配套养殖体系中部分抗生素的污染特征

采用超声提取-固相萃取-高效液相色谱串联质谱技术分析配套养殖体系粪便、水体和沉积物中4种磺胺类(SAs)、2种四环素类(TCs)、2种大环内酯(MLs)和2种喹诺酮类(QLs)抗生素的含量和分布特征.研究结果显示,在水体中共检出8种抗生素,浓度在ND—382 ng·L-1,2种四环素类抗生素未被检出,且水体中抗生素的浓度呈现旱季高于雨季;沉积物中共检出7种抗生素,其浓度分别在ND—3400μg·kg-1范围内,磺胺嘧啶(SDZ)、磺胺甲噁唑(SMX)和罗红霉素(RTM)未被检出;在猪粪和鸭粪中均检出甲氧苄啶(TMP)、诺氟沙星(NFX)、脱水红霉素(ETM-H2O)和罗红霉素(RTM),同时猪粪中还检出2种四环素类,鸭粪中检出磺胺二甲嘧啶(SMZ)和环丙沙星(CFX),其中鸭粪中甲氧苄啶的最高浓度达到6.11 mg·kg-1.研究结果表明,不同介质中抗生素的含量存在一定差异,其中磺胺类抗生素在水体中浓度最高,喹诺酮类和四环素类在沉积物中的浓度最高;粪便中抗生素的种类与施药的种类密切相关,并且可能会加剧抗生素对水体环境的污染.     

Quantitative Assessment of a Tanzanian Integrated Conservation and Development Project Involving Butterfly Farming

Abstract: Scientific understanding of the role of development in conservation has been hindered by the quality of evaluations of integrated conservation and development projects. We used a quasi‐experimental design to quantitatively assess a conservation and development project involving commercial butterfly farming in the East Usambara Mountains of Tanzania. Using a survey of conservation attitudes, beliefs, knowledge, and behavior, we compared 150 butterfly farmers with a control group of 170 fellow community members. Due to the nonrandom assignment of individuals to the two groups, we used propensity‐score matching and weighting in our analyses to control for observed bias. Eighty percent of the farmers believed butterfly farming would be impossible if local forests were cleared, and butterfly farmers reported significantly more participation in forest conservation behaviors and were more likely to believe that conservation behaviors were effective. The two groups did not differ in terms of their general conservation attitudes, attitudes toward conservation officials, or knowledge of conservation‐friendly building techniques. The relationship between butterfly farming and conservation behavior was mediated by dependency on butterfly farming income. Assuming unobserved bias played a limited role, our findings suggest that participation in butterfly farming increased participation in conservation behaviors among project participants because farmers perceive a link between earnings from butterfly farming and forest conservation.     

水作和旱作对叶菜吸收镉的影响差异研究

采用盆栽试验,以适宜水旱2种模式栽培的空心菜（Ipomoea aquatica）为对象,研究了水作和旱作两种栽培模式对Cd污染土壤上空心菜吸收积累Cd的差异及其影响因素。结果表明,水作和旱作对空心菜生物量和Cd质量分数影响显著。水作条件下,空心菜地上部和根系生物量分别比旱作处理增加了16.3%和190.6%,而地上部和根系Cd质量分数则较旱作处理降低了52.2%和49.3%。水作和旱作对土壤pH和DTPA-Cd质量分数也有不同影响,其中种植空心菜的处理土壤pH较旱作处理增加了0.99个单位,土壤DTPA-Cd质量分数降低了40.0%,不种空心菜的处理土壤pH较旱作处理增加了1.48个单位,土壤DTPA-Cd质量分数降低了30.4%。逐步回归分析发现,空心菜地上部Cd质量分数受土壤DTPA-Cd质量分数和土壤pH影响最大。因此,在Cd污染土壤上,通过旱作改水作可降低空心菜可食部分Cd质量分数,是一种环境友好、价格低廉的土壤重金属污染的调控措施。     

