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

Rice yields in the black soil region of Northeast China have 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 high cost effectiveness and great potential to improve soil fertility. However, the specific effects of A-HS on rice nursery soil nutrient levels 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 to better understand the application mechanism of A-HS. The results indicated that application of A-HS significantly increased DOM content of the native or seedling soils and improved soil nutrients. In addition, the root growth and yield of the seedlings at maturity were effectively promoted. More interestingly, the application of A-HS significantly altered growth-promoting bacteria, such as Noviherbaspirillum, Klebsiella and Pedobacter, improving natural barrier formation and soil nutrient conversion. Current results indicate that by altering soil bacterial communities, A-HS significantly enhanced nutrient uptake and accumulation by the crop. In general, this research from multiple aspects demonstrated that the application of A-HS in rice production could be profitable and sustainable. The current study provides valuable insights into the benefits of A-HS in promoting plant growth and development, which could have important implications for agriculture and food security.