Phenology of the landscape: the role of organic agriculture

It is becoming increasingly clear that the agricultural sector will have to find an additional raison d'être beyond the production of food alone. One of the new services that agriculture can provide is contributing to the environmental quality of rural areas. In this respect a great burden of expectation is placed on organic farming. Here we examine how organic farming can contribute to the quality of specific regional landscapes. We do this with the help of a new instrument, the phenology of the landscape, which measures the contributions made by organic and conventional farming to the succession of colours and shapes during the seasons. This seasonal development plays an important role in people's appreciation of the landscape. The study shows that seasonal development is more recognizable on organic farms than on conventional farms, and that seasonal development is a scientifically‐usable criterion for evaluating the environmental quality of farms.     

Snails as indicators of pesticide drift, deposit, transfer and effects in the vineyard

This paper presents a field-study of real pesticide application conditions in a vineyard. The objective was to measure the exposure, the transfer and the effects of pesticides on a non-target soil invertebrate, the land snail Helix aspersa. There was no drift of the herbicides (glyphosate and glufosinate) whereas the fungicides (cymoxanil, folpet, tebuconazole and pyraclostrobin) were detected up to 20 m from the treated area. For folpet and particularly tebuconazole, spray deposits on soil (corresponding to losses for the intended target i.e. the vine leaves) were high (41.1% and 88.8% loss of applied dose, respectively). For herbicides, the target was the soil and losses (percentage of compounds which did not reach the soil) were of 22% for glufosinate and 52% for glyphosate. In the study plot, glyphosate was transferred to and accumulated in snail tissues (4 mg kg⁻¹ dry weight, dw), as was its metabolite AMPA (8 mg kg⁻¹ dw) which could be in relation with the reduced growth observed in snails. No effects on snail survival or growth were found after exposure to the other organic compounds or to copper and sulphur-fungicides, although transfer of tebuconazole, pyraclostrobin and copper occurred. This study brings original field data on the fate of pesticides in a vineyard agro-ecosystem under real conditions of application and shows that transfer and effects of pesticides to a non-target organism occurred.     

Fire and Pesticides, A Review and Analysis of Recent Work

There are a number of circumstances that involve the burning of toxic materials, including pesticides, herbicides, insecticides, and poisonous plant or plant products. Toxicity issues of smoke from the Anacardiaceae family and the Oleander are discussed and contrasted with that from pesticides, herbicides, insecticides, and other organic materials. Work in two major European programs is reviewed. Survival fractions in smoke of 1 to 10% can be expected for some toxic compounds in fires. Survival fractions are dependent not only upon the specific toxic compound but on the fire scenario and other fuels present. Of importance, flaming combustion mat not ensure destruction of such compounds in real fire incidents.     

River eutrophication: irrigated vs. non-irrigated agriculture through different spatial scales

The main objective of this study was to determine how spatial scale may affect the results when relating land use to nutrient enrichment of rivers and, secondly, to investigate which agricultural practices are more responsible for river eutrophication in the study area. Agriculture was split into three subclasses (irrigated, non-irrigated and low-impact agriculture) which were correlated to stream nutrient concentration on four spatial scales: large scale (drainage area of total subcatchment and 100 m wide subcatchment corridors) and local scale (5 and 1 km radius buffers). Nitrate, ammonium and orthophosphate concentrations and land use composition (agriculture, urban and forest) were measured at 130 river reaches in south-central Spain during the 2001-2009 period. Results suggested that different spatial scales may lead to different conclusions. Spatial autocorrelation and the inadequate representation of some land uses produced unreal results on large scales. Conversely, local scales did not show data autocorrelation and agriculture subclasses were well represented. The local scale of 1 km buffer was the most appropriate to detect river eutrophication in central Spanish rivers, with irrigated cropland as the main cause of river pollution by nitrate. As regards river management, a threshold of 50% irrigated cropland within a 1 km radius buffer has been obtained using breakpoint regression analysis. This means that no more than 50% of irrigation croplands should be allowed near river banks in order to avoid river eutrophication. Finally, a methodological approach is proposed to choose the appropriate spatial scale when studying river eutrophication caused by diffuse pollution like agriculture.     

