Nutrient budgets on organic farms: a review of published

This report was presented at the UK Organic Research 2002 Conference. On organic farms it is important that a balance between inputs and outputs of nutrients is achieved. This paper collates nutrient budgets collated at the farm scale for 88 farms in 9 temperate countries. The majority of budgets were compiled for dairy farms (56). All the nitrogen budgets showed an N surplus (average 83 kg N ha-1 year-1). The phosphorus (P) and potassium (K) budgets showed both surpluses and deficits (average 3.4 kg P ha-1 year-1; 13.7 kg K ha-1 year-1). For all nutrients as nutrient inputs increased the surplus increased more significantly than the nutrient outputs. Overall, the data illustrate the diversity of management systems in place on organic farms, which consequently lead to significant variability in nutrient use efficiency and potential nutrient sustainability between farms. There are opportunities for almost all organic farmers to improve the efficiency of nutrient cycling on the farm and increase short-term productivity and long-term sustainability

The νόστοι of Helen and Menelaos and the Path to μῆτις

Νόστος ist ein zentrales Element von Homers Odyssee. Das Epos enthält viele νόστοι und die wichtigste ist die νόστος des Odysseus. Dieser Beitrag diskutiert die νόστοι von Helena und Menelaos und wie sie getrennt von ihrer Reise berichten. Ziel ist die bei dieser Reise gewonnenen Erkenntnisse herauszuarbeiten. Im Gesamt­zusammenhang der Odyssee ist μῆτις ein wichtiger Aspekt von νόστος, und deshalb passen Helena, Menelaos und ihre Reise auch in dieses Schema. Ein weiteres Ziel ist, κλέος zu erörtern, das jedem der beiden durch das Berichten des eigenen νόστος zukommt. Ihr jeweiliges Erzählen zeigt, dass sie an denselben Orten waren, ähnliche Begegnungen hatten, beide Erkenntnisse gewonnen haben, sich beide verändert haben und nach Sparta zurückgekehrt sind. Dieser Beitrag weist nach, dass sich Helena und Menelaos auf dieselbe νόστος begeben haben: ein gemeinsamer Weg aber mit je andersartiger μῆτις

Nutrient cycling on organic farms

This paper examines the sustainability of nutrient cycling on organic farms. After a brief consideration of the principles of nutrient cycling in organic agriculture, data on soil P and K indices and farm nutrient budgets is used to assess the integrity of nutrient cycling, including some consideration of losses to the environment. An attempt is made to assess the wider sustainability of organic farming in the context of the limited amount of recycling possible

Nitrogen supply for organic crops

An integrated series of field, laboratory and pot experiments was carried out between 1990 and 1993 to study the release of nitrogen from organic manures and its subsequent recovery by crops. The aim was to increase understanding of the soil processes controlling N release from manures and therefore enable N supply to be more closely matched to crop demand in organic cropping systems.The study of N release from manures is handicapped by the lack of appropriate methods to measure rates of mineralisation (both net and gross) in the field. The use of isotope dilution techniques under field conditions was found to be difficult due to the slow diffusion of ammonium ions in soils. The release of N from manures was therefore studied indirectly by monitoring plant uptake and changes in the soil mineral N pool. Indices, used to predict N release, w ere not found to be applicable where additions of manure had been made.Various management strategies aimed at maximising N supply for organic crops were studied. The N released from manures in the first year was shown to be derived mainly from the pool of mineral N added in the manure. The availability of this pool was controlled by the supply of soluble carbon also added in manures, which stimulates the growth of the microbial biomass and therefore leads to immobilisation of the mineral N. The availability of any immobilised N for crop growth is not clear, though some evidence suggested that it was completely recovered by a spring barley crop. The organic N pool of the manure did not seem to be important in supplying N for crop growth in the first year.The use of 15N-labelled manures enabled the separation of the N taken up by plants into that derived from the soil and that derived from the manure. Manures were labelled non-uniformly by incubation with 15 N salts for a short period before application. W here the assumption could not be made that the manure was uniformly labelled, a simple model was developed based on isotope dilution theory, to calculate the percentage of plant N uptake from the manure. 15N was also used to determine the source of the N extracted by a number of methods, used to assess potential N availability.The structure of a simple model was described, which could be used to select a manurial strategy, which maximised crop yields and estimated the potential N losses for an organic farm. It was suggested that this could be constructed using an expert system approach, which was able to refer to databases and simple models to provide the final output. The full development of such a model is not yet possible, as the availability of the N applied in organic manures is only partly understood. However, our understanding of the complex processes controlling the release of N from manures has been increased as a result of the work described

