Mechanisms of organic amendments in ameliorating black soil acidification: a review

In natural conditions, the acidification process of black soil is extremely slow. However, due to the over-reclamation of cultivated land, especially the long-term and excessive application of chemical nitrogen fertilizers, the acidification of black soil has been accelerated. Owing to their unique physical and biological properties, organic amendments can effectively regulate soil pH and thus improve the quality of black soil, which has attracted widespread attention. Nevertheless, the comprehensive effects of different types of organic fertilizers on the acidification of black soil remain unclear. This paper summarizes the research progress of organic amendments on the amelioration of black soil acidification from three aspects: reducing acidity, improving the physical and chemical properties, and enhancing its biological characteristics. It clarifies the influencing factors and existing problems of organic amendments in mitigating black soil acidification, and outlines the future research directions. The aim is to provide practical references for alleviating the acidification of Northeast China's black soil, and thus ensuring food security, and promoting the sustainable use of black soil.