Selected organic pesticides, behavior and removal from domestic wastewater by chemical and physical processes

A study was conducted to evaluate the effectiveness of chemical and physical wastewater treatment processes in removing selected organic pesticides from domestic wastewater. A 3785 m³ day⁻¹ (1 MGD) nominal capacity pilot plant consisting of biological, chemical and physical units was used for the study. Biologically treated domestic wastewater was subjected to chemical coagulation, multimedia filtration, and activated carbon adsorption. Eight sequences of treatment processes were studied. Influent and effluent samples were analyzed for selected chlorinated hydrocarbon pesticides and chlorophenoxy herbicides using EC-GC. Confirmatory tests such as TLC, extraction of p-value and CPU-MS-GC were applied on selected samples. Results of the study provided qualitative and quantitative evaluation of the performance of the treatment processes studied. Qualitatively characteristic profiles consisting of a limited number of refractory organic residues were detected as peaks on EC chromatograms of extracts from each treatment unit. Thirteen compounds were confirmed in the biologically treated wastewater. These included DDT and its metabolites, aldrin, dieldrin, and 2,4-D alkyl esters and salts. Concentration levels of these compounds in wastewaters were at the ng l⁻¹ (part per trillion) level. Chemical coagulation with alum-lime or lime-ferric chloride was found to effect slight reduction of the organic residues detected on EC chromatograms. Quantitatively only DDT compounds were more completely removed by chemical treatment. Multimedia filters had no discernible effect in removing organic residues from biologically and chemically treated wastewater. Activated carbon columns were found to be the most effective means for removing the refractory organic residues detected. However, breakthrough of some organic residues was noted after usage of the carbon for over 1 year. The overall results of the study showed that application of several sequences of treatment processes on domestic wastewater can produce a high quality effluent which is virtually free from EC detectable organic residues.     

Stability and sustainability of modern chemical farming: a viewpoint

It is demonstrated that modern farming techniques, based on a short‐run, profit maximizing economic approach, using an array of artificial fertilizers, pesticides, herbicides and fungicides, is dynamically unstable and unsustainable. The result is the erosion of top soil which can't be regenerated, substituted for or recycled once lost, since its development over geological time required hundreds of thousands of years.     

城市周边土地利用模式初探

以沈阳市沈北新区为例,提出了城市周边地区的土地利用模式———新型绿环模式,指出应建立永久农地,统筹协调好城市周边农业与城市空间的有机契合,为城市创造一个健康的生态保护圈,并最终实现城乡良性发展。     

Occurrence and concentrations of pharmaceutical compounds in groundwater used for public drinking-water supply in California

Pharmaceutical compounds were detected at low concentrations in 2.3% of 1231 samples of groundwater (median depth to top of screened interval in wells = 61 m) used for public drinking-water supply in California. Samples were collected statewide for the California State Water Resources Control Board's Groundwater Ambient Monitoring and Assessment (GAMA) Program. Of 14 pharmaceutical compounds analyzed, 7 were detected at concentrations greater than or equal to method detection limits: acetaminophen (used as an analgesic, detection frequency 0.32%, maximum concentration 1.89 μg/L), caffeine (stimulant, 0.24%, 0.29 μg/L), carbamazepine (mood stabilizer, 1.5%, 0.42 μg/L), codeine (opioid analgesic, 0.16%, 0.214 μg/L), p-xanthine (caffeine metabolite, 0.08%, 0.12 μg/L), sulfamethoxazole (antibiotic, 0.41%, 0.17 μg/L), and trimethoprim (antibiotic, 0.08%, 0.018 μg/L). Detection frequencies of pesticides (33%), volatile organic compounds not including trihalomethanes (23%), and trihalomethanes (28%) in the same 1231 samples were significantly higher. Median detected concentration of pharmaceutical compounds was similar to those of volatile organic compounds, and higher than that of pesticides.Pharmaceutical compounds were detected in 3.3% of the 855 samples containing modern groundwater (tritium activity > 0.2 TU). Pharmaceutical detections were significantly positively correlated with detections of urban-use herbicides and insecticides, detections of volatile organic compounds, and percentage of urban land use around wells. Groundwater from the Los Angeles metropolitan area had higher detection frequencies of pharmaceuticals and other anthropogenic compounds than groundwater from other areas of the state with similar proportions of urban land use. The higher detection frequencies may reflect that groundwater flow systems in Los Angeles area basins are dominated by engineered recharge and intensive groundwater pumping.     

