Exogenous application of artificial humic substance can improve black soil properties and rice yield

Rice yield in the black soil region of Northeast China has been declining due to severe soil fertility degradation caused by both biotic and abiotic factors. Artificial humic substance (A-HS) has attracted much attention due to its high cost-effectiveness and great potential to improve soil fertility. However, the specific effects of A-HS on nutrient contents in rice nursery soils remain unclear. This study systematically investigated the effects of rational application of A-HS on soil nutrient turnover and yield and analyzed the changes in soil nutrients and microbial communities at Qianfeng Farm, Northeast China. The results indicated that the application of A-HS significantly increased soil dissolved organic matter and nutrient contents in the native and seedling soils. In addition, the root growth and yield of the seedlings at maturity were effectively promoted. More interestingly, the application of A-HS significantly altered plant growth-promoting rhizobacteria, such as Noviherbaspirillum, Klebsiella, and Pedobacter, improving natural barrier formation and soil nutrient conversion. It could be concluded that A-HS significantly enhanced crop nutrient uptake and accumulation by altering soil bacterial communities. In general, the application of A-HS could be profitable and sustainable in rice production. The current study from multiple aspects provides valuable insights into the benefits of A-HS in promoting crop growth and development, which could have important implications for agriculture and food security.