Scenario Modeling Potential Eco-Efficiency Gains from a Transition to Organic Agriculture: Life Cycle Perspectives on Canadian Canola,Corn, Soy,and Wheat Production

We used Life Cycle Assessment to scenario model the potential reductions in cumulative energy demand (both fossil and renewable) and global warming, acidifying, and ozone-depleting emissions associated with a hypothetical national transition from conventional to organic production of four major field crops [canola (Brassica rapa), corn (Zea mays), soy (Glycine max), and wheat (Triticum aestivum)] in Canada. Models of these systems were constructed using a combination of census data, published values, and the requirements for organic production described in the Canadian National Organic Standards in order to be broadly representative of the similarities and differences that characterize these disparate production technologies. Our results indicate that organic crop production would consume, on average, 39% as much energy and generate 77% of the global warming emissions, 17% of the ozone-depleting emissions, and 96% of the acidifying emissions associated with current national production of these crops. These differences were almost exclusively due to the differences in fertilizers used in conventional and organic farming and were most strongly influenced by the higher cumulative energy demand and emissions associated with producing conventional nitrogen fertilizers compared to the green manure production used for biological nitrogen fixation in organic agriculture. Overall, we estimate that a total transition to organic production of these crops in Canada would reduce national energy consumption by 0.8%, global warming emissions by 0.6%, and acidifying emissions by 1.0% but have a negligible influence on reducing ozone-depleting emissions.     

Human urine as a source of alternative natural fertilizer in agriculture: A flight of fancy or an achievable reality

Organically agricultural products are gaining popularities through out the world as it gives the consumer satisfaction with a basket of safer and better trusted foods. It is also well established that intensive conventional agricultural practices can introduce contaminants into the food chain with adverse affect on environment. However, organic agricultural practices give an alternative environmental friendly sustainable agriculture among the farmers. Beside this fact, organic crops contain fewer nitrates, nitrites, pesticide residues and trace elements than conventional crops. Even though, in organic systems generally have 20% lower yields than conventionally produced crops. One of the major constrains of organic farming is decrease of raw organic matters to prepare compost. Therefore, scientists are looking forward for different organic sources which are plenty in nature and available at little-to-no cost. Human urine is one of them, and has been gaining popularities as a raw material for organic cultivation. However, several important merits and demerits of application of human urine are needed to be addressed in agriculture.     

Fenton氧化法处理难降解有机废水的研究进展

Fenton氧化法在处理难降解有机污染物时具有独特的优势,是一种很有应用前景的废水处理技术。在阐述传统Fenton氧化、光Fenton氧化、电Fenton氧化技术的基础上,介绍了三种氧化技术在难降解有机废水处理中的应用现状,并对其在废水处理中的优势、存在问题和研究方向作出了系统评述。     

A framework to assess regional environmental impacts of dedicated energy crop production

Numerous studies have evaluated air quality and greenhouse gas mitigation benefits of biomass energy systems, but the potential environmental impacts associated with large-scale changes in land-use patterns needed to produce energy crops have not been quantified. This paper presents a framework to assess the potential soil, water, and biodiversity impacts that may result from the large-scale production of dedicated energy crops. The framework incorporates producer economic decision models with environmental models to assess changes in land use patterns and to quantify the consequent environmental impacts. Economic and policy issues that will affect decisions to produce energy crops are discussed. The framework is used to evaluate erosion and chemical runoff in two Tennessee regions. The analysis shows that production of dedicated energy crops in place of conventional crops will significantly reduce erosion and chemical runoff.     

Nitrogen turnover on organic and conventional mixed farms

Separate focus on crop fertilization or feeding practices inadequately describes nitrogen (N) loss from mixed dairy farms because of (1) interaction between animal and crop production and between the production system and the manager, and (2) uncertainties of herd N production and crop N utilization. Therefore a systems approach was used to study N turnover and N efficiency on 16 conventional and 14 organic private Danish farms with mixed animal (dairy) and crop production. There were significant differences in N surplus at the farm level (242 kg. N/ha. vs. 124 kg. N/ha. on conventional and organic dairy farms respectively) with a correlation between stocking rate and N surplus. N efficiency was calculated as the output of N in animal products divided by the net N import in fodder, manure and fertilizer. N turnover in herd and individual crops calculated on selected farms showed differences in organic and conventional crop N utilization. This is explained via a discussion of the rationality behind the current way of planning the optimum fertilizer application in conventional agriculture. The concept of marginal N efficiency is insufficient for correcting problems of N loss from dairy farms. Substantial reductions in N loss from conventional mixed dairy farms is probably unlikely without lower production intensity. The concept of mean farm unit N efficiency might be a way to describe the relation between production and N loss to facilitate regulation. This concept is linked to differing goals of agricultural development—i.e. intensification and separation vs. extensification and integration. It is discussed how studies in private farms—using organic farms as selected critical cases—can demonstrate possibilities for balancing production and environmental concern.     