Evaluation of the population dynamics of annual weeds to test integrated weed management at a farming system level

In the Netherlands, several research projects are being carried out to develop sustainable farming systems that are characterized by markedly reduced inputs of pesticides and fertilizers. In these long-term projects, weed management appeared to be a serious constraint on the introduction of sustainable agriculture. A method to monitor the population dynamics of annual weeds in crop rotations and to compare the results for farming systems is presented. Preliminary results show that, after 3–5 years, weed densities tended to be higher in the integrated systems than in the conventional reference systems. This trend in the population dynamics of weeds is discussed with respect to differences in inputs in weed management (active ingredients), possible effects on crop yields and improved strategies to prevent increases in weed abundance.     

四川旺苍县化龙乡土地质量及生态农业建设

为研究四川省旺苍县化龙乡土地质量,通过对449件土壤样品测试分析。结果显示:研究区土壤养分TFe₂O₃丰富(一等),Zn、Cu、MgO、K较为丰富(二等),P、CaO、Se较为缺乏,Ge、Mo缺乏,局部具富Ge土壤。综合养分以三等土壤为主,面积为25.96 km²,占81.13%；二等土壤面积为3.69 km²,占11.52%,四等土壤面积2.35 km²,占7.37%。土壤质量综合评价一等优质土壤面积为0.02 km²；二等良好土壤面积为0.44 km²；三等中等土壤面积为17.84 km²；四等差等土壤面积为13.64 km²；五等劣等土壤面积为0.08 km²。龙乡优质(一级)土地可适于发展有机、绿色食品。良好(二级)土地可适于发展无公害食品。中等(三级)土地种植较为安全。较差(四级)土地可适当发展林业。劣等(五级)土地可改造成建筑用地。为生态农业建设、振兴乡村经济提供技术支撑。     

Impact of urbanization and agriculture on the occurrence of bacterial pathogens and stx genes in coastal waterbodies of central California

Fecal pollution enters coastal waters through multiple routes, many of which originate from land-based activities. Runoff from pervious and impervious land surfaces transports pollutants from land to sea and can cause impairment of coastal ocean waters. To understand how land use practices and water characteristics influence concentrations of fecal indicator bacteria (FIB) and pathogens in natural waters, fourteen coastal streams, rivers, and tidal lagoons, surrounded by variable land use and animal densities, were sampled every six weeks over two years (2008 & 2009). Fecal indicator bacteria (FIB; Escherichia coli and Enterococci) and Salmonella concentrations, the occurrence of Bacteroidales human, ruminant, and pig-specific fecal markers, E. coli O157:H7, and Shiga toxin (stx) genes present in E. coli, were measured. In addition, environmental and climatic variables (e.g., temperature, salinity, rainfall), as well as human and livestock population densities and land cover were quantified. Concentrations of FIB and Salmonella were correlated with each other, but the occurrence of host-specific Bacteroidales markers did not correlate with FIB or pathogens. FIB and Salmonella concentrations, as well as the occurrence of E. coli harboring stx genes, were positively associated with the fraction of the surrounding subwatershed that was urban, while the occurrence of E. coli O157:H7 was positively associated with the agricultural fraction. FIB and Salmonella concentrations were negatively correlated to salinity and temperature, and positively correlated to rainfall. Areal loading rates of FIB, Salmonella and E. coli O157:H7 to the coastal ocean were calculated for stream and river sites and varied with land cover, salinity, temperature, and rainfall. Results suggest that FIB and pathogen concentrations are influenced, in part, by their flux from the land, which is exacerbated during rainfall; once waterborne, bacterial persistence is affected by water temperature and salinity.     

