A review of microplastics pollution in the soil and terrestrial ecosystems
Biogas production is an emerging energy technology, which serves likewise as a waste treatment and reduction method. As the biogas production process undergoes sustainable economic and waste management development, biogas residue, digestate, should have a useful purpose. Due to its high-value nutrient content, digestate is often acknowledged as an inexpensive fertilizer or soil improver in agriculture.
Preceding the review, biogas, anaerobic digestion, and digestate reviewed in basics, presenting background information for digestate applications. Recent articles report the agricultural potential and conflicting results of digestate performances. Consequently, the effectiveness of the digestate as an organic amendment and fertilizer is still under deliberation.
The objective of this thesis is to study the effects of digestate on the properties of soil fertility and productivity literature of anaerobic digestates. These physical, chemical, and biological properties of the digestates, and their influence on soil subsurface’s fertility and plant growth, were characterized. This is validated through a comparative analysis study between anaerobic digestates, animal manure, and synthetic fertilizers from short to mid-term soil and crop yield for lettuce, tomatoes, maize. The organic substance and the nutrient content of the digestates varied largely between the digestates with the feedstock materials as major influencing factors. The N-mineralization potential of digestate added to soil showed that a high proportion of digested municipal solid household waste & composted municipal solid household waste immobilized the nitrogen in the soil. Two compost parameters allowed to predict the risk of nitrogen immobilization in soil: the NO3- and the C/N dynamic. It is found that digestates can be regarded as organic amendments or organic fertilizers when adequately handled, managed, and optimized. Indeed, it’s further established that anaerobic digestates can have positive effects on their yield properties such as soil organic carbon, potential ammonia-oxidizing rate, and potential nitrification activity. A combination of inorganic fertilizer with digestate did better than digestate or synthetic fertilizer only application. Digestates and composts increased the biological activity of soil. Regarding the fertilizer properties of digestates, it's shown that their efficacies lie between those of livestock manures and NPK fertilizers, with many occurrences where digestates equaled mineral fertilizers. It detailed that the fertilizer efficacy of liquor digestates depends on the nature of the feedstock. Although some research progress has been accomplished, it needs more specific studies to advance knowledge on anaerobic digestates and their contribution to sustainable and environmentally sound agriculture.
