Phosphorus fertilizing Potential of Biochar derived from agricultural residues: A review

Phosphorus (P) is the second most important nutrient after nitrogen for plant growth. 30-40% of the arable soils are low in P over the world. To guarantee food security for the increasing world population, mineral fertilizers including P fertilizers have been widely supplied to maintain soil nutrients at a high-level favoring crop growth. On the other hand, a high P rate to create a high soil P availability may increase the risk of P loss through soil leaching, runoff, and erosion. In the recent world introduced Biochar as a potential material for making slow-releasing phosphorus (P) fertilizers for the sake of increasing soil P use efficiency and mitigating P losses. Therefore, the recycling of P in agricultural residues is critical for P sustainability in agricultural systems, which is dominated by the route of direct land application. Biochar production from agricultural residues and its subsequent land application has been suggested as solutions for waste biomass disposal, carbon sequestration, soil amendment/remediation, and crop production promotion. Phosphorus in agricultural residues can be retained and transformed into stable forms of P in the resulting biochar. Thus, compared to agricultural residues, biochar provides lower amounts of labile P and releases its P more slowly while providing a long-lasting P source, and the loss potential of P from biochar is reduced by low mobility of its P, indicating that the biochar based P recycling route could substantially promote P recycling by acting as sustainable P source and diminishing the loss of P applied to the soil. It was also reviewed that biochar has a high potential of improving phosphorus availability in P fixing acid soils and its high liming potential to decrease soil acidity. On the other hand physical and activation of biochar produced from agricultural residues by using different single and dual metal oxides was suggested as a novel strategy to adsorb phosphate from wastewater which in turn cause severe environmental pollution.

Author(s): Guta Amante

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