Reactions in the aqueous environment of low molecular weight organic molecules

The origin of small organic molecules in surface waters of the United States, for the most part, stems from industrial, urban and agricultural sources. Agricultural materials were examined, particularly the chlorinated pesticides and herbicides, to determine concentration ranges within which the characteristic interactions of these solutes could be defined. It was found that chlorinated hydrocarbon concentrations of bottom sediments at selected locations range from 5 ng/kg (nanograms per kilogram) to 3.5 μg/kg (micrograms per kilogram), and in water from 5 ng/l to 0.06 μg/l. Herbicide concentrations in water ranged from 5 ng/l to 1.5 μg/l for the same samples. Total organic carbon concentrations at these locations ranged from less than 0.1 mg/l to 42 mg/l (milligrams per litre).     

Climate impacts on European agriculture and water management in the context of adaptation and mitigation—The importance of an integrated approach

We review and qualitatively assess the importance of interactions and feedbacks in assessing climate change impacts on water and agriculture in Europe. We focus particularly on the impact of future hydrological changes on agricultural greenhouse gas (GHG) mitigation and adaptation options. Future projected trends in European agriculture include northward movement of crop suitability zones and increasing crop productivity in Northern Europe, but declining productivity and suitability in Southern Europe. This may be accompanied by a widening of water resource differences between the North and South, and an increase in extreme rainfall events and droughts. Changes in future hydrology and water management practices will influence agricultural adaptation measures and alter the effectiveness of agricultural mitigation strategies. These interactions are often highly complex and influenced by a number of factors which are themselves influenced by climate. Mainly positive impacts may be anticipated for Northern Europe, where agricultural adaptation may be shaped by reduced vulnerability of production, increased water supply and reduced water demand. However, increasing flood hazards may present challenges for agriculture, and summer irrigation shortages may result from earlier spring runoff peaks in some regions. Conversely, the need for effective adaptation will be greatest in Southern Europe as a result of increased production vulnerability, reduced water supply and increased demands for irrigation. Increasing flood and drought risks will further contribute to the need for robust management practices.The impacts of future hydrological changes on agricultural mitigation in Europe will depend on the balance between changes in productivity and rates of decomposition and GHG emission, both of which depend on climatic, land and management factors. Small increases in European soil organic carbon (SOC) stocks per unit land area are anticipated considering changes in climate, management and land use, although an overall reduction in the total stock may result from a smaller agricultural land area. Adaptation in the water sector could potentially provide additional benefits to agricultural production such as reduced flood risk and increased drought resilience.The two main sources of uncertainty in climate impacts on European agriculture and water management are projections of future climate and their resulting impacts on water and agriculture. Since changes in climate, agricultural ecosystems and hydrometeorology depend on complex interactions between the atmosphere, biosphere and hydrological cycle there is a need for more integrated approaches to climate impacts assessments. Methods for assessing options which “moderate” the impact of agriculture in the wider sense will also need to consider cross-sectoral impacts and socio-economic aspects.     