Environmentally Virtuous Agriculture: How and When External Goods and Humility Ethically Constrain (or Favour) Technology Use

This paper concerns virtue-based ethical principles that bear upon agricultural uses of technologies, such as GM crops and CRISPR crops. It does three things. First, it argues for a new type of virtue ethics approach to such cases. Typical virtue ethics principles are vague and unspecific. These are sometimes useful, but we show how to supplement them with more specific virtue ethics principles that are useful to people working in specific applied domains, where morally relevant domain-specific conditions recur. We do this while still fulfilling the need for principles and associated practical reasoning to flexibly respect variation between cases. Second, with our more detailed approach we criticize and improve upon a commonly discussed principle about ecosystemic external goods that are crucial for human flourishing. We show this principle is far more conservative than appreciated, as it would prohibit many technology uses that are uncontroversially acceptable. We then replace this principle with two more specific ones. One identifies specific conditions in which ecosystem considerations are against a technology use, the other identifies favorable conditions. Third, we uncover a humility-based principle that operates within an influential “hubris argument” against uses of several biotechnologies in agriculture. These arguments lack a substantive theory of the nature of humility. We clarify such a theory, and then use it to replace the uncovered humility-based principle with our own more specific one that shifts focus from past moral failings, to current epistemic limits when deciding whether to support new technologies.     

垃圾填埋气中微量挥发性有机物的净化技术

垃圾填埋气中存在的多种微量挥发性有机物(VOCS),既造成二次污染,影响了人类健康;又对填埋气的回收利用产生了不利影响。本文综述了几种VOCS常规净化技术的基本原理、优势及限制,介绍了几种新兴技术,并预期有效的联合工艺是净化填埋气中微量VOCs的研究方向。     

Impact of genetically modified crops and their management on soil microbially mediated plant nutrient transformations

One of the potential environmental effects of the recent rapid increase in the global agricultural area cultivated with transgenic crops is a change in soil microbially mediated processes and functions. Among the many essential functions of soil biota are soil organic matter decomposition, nutrient mineralization and immobilization, oxidation-reduction reactions, biological N fixation, and solubilization. However, relatively little research has examined the direct and indirect effects of transgenic crops and their management on microbially mediated nutrient transformations in soils. The objectives of this paper are to review the available literature related to the environmental effects of transgenic crops and their management on soil microbially mediated nutrient transformations, and to consider soil properties and climatic factors that may affect the impact of transgenic crops on these processes. Targeted genetic traits for improved plant nutrition include greater plant tolerance to low Fe availability in alkaline soils, enhanced acquisition of soil inorganic and organic P, and increased assimilation of soil N. Among the potential direct effects of transgenic crops and their management are changes in soil microbial activity due to differences in the amount and composition of root exudates, changes in microbial functions resulting from gene transfer from the transgenic crop, and alteration in microbial populations because of the effects of management practices for transgenic crops, such as pesticide applications, tillage, and application of inorganic and organic fertilizer sources. Possible indirect effects of transgenic crops, including changes in the fate of transgenic crop residues and alterations in land use and rates of soil erosion, deserve further study. Despite widespread public concern, no conclusive evidence has yet been presented that currently released transgenic crops, including both herbicide and pest resistant crops, are causing significant direct effects on stimulating or suppressing soil nutrient transformations in field environments. Further consideration of the effects of a wide range of soil properties, including the amount of clay and its mineralogy, pH, soil structure, and soil organic matter, and variations in climatic conditions, under which transgenic crops may be grown, is needed in evaluating the impact of transgenic crops on soil nutrient transformations. Future environmental evaluation of the impact of the diverse transgenic crops under development could lead to an improved understanding of soil biological functions and processes.     

