Abstract: Over the last 30 years, water eutrophication caused by excessive application of phosphorus (P) fertilizer to soil has attracted much attention. Lowmolecularweight organic acids in root exudates can mobilize the accumulated P in soils and thus enhance P availability, which has become a research hotspot. We reviewed recent advances about the activation effects of lowmolecularweight organic acids on soil inorganic and organic P, as well as the activation mechanisms by comparing the changes of different P forms in experiments before and after soil P activation. Release of soil inorganic P induced by low molecular weight organic acids mainly contributes to P transformation from low availability to high availability. However, release mechanisms of soil organic P induced by low-molecular-weight organic acids are still not clear, which needs to be further studied. Future studies should focus on the synergistic mechanisms between low-molecular weight organic acids and P fertilizers. Moreover, more studies are needed on the release mechanisms of soil P (especially organic P) induced by low-molecular-weight organic acids.

Key words: shading, rice, CH₄ flux, hyperspectral estimation, vegetation index