Sampling Strategies for Mapping Soil Phosphorus and Soil Potassium Distributions in Cool Temperate Grassland

Unlike the situation for arable soils, virtually nothing is known about the spatial dependencies of soil properties in cool temperate grassland or about what the optimal sampling strategies ought to be for mapping soil nutrient distributions in such situations. The aim of this study was to investigate the spatial variability in plant-available (soil) phosphorus and potassium in a grass silage field in Northern Ireland and devise optimal sampling strategies for mapping their distributions. Soil samples were collected from the field at 25 m intervals in a regular rectangular grid to provide a database of soil properties. Different data combinations were subsequently abstracted from this database for comparison purposes, and ordinary kriging used to produce interpolated soil maps. Soil potassium displayed greater spatial variability than soil phosphorus. In keeping with this observation, the results of three separate statistical procedures demonstrated that the optimal sample size for estimating the true population means was about twice as large for soil potassium as for soil phosphorus. Optimal sampling strategies, however, related not just to sample size but to sample combination and field shape as well.     

How biotechnology regulation sets a risk/ethics boundary

In public debate over agricultural biotechnology, at issue hasbeen its self-proclaimed aim of further industrializingagriculture. Using languages of risk, critics and proponentshave engaged in an implicit ethics debate on the direction oftechnoscientific development. Critics have challenged thebiotechnological R&D agenda for attributing socio-agronomicproblems to genetic deficiencies, while perpetuating the hazardsof intensive monoculture. They diagnosed ominous links betweentechnological dependency and tangible harm from biotechnologyproducts.In response to scientific and public concerns, theEuropean Community enacted precautionary legislation for theintentional release of genetically modified organisms (GMOs). Inits implementation, choices for managing and investigatingbiotechnological risk involve an implicit environmental ethics.Yet the official policy language downplays the inherent valuejudgments, by portraying risk regulation as a matter ofobjective science.In parallel with safety regulation, thestate has devised an official bioethics that judges where todraw the line in applying biotechnological knowledge, as ifthe science itself were value-free. Bioethics may also judge howto balance risks and benefits, as if their definition were notan issue. This form of ethics serves to compensate for theunacknowledged value-choices and institutional commitmentsalready embedded in R&D priorities.Thus the state separatesrisk and ethics, while assigning both realms to specialists.The risk/ethics boundary encourages public deference to theexpert assessments of both safety regulators and professionalethicists. Biotechnology embodies a contentious model of controlover nature and society, yet this issue becomes displaced andfragmented into various administrative controls. At stake arethe prospects for democratizing the problem-definitions thatguide R&D priorities.     

Dirt in our mouths and hunger in our bellies: Metaphor, theory-making, and systems approaches to sustainable agriculture

The metaphor of the food system,dominant in current research approaches to sustainableagriculture, mirrors the productionist paradigm, whichreduces our relationship to land and food to theproduction and consumption of commodities. Theenactment of the familiar values of nourishment andhospitality is what the goal of sustainableagriculture would amount to in terms of our day to daylived experience. The metaphor of an earthen bowl asa theory of food and agriculture can embody thesevalues such that broader change might be achievedthrough embracing the idea and practice of theories asnourishing and theorizing as hospitable.     

A Methodology for Precision Nitrogen Fertilization in High-Input Farming Systems

Nitrogen (N) emissions to ground and surface waters have become a major concern in many regions. In reaction, policy makers are tightening environmental constraints on agriculture, resulting in a call for more efficient management systems. This study presents a methodology for precision N fertilization in high-input farming systems applying split fertilizer strategies. Essentially, the method uses a mechanistic simulation model to quantify (i) soil mineral-N levels and (ii) N uptake rates on a real-time basis. Early warning signals are generated once N concentrations drop below a critical threshold level, indicating that additional fertilizer should be applied. Thresholds are not static, but defined in relation to actual uptake rates. Spatial variation is incorporated through the concept of management units: i.e., stable units with relatively homogeneous characteristics in terms of water regimes and nutrient dynamics. Separate simulations are conducted for each management unit, based on selected representative soil profiles. The proposed methodology was tested in a winter wheat (Triticum aestivum L.) field during the 1998 growing season. Six experimental strips were delineated receiving either precise or traditional fertilization. Precision fertilization proved efficient in reducing fertilizer inputs (–23%), while slightly improving grain yields (+3%) and hectoliter weights (+4%). Results clearly illustrate the significance of precision management in the process of increasing fertilizer use efficiency.     