How farmers develop local ecological knowledge for on-farm tree management: The perspectives of some farming communities of Ghana

Scientific insights into what it means to manage on-farm trees by local farmers, is an essential step towards documenting local ecological knowledge for sustainable landscape management. A study was therefore conducted in the Kumawu Forest District in the Ashanti Region of Ghana to assess how farmers conceptualise on-farm tree management and develop local knowledge for it. Using a case study approach, data were collected through informal interviews and focus group discussions with 120 farmers drawn from 15 communities who were involved in the management of three cropping systems; cocoa, maize and cassava-cocoyam-plantain mix. It was observed that the farmers regard on-farm tree management as a continuous process which occurs in three phases of the farming cycle; land preparation, crop cultivation and fallow management. For each of the three phases, farmers are guided by specific principles that ensure enough light penetration in-between tree crowns in the land preparation phase, suitable spacing between trees and crops in the crop cultivation phase and adequate tree regeneration in the fallow phase. The decisions made during the selection of tree species, spacing of trees adjudged suitable for any particular cropping system and recruitment of saplings prior to the fallow phase of farming constitute tree management. Farmers develop tree management knowledge by studying the physical characteristics of species, matching them to ecological functions they could perform and how they are likely to respond to treatments meant to control or enhance their development. Species are then subjected to trial and recommended or otherwise.     

Land Cover Changes as a Result of Environmental Restrictions on Nitrate Leaching in Dairy Farming

Nitrate leaching forms an important environmental problem because it causes pollution of groundwater and surface water, and adds to already problematic eutrophication. This study analyses the impact of reductions in nitrate leaching on land cover decisions of dairy farms, of which the activities make an important contribution to nitrate leaching. As the level of nitrate leaching depends on groundwater depth as well as on the supply of nitrogen, spatial variation in groundwater levels will cause a spatial variation in land cover under restrictions on nitrate leaching. A non-linear partial optimisation model for the economic and ecological aspects of the problem were used to show how land cover and dairy farms' financial balances change when nitrate losses are reduced. The model is spatially explicit, and describes nitrate leakage and yields of maize and grass as a function of groundwater depth, including the effects of various grazing systems. The model analyses the decisions of a risk neutral agent who minimises costs under the following constraints: (i) production, feed requirements and mass balances for fodder; (ii) constraints for nitrate leaching. Economic costs are attributed to increased costs of fodder and processing of manure when nitrate restrictions are tightened. An important result of the study is the variation in compliance costs and land cover for maize and grass production brought about by spatial variation in groundwater depth. While the effects are negligible for some shallow groundwater classes, it is extremely difficult in other classes – if not impossible – to obtain the EU standard of maximum admissible losses of 34 kg N ha^–1 at low costs. The study shows an important reduction in land cover by maize.     

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.     

Bird conservation and the land sharing-sparing continuum in farmland-dominated landscapes of lowland England

Empirical evidence from many regions suggests that most species would be least negatively affected if human food demand were met through high-yield agricultural production and conservation of nonfarm ecosystems (land sparing), rather than through wildlife-friendly farming over a larger area (land sharing). However, repeated glaciation and a long history of agriculture may lead to different results in regions such as western Europe. We compared the consequences of land sparing and land sharing on breeding bird species in 2 lowland regions of England, The Fens, with 101 species, and Salisbury Plain, with 83. We derived density–yield responses for each species and then estimated regional population size under regional food production strategies, including land sharing and land sparing, a range of intermediate strategies, and a novel mixed strategy. In both regions, more species achieved maximum regional population size under land sparing than land sharing. In The Fens, the majority of birds were loser species (estimated to have smaller populations under all food production strategies than in the preagricultural baseline scenario), whereas in Salisbury Plain the majority were winners (smaller populations in the preagricultural baseline scenario). Loser species overwhelmingly achieved maximum regional population size under land sparing, whereas winner species achieved maximum regional population size under either land sharing or an intermediate strategy, highlighting the importance of defining which groups of species are the target of conservation. A novel 3-compartment strategy (combining high-yield farming, natural habitat, and low-yield farming) often performed better than either land sharing or land sparing. Our results support intermediate or 3-compartment land-sparing strategies to maximize bird populations across lowland agricultural landscapes. To deliver conservation outcomes, any shift toward land sparing must, however, ensure yield increases are sustainable in the long term, do not entail increased negative effects on surrounding areas, and are linked to allocation of land for nature.     

