Losses and recoveries of fish populations in acidified lakes of southern Finland in the last decade

Acid-induced fish damage in small lakes in southern Finland was studied in a fish status survey of eighty lakes from 1985–1987. Later, twenty of these lakes were selected for further monitoring. A sampling of these lakes from 1988–1989 showed that the decrease in some perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) populations still continued. The results from the same lakes in 1992 showed that successful reproduction had taken place with many of the perch populations that had been close to extinction in 1985. In contrast, no signs of recovery in the roach populations were detected. The explanation for the appearance of new cohorts of perch could have been the decrease in acid deposition but the exceptional hydrological conditions of winters in the early 1990s may also have affected them. The different responses of the perch and roach populations were interpreted as a consequence of the different sensitivity of these two species to acidification. Even a slight improvement in the water quality has resulted in the appearance of strong new year-classes of perch, but not of roach. Therefore, more improvement in water quality is needed until a sensitive species like roach can reproduce again.     

建设陕西生态省的循环经济发展研究

基于循环经济的理论,指出循环型经济是可持续发展的战略性理论范式,是建设陕西生态省目标的重要内涵。从自然与人文环境两方面解构建设陕西生态省中发展循环经济模式的制约因素,认为自然环境是制约其发展的基础性影响因素,人文环境是加剧性制约其发展的影响因素。提出了应选择正确的循环经济模式,并从理念、管理和服务的层面上构筑支持体系,推进循环型经济发展,为建设陕西生态省提供最佳的途径。     

Where Is Agricultural Economics and AgriBusiness Research Information Published and Indexed? A Comparison of Coverage in Web of Knowledge,CAB Abstracts,EconLit, and Google Scholar

ABSTRACT

Identifying the best source of information to satisfy the needs of local clientele has always been the challenge facing collection development and instruction librarians. In order to provide users with the best possible access tool and source for comprehensive information, it is important that librarians be aware of the most productive sources of information in a field. This paper identifies where the bulk of agricultural economics research is published and indexed. It also ascertains whether Google Scholar is as productive in covering this information as CAB Abstracts and EconLit. The cited reference counts for the top 50 cited sources in Web of Knowledge and Google Scholar are also compared. The scatter of the journal literature in this field, based on the Library of Congress Subject Headings, is also provided. The study identified a broad range of article scattering in areas where agricultural economics and agribusiness materials are published. On the cited reference count, Google Scholar was as productive as the Web of Knowledge. Google Scholar is a free source of very useful information for cited references and other subject searches in the area of agricultural economics and could be used to complement traditional databases.     

Soil respiration across scales: The importance of a model–data integration framework for data interpretation

Soil respiration represents the second largest CO₂ flux of the terrestrial biosphere and amounts 10 times higher than the current rate of fossil‐fuel combustion. Thus, even a small change in soil respiration could significantly intensify—or mitigate—current atmospheric increases of CO₂, with potential feedbacks to climate change. Consequently, to understand future dynamics of the earth system, it is mandatory to precisely understand the response of soil respiration to changing environmental factors. Among those changing factors, temperature is the one with clearest and most certain future trend. The relationship of soil respiration to environmental factors and particular temperature has been tackled at a variety of scales—from laboratory via field to global scale, with each of the approaches having its particular problems, where results from different scales are sometimes contradictory. Here, we give an overview of modeling approaches to soil respiration, discuss the dependencies of soil respiration on various environmental factors, and summarize the most important pitfalls to consider when analyzing soil respiration at the respective scale. We then introduce a model–data synthesis framework that should be able to reconcile and finally integrate apparently contradictory results from the various scales.     