Gendered participation in water management: Issues and illustrations from water users‘ associations in South Asia

The widespread trend to transferirrigation management responsibility from the stateto communities or local user groups has byand large ignored the implications ofintra-community power differences for theeffectiveness and equity of water management. Genderis a recurrent source of such differences. Despitethe rhetoric on womens participation, a review ofevidence from South Asia shows that femaleparticipation is minimal in water usersorganizations. One reason for this is that theformal and informal membership criteria excludewomen. Moreover, the balance between costs andbenefits of participation is often negative forwomen because complying with the rules and practicesof the organization involves considerable time costsand social risks, whereas other ways to obtainirrigation services may be more effective for femalewater users. Although effective, these other andoften informal ways of obtaining irrigation servicesare also typically less secure. More formalparticipation of women can strengthen womensbargaining position as resource users withinhouseholds and communities. Greater involvement ofwomen can also strengthen the effectiveness of theorganization by improving womens compliance withrules and maintenance contributions. Furtherdetailed and comparative research is required toidentify the major factors that affect womensparticipation and control over resources, ifdevolution policies are to address the tensionbetween objectives of transferring control overresources to community institutions, and ensuringthe participation of all members of the community,especially women.     

Converting or not converting to organic farming in Austria:Farmer types and their rationale

Reasons for converting to organic farming have been studied in a number of instances. However, the underlying rationale that motivates the behavior is not always made clear. This study aims to provide a detailed picture of farmers decision-making and illustrate the choice between organic and conventional farm management. Based on 21 interviews with farmers, a decision-tree highlighting the reasons and constraints involved in the decision of farmers to use, or not to use, organic production techniques was formulated. The accuracy of the decision-tree was tested through a written survey of 65 randomly sampled farmers. The decision-tree permits the identification of decision criteria and examines the decision-making process of farmers in choosing their farming method. It also allows for the characterization of farmer strategies and values, identifying five types of farmers: the committed conventional; the pragmatic conventional; the environment-conscious but not organic; the pragmatic organic; and the committed organic. The importance of taking into account heterogeneity in farmers attitudes, preferences, and goals and their impact on the choice of a farming method is emphasized.Ika Darnhofer is an Assistant Professor at the Institute of Agricultural and Forestry Economics at the University of Natural Resources and Applied Life Sciences Vienna. She received both her MSc and PhD in Agricultural Economics from the University of Natural Resources and Applied Life Sciences Vienna, working on issues of agricultural development in Africa. Her current research interests include economic and sociological analyses of factors that shape farmers land use decision-making behavior, with a particular focus on organic farming.Walter Schneeberger is a Full Professor of Farm Business Management and Head of the Institute of Agricultural and Forestry Economics at the University of Natural Resources and Applied Life Sciences Vienna. His current research interests include the economics of producing and processing agricultural products and farm business management for both conventional and organic farms.Bernhard Freyer is a Full Professor of Organic Farming and Head of the Institute of Organic Farming of the University of Natural Resources and Applied Life Sciences Vienna. His work on organic farming focuses on its agronomic aspects (plant cultivation, crop rotations, and soil fertility) as well as on the analysis of conversion to organic farming (planning process, farm development) and its potential for regional development.     

