The value of a more comprehensive assessment of agroecological farm systems
(Photo: PfL certified Romshed Farm Kent, by Our Isles)
PfL Research Officer Sara highlighted the importance of adopting a truly holistic approach to farm sustainability assessments, built on by this article by PfL Research Officer Charlotte, discussing the trade-offs involved when we prioritise one sustainability metric over another, such as greenhouse gas emissions.
Building on this, Laurence Smith, a member of the PfL Research Group at the University of Reading, makes the case for the value of a more comprehensive view of farm sustainability. He has co-authored this paper advocating for the integration of holistic sustainability assessment tools with life cycle analysis (LCA) to achieve a thorough evaluation of agroecological systems, which doesn’t overlook the multi-functional role of agricultural landscapes that provide ecosystem services and wider benefits to rural society.
Essentially Laurence’s paper looks to compare a Case Study Farm (CSF) defined as a highly diverse crop (carrots) , horticulture (tomatoes) and livestock (beef) organic enterprise with equivalent UK farms that are not as diverse in their production i.e. specialising in only producing one product e.g. beef.
A key conclusion from the study “Life cycle analysis 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 life cycle analysis results, help reveal ‘blind spots’, and encourage adoption by farmers”.
They assessed both the Case Study Farm and the specialist farms in 2 ways.
1. Life Cycle Assessment (LCA)- a mathematical equation to determine the environmental impact of the farm from cradle to the farm gate sale in relation to, climate change , water consumption and land use. LCA is considered by the authors as a detailed but narrow assessment
2. PGT (Public Goods Tool) – a holistic and qualitative approach achieved through interviewing the farmer and using existing farm data that highlights the performance of a farm against multiple criterias in social, economic and environmental sustainability. It is considered by the authors as a Broad but Shallow assessment
(Photo: Public Goods Tool assessment)
The paper concludes that the beef produced by the CSF, due to the lack of intensification and low inputs, had as expected, a higher global warming potential per kg of liveweight and per hectare of land, producing 2kg less of beef per ha than specialist beef farms. This highlights that production efficiency strongly influences climate change impact when calculated in LCAs ie the more beef one animal produces in the shortest amount of time the less methane emissions have to be attributed per kg of produce.
However this leads to Jerons paradox that the production efficiency gains also increase resource consumption (e.g. bought in food, fertiliser and fuel consumption) and overlooks the multifunctional role of agricultural landscapes that provide ecosystem services and wider benefits to rural society.
The authors found that when looking at the performance of farms, based on the completed PGT that the CSF had lower inputs (fuel, bought in forage and fertiliser) and a 50% reduction in water consumption within the system compared to the specialist system. It particularly highlighted the higher social capital, agricultural systems diversity and agri-environmental management of the CSF farm.
Essentially the paper highlights that when LCA is used on its own it is unable to capture the complex, contextual aspects of farm sustainability that reflect diverse and resilient systems and so the results from LCA should be interpreted with caution.
The authors support the proposal for LCAs to adapt into LCSAs (Life Cycle Sustainability Assessments) and that PGTs (Public Goods Tools) could be the best way to inform this development. This will ensure that LCAs evolve, to integrate the socioeconomic and ecosystems services of farms.
