从“治”到“化”的规模化养殖场废物处理的循环经济模式

首先讨论了“治”字思维模式下,我国禽畜养殖业规模化养殖场存在污染物既不经济又不环保的严峻现实问题。事实上,规模化禽畜养殖场产生的“废物”,既是严重的污染源,又是一种必须利用的资源。因此,针对规模化养殖场的污染物“治”字思维问题,在立足于粪便及污水的综合利用100%“资源化”的“化”字思维指导下,遵循循环经济原则,建立无废无污开放式闭合循环的生态经济新模式。一方面,养殖业所有流程按循环利用原则,实行生态工艺或无废工艺的改造;另一方面,在一个大的区域里把畜禽养殖业与其它产业,特别是大农业中的种植业以生态经济循环链锁关系配置成首尾相接的“废料—原料”的循环经济新模式,在达到边际成本最低的同时取得边际效益的最大化。     

Relationships between Danish organic farming and landscape composition

This article presents an investigation of relationships between organic farming and landscape composition in Denmark. Landscape composition was analysed in terms of density of uncultivated landscape elements (I), number of land uses per hectare (II), diversity of land use (III) and mean field size (IV). Two analytical approaches were used. The first was based on an examination of the national agricultural registers for 1998, 2001 and 2004. The second approach used aerial photo interpretation for an analysis of 72 conventional and 40 organic farms within three sample areas for 1982, 1995 and 2002. The national analysis indicated that organic farming has a direct effect on landscape composition. In 2001, organic farms were characterised by a higher number of land uses per ha, a higher land use diversity and smaller mean field sizes. From 1998 to 2004, conversion to organic farming was related to an increasing number of land uses per ha, increasing land-use diversity and decreasing mean field sizes. Relationships between organic farming and landscape composition were independent of variations in regional location, farm size or farm size change. At the level of sample areas, a significant relationship between organic farming and landscape composition was only found for densities of small biotopes. However, when differences in farm size and physical geographical conditions between conventional and organic farms were taken into account, several significant differences in landscape composition were clarified in two of the three sample areas. Furthermore, changes in landscape composition following conversion to organic farming were largely biased by the characteristics of the sample areas. Thus, in contrast to the national level, the sample area study indicated that differences in landscape composition between organic and conventional farms were not a direct implication of organic farming practices, but were related to variations within other parameters and to the location of organically farmed land.     

Emergy evaluation and economic analysis of three wetland fish farming systems in Nansi Lake area,China

Emergy and economic methods were used to evaluate and compare three fish production models, i.e., cage fish farming system, pond intensive fish rearing system and semi-natural extensive pond fish rearing system, in Nansi Lake area in China in the year 2007. The goal of this study was to understand the benefits and driving forces of selected fish production models from ecological and economic points of view. The study considered input structure, production efficiency, environmental impacts, economic viability and sustainability. Results show that the main difference among the three production systems was the emergy cost for fish feed associated with their feeding system, i.e., feeding on natural biomass such as plankton and grass or on commercial feedstock. As indicated by EYR, ELR and ESI, it can be clearly shown that the intensive production model with commercial feed is not a sustainable pattern. However, the point is that more environmentally sound patterns do not seem able to provide a competitive net profit in the short run. The intensive pond fish farming system had a net profit of 2.57E+03 $/ha, much higher than 1.27E+03 $/ha for cage fish farming system and slightly higher than 2.37E+03 $/ha for semi-natural fish farming system. With regard to the drivers of local farmer’s decisions, the accessibility of land for the required use and investment ability determine the farmer’s choice of the production model and the scale of operation, while other factors seem to have little effect. Theoretically, the development of environmentally sustainable production patterns, namely water and land conservation measures, greener feed as well as low waste systems is urgently needed, to keep production activities within the carrying capacity of ecosystems. Coupled emergy and economic analyses can provide better insight into the environmental and economic benefits of fish production systems and help solve the problems encountered during policy making.     