Interactions of formal and informal knowledge systems in village-based tree management in central India

This study critiques the idea of a Western science -- indigenous knowledge dichotomy in agricultural knowledge by examining the hybrid nature of knowledge use and incorporation by villagers in Madhya Pradesh, India. By analyzing knowledge systems as multi-leveled structures consisting of concrete practices linked to more abstract, explanatory concepts, this paper illustrates how information from multiple sources is integrated into local bodies of knowledge about tree management. Practices such as urea fertilization from formal global science might be explained by concepts such as that of a hot/cold duality from informal folk science. Similarly, other pieces of knowledge stemming from diverse knowledge systems are shown to become mixed and matched on practical and conceptual levels. Additionally, several knowledge elements used locally appear to be held in common by many knowledge systems around the world, rendering the determination of their origins in one system or another nearly impossible. These observations lead to the conclusion that local knowledge systems of tree management are better characterized as open systems rather than distinct, closed systems. Furthermore, the constant exchange of material between formal and informal, local and global systems renders untenable any strict dichotomy of knowledge systems.     

Food assistance through “surplus” food: Insights from an ethnographic study of food bank work

In Canada, food assistance is provided through a widespread network of extra-governmental, community-based, charitable programs, popularly termed food banks. Most of the food they distribute has been donated by food producers, processors, and retailers or collected through appeals to the public. Some industry donations are of market quality, but many donations are surplus food that cannot be retailed. Drawing on insights from an ethnographic study of food bank work in southern Ontario, we examined how the structure and function of food banks operate to facilitate the distribution of foods not marketed through the retail system. Our findings indicate that the handling of industry donations of unsaleable products is a labor-intensive activity, made possible by the surfeit of unpaid labor in food banks, the neediness of food bank clients, and clients lack of rights in this system. The marshalling of volunteer labor to serve a corporate need might be construed as a win-win situation because the work of salvaging edible foodstuffs from among industry surplus helps to feed the hungry while also diminishing the amount of refuse deposited in landfill sites, sparing corporations disposal costs and landfill tipping fees, and helping them forge an image of good corporate citizenship. However, the reliance of food banks on industry donations means that food assistance becomes defined as that which the corporate sector cannot retail. Moreover, the intertwining of food bank work with corporate needs may function to further entrench this ad hoc secondary food system and mitigate against initiatives to develop more effective responses to problems of hunger and food insecurity in our communities.     

Sampling Strategies for Mapping ‘Within-field’ Variability in the Dry Matter Yield and Mineral Nutrient Status of Forage Grass Crops in Cool Temperate Climes

In the absence of suitable technology to measure and map the dry matter (DM) yield distributions of forage grass crops within individual fields, a manual procedure of yield mapping has been developed. Samples of herbage are collected just prior to each silage harvest from known grid points within a field, and sward DM yields at each point are predicted from the mineral composition of the herbage, using empirical mathematical models. Yield maps (and maps of sward nutrient status) are then produced by kriging interpolation between the point data. To make the most efficient use of time and resources, however, sampling intensity needs to be kept to the absolute minimum necessary for interpolation purposes. The aim of the present study was to examine the spatial variability in sward DM yield and mineral nutrient status in a large grass silage field under a three-cut system, and devise optimal sampling strategies for mapping the distributions of these parameters at each cut. Herbage samples were collected from the field, prior to each harvest, at 25 m intervals in a regular rectangular grid to provide databases of herbage nutrient contents and DM yields. Different data combinations were abstracted from these databases for comparison purposes, and ordinary kriging used to produce interpolated maps of DM yield and sward N, P, K and S statuses. The results suggested that a sampling density of just seven samples per hectare was adequate for estimating the true population means of sward DM yield and sward N, P, K, and S statuses. For mapping purposes, it was found that the best compromise between interpolation accuracy and sampling efficiency was to collect herbage samples in a 35.4 m×35.4 m equilateral triangular sampling pattern.     