城市污水处理厂污泥利用探讨

采用在污水污泥中按不同比例掺入生活垃圾或黄土与砂,进行高温堆制,开发出含多种微量元素的高效有机／无机复合肥和多微有机营养土,并施用于农作物和花卉。结果表明施用后农作物产量增加,花卉植物的株高、花蕾数、根长、根重明显高于对照组。该课题的研究不仅可获得廉价的微量元素复合肥料,而且消除了污水污泥对环境的污染,可创造一定的社会经济效益。     

The effect of heating technologies on CO(2) and energy efficiency of Dutch greenhouse firms

This paper uses Data Envelopment Analysis to compute measures of the efficiency (relative to a frontier) in terms of the use of all inputs as well as for single inputs like CO(2) and energy for a sample of greenhouse firms in the Netherlands over the period 1991-1995. These efficiency measures are generated for different firms specialised in production of vegetables, flowers, and potplants and with different heating technologies. The empirical results indicate that firms use energy quite efficiently and are less efficient in terms of CO(2) emissions. Firms using conventional heating are overall less efficiently using energy and CO(2) than firms using more advanced heating technologies. Most differences in efficiency between firm types and firms using different heating technologies are statistically significant. Scale adjustments can provide an important contribution to further efficiency improvements.     

Expert knowledge-based assessment of farming practices for different biotic indicators using fuzzy logic

The study presented here describes a modeling approach for the ex-ante assessment of farming practices with respect to their risk for several single-species biodiversity indicators. The approach is based on fuzzy-logic techniques and, thus, is tolerant to the inclusion of sources of uncertain knowledge, such as expert judgment into the assessment. The result of the assessment is a so-called Index of Suitability (IS) for the five selected biotic indicators calculated per farming practice. Results of IS values are presented for the comparison of crops and for the comparison of several production alternatives per crop (e.g., organic vs. integrated farming, mineral vs. organic fertilization, and reduced vs. plow tillage). Altogether, the modeled results show that the different farming practices can greatly differ in terms of their suitability for the different biotic indicators and that the farmer has a certain scope of flexibility in opting for a farming practice that is more in favor of biodiversity conservation. Thus, the approach is apt to identify farming practices that contribute to biodiversity conservation and, moreover, enables the identification of farming practices that are suitable with respect to more than one biotic indicator.     

Vermicomposting: A sustainable tool for environmental equilibria

Improperly managed organic waste constitutes a serious environment threat across the globe. This has led to a worldwide struggle to strike a balance between the rapid generation of such wastes and protection of the environment. With the unique advantages of lower operational and maintenance costs compared with other waste management technologies, the use of vermicomposting to manage organic wastes has been increasing rapidly in recent years. Still, some factors (e.g., characteristics of substrate composition before and after treatment) are in need of additional, specific studies so that researchers can better understand the metabolism involved in the process. Vermicomposting provides employment opportunities as it protects the environment, augmenting crop productivity when it is used as a fertilizer supplement and helping to maintain ecological balance. Thus, vermicompost plays an important role in the circular economy. This article provides an overview of the research activities that have been conducted on the use of vermicomposts to remove pollutants from the soil, in wastewater treatment, and in organic waste recycling throughout the world. Circular economic assessment has revealed that vermicomposting technology is usually feasible except in certain cases. Most other methods of waste disposal lead to soil deterioration, toxic effects, and increased pollution affecting land, air, water, and living beings, in addition to the sometimes considerable expense of their implementation. Thus, an eco‐friendly method that removes waste in one step is needed. Determining the long‐term performance and sustainable operation of vermicomposting systems still poses a challenge, however, as treatment performance is affected by design parameters, operational conditions, and environmental factors. This article summarizes the factors influencing pollutant removal through the vermicomposting process. Finally, this article highlights additional research that should be conducted on these issues to improve the performance of vermicomposting.     

Nitrate nitrogen in surface waters as influenced by climatic conditions and agricultural practices

Subsurface tile drainage from row-crop agricultural production systems has been identified as a major source of nitrate entering surface waters in the Mississippi River basin. Noncontrollable factors such as precipitation and mineralization of soil organic matter have a tremendous effect on drainage losses, nitrate concentrations, and nitrate loadings in subsurface drainage water. Cropping system and nutrient management inputs are controllable factors that have a varying influence on nitrate losses. Row crops leak substantially greater amounts of nitrate compared with perennial crops; however, satisfactory economic return with many perennials is an obstacle at present. Improving N management by applying the correct rate of N at the optimum time and giving proper credits to previous legume crops and animal manure applications will also lead to reduced nitrate losses. Nitrate losses have been shown to be minimally affected by tillage systems compared with N management practices. Scientists and policymakers must understand these factors as they develop educational materials and environmental guidelines for reducing nitrate losses to surface waters.     