Development policies and tropical deforestation in the southern Yucatán peninsula: centralized and decentralized approaches

It is well established that for multiple biophysical contexts there are legacies of past government policies in present land conditions. Despite this recognition, however, investigation of ongoing tropical deforestation dynamics often de‐emphasizes the past. The case of the southern Yucatán peninsula demonstrates the need for historical analysis in identifying key drivers of deforestation. The most important land‐use changes in the region over the past 100 years are connected to shifts in national development policies. These shifts represent tensions between centralized and decentralized approaches to land management—as represented by the policies of Presidents Díaz (1876–1910) and Cárdenas (1934–40)—that persisted throughout the 20th century. The legacies of these reoccurring development strategies include depleted hardwood reserves, large areas of permanently cleared forest, a complicated system of land allocation, and long‐standing tensions between economic, social welfare, and environmental conservation goals. These findings suggest that while centralized and decentralized approaches to development both focus on natural resource exploitation, the rates of deforestation tend to be faster, the patterns of forest clearing more pronounced, and land‐use decision making less democratic under systems of centralized control. These conclusions hold implications for land‐use decision making today. Copyright © 2003 John Wiley & Sons, Ltd.     

The development of Conservation Agriculture in Australia—Farmers as innovators

The Australian story of farmer innovation in Conservation Agriculture reveals a complex interplay of policy, economics, science, and farming. Farmer experimentation with Conservation Agriculture began in the 1960's and has continued to this day where around 80%-90% of Australia's 23.5 million hectares of winter crops are now grown using Conservation Agriculture principles. This remarkable achievement is the result of both sustained investment in agricultural research and development and farmer innovation. Australian economic settings and science policies have encouraged and facilitated farmer participation in the Conservation Agricultural innovation system. Australian farmers have embraced Conservation Agriculture because it has met their needs, maintaining productivity and profitability in the face of declining terms of trade, and sustainably intensifying production with enhanced environmental outcomes. Drawing on individual farmer case studies, the specific strengths of farmer innovation are identified and the enabling conditions necessary for farmer innovation to flourish are discussed.     

Contamination environnementale par les métaux et maladie de Parkinson

Parkinson's disease (PD) has been proposed to result from the interaction of aging and environment in susceptible individuals. The prevalence of PD in Quebec was 84 per 100 000 in 1985. The regional variation observed has been linked with several environmental factors. We intended to verify the existence of a relation between the development of PD with exposure to 3 metal pollutants: Fe, Mn, and Al. The choice of these metals rests on their potential presence in the environment caused by the industrial activity in the region studied, and on the fact that it theoretically favors the prevalence of the illness. Environmental exposure to these metals and the resulting risks were evaluated using red spruce as a bio-indicator. The metal concentrations in tree rings were determined by neutron activation analysis. These concentrations permitted a temporal estimation of contamination in each of the territories studied, from 1938 to 1987. The risk of environmental exposure was assumed to be proportional to the concentration of the metal. The calculated risks combined with the history of residence allowed a comparison between parkinsonians and controls. It appeared that environmental exposure to the metals was not significantly different between those two groups.     

Development paths for rural areas in the european community

Based on the findings from the research project: ‘Alternative Uses for Land and the New Farmworker—Segregation versus Integration’, this paper analyses broad lines of development and available options for rural areas in the European Community. Taking into account various limitations on agricultural, forestry, and nature conservation activities, the emergence of three agro-structural regional types is likely to occur:

• —rural areas with intensive agriculture;
• —rural areas constituting mainly agrarian-touristic peripheries, which exploit their endogenous development potentials on the basis of quasi-tourism
• —less-favoured areas with a tendency towards depopulation, which may serve as ecological balance areas.

     

Acid Deposition in Bandung, Indonesia

LAPAN has measured rain acidity in Bandung, the location is Cipedes since 1985, with average pH in 1985 was 6.25. The pH condition 1985–1999 as follow: The monthly average of pH in period 1985–1992 was >5.6: in the middle of 1996–1997 it had big variation and than decrease until now. The monthly average of pH in 1997 until now was <5.6. The pH has decreasing trend, the reason was increasing fuel combustion for transportation and household because the area around the observation was change from rural to be transportation and settlement area. The rain acidity comparison in Cipedes (rural site), Cicahuem (busy site), and Tanjungsari (remote site) hold in 1986–1987, the result was Tanjungsari the remote site had the lowest pH. It's suggested the reason was sulphur compound from Kamojang crater and air pollution from industrial area in south-east of Bandung were blown by the wind through this place. The influence of air pollution to acid rain was studied by measurement NO₃ ^? and SO₄ ^2? in 5 places around Bandung, the results were: North of Bandung had the lowest NO₃ ^? concentration because the traffics were low: but had the highest SO₄ ^2? concentration; it's caused by emission of sulphur compounds from Tangkuban Perahu Montain. South of Bandung had the highest NO₃ ^? concentration because the traffics were crowded and a lot of industries around it. In general Bandung had SO₄ ^2? concentration higher than NO₃ ^? concentration, it's suggested due to the influence of sulphur compound from Tangkuban Perahu Montain. The observation rain acidity in Ciater at Tangkuban Perahu Montain started in 1996, the result in period 1996–1998 as follow: The pH had decreasing trend, it's due to the traffic near this observation increase, so the air pollution around this area increase, it will influence the rain acidity. The maximum monthly average of ph was 6.78 and minimum was 4.63, the pH monthly average generally < 6. In El NINO year 1997, the monthly average of pH in April and December were > 6.5.     