The “Null Hypothesis” of Precision Agriculture Management

As precision agriculture strives to improve the management of agricultural industries, the importance of scientific validation must not be forgotten. Eventually, the improvement that is imparted by precision agriculture management must be considered in terms of profitability and environmental impact (both short and long term). As one form of precision agriculture, we consider site-specific crop management to be defined as: Matching resource application and agronomic practices with soil and crop requirements as they vary in space and time within a field. While the technological tools associated with precision agriculture may be most obvious, the fundamental concept will stand or fall on the basis of scientific experimentation and assessment. Crucial then to scientifically validating the concept of site-specific crop management is the proposal and testing of the null hypothesis of precision agriculture, i.e. Given the large temporal variation evident in crop yield relative to the scale of a single field, then the optimal risk aversion strategy is uniform management. The spatial and temporal variability of important crop and soil parameters is considered and their quantification for a crop field is shown to be important to subsequent experimentation and agronomic management. The philosophy of precision agriculture is explored and experimental designs for Precision agriculture are presented that can be employed in attempts to refute the proposed null hypothesis.     

Spatial Analysis of Maize Response to Nitrogen Fertilizer in Central New York

An increasing number of farmers are considering the use of site-specific nitrogen (N) applications to maize (Zea mays L.) as a way of maximizing yield potential while minimizing fertilizer cost. The objectives of this 3-years experiment were to evaluate the spatial structure of yield response to N fertilizer and investigate the potential for site-specific N management under maize production in New York. Four experimental N rates (50, 110, 160, or 220 kg ha¹), two tillage systems (chisel till and zone-till) and two crop rotations (maizemaize and maizesoybean (Glycine max L.)) were superimposed over a 12 ha field in central New York State with a complex of Honeoye-Lima, Kendaia, and Lima soils ranging from moderately well to poorly drained soils. Pre-sidedress soil nitrate tests (PSNT) showed significant spatial structure but did not conform to that for crop N response, indicating that N fertilizer recommendations based on PSNT results cannot be simply applied in a site-specific management approach. Optimal N rate varied from 110 kg ha ¹ for the dry years 1999 and 2000 to 220 kg ha¹ for 1998, with a warm wet spring. Tillage treatments were generally comparable in N response. Spatial yield response analysis showed limited field-scale regionalization of both yield and profit response to N, suggesting that site-specific application of nitrogen is impractical. The greatest source of variability in N requirements was observed with the annual effects of weather, and presents a greater potential for precise N application than site-specific application. Annual variations in optimum N rate were not related to annual yield differences and yield potential itself does not appear to be a good predictor of N needs.     

Learning in context through conflict and alignment: Farmers and scientists in search of sustainable agriculture

This article analyzes learning in context through the prism of a sustainable dairy-farming project. The research was performed within a nutrient management project that involved the participation of farmers and scientists. Differences between heterogeneous forms of farmers knowledge and scientific knowledge were discursively constructed during conflict and subsequent alignment over the validity and relevance of knowledge. Both conflict and alignment appeared to be essential for learning in context. Conflict spurred learning when disagreeing groups of actors developed their knowledge in order to strengthen their arguments. Conflict caused self-referentiality when the actors no longer listened to each other. This inhibited self-reflection, thus blocking ongoing learning. Nevertheless, after a period of alignment, scientific models and knowledge of farmers were reevaluated and recontextualized. Through determining how to use scientific models and farmers knowledge for further learning, aimed at a shared goal, the participating actors also learned how to learn.Jasper Eshuis is a PhD candidate in the Department of Communication Management at Wageningen University, The Netherlands. His research deals with multiple land use, governance processes, and farmers decision-making. He is currently interested in monitoring and trust.Marian Stuiver is a PhD candidate in the Department of Rural Sociology of Wageningen University, The Netherlands. Her current research focuses on nutrient management, farmers innovation, and co-production of knowledge within the agricultural sciences.     