Surfactant-coated aluminum hydroxide for the rapid removal and biodegradation of hydrophobic organic pollutants in water

The removal of hydrophobic organic pollutants in water to surfactant-coated aluminum hydroxide [surfactant-Al(OH)₃] was investigated. Anionic surfactants such as sodium dodecyl sulfate (SDS), sodium bis(2-ethylhexyl)sulfosuccinate (AOT), and sodium oleate were sorbed on positively charged aluminum hydroxide at pH 7 and formed hydrophobic aggregates that can incorporate hydrophobic organic pollutants in water. Because of the hydrophobic interaction and decrease in the positive charge, surfactant-Al(OH)₃ was coagulated into precipitates that can readily be separated from water. Hydrophobic organic pollutants such as alkylphenols, polycyclic aromatic hydrocarbons, estrogens, chlorinated antifungals, and pesticides were well collected to the precipitates and thus efficiently removed from water. The collection of hydrophobic organic pollutants was correlated to their aqueous-octanol distribution coefficient. The decomposition of hydrophobic organic pollutants was examined using a bacterial agent (Bacillus subtilis). Hydrophobic organic compounds collected to AOT-Al(OH)₃ or sodium oleate-Al(OH)₃ were insufficiently decomposed. On the other hand, nonylphenol, octylphenol, and pendimethalin collected to SDS-Al(OH)₃ were decomposed within 1 week. The decomposition was accelerated by the collection to SDS-Al(OH)₃.     

Runoff of pyrethroid insecticides from concrete surfaces following simulated and natural rainfalls

Intensive residential use of insecticides has resulted in their ubiquitous presence as contaminants in urban surface streams. For pest eradication, urban hard surfaces such as concrete are often directly treated with pesticides, and wind/water can also carry pesticides onto hard surfaces from surrounding areas. This study expanded on previous bench-scale studies by considering pesticide runoff caused by irrigation under dry weather conditions and rain during the wet season, and evaluated the effects of pesticide residence time on concrete, single versus recurring precipitations, precipitation intensity, and concrete surface conditions, on pesticide transferability to runoff water. Runoff from concrete 1 d after pesticide treatment contained high levels of bifenthrin (82 μg/L) and permethrin (5143 μg/L for cis and 5518 μg/L for trans), indicating the importance of preventing water contact on concrete after pesticide treatments. Although the runoff transferability quickly decreased as the pesticide residence time on concrete increased, detectable residues were still found in runoff water after 3 months (89 d) exposure to hot and dry summer conditions. ANOVA analysis showed that precipitation intensities and concrete surface conditions (i.e., acid wash, silicone seal, stamping, and addition of microsilica) did not significantly affect the pesticide transferability to runoff. For concrete slabs subjected to natural rainfalls during the winter wet season, pesticide levels in the runoff decreased as the time interval between pesticide application and the rain event increased. However, bifenthrin and permethrin were still detected at 0.15-0.17 and 0.75-1.15 μg/L in the rain runoff after 7 months (221 d) from the initial treatment. In addition, pesticide concentrations showed no decrease between the two rainfall events, suggesting that concrete surfaces contaminated by pesticides may act as a reservoir for pesticide residues, leading to sustained urban runoff contamination.     

Impact of urbanization on the quality of water in a natural reservoir: a case study with the Deepor Beel in Guwahati city,India

The Deepor Beel is a natural, freshwater wetland in the south-west corner of Guwahati, India. The Beel harbours a large number of migratory aquatic birds, especially in winter, and is a Ramsar site since 2002. The wetland provides livelihood to the people of the surrounding villages through collection and sale of fish, nymphaea nuts and flower, ornamental fish, orchids, medicinal plants, etc. The water quality of the Beel is threatened by excessive fishing, hunting of water birds, pollution from pesticides and fertilizers and infestation by water hyacinth. The present work reports on the water quality of the wetland by continuous monitoring from February to July, covering the dry, temperate period and the wet, hot and humid period. Sampling was carried out at 10 sites for physical and aggregate properties, metallic and nonmetallic constituents, organic contaminants and microbiological parameters.     