Shellfish aquaculture and First Nations' sovereignty: The quest for sustainable development in contested sea space

Aquaculture tenures or leases have become an increasingly important management tool for regulating access rights to coastal and offshore marine habitat. Tenure, as a form of private property rights to marine space, is generally considered a prerequisite for aquaculture development, as are the associated exclusive access rights which provide necessary incentives for producers to invest in infrastructure. The shellfish industry in British Columbia (BC), Canada, is presented as a case study of a transition from a primarily common property wild fishery to a rights‐based system for aquaculture. In BC, seafood production has grown substantially during the past two decades as a result of aquaculture production. However, despite the inherent economic advantages of the tenuring system for increasing seafood production, rights to aquaculture sites in BC remain highly controversial, particularly in response to environmental concerns and infringements on Aboriginal territorial claims. Shellfish farming has, to‐date, been far less controversial than salmon farming; however, shellfish aquaculture has not been uniformly adopted across the province, and analyses of industry capacity or economic opportunities for coastal communities have failed to adequately explain development patterns. This paper, which identifies perceptions of the risks and benefits of the shellfish aquaculture tenuring system, presents the results of 56 interviews conducted with individuals involved in shellfish production in BC. Results indicate that heightened perceptions of risk about shellfish aquaculture tenuring are related to unresolved Aboriginal territorial claims, economic dependence on wild shellfish resources, as well as place‐based values favouring access to wild resources. Underlying values and cultural understandings also strongly shape public perceptions of the risks of aquaculture, and as such, influence local decisions to either accept or resist industry growth. In this case, interviewees' risk perceptions were found to be more important indicators of the potential for industry expansion than studies of capacity or economic cost‐benefit analyses.     

Conservation impacts of commercial cultivation of endangered and overharvested plants

Overharvesting is one of the greatest threats to species survival. Farming overharvested species is a conservation strategy that can meet growing market demand and conserve wild populations of the target species. This strategy is compatible with the international community's desire to uphold the right of local communities to use biological resources to support their livelihoods. However, studies investigating whether farming can alleviate poaching pressure have focused almost exclusively on animals. To address the shortfall in plant-focused studies, we compiled information on commercial cultivation of threatened plants to assess its conservation benefits. Because China's rising middle class has rapidly intensified demand for wildlife products, we searched the scientific literature published in Chinese (China National Knowledge Infrastructure and Baidu) and in English. We found 32 reports that contained data on 193 internationally or nationally threatened plant species that were under commercial cultivation. These reports showed that cultivations of 82% of the 193 species were sustained by collecting whole plants from the wild periodically or continuously. Although based on a small sample size, species that were maintained in cultivation only through artificial propagation or seeds collected in the wild were likely associated with a reported reduction in wild harvesting of whole plants. Even so, results of correlation analyses suggested that production system, scale, and when a species began being cultivated had little effect on conservation status of the species, either globally or in China. However, species brought into cultivation relatively recently and on a smaller scale were more likely to have undergone a reduction in collecting pressure. Farming of nonmedicinal plants was most problematic for species conservation because wild plants were laundered (i.e., sold as cultivated plants). For effective conservation, policy to guide cultivation operations based on the target species’ biological characteristics, cultural significance, market demand, and conservation status is needed.     

Evaluation of the impact on entomocoenosis of active agents allowed in organic olive farming against Bactrocera oleae (Gmelin, 1790)

Several attempts for evaluating environmental impact of active agents allowed in organic olive farming against Bactrocera oleae have been made, but very few studies were performed contemporaneously on more than one of them. Insects were chosen as indicators because they are known to react very quickly to environmental perturbations, mainly at the community level. In fact, the coenosis is the functional unit interacting with biotic and abiotic environmental parameters. Seven taxa, known for their sensitivity to habitat alterations, were sampled and grouped in functional groups: predators and parasitoids, phytophagouses and pollinators. The coenotic balance between these two functional groups was analyzed. The study was carried out in an organic olive orchard in the municipality of Terranova da Sibari, Cosenza, Southern Italy. The tested active agents (Azadirachtin, Rotenone, Copper Oxychloride) were sprayed twice (end of September and middle October). During the treatments the population dynamics of all the taxa were knocked-down. No one tested compound seems to be harmless to the entomocoenosis, particularly on phytophagouses and pollinators. In truly organic farming it is necessary to provide natural refuge areas to beneficial insects (i.e. pest antagonists) in which no active agents are sprayed and alternative preys could be found.     

