Organic farming leads evidence base on biodiversity and soil health

Organic farming has shown the strongest evidence of delivering Defra’s environmental goals in a major government-backed review.

The review, commissioned by the Department for Environment, Food and Rural Affairs and carried out by the Organic Research Centre, found that organic systems performed consistently well across key indicators including biodiversity, soil health and reduced chemical use.

It was based on more than 300 peer-reviewed studies, alongside farm-level data and assessments of environmental farm assurance standards.

The study examined how organic farming and other assurance schemes contribute to the government’s Environmental Improvement Plan (EIP) goals.

It found that organic farming currently had the strongest evidence base for delivering those goals in practice.

However, the review did not suggest organic systems delivered stronger outcomes in every category, and noted that some benefits depended on context, implementation and farm system design.

LEAF Marque was found to show strong environmental ambition, but the review said more robust farm-level evidence was needed to confirm its impact.

The findings come as farm assurance schemes play an increasingly important role in food supply chains, environmental claims, farm policy and debates over how public funding should support nature-friendly farming.

ORC Senior Researcher Dr Julia Cooper said the review used “robust methods” to assess how certified organic systems delivered against the ten EIP goals.

She said the study had identified “clear benefits from organic farming”.

The analysis combined an AI-assisted review of more than 300 peer-reviewed papers with farm-scale sustainability assessments and standards mapping against EIP goals.

Indicators included biodiversity, water quality, soil health and greenhouse gas emissions.

The review also looked at selected organic practices, including ley phases, genetically diverse seeds and herbicide-free weed control.

Researchers said this helped explain how specific organic management approaches could contribute to environmental goals, although benefits could depend on context, implementation and farm system design.

The Defra-commissioned analysis found that organic farming performed particularly well in promoting biodiversity, improving soil health and reducing chemical exposure.

Evidence for these outcomes was described as consistently strong, with organic systems shown to support wildlife, build more resilient soils and significantly limit pesticide use.

Dr Cooper said organic farming also made positive contributions to water quality and climate resilience, particularly through improved soil structure and greater system diversity.

However, the review found that more research was needed to fully understand organic farming’s impact on greenhouse gas emissions and air quality.

By contrast, LEAF Marque standards were found to reflect a broad commitment to environmental sustainability across a wide range of EIP goals.

These included climate change mitigation, resource efficiency and public engagement.

But Dr Cooper said the study found limited empirical evidence to prove that these ambitions consistently translated into measurable on-farm outcomes.

She said: “While some LEAF Marque farmers report improvements in biodiversity, and standards promote practices such as integrated pest management and nutrient planning, the lack of accessible, farm-level data makes it difficult to draw firm conclusions about overall performance.”

The review found LEAF Marque standards had strong environmental ambition, but said more accessible farm-level data was needed to show how consistently those standards translate into measurable outcomes.

This could include enhanced reporting through its Sustainable Farming Review to show real-world impact more clearly.

Christopher Stopes, Co-chair of the English Organic Forum and Policy Adviser to Organic Farmers & Growers CIC, welcomed the findings.

He said: “This excellent synthesis and analysis of the available evidence for the multi-functional benefits of organic is welcome.

“Defra must be congratulated for commissioning the experts ORC to undertake it.”

Mr Stopes said organic was “widely acknowledged as a well-defined and regulated option” for improving the environmental outcomes of food and farming.

He added: “Consumers and citizens know what organic stands for.

“This review will surely strengthen Defra’s commitment to publish an Organic Action Plan for England and grow the production base.”

The study concluded that stronger monitoring, verification and data sharing across all assurance schemes would be needed to show how they contribute to national environmental targets.