Input output accounting systems in the European community - an appraisal of their usefulness in raising awareness of environmental problems

Input Output Accountingsystems (IOAs) can be used to identify farming practices which are not ‘environmentally neutral’ and thus unlikely to be sustainable in the long term. In an EU sponsored project, European countries were surveyed and over 50 farm level IOAs identified. The subjects covered by the IOAs included nutrients, pesticides, energy, soil/habitat, conservation, wastes (e.g.packagingandtyres)and other items such as veterinary products. Nearly half the IOAs covered more than one subject and nutrient budgets were the most commonly included(91% of the IOAs studied). Looking at the 30 single subject systems, most (26)were nutrients with only three pesticide and one energy based system. In total 50 systems covered nutrients. Overall, where specified, nutrient budgets covered nitrogen (N), phosphorus (P) and potassium (K)in 13 cases, N and P in 12 cases, N only in nine and P only in four cases. The most common indicators for nutrient budgets were calculation of a balance followed by nitrate leached. The method by which indicators were evaluated and presented to farmers varied. Farming sectors were not equally represented with systems for the arable, dairy and pig sectors the most common. Farmers received a detailed interpretation of their results in two thirds of the systems, most commonly related to official limits or targets. Most of the systems were developed to reduce adverse environmental impacts and 65%of the systems were considered by the respondents to have had a positive environmental impact by reducing surpluses or improving waste disposal. Use of five of the systems could lead to a marketing advantage via certified produce with a recognised quality label. Where factual evidence as to effectiveness was available, the benefits varied between subject types(nutrients, energyandpesticides) and between sectors. Farmers’ responses to the systems were generally positive and they appear to be a useful way of raising awareness of environmental problems. However, economic issues need to be considered, if the costs to the farmer outweigh the benefits, uptake will not be sustained. The type and nature of the interpretation is also important as the most successful IOAs interms of continued use and interest appeared to be those where there was regular technical input from an adviser. Overall IOAs could offer a useful tool for voluntary improvement in agri-environmental performance on topics that are not already strongly regulated. But more studies are needed to ensure that farmers in reality change their behaviour and to develop the use of reference values

Studies on the occurrence of ethylene in soil and its effect on root growth.

Soil samples were collectd from different depths of several selected soil types under both arable and grassland situations. The production of ethylene in the laboratory under anaerobic conditions by these soils, in fresh, air dried and oven dried states were compared. Drying was found to stimulate ethylene production, oven drying having most effect on initial ethylene production.Ethylene formation was related to organic matter content, ethylene concentrations increasing with increased organic matter levels. Ethylene concentrations in arable soils were also related to the acidity, low pH favouring ethylene production. Grassland soils did not show this relationship.High levels of added nitrate were found to reduce ethylene formation but even at 2000 ppm production was not inhibited completely. Low levels had a transient inhibitory effect but the maximum level of ethylene produced was unaffected.Ethylene formation was stimulated in air dried soil by the addition of wheat and barley straw and by the addition of caesin, pepsin, ethanol, lactic acid and pyruvic acid. The exact nature of this stimulation is not known. Ethylene production in undried soil depleted of microbial substrates was promoted by all the three organic substrates supplied: ethanol, glucose and butyric acid.Pea plants treated with 1.1 vpm ethylene showed a 50% reduction in root extension, 4.2 and 10 vpm treatments inhibited root extension completely.Exposure of pea and clover plants to air containing 10 vpm. ethylene resulted in a reduction in nodulation and in the nitrogen fixing capacity of those nodules present. Fresh and dry weight yields of pea pods and clover stems were reduced

