Composting with additives to improve organic amendments. A review

Abstract

Composting and vermicomposting are sustainable strategies to transform organic wastes into organic amendments, valuable as potting media or soil conditioner. However, the negative aspects of these processes are emissions of greenhouse gases and odorous molecules and final product potentially containing toxic compounds. These negative aspects can be limited through the addition of organic, inorganic or biological additives to the composted or vermicomposted mixture. The aims of this review are (1) to present the main characteristics of composting and vermicomposting processes with and without additives, (2) to show the influence of additives on greenhouse gas emissions during waste degradation and (3) to report the effects of additives on the properties of the final products (heavy metal and nutrient contents), in view of their use as a soil conditioner or potting media. Finally, the feasibility and potential environmental benefits of co-composting and co-vermicomposting are discussed. Our results show that additives affect composting parameters such as temperature, pH and moisture and thus have an impact on the composting process. They may be used to reduce gas emissions and mobility of mineral ions. The various additives have contrasting effects on the quality of the final product and its impact on soil quality. The use of worms and additives seems to increase plant available nutrient contents, while decreasing N leaching, heavy metal mobility and composting time. Cocomposting and co-vermicomposting strategies need to be locally optimised, involving the generated amendments in a circular economy to improve sustainability of agricultural systems.

Influence of Organic and Inorganic Soil Amendments on Soil pH and Macronutrients

“…As previously reported by Doan et al organic amendments increase the soil carbon content and also the soil structure, which strongly agrees with the findings of this study. Th of this study also agrees with the findings of Barthod et al [22] who reported that use of organic amendment can lead to up to 45 g.kg ; Article no.JAERI.49182…”

Decentralized Community Composting: Past, Present and Future Aspects of Italy

“…Advantages and disadvantages of composting are widely taken apart in the literature. In the most common sense of the practice, composting enables the recycling of biowaste (i.e., kitchen waste, yard waste, agricultural waste) and reduces the amount of waste going to landfilling, helps to cease greenhouse gas (GHG) emissions when properly managed, increases soil fertility and biodiversity as well as decreases the need for chemical fertilizers when applied as fertilizer, and contributes to raising awareness and promoting community-scale waste management practice [6,18,19]. On the other hand, some concerns are also raised for improperly managed composting applications, such as the formation of malodorous or toxic gases and bioaerosols [6,20], odor [21], leachate [6] and a decrease in soil quality when heavily applied [22].…”

Nitrogen supply to arugula from pig slurry composts in contrasting soils

“…Although the use of automated composting has several advantages over traditional composting, as cited above, there are still doubts, especially in regard to the amount of N loss by ammonia (NH 3 ) volatilization and denitrification during the process. Several strategies have been evaluated to mitigate such losses, especially the use of additives during composting (Barthod et al, 2018), such as: acids (Doneda, 2014), zeolites (Giacomini et al, 2014) and retorted oil shale (Giacomini, 2017). Nitrogen loss by denitrification during composting can be reduced through the use of nitrification inhibitors, as demonstrated by Luo et al (2013) with dicyandiamide (DCD), which inhibits the first step of the nitrification process.…”

“…There are several studies involving the use of additives to reduce N losses during composting (Barthod et al, 2018;Cáceres et al, 2018), but none have evaluated the effect of additives on the N supply potential of the compost to crops. Moreover, there is still no recommendation for specific application dose of composts produced by automated composting of PS.…”