走生态农业可持续发展之路--固阳县生态农业建设试点报告

本文对包头市固阳县生态农业建设进行了探讨，通过试点就现状及发展方向总结出了一些经验和成果。     

九孔鲍肠道及其养殖水体中异养细菌抗药性研究

为了解鲍鱼养殖环境中异养细菌的抗药性,对自广东汕尾粤顺鲍鱼养殖场九孔鲍养殖环境及其肠道中的异养细菌进行了分离鉴定,并对所分离鉴定的菌株进行了四环素等16种抗生素的抗药性试验、结果表明,鲍鱼养殖水体的异养细菌主要由鞘氨醇单胞Sphingomonas paucimobilis、巴斯德氏菌属Pasteurella sp、莫拉氏菌属Moraxella sp、假单胞菌属Pseudomonas sp、弧菌属Vibrio minicus等9种组成;鲍鱼消化道异养细菌类群菌株则由鞘氨醇单胞菌属Sphingomonas sp、气单胞菌属Aeromonas sp、黄杆菌属Flavobdcterium sp等7种组成。抗药性试验揭示,大多数异养菌菌株对四环素、青霉素G、卡那霉素、丁胺卡那霉素和新生霉素均产生了抗药性,而对氟哌酸、红霉素、氯霉素以及环丙沙星等的抗药性则相对较弱。     

Soil fertility dynamics in runoff-capture agriculture, Canary Islands, Spain

In the extremely arid (∼150 mm yr⁻¹) eastern Canary Islands of Lanzarote, Fuerteventura and La Graciosa, agriculture has been sustained for decades by a traditional runoff-capture (RC) farming system known as “gavias”. Although the main goal of these systems is to increase water supply for crops, making unnecessary conventional irrigation, a secondary and equally important factor is that this system allows for sustainable agricultural production without addition of chemical or organic fertilizers. A field study was conducted to assess the impact of long-term agriculture (>50 yr) on soil fertility and to evaluate key factors affecting the nutrient sustainability of RC agricultural production. Soil fertility and nutrient dynamics were studied through chemical characterization of the arable layer (0-25 cm) of RC agricultural plots, adjacent natural soils (control) not affected by runoff and cultivation, and sediments contributed by a series of RC events. Results showed that RC soils have enhanced fertility status, particularly because they are less affected by salinity and sodicity (mean electrical conductivity = 1.8 dS m⁻¹ vs. 51.0 dS m⁻¹ in control soils; mean exchangeable sodium percentage = 11.1% vs. 30.6% in control soils), and have higher water and nutrient holding capacities (mean clay plus silt contents ≈87% vs. 69% in control soils). In general, sediments transported with the runoff and deposited in RC plots (average sediment yield ≈ 46 ton ha⁻¹ yr⁻¹), contain sufficient nutrients to prevent a progressive reduction of essential plant nutrients below natural levels in spite of nutrient uptake and removal by the harvested crop. Average additions of nitrogen, phosphorus and potassium with the runoff sediments were 33.6, 35.3 and 48.8 kg ha⁻¹ yr⁻¹, respectively. Results of this study show how a crop production system can be sustained in the long term by natural hydrological and biogeochemical catchment processes. This system maintains a nutrient balance that is not based on energy-intensive inputs of fertilizers, but is integrated in natural nutrient cycling processes, unlike other tropical farming agroecosystems.