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1.
为了解黏土矿物改良剂在新垦耕地地力提升中的作用,选择膨润土、高岭石、沸石和硅藻土4种黏土矿物,在添加量为10%的条件下,采用培养试验研究其对有机肥料矿化及土壤有机碳积累的影响。结果表明,与对照比较,添加黏土矿物可明显增加土壤有机碳的积累,其效果由强到弱为膨润土、高岭石、硅藻土、沸石;团聚体分析和重液分组结果表明,添加黏土矿物可显著增加土壤水稳定性团聚体数量,促进矿物结合态有机碳的形成。研究认为,黏土矿物增加有机碳稳定性是其促进土壤有机碳积累的主要原因。  相似文献   
2.
陈彩虹 《绿色科技》2021,(5):219-222,236
生态文明教育是形成生态意识和生态行为的重要途径,是影响生态文明建设进程的重要因素。理想的生态文明教育系统是包含家庭教育、学校教育、企业教育和社会教育四大分系统在内的、拥有完整功能和流程的服务系统;各分系统在时间维度上相互衔接、在空间维度上相互独立,并在不同时空发挥各自的作用。但现行的生态文明教育系统尚未意识到其服务属性,在自我定位、系统设计和流程安排上仍按照传统教育模式进行,不利于形成节约资源和保护环境的生态意识和生态行为。因此,提出重新设计从受教者角度出发、以产生生态行为为根本目的的生态文明教育系统,是实现生态文明教育目标的有效途径。  相似文献   
3.
The denitrifying woodchip bioreactor is designed to remediate nitrate-rich water, including those produced from aquaculture effluents. Reuse of treated bioreactor outflows in recirculating aquaculture would offer considerable water savings and valuable alkalinity recuperation. However, such bioreactors may leach detrimental wood-bound contaminants, preventing outflow reuse. To determine water reuse potential, woodchip media from two hardwood species (white ash, Fraxinus americana; Norway maple, Acer platanoides) were evaluated for 206 d under a range of operating conditions (start-up, steady-state, reducing conditions, and drying-rewetting cycles) for a spectrum of potentially harmful dissolved contaminants. Aerated outflows also were evaluated for acute and chronic toxicity to the biologically sensitive invertebrate Ceriodaphnia dubia. Dissolved metal leaching subsided within the first few weeks of operation, though initial concentrations of copper and zinc were detected at concentrations of concern. Elevated concentrations of tannins-lignin and total ammonia nitrogen were detected throughout the study and were influenced by operational phase. Acute toxicity was not generally detected, though chronic toxicity was observed during drying-rewetting cycles in the maple outflows. The measured toxicity was not correlated with water chemistry, indicating an additive effect of several toxicants. Overall, significant differences in outflow water quality between ash and maple wood species were negligible. Results indicated that bioreactor outflows may be applicable for aquacultural reuse, though reusing outflows immediately following start-up or restarting after a dry period would not be recommended.  相似文献   
4.
The aim of this research was to determine the effect of three different fertilizing systems, including organic, conventional, and integrated ones, on the yield, fruit quality, antioxidant activity, and some phenolic compounds of white seedless grape. The study was carried out on several 6-year-old white seedless grapevine located in the Urmia Province (North-West Iran). The results showed that the fruit physical characteristics and yield were affected significantly by different fertilization systems. The highest yield was observed in the conventional fertilization, followed by organic and integrated systems. The leaf mineral contents were obviously dependent on the different fertilization used, whereas pH and titratable acidity were not affected. Based on our results, the highest values of antioxidant activity and total flavonoid were found in the organic and integrated fertilization systems, respectively. Also, the highest contents of total phenolic, catechin, and quercetin-3-galactoside were observed in the organic fertilization system. Overall, the highest nutritional quality and biochemical characteristics of white seedless grape were obtained in organic fertilization system, which improved antioxidant capacity by enhancing total phenolics, total flavonoids and valuable phenolic compounds.  相似文献   
5.
Vegetatively propagated crop (VPC) seed tends to remain true to varietal type but is bulky, often carries disease, and is slow to produce. So VPC seed needs to be handled differently than that of other crops, e.g., it tends to be sourced locally, often must be fresh, and it is less often sold on the market. Hence, a framework was adapted to describe and support interventions in such seed systems. The framework was used with 13 case studies to understand VPC seed systems for roots, tubers, and bananas, including differing roles and sometimes conflicting goals of stakeholders, and to identify potential coordination breakdowns when actors fail to develop a shared understanding and vision. In this article, we review those case studies. The framework is a critical tool to (a) document VPC seed systems and build evidence; (b) diagnose and treat coordination breakdown and (c) guide decision-makers and donors on the design of more sustainable seed system interventions for VPCs. The framework can be used to analyze past interventions and will be useful for planning future VPC seed programs.  相似文献   
6.
