Recycling Organic Wastes in Agriculture

Dear Colleagues,

Agricultural recycling of organic wastes (including the residuals from municipal or industrial biodegradable waste treatment and biosolids from municipal wastewater treatment) enables the beneficial recovery of essential plant nutrients to maintain agronomic productivity, and of organic matter, to improve soil physico-chemical properties. As nutrient sources, these materials provide effective fertilizer replacements, and their agricultural utilization contributes to the development of a circular economy for nutrients. For instance, recycling organic wastes in agriculture conserves finite phosphate resources and the embodied energy from industrial nitrogen fixation, thus supporting the goal of sustainable food production. Organic wastes, such as waste wood and paper sludge, also provide alternative types of livestock bedding. The agricultural uses of municipal and industrial wastes are regulated to protect human health and the environment. Source-separated materials may be eligible for end-of-waste status if they meet recognized quality criteria, in which case they become fully recovered products. In some jurisdictions, however, treated residuals derived from mixed waste streams, such as compost or digestates from mechanically segregated biodegradable municipal solid waste, may be considered unsuitable for end-of-waste status or for agricultural use altogether due to quality concerns, despite them potentially achieving relatively similar standards. Without a sound scientific rationale, policy development to agricultural recycling becomes confused and illogical, restricting the opportunities for beneficial use. Understanding the fundamental agronomic properties of different types of organic waste materials applied to land is essential for the development of appropriate fertilizer guidance and best management practices. These need to consider not only phosphate losses and nitrate leaching, but also the relationships between waste and soil properties and possible denitrification mechanisms and nitrous oxide production as a potential greenhouse gas emission source. The survival of infectious microorganisms, the consequences for the food chain and the environment of the long-term accumulation of potential toxic elements in soil and of organic contaminants in organic residuals, and potential odor emissions, are further important challenges to agricultural recycling. However, these can also be managed and addressed by sound scientific understanding.

This Special Issue invites contributions from authors of original research or review articles on any aspect of agricultural recycling of organic wastes, including, for example, fertilizer use efficiency, nutrient transformations and transport, denitrification, best management practices, effects on soil physical properties, crop production and quality, potentially toxic elements, organic contaminants, microbial pathogens, odour control, livestock bedding materials and environmental risk assessment.

Stephen R Smith
Guest Editor

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• biowaste
• biosolids
• nutrients
• fertilizer value
• soil quality
• organic matter
• pathogens
• potentially toxic elements
• organic contaminants
• plant uptake
• food chain
• nitrogen
• phosphorus
• odour
• denitrification
• nitrous oxide
• livestock bedding