Gender, land, and water: From reform to counter-reform in Latin America

Rural women did not fare very well inthe land reforms carried out during the Latin Americanreformist period of the 1960s and 1970s, with womenbeing under-represented among the beneficiaries. It isargued that women have been excluded from access toand control over water for similar reasons that theywere excluded from access to land during thesereforms. The paper also investigates the extent towhich women have gained or lost access to land duringthe counter-reforms of the 1980s and 1990s. Underthe neo-liberal agenda, production cooperatives aswell as communal access to land have largely beenundermined in favor of privatization and theindividual parcelization of collectives. Significantland titling efforts are also being carried outthroughout the region to promote the development of avigorous land market. This latter period has also beencharacterized by the growth of the feminist movementthroughout Latin America and a growing commitment bystates to gender equity. The paper reviews the extentto which rural womens access to land and, thus, waterhas potentially been enhanced by recent changes inagrarian and legal codes.     

Bringing political economy into the debate on the obesity epidemic

This paper takes what has been termed the epidemic of obesity as the point of departure to examine the way in which political economic factors intersect with diet and nutrition to determine adverse health outcomes. The paper proposes several concepts to better understand the dynamics of the foodscape – institutional sites for the merchandising and consumption of food. These include the concepts of spatial colonization and pseudo foods. With a focus on critical dimensions of the contemporary foodscape, principally supermarket merchandising practices, as well as trends in other food vending operations, the paper explores incentives that motivate capital to spatially colonize the foodscape with aggressively promoted high fat/high sugar pseudo foods. The paper reports on extensive research on trade industry publications as well as data collected through onsite investigations of supermarket practices of the three largest Canadian retail supermarket operations. In addition, current merchandising practices of convenience chain store operations and some non-traditional food vending sites are examined. In concluding, it is argued that the rapidly evolving interdisciplinary debate around the obesity crisis would benefit considerably from the insights to be gained from political economic analysis of retail food industry practices and trends.     

Constructing “green” foods: Corporate capital, risk, and organic farming in Australia and New Zealand

Public concern over environmentalquality and food safety has culminated in thedevelopment of markets for green foods – foodsthat are variously construed as fresh, chemical-free,nutritious, natural, or produced in anenvironmentally-sustainable manner. Understanding theemergence of green foods is dependent on analysisboth of the ways in which foods are produced andprocessed, and of the meanings that are attached tothem at each stage of their production,transformation, and consumption. The notion of greenfoods is thereby understood here as a fluid andcontestable signifier that myriad actors involved inthe production/consumption cycle may attempt to shapefor their own purposes. This paper explores corporate capital's recent attempts, through certification logosand advertising, to signify the healthiness andenvironmental virtues of organically-produced foods inAustralia and New Zealand. These attempts have not,however, been universally successful either in termsof gaining consumer interest, or in gaining agreementsbetween farmers, certifying organizations, andcapitalist firms over the meaning of organic and thepractice of sustainable agriculture. The experienceof corporate involvement in the organics industry isillustrative of yet-to-be-resolved processes ofreflexive modernization. As food production andtransformation continues to produce environmental andsocial risks, the question of just what makes foodgreen will continue to be a source of social conflict.     

Environmental and social risks, and the construction of “best-practice” in Australian agriculture

Amongst the environmental and social externalities generated by Australian agriculture are a number of risks both to the health and safety of communities living near sites of agricultural production, and to the end consumers of agricultural products. Responses to these potential risks – and to problems of environmental sustainability more generally – have included a number of programs to variously: define best-practice for particular industries; implement Quality Assurance procedures; and encourage the formation of self-help community Landcare groups. Taken together, these programs appear to deal comprehensively with both the social and environmental risks associated with agricultural production and products. However, these programs may also be interpreted as strategies that actually encourage the further intensification of agriculture, while attempting to reassure consumers that their food is safe and that farmers are doing all they can to protect the environment. Investigation of the Australian cotton and beef industries illustrates a number of strategies that have become evident between farmers, agri-science agencies, and the retail sector to manage these risks and define good farming practices in ways that satisfy their own perceived interests. Contrary to the image, therefore, of green consumption that is emerging as an integrated concern for clean (and thereby healthy) and sustainably produced foods, it appears that mainstream agricultural industries have bifurcated these concerns in ways that distract attention from production and processing methods, leaving conflict over on-farm production methods a characteristic only of those industries believed to have direct health impacts on nearby communities.     