It is most important to determine areas with recreation potential that can permit sustainable use of forest resources and also meet recreational uses. Under the method described in this study, using the Geographic Information System (GIS), a spatial suitability model for recreational use was combined with a recreational priority perceptual suitability model that depends on principal component analysis (PCA) and is based on the perceptions of both recreational users and experts. Using principal component analysis, five priority components explaining 69.371% of the total variance were identified out of 12 perceptual suitability components. These components are scenic beauty, accessibility, the surface of the landscape, tree type, and forest stand condition. The recreation terrain suitability value of an area with recreational potential was assessed with the assistance of these five priority components. This enabled us to generate a recreation terrain suitability value equation and a recreation terrain suitability value scale for a potential recreation area. This applicability of this approach was demonstrated in the identification of potential recreation areas in Trabzon, Turkey.  相似文献   
7.
Many studies have evaluated the adequacy of alternate ingredient diets for Atlantic salmon, Salmo salar, mainly with focus on fish performance and health; however, comprehensive analysis of fillet quality is lacking, particularly for salmon fed these diets in recirculation aquaculture systems (RAS). To this end, a study was conducted comparing fillet quality and processing attributes of postsmolt Atlantic salmon fed a fishmeal‐free diet (FMF) versus a standard fishmeal‐based diet, in replicate RAS. Mean weight of Atlantic salmon fed both diets was 1.72 kg following the 6‐mo trial and survival was >99%. Diet did not affect (P > 0.05) processing and fillet yields, whole‐body proximate composition(fat, moisture, protein), fillet proximate composition, cook yield, fillet texture, color, or omega‐3 fatty acid fillet content, including eicosapentaenoic acid and docosahexaenoic acid levels. Whole‐body ash content was greater in salmon fed the FMF diet. The FMF diet resulted in a wild fish‐in to farmed fish‐out ratio of 0:1 per Monterey Bay Aquarium's Seafood Watch criteria due to its fishmeal‐free status and use of lipids from fishery byproduct. Overall, fillet quality and processing attributes were generally unaffected when feeding a diet devoid of fishmeal to postsmolt Atlantic salmon cultured in RAS. [Correction added on 7 September 2017, after first online publication: the P value in Abstract has been changed from “P < 0.05” to “P > 0.05”.].  相似文献   
8.
The aim of the study was to determine the possibility of experimental media (agglomerate elastomers EPP) application as biological media bed, which serves the purpose of water purification in recirculating aquaculture systems (RAS). RAS enables mass‐production of fish in small volume of water in a limited area. This involves the possibility of multiple usage of water during culture. However, for that purpose of maintaining proper physico‐chemical parameters, water purification from products of metabolism, especially toxic nitrogen compounds, is required. One of the simplest and most effective ways to achieve it is combining application of two types of water filtration: mechanical and biological. It is needed to study new media for biological bed with proper filling is able to purify water from toxic nitrogen compounds.  相似文献   
9.
长江中游地区水旱复种轮作模式资源利用率比较研究   总被引:1,自引:0,他引:1  
为了实现农田资源高效利用,维护农业生态良性循环,优化长江中游地区传统种植模式,本研究于2013年10月—2015年11月,以冬闲连作为对照,分析比较了不同水旱复种轮作模式(冬闲-早稻-晚稻→冬闲-早稻-晚稻、马铃薯-玉米‖大豆-晚稻→蔬菜-花生‖玉米-晚稻、蔬菜-花生‖玉米-晚稻→绿肥-早稻-晚稻、绿肥-早稻-晚稻→油菜-花生-晚稻、油菜-花生-晚稻→马铃薯-玉米‖大豆-晚稻)的光、温、水、土资源利用效率。结果表明:水旱复种轮作模式的冬季、晚季和周年的光能利用率均比冬闲连作处理高,周年光能利用率两年间分别高8.26%~82.50%和2.63%~121.42%,其中均以"蔬菜-花生‖玉米-晚稻→绿肥-早稻-晚稻"轮作模式最高。水旱复种轮作模式的年有效积温利用率均高于冬闲连作模式,两年间分别高12.87%~21.26%和11.17%~25.88%,以"蔬菜-花生‖玉米-晚稻→绿肥-早稻-晚稻"轮作模式最佳。两年间水旱复种轮作模式的冬季、晚季和周年的水分利用率均比冬闲连作处理高,其中周年水分利用率分别高45.36%~83.50%和40.00%~118.75%,以"马铃薯-玉米‖大豆-晚稻→蔬菜-花生‖玉米-晚稻"轮作模式的晚季和周年水分利用率最高,"蔬菜-花生‖玉米-晚稻→绿肥-早稻-晚稻"模式的冬季水分利用率最高。两年间土地利用率均以"绿肥-早稻-晚稻"复种模式最高,平均利用率达96.11%,"蔬菜-花生‖玉米-晚稻→绿肥-早稻-晚稻"轮作模式的土地利用率表现最好。因此,各水旱复种轮作模式的周年光能利用率、年有效积温利用率、水分利用率和土地利用率均高于冬闲对照,其中以"蔬菜-花生‖玉米-晚稻→绿肥-早稻-晚稻"和"绿肥-早稻-晚稻→油菜-花生-晚稻"轮作模式表现较好,适宜在长江中游地区推广应用。  相似文献   
10.
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