畜禽养殖废水处理技术探讨

介绍了畜禽养殖废水有机物和氨氮含量高、可生化性好等特点及其污染现状,从物化法和生物法两个方面综述了近年来国内外有关畜禽养殖废水处理技术的研究进展,并分析了现有处理方法的优缺点和存在的问题。在此基础上提出了现阶段厌氧（缺氧）一好氧组合工艺技术是处理较大规模畜禽养殖废水的主要方法。并建议畜禽养殖废水的治理应从“防”、“治”两个方面入手。     

石油污染土壤的生物修复技术研究及其前景

根据污染土壤的生物修复技术具有高效、无二次污染和操作管理简便的优点，本文介绍谊类技术在石油污染治理领域的应用。在概述石油的组成成分及其对环境造成的污染的基础上，重点论述了微生物和植物修复技术有效去除有机污染物的应用条件，并就目前两种技术的最新研究成果即基因技术的应用作了介绍，同时指出了石油污染土壤生物修复技术的发展趋势和应用前景。     

Rural development and ecological management of endogenous resources: the case of mountain olive groves in Los Pedroches comarca (Spain)

In this paper, we explore the dissemination potential of organic farming in Andalucía, using the case of Olivarera de los Pedroches, a small farmer cooperative. This will be done in the search for an agroecological strategy in the olive tree organic agricultural sector. A comparative analysis of organic and conventional olive oil production is made: both in economic terms, and regarding employment creation, taking into account its environmental benefits. This will permit us to shed light on certain elements necessary in the design of rural policies linked to this economic sector, and in the family farming social stratum. After a brief analysis of the Andalucían inequality structure in rural areas—both historically and at present times—this work presents the following issues: (i) a systematic characterization of European olive cultivation, with special reference to the Spanish and Andalucían situations; (ii) an exploration of the socio-economic impact of the case study within the context of the major actors involved, and their relations in terms of its reproducibility, taking into account their relationships with institutional and policy arrangements. Organic agriculture in Spain has developed slowly since 1995—the year in which aid towards this type of production began to be established—and, at present, begins to show an exponential increase. Many farmers began the transition to ecological handling of olive groves. Consequently, the organic management of the olive groves and the sale of organic olive oil can be a stimulus to farmers to increase their profits. Hence, it can be a fundamental pillar on which to establish rural development in areas with a high level of importance concerning this crop. In this work, data clearly show that, in spite of high costs, organic olive farming has advantages over conventional agriculture in terms of incomes and employment. Copyright © 2001 John Wiley & Sons, Ltd.     

Sustainability of farmers' soil fertility management practices: a case study in the North China Plain

To ensure regional self-sufficiency and adequate rural livelihoods in the North China Plain (NCP), tremendous efforts were made over the last two decades by the Chinese government to raise the productivity of crops, despite increasing pressure on the land caused by a growing population. Emphasis was placed on high external input use, especially for wheat, maize and cotton, ignoring the particularities and limitations of the natural resource base. This study assesses the sustainability of current soil fertility management practices on the basis of selected location-specific indicators, such as fertilizer use, soil pH, soil organic matter content, levels of nitrogen (N), phosphorus (P) and potassium (K) in the soil, and identifies determining factors of the yield and environmental impacts of inputs use. Data used for the analysis were gathered from soil tests, groundwater and chive plant tests, household surveys, and statistical yearbooks. Stepwise multiple regression analysis is applied to determine factors affecting the yields. The study revealed unbalanced use of nutrients. Organic fertilizers (manure, crop residues) and K are insufficiently applied, whereas N and P are considerably overused in comparison with recommended doses. The intensive cropping in the area using high-input technologies -particularly fertilizer- has resulted in a remarkable general enhancement of crop productivity and improvement of soil fertility over the years. The yield of wheat and maize has increased 173 and 180 kg ha(-1) annually from 1982 to 2000, respectively and soil fertility status also improved over the years and the values of the selected indicators are within the borderline for sustainability. Irrigation water, FYM application, and total labor used during the cultivation season (with the exception of cotton and chive) for production are the main factors determining the yields of four major crops under study, while popularly and overly used N did not appear to be a significant factor affecting the yield. Its overuse, however, leads to leaching of nitrate into groundwater and nitrate enrichment of vegetables. Of 20 groundwater samples, 16 showed nitrate levels between 55 and 180 mg l(-1), which exceeds recommendations for drinking water (相似文献   

Assessment of the greenhouse effect impact of technologies used for energy recovery from municipal waste: A case for England

