to chilies and tomatoes. The FFS are expected to enhance farmers’ capacity such that they can increase production. This study employs a difference‐in‐differences (DiD) method to overcome selection bias. A survey of 250 FFS‐graduated farmers and 250 non‐FFS farmers were purposively randomly selected from the overall community of farmers. Focus group discussion was used to support the survey. The results indicate that FFS were successful for enhancing farmers’ capability in vegetable farming. Farmers who participated in FFS have higher productivity than those who did not. Farmers also could adapt and adopt the knowledge gained from FFS as they underwent a process of learning by doing. The impacts of the increase in farmers’ capacity can be more evident if weaknesses during the FFS preparation and implementation can be overcome, to ensure more participation, flexibility to fit different conditions/needs and continuous learning. 相似文献
964.
Groundwater management and socio-economic responses 总被引:1,自引:0,他引:1
Jacob J. Burke Claude Sauveplane and Marcus Moench President 《Natural resources forum》1999,23(4):303-313
The socio-economic aspects of groundwater development and management are briefly examined and set against a background of highly technical management. The variability of socio-economic responses to groundwater and the problems of engaging large numbers of individual users are highlighted. The paper argues that social, institutional and political factors are the primary obstacles to sustainable management of the world's groundwater resources. 相似文献
965.
Upton Hatch Shrikant Jagtap Jim Jones Marshall Lamb 《Journal of the American Water Resources Association》1999,35(6):1551-1561
ABSTRACT: Climate change has the potential to have dramatic effects on the agricultural sector nationally and internationally as documented in many research papers. This paper reports on research that was focused on a specific crop growing area to demonstrate how farm managers might respond to climate-induced yield changes and the implications of these responses for agricultural water use. The Hadley model was used to generate climate scenarios for important agricultural areas of Georgia in 2030 and 2090. Linked crop response models indicated generally positive yield changes, as increased temperatures were associated with increased precipitation and CO2. Using a farm management model, differences in climate-induced yield impacts among crops led to changes in crop mix and associated water use; non-irrigated cropland received greater benefit since irrigated land was already receiving adequate moisture. Model results suggest that farm managers will increase cropping intensity by decreasing fallowing and increasing double cropping; corn acreage decreased dramatically, peanuts decreased moderately and cotton and winter wheat increased. Water use on currently irrigated cropland fell. The potential for increased water use through conversion of agriculturally important, but currently non-irrigated, growing areas is substantial. 相似文献
966.
有机污染物在水体表面微层的富集行为 总被引:7,自引:0,他引:7
研究邻苯二甲酸二丁酯(DBP),邻苯二甲酸二异辛酯(DEHP)和阴离子表面活性剂在水体表面微层的富集行为.现场分析结果表明邻苯二甲酸酯在小型封闭湖泊表面微层中存在富集现象,富集倍数在1~11之间,湖水的理化性质及采样方式均影响富集倍数的大小.室内微宇宙研究表明DBP和DEHP在微宇宙水体表面微层中均存在富集现象,富集倍数分别为2.81和1.98,藻类、颗粒物和腐殖酸也同时在微宇宙水体表面微层中富集.当水体中加入表面活性物质和腐殖酸时,邻苯二甲酸酯(DBP、DEHP)在表面微层的富集倍数随加入的2种物质浓度的增大而降低.对阴离子表面活性剂的富集动力学研究表明,当表面微层遭到破坏后,其在表面微层达富集平衡需较长时间,水体浓度也影响富集倍数 相似文献
967.
968.
南京市机动车排气污染控制和管理对策 总被引:11,自引:6,他引:5
刘继明 《环境监测管理与技术》2004,16(2):14-17
简述了南京市机动车排气污染控制和管理对策。对新机动车排气控制实施了新车上牌的环保注册登记目录制,鼓励生产厂家采用先进的排放控制技术,达到国家制定的排放控制目标和排放标准;对在用机动车排气控制实施检测/维护(I/M)制度,对尾气排放不达标车辆进行正常的维修和保养,保证其发动机处于正常技术状况;对高排放污染机动车辆,安装尾气净化装置,以改善机动车排放水平。定期检测中各类型车辆维护前后排气污染物削减结果表明,85%的高排放污染车辆能达标,且CO的削减率最高,达50%左右;定期检测中各类型车辆安装机内净化器前后排气污染物削减结果表明,二次补气机内净化器对CO的净化率为22.5%~30.0%,对HC的净化率为9.7%~30.0%;高能电子点火机内净化器对CO的净化率为5.4%~22.2%,对HC的净化率为17.2%~30.8%。不定期检测中,一些高排放污染车辆安装三元催化反应器后,其净化率可达80%~90%。 相似文献
969.
清水塘地区土壤重金属污染现状及修复技术研究 总被引:7,自引:0,他引:7
阐述了清水塘地区土壤和农作物重金属污染现状,提出了对受污染土壤的修复措施及土地利用构想。 相似文献
970.