Better land husbandry in Honduras: towards the new paradigm in conserving soil,water and productivity

Land shortages are forcing more smallholder farmers to cultivate tropical steeplands. Resulting accelerated soil erosion is being countered by the promotion of soil conservation (SC) technologies, such as cross‐slope barriers, which aim to reduce soil loss and preserve land productivity. However, farmer adoption rates tend to be low. This is often attributed to the farmers' conservatism or lack of education. Research in Honduras's steeplands demonstrates that farmers value SC, provided that it promotes agricultural production. Field research from 1995–98, involving farmed test plots on slopes greater than 35 per cent (19 degrees), demonstrates that at least one typical SC technology—live barriers of Vetiveria zizanioides (vetiver grass)—has little or no impact on maize yield. This means that farmers see little benefit from their investment in the SC method. They find that erratic rainfall, pests and diseases and a lack of economic resources are far greater threats to their livelihoods than soil erosion. Consequently, SC has a low priority. Keeping soil in place avoids major off‐farm disbenefits. However, the SC technique tested here made no discernible difference to slope foot sediment yields during the life of this study. In sum, a new approach is needed. Promoting ‘Better Land Husbandry’ strategies, which seek to combine farmers' concerns about productivity with conservationists' concerns about reducing soil erosion—often via cover‐management—seem to be the best way forward. Copyright © 2002 John Wiley & Sons, Ltd.     

基于能值分析的马尾松低效林林下种草养鸡耦合模式评价

马尾松低效林是红壤侵蚀区典型植被类型。林下种草养鸡则是林下种草与林下养鸡的耦合新模式,既能解决马尾松林下水土流失问题,又能提高经济效益,实现生态种养循环,驱动水土流失治理。为科学评价马尾松低效林林下种草养鸡模式的生态经济效益,本文应用能值分析法,测评福建省长汀县三洲镇垌坝村传统林下养鸡(对照)、林下种草养鸡两种模式的能值自给率、能值投资率、净能值产出率、环境负载率、可持续发展指数和能值反馈率。结果表明,传统林下养鸡模式的能值自给率、能值投资率、净能值产出率、环境负载率、可持续发展指数和能值反馈率分别为0.860、0.166、2.125、3.380、0.629和0.026,林下种草养鸡模式上述指标值分别为0.400、1.510、0.870、1.370、0.635和0.290。林下种草养鸡模式的能值投资率、可持续发展指数比对照提高1.344和0.006个单位,显示更强的经济活力;能值自给率、环境负载率比对照下降0.460、2.010个单位,显示更低的环境负载。林下种草养鸡模式的净能值产出率低于对照1.255个单位,而能值反馈率高出对照0.264个单位。总体而言,林下种草养鸡耦合模式经济活力更强,环境负载更低,符合脆弱区林下经济发展趋势。侵蚀区土壤结构性差,限制了从系统外导入的化肥在循环系统中功能的发挥,导致系统净能值产出率、能值反馈率较低,这为该模式的优化指明了方向。     

