Summary
This long-term field study evaluated biosolids recycling to agricultural land at four English sites over 20 years, comparing plots receiving digested sludge cake (2.9–3.4 t ha⁻¹ y⁻¹) against untreated controls. Biosolids applications significantly increased soil organic matter (10–17%), available water capacity (up to 10%), and key nutrients (nitrogen up to 20%, phosphorus 48%, sulphur 30%), whilst approximately doubling earthworm populations where low-metal biosolids were applied. The findings support biosolids recycling as a sustainable means of maintaining soil fertility and structure without observed adverse effects on crop quality.
UK applicability
This study was conducted in England across multiple soil types and agroclimatic zones, making the findings directly applicable to UK agricultural policy and practice. The results provide evidence supporting the continued inclusion of biosolids recycling within UK sustainable agriculture and waste management frameworks, particularly for maintaining soil organic matter in conventional farming systems.
Key measures
Soil organic matter (SOM) content and light fraction SOM; available water capacity; water infiltration rate; aggregate stability; soil total nitrogen, extractable phosphorus, and total sulphur; earthworm numbers and weights; crop quality
Outcomes reported
The study quantified long-term impacts of 20 annual biosolids applications on soil physical, chemical, and biological properties across four contrasting English sites, measuring changes in soil organic matter, nutrient content, water capacity, and earthworm populations relative to untreated control plots.
Topic tags
Dig deeper with Pulse AI.
Pulse AI has read the whole catalogue. Ask about this record, its theme, or how the findings apply to UK farming and policy — every answer cites the underlying studies.