From Field Waste to Soil Resource: Recycling Agricultural and Biomass By-Products for the Conservation and Remediation of Soil in Agroecosystems

Agroindustrial and biomass-processing activities generate substantial volumes of organic residues — including crop biomass ash, woody by-products, and brewer’s spent grain — that are routinely landfilled or left with no structured end-of-life management. Simultaneously, and most urgently, agroecosystems face mounting pressure from soil degradation, declining organic matter, and contamination by potentially toxic elements (PTEs) linked to decades of intensive land use, industrial activity, and mismanaged waste disposal. The remediation of PTE-contaminated and structurally degraded soils represents one of the most critical challenges in contemporary agronomy and environmental science. The convergence of these two challenges presents a significant opportunity: redirecting organic waste streams toward productive use as soil amendments, with particular emphasis on their application in contaminated, degraded, and marginal land systems, and with broader benefits for soil quality, carbon sequestration, phytoremediation-integrated management, and the ecological restoration of impaired agroecosystems. This approach is central to circular economy principles in agriculture and aligns directly with global sustainability goals, including SDGs 2, 12, 13, and 15, making it a research priority across environmental science, agronomy, and waste management.Despite a growing body of work on individual materials, the evidence base for using agricultural and biomass-derived by-products as soil amendments remains fragmented across crop types, soil conditions, and geographical contexts. Key questions remain unresolved: how do pre-treatment and bioprocessing methods — such as pyrolysis, composting, or thermal conversion — determine the safety and agronomic function of the resulting amendment? What are the risks of introducing phytotoxic compounds or potentially toxic elements into agroecosystems via insufficiently treated materials? How do these amendments interact with soil microbial communities, nutrient cycling, and plant uptake specifically in PTE-contaminated or structurally degraded soils? And how can circular phytomanagement — the deliberate cultivation, harvest, and reprocessing of biomass grown on contaminated or marginal land — generate safe, agronomically effective amendments that close the remediation loop?This Research Topic addresses these questions with contaminated-soil remediation and circular phytomanagement as its organising framework. It brings together studies that evaluate the full cycle from organic waste generation and bioprocessing through to field-scale amendment application, with a particular focus on degraded, contaminated, and marginal soils as the primary target systems. Environmental safety assessment, bioprocessing, soil-plant interactions, and scalability within circular agricultural systems are all in scope, but contributions grounded in contaminated-soil or phytomanagement contexts are especially encouraged.This Research Topic welcomes contributions that examine the productive reuse of agricultural, agroindustrial, and biomass-derived by-products as soil amendments and organic inputs in agroecosystems. All submissions should connect findings to waste management outcomes, environmental impact, or agroecosystem implications. Specific subthemes include, but are not limited to:• By-product amendment characterisation and bioprocessing: Physicochemical properties, trace element content, safety assessment, and pre-treatment methods (e.g. pyrolysis, composting, and thermal stabilisation) that render organic amendments derived from crop residues, woody biomass, and energy crops safe and agronomically effective — including ashes, thermally converted chars and biochars (as relevant for soil carbon sequestration and PTE control or reduction), composts, and processed agroindustrial residues.• Phytotoxicity and food safety: Detection and mitigation of toxic compounds and potentially toxic elements in treated and untreated organic amendments.• Soil remediation and PTE interactions in the soil-plant system: Effects of organic amendments on PTE immobilisation, bioavailability, and plant uptake in contaminated soils; soil quality recovery, microbial community responses, nutrient cycling, carbon sequestration, and crop performance in degraded or impaired agroecosystems.• Circular phytomanagement: The full management cycle for biomass harvested from phytoremediation or marginal-land systems — from contaminant uptake and harvest through bioprocessing to safe reintegration back into agroecosystems as amendments, including risk assessment at each stage.• Environmental risk and LCA: Life-cycle assessment and ecological risk evaluation of organic amendment supply chains and circular reuse strategies.• Policy and scalability: Regulatory frameworks, regional waste stream availability, and economic feasibility of organic amendment supply chains. Topic editors: Valentina Pidlisnyuk, Abdulmannan Rouhani, Karim Al Souki, Paula Alvarenga Source: https://www.frontiersin.org/research-topics/83164/from-field-waste-to-soil-resource-recycling-agricultural-and-biomass-by-products-for-the-conservation-and-remediation-of-soil-in-agroecosystems