Does Organic Farming Face Distinctive Livestock Welfare Issues? – A Conceptual Analysis

The recent development and growth oforganic livestock farming and the relateddevelopment of national and internationalregulations has fueled discussions amongscientists and philosophers concerning theproper conceptualization of animal welfare.These discussions on livestock welfare inorganic farming draw on the conventionaldiscussions and disputes on animal welfare thatinvolve issues such as different definitions ofwelfare (clinical health, absence of suffering,sum of positive and negative experiences,etc.), the possibility for objective measuresof animal welfare, and the acceptable level ofwelfare. It seems clear that livestock welfareis a value-laden concept and that animalwelfare science cannot be made independent ofquestions of values and ethics. The questioninvestigated here is whether those values thatunderpin organic farming, in particular, alsoaffect the interpretation of livestock welfare,and, if so, how. While some of the issuesraised in connection with organic farming arerelatively uncontroversial, others are not. Theintroduction of organic farming values seems tointroduce new criteria for what counts as goodanimal welfare, as well as a different ethicalbasis for making moral decisions on welfare.Organic farming embodies distinctive systemicor communitarian ethical ideas and the organicvalues are connected to a systemic conceptionof nature, of agriculture, of the farm, and ofthe animal. The new criteria of welfare arerelated to concepts such as naturalness,harmony, integrity, and care. While the organicvalues overlap with those involved in theconventional discussion of animal welfare, someof them suggest a need to set new prioritiesand to re-conceptualize animal welfare – forexample, with respect to ``naturalness,' inrelation to the possibilities for expression ofnatural behavior and in relation to animalintegrity as a concept for organismic harmony.The organic perspective also seems to suggest awider range of solutions to welfare problemsthan changes in farm routines or operations onthe animals. The systemic solutions include thechoice and reproduction of suitable breeds,changes in the farm structure, and changes inthe larger production and consumption system – including consumer perceptions andpreferences. But the organic values may alsocall for sacrifices of individual welfare in aconventional sense in order to advance welfarefrom the perspective of organic farming.Whether this is good or bad cannot be decidedwithout entering into an inquiry and discussionof the values and ethics involved.     

Efficiency analysis for organic agricultural producers: the role of soil-improving inputs

Greater emphasis is being placed on indicators of agri-environmental efficiency of organic production systems. Linking environmental measures with profitability measures based on net income is the only way to develop such indicators. A stochastic production frontier model that explicitly incorporates farm decisions about acquiring and managing organic soil-improving inputs is used to measure efficiency. The results confirm that on-farm self-sufficiency in soil-improving inputs is positively related to farm-level efficiency.     

Modelling the effect of support practices (P-factor) on the reduction of soil erosion by water at European scale

The USLE/RUSLE support practice factor (P-factor) is rarely taken into account in soil erosion risk modelling at sub-continental scale, as it is difficult to estimate for large areas. This study attempts to model the P-factor in the European Union. For this, it considers the latest policy developments in the Common Agricultural Policy, and applies the rules set by Member States for contour farming over a certain slope. The impact of stone walls and grass margins is also modelled using the more than 226,000 observations from the Land use/cover area frame statistical survey (LUCAS) carried out in 2012 in the European Union.The mean P-factor considering contour farming, stone walls and grass margins in the European Union is estimated at 0.9702. The support practices accounted for in the P-factor reduce the risk of soil erosion by 3%, with grass margins having the largest impact (57% of the total erosion risk reduction) followed by stone walls (38%). Contour farming contributes very little to the P-factor given its limited application; it is only used as a support practice in eight countries and only on very steep slopes. Support practices have the highest impact in Malta, Portugal, Spain, Italy, Greece, Belgium, The Netherlands and United Kingdom where they reduce soil erosion risk by at least 5%. The P-factor modelling tool can potentially be used by policy makers to run soil-erosion risk scenarios for a wider application of contour farming in areas with slope gradients less than 10%, maintaining stone walls and increasing the number of grass margins under the forthcoming reform of the Common Agricultural Policy.     

OUTPUT AND INVESTMENT FRONTIERS OF UNITED STATES IRRIGATED AGRICULTURE1

ABSTRACT: Economic models sometimes indicate that irrigation water is misallocated in agriculture, especially when it appears that the marginal value product is higher in other uses (such as for hydro-power). Historically, trends tend to contradict this reasoning, however, especially since irrigation has grown from 20 million acres in 1940 to over 50 million acres in 1980. Results of this study tend to indicate that as agriculture becomes more and more intensive (in terms of inputs), irrigation is part of that long term trend. Further, major economic variables, such as output and investments in agriculture, appear to be more highly correlated with irrigated land than with dryland agriculture. Recent data indicate an upper limit of about 320 million acres for dryland farming in the United States, while no such constraint is apparent for irrigated agriculture.