Achieving Rapid Soil Regeneration by Reducing Pollution

Aled Rhys Davies NSch, Founder of Pruex Ltd

Abstract

Pollution from livestock systems is often seen as inevitable, yet new microbiological approaches show that this need not be the case. The Welsh Government contracted Pruex to demonstrate how managing microbial biofilms in water, housing and slurry systems reduces ammonia emissions and accelerates soil regeneration. Trials on Welsh dairy farms show that stabilising nitrogen as ammonium within slurry reduces odour, improves silage sugar and true digestible protein levels, and strengthens soil biology. By reducing ammonia losses, less nitrogen is lost to the atmosphere and more remains available for plant uptake, cutting fertiliser dependence. These results reveal how microbial management offers a scalable and rapid, low-cost route to cleaner air, healthier soils, and more profitable livestock farming.

Introduction

Who knew that rotting, fermenting slurry could have such a detrimental effect on cow health, grazing, and silage quality? When we first started measuring what was happening on farms, it became clear that pollution from slurry wasn’t just an odour problem – it was making cows sick, spoiling feed, polluting the environment, and driving the demand for synthetic fertiliser. Ammonia on dairy farms wasn’t just an air issue; it was holding soils back.

Ammonia (NH₃) emissions from livestock systems represent a major nitrogen loss pathway. Once released, ammonia reacts in the atmosphere to form fine particulates, contributes to acid rain, and reduces biodiversity. Yet within slurry and soil, nitrogen is valuable – essential for plant growth. The challenge, therefore, is to retain nitrogen in the system in a stable, bioavailable form. Pruex has approached this problem biologically, working to shift microbial communities from putrefactive, gas-forming processes toward stable, nutrient-cycling biofilms.

Materials and Methods

Between 2022 and 2024, eight dairy farms in Wales participated in comparative trials: four treatment farms using the Pruex protocol and four control farms.

• On treatment farms, Pruex bacteria were added to cows’ drinking water, sprayed post milking on udders and cubicles, and applied daily to concrete floors where slurry collects.
• Control farms received no microbial intervention.

Samples of slurry, soil, and forage were taken periodically and analysed for:

• Ammonium (NH₄⁺) concentration using standard Kjeldahl methods.
• pH, density, and odour via hydrometer and sensory assessment.
• Silage quality, including sugars (g kg⁻¹ DM) and true digestible protein (TDP).
• Soil health indicators: earthworm activity, texture, and organic matter content.

Statistical analysis used paired t-tests to compare treatment vs control outcomes.

The goal was to quantify how microbial intervention influenced nitrogen stabilisation, soil biology, and feed quality. In parallel, observations of animal health, bedding cleanliness, and air quality were recorded to link environmental improvement with cow welfare and productivity.

Results

• Ammonium retention: Treated slurry contained 43% more bound ammonium than control (p = 0.006).
• Odour and consistency: Treated slurry was denser, darker, and less malodorous, with minimal solid and liquid separation.
• Soil response: Earthworm survival and activity increased markedly in contact with treated slurry, confirming reduced toxicity.
• Silage analysis: Grass grown from treated fields yielded silage with 262g kg⁻¹ DM sugar and 96g kg⁻¹ DM true digestible protein, compared with control values of 55g kg⁻¹ DM sugar and 60g kg⁻¹ DM TDP.
• Fertiliser requirement: Farmers reported reduced need for synthetic nitrogen, as nutrients recycled more effectively through slurry and soil.
• Animal environment: Cows in treated housing showed cleaner flanks and improved lying behaviour, with fewer signs of respiratory irritation.

These outcomes suggest that shifting microbial populations from anaerobic, putrefactive communities toward beneficial biofilms stabilises nitrogen, suppresses pathogens, and enhances the soil-plant-animal cycle.

Discussion

Ammonia reduction delivers far more than an air-quality benefit. By retaining nitrogen as ammonium, we preserve a key nutrient that otherwise volatilises and is lost. The stabilised slurry effectively acts as a slow-release fertiliser. When applied to land, it feeds soil microorganisms that build humus, increase water retention, and release nutrients in synchrony with plant demand. This regenerative feedback loop rebuilds soil structure and fertility. The biological principle is straightforward:

• Pathogenic and putrefactive bacteria dominate when organic waste accumulates in oxygen poor, nutrient-imbalanced environments.
• Introducing beneficial, spore-forming bacteria within animal housing re-balances that ecology.
• These species form protective biofilms to out-compete harmful microbes.

As soil and slurry ecosystems stabilise, greenhouse-gas-producing reactions (ammonification, methanogenesis, denitrification) are moderated. Farmers benefit through improved feed conversion, lower fertiliser costs, and reduced disease pressure – aligning profitability with environmental responsibility. This approach complements national and Welsh Government targets on air-quality improvement and nutrient management. The data demonstrate that microbial solutions can provide measurable, practical progress toward Net Zero and Sustainable Farming Scheme goals.

Conclusion

The work demonstrates that rapid soil regeneration is achievable when pollution is biologically managed rather than chemically tolerated. By reducing ammonia emissions through microbial intervention, nitrogen remains in circulation, soil life flourishes, and farm inputs decline. These results bridge the gap between air-quality policy and soil-health reality: fewer emissions mean more fertility retained on farm.

For the British Cattle Breeders Club audience, this signals an integrated future where microbiology, animal welfare, and profitability align. The next steps include broader adoption studies, longer-term soil carbon tracking, and the development of regional demonstration farms showing how reducing pollution restores resilience across livestock systems.

References

Flemming, H.-C. & Wingender, J. (2010). The biofilm matrix. Nature Reviews Microbiology, 8(9), 623-633.

Wang, C. et al. (2019). Bacillus species and nitrogen transformation in manure systems. Applied and Environmental Microbiology, 85(15).

D’Accolti, M. et al. (2021). Reduction of antimicrobial resistance through environmental microbiota management. International Journal of Environmental Research and Public Health, 18(10)