Production and physico-chemical properties of biochar and its impact on phosphorous release for soil improvement: A review

Through a process known as pyrolysis, biomass of various biological origins is thermally decomposed to produce biochar, a solid carbon-rich substance. Biochar has enormous potential to cut greenhouse gas emissions, sequestering carbon in the soil, revitalizing depleted soils, and reducing the dependence on chemical fertilizers in agricultural practices. Furthermore, it improves the soil's physical, chemical, and biological properties while raising healthier plant growth. As a result of these attributes, there is a growing interest in integrating its utilization in agriculture, soil and land rehabilitation, and strategies aimed at mitigating climate change. The impact of biochar application can range from neutral to highly beneficial, contingent upon several factors, such as the source of the raw materials, the conditions during carbonization, the frequency and method of application, as well as the quantity applied. A suitable niche that biochar can provide for soil bacteria can lead to an improved pattern of growth and proliferation. The vital mineral phosphorus (P), which is usually lacking in plant nutrition, must be managed sustainably in order to preserve soil fertility and crop yield over the long term. Biochar may also help to improve P availability in soil by providing habitat and carbon supply to phosphate solubilizing bacteria (PSB) which can solubilize P compounds of low solubility. Integrated application of biochar and PSB can therefore, be exploited as ecofriendly strategy for the enhancement of PSB activity in soil to mobilize higher P for increased plant productivity. In conclusion, this review suggests that improving soil chemical properties by adding biochar not only requires consideration of biochar application rates and chemical properties but also the local soil environmental factors, especially soil initial pH and sand content of the soil, should be considered. © 2023 The Author(s)