Radioactivity in otter scats in Britain following the chernobyl reactor accident

Radioactivity was determined in samples of otter (Lutra lutra) faeces (scats) collected from various regions of Great Britain in 1986 and 1987, following the Chernobyl nuclear reactor accident, and compared with a sample of scats collected in 1985 from central Wales. Samples of scats were also collected from the seashore adjacent to the Dounreay nuclear power station, northern Scotland, and compared with a control site, 40 to 60 km distant. Samples collected in 1986 from central Wales, Galloway and northern Scotland all contained significantly higher amounts of radioactivity than the 1985 sample from central Wales, with Galloway (mean 13 000 Bq kg^?1 dry weight) having significantly more radioactivity than other regions. A sample collected in central Wales in January 1987 had returned to the 1985 level of radioactivity, but a sample from Galloway in January 1987 remained high; this difference in response may be related to the acidic nature of Galloway rivers. No significant differences were found between samples collected from near Dounreay and the control site, though fallout from Chernobyl may have masked the effects of local discharges of radioactivity. The significance of the results to otter populations is discussed.     

Accumulation of fluoride by lichens in the vicinity of Etna volcano

Volcanoes are known to discharge gaseous fluorides to the atmosphere, but measurement of these is difficult, and the dispersion characteristics have not previously been studied in detail. Samples of lichens were collected from the slopes of Etna Volcano in 1985 and 1987, in order to monitor these gases. Subsequent analysis for fluoride showed levels ranging from 2 to 141 μg g^?1, compared with control values of < 2 μg g^?1 The fluoride accumulation patterns clearly show that there is a major input from the volcano's plume, with the highest levels on the downwind side; these are attributed to the prevailing winds and to the local topographic influences. The fluoride levels in the lichens are compared with those resulting from industrial pollution.     

Nutrient cycling in adirondack conifer plantations: Is acidic deposition an influencing factor?

An evaluation of the influences of acidic deposition and forest development on nutrient cycling and conifer productivity at the Charles Lathrop Pack Demonstration Forest, near Warrensburg, New York, was made. This site has a known land use history and is the source of 60 years of soils and silviculture research. Soils were characterized by a nutritional imbalance and support conifer plantations that exhibited declining growth. Historical and contemporary evaluations of nutrient cycling in 47- to 57-yr-old red pine plantations provided no evidence that acidic deposition has had an adverse influence on nutrient cycling. Ap horizon pH decreased from 1949 to 1962 but remained the same from 1962 to 1985. In the B horizon, pH was stable from 1962 to 1985. Exchangeable potassium levels in the Ap horizon fluctuated but did not significantly change from 1949 to 1985: in the B horizon it increased during the period 1962 to 1985. Levels of potassium in the foliage of red pine in unfertilized plots increased from 1949 to 1985, paralleling increases in B horizon potassium levels during that period. There was no increase in cation leaching from the mineral soil that could be attributed to anthropogenic inputs of NO₃ ^? and SO₄ ^2? due to retention of N and S in this ecosystem. Soil solution K⁺ chemistry was similar between the 1960's and the 1980's. Mineral soil pH and base cation status were differentially influenced by tree species since 1930. In general, temporal and contemporary trends of mineral soil pH and base cation status of the soil and foliage indicated that forest development has been the dominant factor influencing nutrient cycling in these conifer plantations. While results of these studies do not conclusively preclude involvement of acidic deposition effects as part of a forest decline syndrome, they indicate the importance of recognizing and measuring natural variability in forest soil processes due to differential species effects and forest aggradation. Because these effects may have a greater impact on stand productivity than the effects of acidic deposition, they can confound interpretation of acidic deposition research if not clearly understood.     

Comparison of statistical models for predicting cost effective nitrogen rate at rice–wheat cropping systems

Due to increased economic and environmental concerns, developing statistical models of crop yield has become one of the most important steps in determination of the cost effective rates (CERs) of nitrogen (N) fertilization. Although quadratic models are commonly used to describe wheat and paddy rice yield response to fertilizer rates in the Taihu Lake region of China, few studies have investigated why this model is selected over others. This study evaluated quadratic, exponential and square root models describing the wheat (Triticum aestivum L.) and rice (Oryza sativa L.) yield response to N fertilizer when determining the CERs, while also considering the environmental costs of N losses. All models fit the data almost equally well when evaluated using the variability and standard error statistics. However, there were marked discrepancies among models when calculating the CER of fertilization and the economic returns form Z-test. The quadratic model had a greater CER value (194?kg N ha^–1 for rice and 185?kg N ha^–1 for wheat) averaged over all sites than the exponential and square root models. The residuals obtained from the quadratic models were closer to a normal distribution than those of the other two models, indicating a less systematic bias. The mean economic uncertainties resulting from the quadratic model were more dependable than the other two models evaluated. These results show that the quadratic model best describes the rice and wheat yield responses and tends to indicate the optimal rates of fertilization while considering the environmental and economic effects of over fertilization for rice and wheat in the Taihu Lake region.     