Study on Input/Output Accounting Systems on EU agricultural holdings

Of 241 questionnaires sent out to 20 countries 55 completed forms were returned. No information could be obtained about systems in Portugal or the USA. The subject of nutrients was covered by 91% of systems, pesticides 38%, energy 29% and other subjects including wastes 44%. Nearly half of the systems covered more than one subject, the most common single subject system was nutrients. The arable sector was covered most often by the systems (76%), with dairy (62%) and pig (56%) the most prominent of the livestock sectors. The respondents judged that 65% of systems were at least moderately effective in improving the ratio of inputs to outputs. The highest levels of ratio reduction tended to occur with systems which included the livestock sectors or protected horticultural crops. Over half (56%) of farmers had a good opinion of the system, indifferent or bad opinions were more likely to be due to effect on income than the type of system or who managed it. High uptake was more likely in compensated systems. Farm incomes in the arable and dairy sectors were most likely to be improved by systems, negative effects were most likely in the horticultural sector. Government was the main driving force in 38% of the systems, but government was not necessarily the driving force behind the 15% compulsory systems and only one of these was compensated. Increasing concern about environmental issues was the driving force behind development of each of the systems studied. In most cases a major part of the funding to develop the system or run pilot projects came from government. Benefits in terms of increased awareness of problem areas were identified by several systems originators. Anecdotal evidence suggests that farmers are encouraged to make actual changes to their management on the basis of the systems, if they receive detailed help from an adviser associated with the system, or if the system results in a marketing advantage. It seems likely that input output accounting systems could be used to increase awareness and provide evidence of the impact of management changes, they may need to be linked to supporting systems of technical advice. More than 40 IOA systems representing very different approaches have been developed and applied on farms in European countries with the aim of improving environmental performance. Major differences regard especially two characteristics: The no topics covered (single or multiple) and the way indicators are presented. In many systems the indicators used are presented as calculations of input related to output and are derived from accounts based data. Other systems present indicators that are transformed to a standard scale and often these indicators are based on a combination of practise and account data compared with norms for Good Agricultural Practices. Moreover, the systems differ in their origin and driving force: Only a few systems have been developed for mandatory use or for labelling and formal auditioning. Most systems have been developed for the use by advisory services on a voluntary basis. A number of very different systems seem to have been successful. Effectiveness is defined here as the combination of a system with high (potential) impact on the participating farmers in combination with high uptake in terms of the no of farmers willing to use the system. Generally documentation of effects and uptake is poor and more investigations into this are needed. It seems that many systems have not passed the pilot phase, even though some of them did get a positive evaluation by the farmers. In several examples the effort of researchers to develop a scientifically valid concept was not matched by efforts to secure the uptake by advisors or other institutions afterwards. The right institutional setting and political context seems to be more important than the character of the indicators used for the question of farmer uptake. But that does not mean that the choice of indicators is not important from another point of view. In none of the reviewed systems were the use of confidence intervals or variation coefficients an established part of the procedure. Only few reports exist that analyse the variation between farms or between years on specific farms in order to decide to which degree differences are due to systematically different management practices

