Modulating effects of biochar on phosphorus dynamics in soil–biota–plant system: a comprehensive review
摘要
Phosphorus dynamics in soil–biota–plant system of the charosphere was reviewed. Phosphorus content of biochar is a feedstock–and pyrolysis temperature–dependent. Biochar stimulates colonization of microorganisms mediating phosphorus availability. Modulating effects of biochar on phosphorus use efficiency was highlighted. Tailoring functionalized biochar to unlock phosphorus reserves was reviewed.
Phytoavailability of phosphorus (P) is limited in most soil orders due to insoluble precipitates formation in the rhizosphere with ions of calcium, iron, and aluminum. Therefore, biochar has been adopted as an eco-friendly soil amendment to unlock soil P reserves and modulate P dynamics in soil–biota–plant system. However, this hotspot area of research has not been critically reviewed up to now. This review delves into the specific mechanisms responsible for improving P phytoavailability in the charosphere, either directly by its inherent P content or indirectly via modulating soil physicochemical characteristics that would solubilize the legacy P. Data of this review were extracted from recent publications to evaluate the beneficial effects of biochar on mechanisms responsible for modulating P phytoavailability in the charosphere. Data analysis illustrated that inherent P content in biochar is a feedstock–and pyrolysis temperature–dependent, in which bones feedstock and the high pyrolysis temperature (>600 °C) could produce the highest P concentration (124 216 and 31 160 mg kg−1, respectively). Biochar showed pivotal roles in stimulating the colonization of microorganisms mediating P phytoavailability involved in organic P mineralization and legacy P solubilization. The high functionality of biochar also showed a beneficial effect in minimizing the vulnerability of P losses through surface runoff and percolation into groundwater. These modulating effects of biochar were responsible for maximizing P use efficiency (PUE) relative to the unamended soils (43.36% vs. 20.26%). %Average values of PUE varied widely according to biochar’s feedstock (29.1%–38.5%), pyrolysis temperature (9.4–60.1) and application rate (29.9%–88.1%). Nonetheless, this data showed contradictory results with obvious significant effects under lab investigations and only minimal effects under field-scale experimentations.