Sustaining local agriculture Barriers and opportunities to direct marketing between farms and restaurants in Colorado

Research explored methods for shortening the food links or developing the local foodshed by connecting farmers with food service buyers (for restaurants and institutions) in Colorado. Telephone interviews were used to investigate marketing and purchasing practices. Findings include that price is not a significant factor in purchasing decisions; that food buyers prioritize quality as their top purchasing criterion but are not aware that local farmers can provide higher quality, that institutions are interested in buying locally; that small farms can offer comparable or higher quality produce andservice; and that farmers need to show buyers what the quality of produce and service they can provide.     

Method for Precision Nitrogen Management in Spring Wheat: I Fundamental Relationships

Wheat (Triticum aestivum L.) fields in the semi-arid Northern Great Plains are spatially variable in soil N fertility and crop productivity. Consequently, there is interest in applying variable, rather than uniform rates of fertilizer N across the landscape. Intensive soil sampling as a basis for variable-rate fertilizer management is too costly when compared to the value of wheat in this region. The objective of this research was to determine relationships between yield and protein, and protein and available N as needed to develop a cost-effective variable-rate N fertilizer strategy for spring wheat. A three-year study (1996–1998) was carried out at a site near Havre, Montana, USA (48°30N, 109°22W). Treatments consisted of three water regimes, four cultivars, and five fertilizer N levels per water regime in a randomized complete block design with four replicates. Scatter diagrams of relative yield vs. grain protein were consistent with earlier investigators, and indicated protein concentrations at harvest provided a method for indexing N nutrition adequacy (deficiency vs. sufficiency) in wheat. A critical protein concentration of 13.2% was defined using a graphical Cate-Nelson analysis. This value appeared to be consistent across the three water regimes and four cultivars as 159 (88%) of the 180 water×cultivar×N level episodes were in positive quadrants. No correlation could be found between relative yield and protein for episodes below the critical level (r²=0.1). Hence, grain protein concentrations could not be used to predict the magnitude of yield losses from N deficiency. Grain protein content would be useful for prescribing fertilizer recommendations where N deficiency (<13.2% protein) reduces grain yield under semi-arid conditions. Inverse slopes (dy/dx) of the protein-available N curves reveal that it takes 12–18 kg N/ha to change protein 1% (e.g., 12% vs. 13%) where wheat is under water stress during grain fill. The total N requirement could then be computed by summing the N required for raising protein and the N removed by the crop in the year when the grain was harvested.     

Identifying Potential Within-Field Management Zones from Cotton-Yield Estimates

Remotely-sensed cotton yield estimates, collected mid-season over the past 11 years, were investigated to identify the degree of temporal stability exhibited in two irrigated fields on Colly Central farm, Collarenabri, NSW, Australia. In particular, the aims of the investigation were: (1) to develop stable yield zones from multi-year yield estimates derived from 11 consecutive years' mid-season Landsat TM imagery; (2) to discover the number of consecutive years of yield estimates required to give similar stable estimates of yield zones to those derived from all 11 years of available data. Results of the investigation indicate that the fields described in the study exhibit a strong degree of temporal stability. Additionally, where an assumption is made that 11 years worth of yield estimates will cluster to generate the most temporally stable regions of similarity, the mapping of clusters generated using 5 or more years will generate comparable regions of similarity with high confidence that the regions will indeed closely match those of the temporally stable 11 year estimates.     

Close encounters with a CSA: The reflections of a bruised and somewhat wiser anthropologist

This essay tells a story. It is a story of the author's experience with community supported agriculture (CSA). It is also a story that depicts the difficulties of academic activism and grass-roots engagement. As an academic and an activist, the author argues that it is important to admit and share experiences that are less than perfect, since they are the basis for a more complete knowledge and a more organic existence, individually, collectively, sensually, and intellectually.