Amino acid fertilizer strengthens its effect on crop yield and quality by recruiting beneficial rhizosphere microbes.

Background: There is currently an increase in the use of new types of fertilizers in modern agriculture. Studies have shown that amino acid fertilizers can improve crop yield and quality. However, their effects on crop rhizosphere ecology and their ecological impacts on crop yield are largely unknown. This study evaluated the effects of a water-soluble amino acid fertilizer (WAAF) on tomatoes and its ecological effects on rhizosphere bacterial communities using greenhouse pot experiments.

Results: The results showed that WAAF could promote the growth of tomatoes and improve the quality of fruits more effectively than water-soluble chemical fertilizer controls. Interestingly, WAAF showed a different regulating pattern on root exudates and increased the secretion of 17 major water-soluble root exudates, including hexadecanoic acid and 3-hydroxy-γ-butyrolactone. Water-soluble amino acid fertilizer also affected noticeably the composition, abundance, and beta-diversity of rhizosphere bacterial communities, and strengthened the potential relationships between community members. Water-soluble amino acid fertilizer showed a significant selective enrichment ability and recruited some members of the genera such as Cupriavidus, Ralstonia, Chitinophaga, Gemmatimonas, Mitsuaria, Mucilaginibacter, Paracoccus, Sphingopyxis, and Variovorax. Network analysis and functional prediction implied that, besides fertilizer effects, the recruiting of beneficial microbes involved in chemotaxis and biofilm formation was also a considerable factor in tomato yield and quality improvement.

Conclusion: Our study revealed ecological and recruiting effects of WAAF on rhizosphere microbes and potentially beneficial microbiota, and provided a basis for the amino acid fertilizer regulation of rhizosphere ecology to improve soil health and further improve crop yield and quality. © 2023 Society of Chemical Industry.