Sustainable Application for Agriculture Using Biochar-Based Slow-Release Fertilizers: A Review

The continuous increase in the world population, combined with the rapid degradation of arable land, has put a strain on agricultural production. The excessive use of conventional fertilizers leads to environmental issues associated with the loss of nutrients through leaching, volatilization, denitrification, and surface runoff. Biochar-based slow-release fertilizers (BSRFs) derived from biomass waste could effectively alleviate environmental issues by improving soil properties, slowing nutrient release, and enhancing plant nutrient uptake efficiency. The goal of this review is to outline current progress in the agricultural application of BSRFs. The properties and construction of BSRFs were described. The raw materials source, preparation conditions, and slow-release mechanisms of BSRFs were introduced in detail. Nutrient composition and physicochemical properties of BSRFs could be selectively given, which provides a basis for practical agricultural application. Based on the evaluation of technical, economic, environmental, and political factors of BSRFs, it is proposed to apply BSRFs to agriculture and other fields such as urban parks and gardens.