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There is an urgent need for transformational change in global and UK agriculture. Current practices undermine the long-term future of farming and impoverish ecosystems in the UK and elsewhere. However, change is not happening at the scale and pace which is needed. Work by David Abson, drawing on ideas by Donella Meadows, explored this failure of progress and proposed a research agenda focused on transformational leverage points which influence sustainability. These points are centred on three realms of leverage: reconnecting people to nature, restructuring institutions and rethinking how knowledge is created and used in pursuit of sustainability. In this paper, these ideas are explored through a combined researcher/stakeholder workshop focused on transformational change in UK livestock systems. Workshop participants were asked to discuss and identify potential levers of change under the three realms identified by Abson. The multiplicity of levers identified and the interactions across realms emphasise the need for new kinds of knowledge creation which are highly transdisciplinary, as well as emphasising the complexity of levers which are likely to play a role in the transformation of livestock food systems in the UK and elsewhere. [ABSTRACT FROM AUTHOR]

We assess the production impacts of a 100% conversion to organic agriculture in England and Wales using a large-scale linear programming model. The model includes a range of typical farm structures, scaled up across the available land area, with the objective of maximising food production. The effects of soil and rainfall, nitrogen (N) supply/offtake and livestock feed demand are accounted for. Results reveal major reductions in wheat and barley production, whilst the production of minor cereals such as oats and rye increase. Monogastric livestock and milk production also decreased considerably, whilst beef and sheep numbers increased. Vegetable production was generally comparable to that under conventional farming. Minimising the area of fertility building leys and/or improving rates of N fixation increased the food supply from organic agriculture at the national level. The total food output, in terms of metabolisable energy, was 64% of that under conventional farming. This would necessitate substantial increases in food imports, with corresponding expansion of cultivated agricultural land overseas. Significant changes in diet and reductions in food waste would be required to offset the production impacts of a 100% conversion to organic farming. [ABSTRACT FROM AUTHOR]

Growing populations and a constrained fossil-manufactured energy supply present a major challenge for society and there is a real need to develop forms of agriculture that are less dependent on finite energy sources. It has been suggested that organic agriculture can provide a more energy efficient approach due to its focus on sustainable production methods. This review has investigated the extent to which this is true for a range of farming systems. Data from about 50 studies were reviewed with results suggesting that organic farming performs better than conventional for nearly all crop types when energy use is expressed on a unit of area basis. Results are more variable per unit of product due to the lower yield for most organic crops. For livestock, ruminant production systems tend to be more energy efficient under organic management due to the production of forage in grass–clover leys. Conversely, organic poultry tend to perform worse in terms of energy use as a result of higher feed conversion ratios and mortality rates compared to conventional fully housed or free-range systems. With regard to energy sources, there is some evidence that organic farms use more renewable energy and have less of an impact on natural ecosystems. Human energy requirements on organic farms are also higher as a result of greater system diversity and manual weed control. Overall this review has found that most organic farming systems are more energy efficient than their conventional counterparts, although there are some notable exceptions. [ABSTRACT FROM AUTHOR]

A correction to the article "Predicting the effect of rotation design on N, P, K balances on organic farms using the NDICEA model" by Laurence G. Smith and colleagues published in the October 29, 2015 issue is presented.