Enhancing the productivity of high‐magnesium soil and water resources in Central Asia through the application of phosphogypsum

Recent evidences from some irrigated areas worldwide, such as Central Asia, suggest that water used for irrigation contains magnesium (Mg²⁺) at levels higher than calcium (Ca²⁺). Excess levels of Mg²⁺ in irrigation water and/or in soil, in combination with sodium (Na⁺) or alone, result in soil degradation because of Mg²⁺ effects on the soil's physical properties. More than 30 per cent of irrigated lands in Southern Kazakhstan having excess levels of Mg²⁺ are characterized by low infiltration rates and hydraulic conductivities. The consequence has been a gradual decline in the yield of cotton (Gossypium hirsutum L.), which is commonly grown in the region. These soils require adequate quantities of Ca²⁺ to mitigate the effects of excess Mg²⁺. As a source of Ca²⁺, phosphogypsum—a byproduct of the phosphorous fertilizer industry—is available in some parts of Central Asia. In participation with the local farming community, we carried out a 4‐year field experiment in Southern Kazakhstan to evaluate the effects of soil application of phosphogypsum—0, 4·5, and 8·0 metric ton per hectare (t ha⁻¹)—on chemical changes in a soil containing excess levels of Mg²⁺, and on cotton yield and economics. The canal water had Mg²⁺ to Ca²⁺ ratio ranging from 1·30 to 1·66 during irrigation period. The application of phosphogypsum increased Ca²⁺ concentration in the soil and triggered the replacement of excess Mg²⁺ from the cation exchange complex. After harvesting the first crop, there was 18 per cent decrease in exchangeable magnesium percentage (EMP) of the surface 0·2 m soil over the pre‐experiment EMP level in the plots where phosphogypsum was applied at 4·5 t ha⁻¹, and a 31 per cent decrease in EMP in plots treated with phosphogypsum at 8 t ha⁻¹. Additional beneficial effect of the amendment was an increase in the soil phosphorus content. The 4‐year average cotton yields were 2·6 t ha⁻¹ with 8 t ha⁻¹ phosphogypsum, 2·4 t ha⁻¹ with 4·5 t ha⁻¹ phosphogypsum, and 1·4 t ha⁻¹ with the control. Since the amendment was applied once at the beginning, exchangeable Mg²⁺ levels tended to increase 4 years after its application, particularly in the treatment with 4·5 t ha⁻¹ phosphogypsum. Thus, there would be a need for phosphogypsum application to such soils after every 4–5 years to optimize the ionic balance and sustain higher levels of cotton production. The economic benefits from the phosphogypsum treatments were almost twice those from the control. Copyright © 2007 John Wiley & Sons, Ltd.     

Yield Stability Parameters of Barley under Finnish Conditions

Abstract

The objective of this study was to evaluate whether it is possible to obtain reliable estimates of yield stability of barley on the basis of single year trials. The stability was analysed by using some of the most common stability parameters. The other objective was to study the influence of variation between locations and years on the yield stability of barley under growing conditions in Finland. Barley breeder's trials of the Agricultural Research Centre of Finland from the years 1987-89 were used as material in this study. In each of these years six trials from different parts of Finland and six genotypes were analysed. Four parameters were used in analysis of yield stability: b _i (Finlay & Wilkinson, 1963), s ² d _i (Eberhart & Russell, 1966), r ² _i (Pinthus, 1973) and environmental variance s ² _i. Each parameter was calculated from single- and multi-year results. The multi-year results were considered as reliable data with which to estimate yield stability. The reliability of the stability parameters was tested by Spearman's rank correlation coefficient between single- and multi-year stability values of each parameter. Although the variation between years was highly significant, there was no interaction between genotypes and years. In two experimental years genotype × location interaction was highly significant, and on the basis of this study, the genotype × location interaction seems to be a more important factor than genotype × year interaction in barley breeding for Finnish conditions. However, a series of three years may not be sufficient for indicating genotypes × years interactions. In this study two stability parameters, b _i and s ² _i, gave a reliable estimate of yield stability on the basis of single-year trials.     