Arbuscular mycorrhizal fungi in organic systems

Arbuscular mycorrhizal fungi (AMF) are potential contributors to plant nutrition and pathogen suppression in low input agricultural systems, although individual species of AMF vary widely in their functional attributes. Recent studies at HRI and elsewhere have suggested that in some agricultural systems inoculum of AMF is substantially lower under conventional management relative to that under organic management. Further studies have suggested that conventional management selects AMF communities with limited benefits to their plant hosts relative to those in organic systems. There is a need to investigate the generality of these findings, and their implications for the productivity of organic systems, particularly during the period following conversion to organic management. The current project was designed to pull together existing understanding of the role, and potential role, of AMF in organic systems, and to identify sites and develop methods for use in a subsequent research programme. The project had three objectives: 01 To deliver a literature review covering current knowledge of the role of AMF in conventional and organic agricultural systems. The review considered the ways in which management influences the structure and functioning of AMF communities, including their contributions under conventional and organic management, and recommendations for future research needs. 02 To establish the extent of differences in AMF inoculum between organic and conventional systems, covering a range of management practices. Paired organic and conventional fields at 12 sites from across England were selected to investigate the relationships between management, AMF communities and soil chemistry. Organic and conventionally managed soils showed no significant difference in soil chemical properties (Organic C, total N, total P, extractable P, K, Mg). However, organically managed soils had greater AMF spore numbers and root colonisation potential, and therefore higher AMF inoculum potential, than conventionally managed soil. The relative difference in AMF spore numbers between organic and conventionally managed fields increased with time since conversion. Differences in AMF inoculum potential between organic and conventionally managed fields, and between farm sites, could not be related to differences in soil chemistry. 03 To develop a method suitable for characterising AM fungus communities in soil libraries, based on 18S rRNA terminal restriction fragment length polymorphism (T-RFLP) T-RFLP was shown to provide a rapid semi-quantitative method for analysis of AMF community diversity. However it was clear that primers currently used to amplify AMF are selective and do not allow diversity of the whole AMF community to be determined. Additionally these primers amplify contaminant fungi which need to be removed from the T-RFLP profile prior to analysis. However, contaminant diversity was shown to be low. The project has identified sites and techniques which could be valuable in future research to study the role of AMF under organic management. The study has also highlighted a number of key areas in which further research is needed in order to harness AMF to improve sustainability and productivity of organic and other agricultural systems. In particular, there is a need to determine the extent to which AMF diversity varies between organic and conventional management, the rate and mechanisms by which AMF diversity increases following conversion to organic production, the relationships between AMF diversity and crop nutrition/ pathogen control, and the soil factors controlling the effectiveness of AMF inoculum

Field Experiments to Help Optimise Nitrogen Fixation by Legumes on Organic Farms

During an organic rotation, the aim is to increase the nitrogen (N) content of the soil (and hence build up soil fertility) by recycling crop residues, applying manures/composts and from N fixed by legumes. IGER, with ADAS, Duchy College Cornwall and Abacus Organic Associates are developing improved guidance for organic farmers in the use of fertility-building crops. The main questions are: how to maximise N fixation and how to make the most efficient use of the fixed N? Available soil mineral N, which is generally thought to reduce N fixation, will be increased by manure applications, cutting/mulching and grazing. We describe an experiment to establish the extent to which animal and green manures can adversely affect N fixation. The results from the first year (2003) were reported recently (Hatch et al., 2004). Here we summarise the findings from 2 years’ results (2003-4) to show the changes that occurred after the legume crop became fully established

A Model for the Development of the Rhizobial and Arbuscular Mycorrhizal Symbioses in Legumes and Its Use to Understand the Roles of Ethylene in the Establishment of these two Symbioses

We propose a model depicting the development of nodulation and arbuscular mycorrhizae. Both processes are dissected into many steps, using Pisum sativum L. nodulation mutants as a guideline. For nodulation, we distinguish two main developmental programs, one epidermal and one cortical. Whereas Nod factors alone affect the cortical program, bacteria are required to trigger the epidermal events. We propose that the two programs of the rhizobial symbiosis evolved separately and that, over time, they came to function together. The distinction between these two programs does not exist for arbuscular mycorrhizae development despite events occurring in both root tissues. Mutations that affect both symbioses are restricted to the epidermal program. We propose here sites of action and potential roles for ethylene during the formation of the two symbioses with a specific hypothesis for nodule organogenesis. Assuming the epidermis does not make ethylene, the microsymbionts probably first encounter a regulatory level of ethylene at the epidermis–outermost cortical cell layer interface. Depending on the hormone concentrations there, infection will either progress or be blocked. In the former case, ethylene affects the cortex cytoskeleton, allowing reorganization that facilitates infection; in the latter case, ethylene acts on several enzymes that interfere with infection thread growth, causing it to abort. Throughout this review, the difficulty of generalizing the roles of ethylene is emphasized and numerous examples are given to demonstrate the diversity that exists in plants