Waste management activities contribute to global greenhouse gas emissions approximately by 4%. In particular the disposal of waste in landfills generates methane that has high global warming potential. Effective mitigation of greenhouse gas emissions is important and could provide environmental benefits and sustainable development, as well as reduce adverse impacts on public health. The European and UK waste policy force sustainable waste management and especially diversion from landfill, through reduction, reuse, recycling and composting, and recovery of value from waste. Energy from waste is a waste management option that could provide diversion from landfill and at the same time save a significant amount of greenhouse gas emissions, since it recovers energy from waste which usually replaces an equivalent amount of energy generated from fossil fuels. Energy from waste is a wide definition and includes technologies such as incineration of waste with energy recovery, or combustion of waste-derived fuels for energy production or advanced thermal treatment of waste with technologies such as gasification and pyrolysis, with energy recovery. The present study assessed the greenhouse gas emission impacts of three technologies that could be used for the treatment of Municipal Solid Waste in order to recover energy from it. These technologies are Mass Burn Incineration with energy recovery, Mechanical Biological Treatment via bio-drying and Mechanical Heat Treatment, which is a relatively new and uninvestigated method, compared to the other two. Mechanical Biological Treatment and Mechanical Heat Treatment can turn Municipal Solid Waste into Solid Recovered Fuel that could be combusted for energy production or replace other fuels in various industrial processes. The analysis showed that performance of these two technologies depends strongly on the final use of the produced fuel and they could produce GHG emissions savings only when there is end market for the fuel. On the other hand Mass Burn Incineration generates greenhouse gas emission savings when it recovers electricity and heat. Moreover the study found that the expected increase on the amount of Municipal Solid Waste treated for energy recovery in England by 2020 could save greenhouse gas emission, if certain Energy from Waste technologies would be applied, under certain conditions.     

An operational method for the evaluation of resource use and environmental impacts of dairy farms by life cycle assessment

This paper describes and applies EDEN-E, an operational method for the environmental evaluation of dairy farms based on the life cycle assessment (LCA) conceptual framework. EDEN-E requires a modest amount of data readily available on-farm, and thus can be used to assess a large number of farms at a reasonable cost. EDEN-E estimates farm resource use and pollutant emissions mostly at the farm scale, based on-farm-gate balances, amongst others. Resource use and emissions are interpreted in terms of potential impacts: eutrophication, acidification, climate change, terrestrial toxicity, non-renewable energy use and land occupation. The method distinguishes for each total impact a direct component (impacts on the farm site) and an indirect component (impacts associated with production and supply of inputs used). A group of 47 dairy farms (41 conventional and six organic) was evaluated. Expressed per 1000 kg of fat-and-protein-corrected milk, total land occupation was significantly larger for organic than for conventional farms, while total impacts for eutrophication, acidification, climate change, terrestrial toxicity, and non-renewable energy use were not significantly different for the two production modes. When expressed per ha of land occupied all total impacts were significantly larger for conventional than organic farms. This study largely confirms previously published findings concerning the effect of production mode on impacts of dairy farms. However, it strikingly reveals that, for the set of farms examined, the contribution of production mode to overall inter-farm variability of impacts was minor relative to inter-farm variability within each of the two production modes examined. The mapping of impact variability through EDEN-E opens promising perspectives to move towards sustainable farming systems by identifying the structural and management characteristics of the farms presenting the lowest impacts.     

Manure and adoption of modern seeds in cereal‐based systems in West African drylands: linkages and (non)complementarities

Using a stepwise approach that combines several econometric methods, we assessed whether or not the adoption of modern seeds and the use of manure in cereal‐based systems are linked and, if so, what are the driving forces of the linkages between these two agricultural technologies under dry‐climate conditions in West Africa. We found complementary and substitutability linkages arising from jointness and endogeneity between the two technologies. Specifically, our findings reveal positive joint determination along with negative endogeneity between the two technologies indicating that, controlling for observable variables, both technologies are positively linked, but unobserved factors that affect one adoption decision are negatively correlated with the other. After controlling for jointness and endogeneity, we found significant complementarity linkages showing a significant positive effect of manure use on the adoption of modern seeds, which is also significantly and positively affected by the number of cash crops grown and remittances. The two technologies are reversely affected by schooling and the incidence of soil fertility problems within the farm, whereas the amount of healthy land has a positive effect on both. The study suggests that organic fertilizer can serve as an enabling factor for greater adoption of modern seeds, especially in less favourable climate areas, and strongly supports the argument behind the need to breed seeds suitable for the use of organic fertilizers. These findings provide avenues for re‐orientation of policies that promote the use of modern seeds in dryland areas in sub‐Saharan Africa, with a possibility of breeding and promoting them in packages with organic fertilizers to upscale their adoption.