Worldwide greenhouse gas emissions (GHG) reached 59 Gt of CO 2 eq in 2019 and agricultural soils are the primary source of N 2 O emissions. Life cycle assessments (LCA) have been successful in assessing GHG from agricultural systems. However, no review and harmonization attempt has been focused on soil N 2 O emissions, despite the need to improve LCA methodologies for assessing GHG in agricultural LCA. We therefore undertook a review and harmonization of existing methods to account for soil N 2 O emissions in LCA of agricultural systems and products: i) to compare current methods used in LCA; ii) to identify advantages and iii) disadvantages of each method in LCA; iv) to suggest recommendations for LCA of agricultural systems; v) to identify research needs and potential methodological developments to account for soil N 2 O emissions in the LCA of agricultural systems. In this paper, we consider as soil N 2 O emissions, those originated from soils in relation to fertilisers (organic and manufactured), crop residues, land use/land management change, grassland management, manure and slurry applications and from grazing animals. The approach adopted was based on two anonymous expert surveys and a series of expert workshops (n = 21) to define general and specific criteria to review LCA methods for GHG emissions used in LCA of agricultural systems. A broad list of keywords and search criteria was used as the research involved GHG assessment in agricultural LCA. Reviewed papers and methodology were then assessed by LCA and soil N 2 O emission experts (n = 14). >25,000 scientific papers and reports were identified, 1175 were screened, 263 included in the final review and 31 scientific papers were related to soil N 2 O emissions. The results showed that a high level of accuracy corresponded to a low level of applicability and vice versa, following the assessment framework developed in this work through participatory approaches. The choice of LCA methods, critical for high quality LCA of agricultural systems, should be based on the assessment objectives, data availability and expertise of the LCA practitioner. However, it is preferable to use DNDC model after calibration and validation or direct field measurements, considering system effects. When necessary data are lacking, IPCC tier 2 methodology where available should be used, otherwise 2019 IPCC Tier 1 methodology. This LCA method development should be synchronous with improvements of quantification methods and the assessment of a wider range of agricultural management practices and systems. [Display omitted] • Methods used in life cycle assessment (LCA) of agricultural systems to account for soil N 2 O need to be improved. • A method harmonization was carried out and recommendations for soil N 2 O emissions were identified in agricultural LCA. • The results showed that a high level of accuracy corresponded to a low level of applicability and vice versa. • DNDC, DAYCENT and direct measurements scores high on accuracy to assess soil N 2 O emissions in LCA of agricultural systems. • Alternative to DNDC and measurements are IPCC Tier 1 or 2 methodologies to assess soil N 2 O emissions in agricultural LCA. [ABSTRACT FROM AUTHOR]

Life cycle analysis (LCA) is increasingly used to assess the environmental impacts of primary food production. As an alternative, impacts can be assessed at the farm level using holistic sustainability assessment tools. The purpose of this study was to evaluate whether an integrated approach combining a "detailed and narrow" LCA with a "broad and shallow" sustainability assessment could help integrate socioeconomic and ecosystem service evaluations in LCA by including a wide range of impact criteria. To address this overarching objective, we present results from whole-farm sustainability assessments using the Public Goods Tool (PGT), a tool developed in the United Kingdom (UK) by the Organic Research Centre, and cradle-to-farm-gate LCAs of beef, carrots and tomatoes for (i) a diverse agroecological case study farm (CSF) and (ii) a specialised agroecological production system. The use of the PGT enabled comparison with similar UK farm systems and was extended to develop biodiversity and social indices to complement the LCA. Results of the CSF demonstrated a relationship between environmental impacts and increased production efficiency, as the climate change impact per kg of product was strongly associated with higher yields, but this was less clear when impacts expressed per ha. The CSF produced less beef than the specialised system but more tomatoes and carrots, which reflects its higher labour input and less intensive production methods. The CSF generally used fewer external inputs, which decreased its overall impacts. Purchased feed contributed disproportionately to the water consumption of beef from the specialised system. PGT results highlighted the environmental benefits that can be delivered by 'diverse' agricultural systems and added detail to LCA results; for example the high labour input at the CSF helped generate social capital whilst partially explaining the reduced emissions from tractor operations modelled in the carrot LCA. We conclude that LCA may not be the most suitable tool to consider these wider aspects of sustainability and can only provide an estimate of environmental impacts. LCA helps understand which parts of the food system have the greatest impacts, and how they could become more sustainable, but it cannot determine sustainable agriculture alone. The addition of rapid farm-level multi-criteria sustainability assessment tools can complement the LCA results, help reveal 'blind spots', and encourage adoption by farmers. [Display omitted] • Life cycle assessment (LCA) of primary food production is challenging due to the inherent complexity of biological systems. • This study evaluates the extent to which LCA methods can capture the wider impacts of contrasting agroecological systems. • LCA is not the most suitable tool to consider these wider aspects and can only provide an estimate of environmental impacts. • The addition of rapid on-farm sustainability assessment tools complements LCA results and can encourage adoption by farmers. [ABSTRACT FROM AUTHOR]