Encapsulated biochar-based sustained release fertilizer for precision agriculture: A review

The excessive use of conventional fertilizers leads to environmental issues associated with the loss of nutrient through leaching, volatilization, denitrification and surface run-off. Biochar-based fertilizer has gained much research interest as it can be used as a slow release fertilizer. Biochar-based fertilizer can alleviate the properties of soil to slow down the nutrient release rate. However, the sustained release mechanism of biochar-based fertilizer is still facing limitations. As a solution to mitigate this issue, the integration of encapsulating technology and biochar-based fertilizer has been introduced to improve the sustained release mechanism. This paper presents an extensive overview on the various formulations of biochar-based fertilizer and encapsulated biochar-based fertilizer. Additionally, the influence of the inorganic mineral, polymer and hydrogel-based fertilizers on the nutrient release behaviour are also critically discussed. The various methods used to synthesize the fertilizers and their effects on soil amendment are also discussed in detail. This paper could be used as a good source of information on the current advances and future perspectives of encapsulated biochar-based sustained release fertilizer for precision agriculture.The authors acknowledge the research grant provided by Universiti Malaysia Sarawak under Cross Disciplinary Research Grant [ F02/CDRG/1830/2019 ].Scopu