Utilising the concept of nutrients as a currency within organic farming system

This report was presented at the UK Organic Research 2002 Conference.Within organic systems, the successful management of nutrients at the field level is crucial for maximising production and minimising the environmental impacts. This requires that the farmer makes the best possible use of nutrients excreted by the grazing or housed livestock. In addition, the farmer must successfully manage the nutrients built-up in the ley phase of the crop rotation over the whole of the arable phase period. To analyse these complex flows, a nutrient budget model has been developed that describes the spatial and temporal flows within the organic farming system. The concept is analogous to treating nutrients as a currency where the flow of nutrients represents a cashflow. A spatial nutrient budget permits the analyses of the performance of the nutrient flows to be examined for the housing, manure, livestock, rotational land and permanent pasture to be analysed separately. This analysis will allow the farmer to better understand the weaknesses in the system, and hence take preventative measures

Long-term management of nutrients in organic farming - priciples and practice

Organic farming faces a number of challenges as it moves forward. It has become a part of the global agricultural industry and therefore organic products are traded not just between farms and regions but between countries and continents. Inevitably, large amounts of nutrients are exported from farms as part of this process. These farms can only continue to produce acceptable quantities of quality food if these nutrients are replaced. Soil has a finite capacity to supply crop nutrients unless they are replenished. The solution is perhaps easiest for nitrogen where biological fixation by legumes can be harnessed to provide the engine for crop production. For other major and micronutrients more consideration needs to be given to acceptable sources for organic production; in situ mineral weathering from soil parent materials will only rarely meet crop demand. In addition we need to understand and improve the recycling and management of all nutrients on farm to optimise crop and livestock production and quality while minimising losses

Development of software to plan conversion to organic production (OrgPlan)

This report was presented at the UK Organic Research 2002 Conference. OrgPlan is a computer programme aimed at farmers and advisors assisting with the planning of an organic conversion. The programme is divided into technical modules, supported by a standard enterprise database, a report builder and an advisory section. Through the farm profile builder, rotation, cropping and livestock planner, conversion scenarios over several years can be developed and are evaluated for technical and financial feasibility by calculating farm gate budgets for key resources (forage energy and key nutrients) and financial reports (cash flow budget and profit and loss account). The poster illustrates the basic functioning of the software as well as the underlying rationale for the scenario evaluation

“Giving something back”: a systematic review and ethical enquiry into public views on the use of patient data for research in the United Kingdom and the Republic of Ireland

Background: Use of patients’ medical data for secondary purposes such as health research, audit, and service planning is well established in the UK. However, the governance environment, as well as public understanding about this work, have lagged behind. We aimed to systematically review the literature on UK and Irish public views of patient data used in research, critically analysing such views though an established biomedical ethics framework, to draw out potential strategies for future good practice guidance and inform ethical and privacy debates. Methods: We searched three databases using terms such as patient, public, opinion, and electronic health records. Empirical studies were eligible for inclusion if they surveyed healthcare users, patients or the public in UK and Ireland and examined attitudes, opinions or beliefs about the use of patient data for medical research. Results were synthesised into broad themes using a framework analysis. Results: Out of 13,492 papers and reports screened, 20 papers or reports were eligible. While there was a widespread willingness to share patient data for research for the common good, this very rarely led to unqualified support. The public expressed two generalised concerns about the potential risks to their privacy. The first of these concerns related to a party’s competence in keeping data secure, while the second was associated with the motivation a party might have to use the data. Conclusions: The public evaluates trustworthiness of research organisations by assessing their competence in data-handling and motivation for accessing the data. Public attitudes around data-sharing exemplified several principles which are also widely accepted in biomedical ethics. This provides a framework for understanding public attitudes, which should be considered in the development in any guidance for regulators and data custodians. We propose four salient questions which decision makers should address when evaluating proposals for the secondary use of dat

A Guide to Nutrient Budgeting on Organic Farms

The leaflet gives practical guidance on using data and calculating farm-gate nutrient budgets with sections on soil analysis, nutrient inputs, nutrient losses and flows, nitrogen fixation through leys and how inputs and outputs from organic manures and livestock feed can be recorded. It contains one example table of a farm-gate annual nutrient budget for a mixed cattle and arable farm. The tool is specific to organic farming. It was drafted for the UK but has relevance in other countries