Work

Fulvic acid alleviates apple replant disease by promoting nitrogen uptake and regulating rhizosphere soil microbial communities

Year: 2026

Type: article

Abstract: Apple replant disease (ARD) poses a significant threat to the health and sustainable development of the apple industry. Chemical fumigation, as the most effective method, is limited due to residual pollution mitigation and other problems. It is crucial to find green and pollution-free prevention and control measures to replace chemical fumigation. Fulvic acid (FA) demonstrates considerable potential in promoting plant growth, resisting soil pathogen infection, and improving soil quality. In this study, we conducted a pot experiment to compare the changes in photosynthetic capacity, reactive oxygen species (ROS) scavenging capacity, 15 N uptake and utilization efficiency, and the abundance and community composition of soil bacteria and fungi in replanted apple rootstocks ( Malus hupehensis Rehd.) after exogenous application of different concentrations of FA, and explored the biocontrol effect of FA on ARD. We found that application of FA at 2 g·L -1 effectively mitigated replanting-induced ROS accumulation by enhancing photosynthesis and increasing the activities of defense enzymes in M. hupehensis Rehd. seedling roots. Furthermore, FA supplementation improved 15 N absorption and utilization by enhancing nitrogen-metabolizing enzyme activities in roots. Notably, significant changes were observed in the community structure of both soil bacteria and fungi, along with a substantial increase in bacterial and fungal abundance compared with treatments without FA addition. Additionally, FA supplementation significantly increased soil enzyme activities. Mantel test results indicated positive correlations between soil properties (except for pH), growth indices, 15 N uptake rate, and utilization efficiency. Spearman correlation analysis further revealed relationships of these factors with bacterial/fungal community composition, suggesting that microbial community composition plays a pivotal role in mediating changes within the replant soil environment, thereby affecting plant growth and nutrient uptake and utilization. In conclusion, FA can effectively alleviate ARD by promoting plant nitrogen uptake and optimizing soil microbial community structure.

Source: Horticultural Plant Journal

DOI: 10.1016/j.hpj.2026.01.008