A review of the role of urban agriculture in the sustainable city discourse

The debate on the role of urban agriculture in the sustainable city discourse remains unresolved in the conventional literature. Therefore, the purpose of this study was to review relevant literature to clarify the role of urban agriculture in sustainable cities. The search for literature was guided by themes such as: a) urban agricultural practices, b) indicators for the measurement of sustainable cities, c) economic, social and environmental benefits of urban agriculture, and d) negative effects of urban agriculture on the city. The results from a synthesis of the literature indicate that urban agriculture supports the economic, social and environmental sustainability of cities. However, if the discussion gives credence to only the economic dimension of sustainability, then urban agriculture loses the debate. This is because the economic benefits of prime city land that is used used for non-agricultural purposes (such as commercial or industrial) is profound. However, the social and environmental functions of responsible urban agriculture, particularly in reducing the rift between urbanisation and nature, may be difficult to quantify. These social and environmental functions underscore the importance of urban agriculture in the city landscape. The paper concludes by arguing that focussing on only economic sustainability in the urban agriculture-sustainable city discourse is a travesty of the idea of sustainable development. The paper presents practical steps that can be taken to preserve agriculture in cities towards their sustainability.     

Fluctuations in nitrate concentrations utilized as an assessment of agricultural contamination to an aquifer of a semiarid climatic region

Aquifer water has become contaminated in regions that have been developed for agriculture. Nitrate contamination has been shown to be permeable to the aquifer and harmful to human health. An assessment of agricultural practices and their roles in contamination of aquifers has been undertaken with difficulty in the past. Nitrate concentrations have been utilized in this study to demonstrate their applicability to examining agriculture practices which contaminate aquifer water. Areas treated with nitrogenous fertilizers and subsequently irrigated were found to contain aquifer fluctuations in nitrate content directly in proportion to irrigation seasons. Agricultural industries with high animal densities per land area, and high water consumption for maintenance, were found to have high, but non-fluctuating, nitrate concentrations. Areas with high animal density per land area with low water usage for maintenance; areas with low animal density per land area; and agricultural practices for which little or no nitrogenous fertilizers were used demonstrated low aquifer nitrate concentrations regardless of water usage.     

Indoor persistent organic pollutants in agricultural areas from Argentina

Persistent Organic Pollutants (POPs) are anthropogenic chemicals extensively used in the past for industrial and agricultural purposes, characterized by their lipophilicity, ubiquity, volatility and environmental persistence. By other hand, chlorpyrifos is the most widely used current pesticide (CUPs) being the main insecticide used for crops in Argentina. The aim of this work was to assess levels of POPs and CUPs in different fractions of airborne particles collected indoor in agricultural areas from Argentina. Particles higher than 2.5 µm were trapped in polyurethane foams (PUF) while particles smaller than 1 µm and volatile compounds were adsorbed on activated charcoal. Compounds were analyzed by gas chromatograph with electron capture detector (GC-ECD). Endosulfans, chlordanes, PCBs, and HCHs were detected in all PUF samples, while endosulfans, chlorpyrifos, PCBs, and HCHs were the most abundant in smaller particles. Majority of pesticides showed higher concentrations during the summer season (1397.7 vs 832.5 pg/m³). Even adding up all measured organic compounds, no sample reaches the threshold limit value for indoor pesticides levels (0.1 pg/m³), neither in the large or small particle fraction. However, the fact that chronic exposure to POPs has been linked to several diseases raises concern for human health.     

Conservation practices in US agriculture and their implication for global climate change

Increase in the use of conservation practices by agriculture in the United States will enhance soil organic carbon and potentially increase carbon sequestration. This, in turn, will decrease the net emission of carbon dioxide. A number of studies exist that calibrate the contribution of various individual, site-specific conservation practices on changes in soil organic carbon. There is a general absence, however, of a comprehensive effort to measure objectively the contribution of these practices including conservation tillage, the Conservation Reserve Program and conservation buffer strips to an change in soil organic carbon. This paper fills that void. After recounting the evolution of the use of the various conservation practices, it is estimated that organic carbon in the soil in 1998 in the United States attributable to these practices was approximately 12,200,000 metric tons. By 2008, there will be an increase of approximately 25%. Given that there is a significant potential for conservation practices to lead to an increase in carbon sequestration, there are a number of policy options that can be pursued. These include education and technical assistance, financial assistance, research and development, land retirement and regulation and taxes.