Trends in Emissions of Acidifying Species in Asia, 1985–1997

Acid deposition is a serious problem throughout much of Asia. Emissions of sulfur dioxide (SO₂) and nitrogen oxides (NO_x) have been increasing steadily, as nations strive to increase their levels of economic development. Coal and fuel oil have been the main choices for powering industrial development; and, until recently, only a few countries had taken steps to avert the atmospheric emissions that accompany fuel combustion. This paper discusses trends in emissions of SO₂ and NO_x that have occurred in Asian countries in the period 1985–1997, using results from the RAINS-Asia computer model and energy-use trends from the IEA Energy Statistics and Balances database. Emissions of SO₂ in Asia grew from 26.6 Tg in 1985 to 33.7 Tg in 1990 and 39.2 Tg in 1997. Though SO₂ emissions used to grow as fast as fossil-fuel use, recent limitations on the sulfur content of coal and oil have slowed the growth. The annual-average emissions growth between 1990 and 1997 was only 2.2%, considerably less than the economic growth rate. Emissions of NO_x, on the other hand, continue to grow rapidly, from 14.1 Tg in 1985 to 18.7 Tg in 1990 and 28.5 Tg in 1997 (6.2% per year between 1990 and 1997), with no signs of abating. Thus, though SO₂ remains the major contributor to acidifying emissions in Asia, the role of NO_x will become more and more important in the future.     

Phytoextraction of heavy metal contaminated soils with Thlaspi goesingense and Amaranthus hybridus: Rhizosphere manipulation using EDTA and ammonium sulfate

Selection of appropriate plant species and rhizosphere manipulation to enhance metal uptake are considered key factors in the development of phytoextraction technologies. A pot trial was conducted with two contaminated soils to investigate the effect of EDTA and ammonium sulfate on the accumulation of heavy metals into shoots of the low‐biomass hyperaccumlator Thlaspi goesingense Hálácsy (Brassicaceae) and the high‐biomass non‐hyperaccumulating plant Amaranthus hybridus (Amaranthaceae). Upon application of 1 g EDTA (kg soil)^—1 metal extractability with 1 M NH₄NO₃ increased substantially, whereas the application of (NH₄)₂SO₄ was less effective. The EDTA treatment increased the heavy metal concentrations in both plant species, however, the difference to the control was larger for A. hybridus. EDTA enhanced shoot concentrations in A. hybridus grown on soil Arnoldstein from 32.7 mg kg^—1 to 1140 mg kg^—1 for Pb and from 3.80 mg kg^—1 to 10.3 mg kg^—1 for Cd. Cd concentrations in shoots of T. goesingense were also increased by EDTA application, however, a slight decrease was observed for Pb. T. goesingense accumulated 2840 mg Pb kg^—1 without any treatment. This is the first report of Pb hyperacumulation by T. goesingense. A decrease of shoot Pb concentration was observed in T. goesingense upon treatment with ammonium sulfate. Although metal concentrations in the shoots were rather large and significantly increased upon application of EDTA, plant growth and heavy metal removal were still too small to obtain reasonable extraction rates in soils heavily polluted by metals. It should be also noted that metal lability largely increased in EDTA‐treated soils and this lability persisted for several weeks after the application of the chelating agent, which is likely to be associated with the risk of groundwater contamination.     

Scholarly Journals in Agricultural Economics Libraries/Reference Rooms: A Survey

ABSTRACT

The purpose of this study was to develop a core list of journals for the field of agricultural economics. For this study, the holdings of members of the Agricultural Economics Reference Organization who represent agricultural economics libraries in the U.S. and Canada were surveyed. The resulting list of titles is compared to four similar lists, three in agricultural economics and the fourth in economics. Using any one list of journals is inadequate for collection development in agricultural economics. This survey list, along with other similar lists, can be used for decision making in selection and management of journal titles in the field.