Improving sustainability and mitigating environmental impacts of agro-biowaste compost fertilizer by pelletizing-drying

Although for the past 100 years, fertilizer technologies have increasingly used renewable resources, the majority of manufactured products are still based on mineral deposits and fossil fuels. The European Commission has set a goal of 30% reduction of non-renewable resources in fertilizer production. This can only be accomplished if there are incentives for wastes valorization and fines for making use of non-renewable raw materials. This will enable the reduction of eutrophication of surface waters due to the presence of nitrogen and phosphorus, originating from agricultural fields fertilizers. The use of biological waste is a practical solution to recover valuable fertilizer components. In order to effectively implement technologies based on biological resources, it is necessary to construct small wastes solubilization or fertilizer installations at the site of waste generation, which will solve the problem of waste transport or sanitary hazards. Show more

The vegetables supply chain of intensive farming systems has gained huge relevance due to environmental pollution, residual toxicity towards microorganisms and humans, development of plant pathogen resistance, biodiversity loss, and hazard to human health. Studies addressed to clean from misuse of plant fungicides, soil fumigants, and fertilizers have encouraged the search of eco-friendly alternatives. This paper aims to give deeper understand of new insights for on-farm composting and compost-based tea application for soil and plant through the virtuous reuse of agricultural waste. On-farm composting is viable option thanks to benefits on soil quality and plant health which valorize underused biomass. This paper critically discusses and compares the most promising technologies in order to recycle in situ residual biomass into high-value added products for soil amendment (compost) and plant treatment (compost-based tea). Compost contains minerals, heavy metals, humic substances, and endogenous microorganisms to improve soil quality. Compost application had many benefits against plant pathogens and diseases due to innovative tailored formulates. Compost can be employed either alone or in combination with exogenous microbial consortia (protists, fungi, oomycetes, yeast, actinomycetes, and bacteria) acting as biological control agents by fitting the agrochemical market requirements for improving soil quality and plant health. Liquid formulations made of crude compost-based teas and/or tailored mixtures of humic acids, fulvic acids, humin, macro-micronutrients, and endogenous microbiota have many benefits for plant growth and crop health. Nonetheless, the complex European regulations and national laws, manure surplus, variability in availability and transporting of compost, variability in compost quality and feedstock composition, greenhouse gas emissions, and energy requirement were very hard barriers for on-farm composting and compost derivatives application. Recommendations, novelties, innovations, sustainability, and directions of future researches that may help to solve a number of these issues under the new perspective of a circular economy system were presented and discussed. Show more