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81.
为回答都市畜牧业能否发展、怎样发展的问题,对上海主要畜产品产业规模波动、畜产品保障供给与畜牧业环境污染的矛盾和畜牧业对环境的双刃剑作用进行分析,揭示了上海都市畜牧业的困境与出路.研究表明上海都市畜牧业的出路在于由环境污染型转变为生态维护型.生态维护型都市畜牧业在宏观层面需要进行畜牧场的合理规划布局和建立种养结合废弃物循环利用机制.畜牧场的合理规划布局不仅需要以土地承载力为基础对养殖场合理配置农田面积,还需要考虑都市农区“小集中,大分散”的空间格局特征,按照“种养结合单元”进行选址布局.种养结合废弃物循环利用可建立基于市场经营主体的3种循环利用机制:封闭自循环,封闭它循环,开放它循环. 相似文献
82.
基于蒙特卡罗模拟的绿色建筑节水和中水回用的决策模型 总被引:1,自引:0,他引:1
通过对绿色建筑节水和中水回用项目的全寿命周期成本构成的分析,采用净现值衡量的指标形式,构建了绿色建筑全寿命周期经济决策模型,运用蒙特卡罗模拟的方法,以实际示范项目进行模拟应用,分别对绿色建筑和传统建筑的节水项目进行建模分析,实际验证了该模型和模拟方法的合理性和实用性,以期为绿色建筑项目的决策提供一种可借鉴、可操作的方法,以及为政府机构、决策部门和开发商的正确决策提供科学方法和理论依据. 相似文献
83.
综述了反刍动物体内氨与尿素代谢的研究进展,阐述了氨在胃肠道的来源和去路,讨论了尿素循环的过程及其影响因素,介绍了研究氨的产生、吸收与尿素循环的方法,探讨了调控尿素循环的途径。综合分析认为,尿素循环利用是反刍动物机体内源氮重吸收中最重要的组成部分,通过减少氨吸收和氨基酸分解代谢来减少日粮氮转化成尿素,或者提高肝脏中合成的尿素及再循环至胃肠道的尿素转化成微生物蛋白质的效率,可提高日粮氮素的利用效率。因此,开展尿素循环规律的研究,以建立实用日粮条件下含氮化合物的整体代谢模型,对调控反刍动物体内氮素营养至关重要。 相似文献
84.
85.
以臭氧在大菱鲆亲鱼养殖回用水系统中的工程实例数据,分析臭氧在养殖水处理系统中的杀菌效果、脱除转化氨氮的效能。结果表明,臭氧在该工艺流程中杀菌率可达51.82%,对氨氮 亚硝酸氮的平均去除率达56.30%,这表明臭氧应用于工厂化养殖水处理中具有较好效果。 相似文献
86.
通过实验室烧杯试验,将滤池反冲洗废水直接与原水按一定比例混合进行混凝试验。采用聚合氯化铝PAC为混凝剂,在投量为60mg/L的条件下,对色度、浊度、CODMn及UV254的去除效果进行了考察。试验结果表明:反冲洗废水可以提高对原水浊度和色度的去除,不会提高出水的有机物含量。同时结果也显示,投加10%反冲洗废水不仅可以回收水量,而且可以达到改善混凝性能、提高混凝效率、减少混凝成本的目的,可以为水厂的运行提供参考。但是回收滤池反冲洗水明显提高了滤后水中细菌总数,给后续消毒工艺提出了更高的要求。 相似文献
87.
Development of inland aquaculture in arid climates: water utilization strategies applied in Israel 总被引:1,自引:0,他引:1
D. Mires 《Fisheries Management and Ecology》2000,7(1-2):189-195
Israel has a temperate climate with marked differences between the northern and southern regions. Rainfall ranges between 250 and 600 mm year−1 in the former and between only 25 and 200 mm year−1 in the latter. During the last 30 years, water consumption has increased markedly in all sectors. Although a water allocation for inland aquaculture is made, in most cases it is given the lowest priority, and aquaculturists have learned to contend with difficulties, and thrive on brackish water sources not fit for human consumption or agricultural crops. Since most water sources are already fully exploited, further development of all sectors will depend on their respective capacity to use recycled city water, desalinated brackish or sea water, or recycled pond water. In this respect, inland aquaculture is handicapped by public prejudices which will not allow the use of water from the first source and farms are still not able to cope with the cost of the second. Therefore, further development of inland aquaculture will depend on the capacity of farmers to use sea water, and to recycle pond water time and again to produce more fish with less (inland) water. Various strategies have already been developed in Israel and new ones are under study. These include water harvesting in dual-purpose reservoirs, recycling of pond water from one year to another, development of intensive flow-through systems based on recycled pond water and colleagues based on biofiltration. 相似文献
88.
Fermented fish-offal (FO) meal was used as a protein supplement to replace fishmeal (FM) in the formulation of experimental diets for the Indian minor carp Labeo bata. The two supplementary diets, one containing 25% FM plus 25% FO and the other containing 20% FM and 30% FO, showed significantly higher digestibility, growth, and protein deposition than the reference diet containing 40% FM. Partial budgeting of diet formulation and net return revealed that 50% replacement of FM by fermented fish-offal meal rendered a total positive benefit of 134% as compared with the reference diet. 相似文献
89.
Jianbo SHEN Liyang WANG Xiaoqiang JIAO Fanlei MENG Lin ZHANG Gu FENG Junling ZHANG Lixing YUAN Lin MA Yong HOU Tao ZHANG Weifeng ZHANG Guohua LI Kai ZHANG Fusuo ZHANG 《农业科学与工程前沿(英文版)》2019,6(4):321
Phosphorus (P) is a non-renewable resource, therefore ensuring global food and environmental security depends upon sustainable P management. To achieve this goal, sustainable P management in the upstream and downstream sectors of agriculture from mineral extraction to food consumption must be addressed systematically. The innovation and feasibility of P sustainability are highlighted from the perspective of the whole P-based chain, including the mining and processing of P rock, production of P fertilizers, soil and rhizosphere processes involving P, absorption and utilization of P by plants, P in livestock production, as well as flow and management of P at the catchment scale. The paper also emphasizes the importance of recycling P and the current challenges of P recovery. Finally, sustainable solutions of holistic P management are proposed from the perspective of technology improvement with policy support. 相似文献
90.