Vermicompost and humic fertilizer improve coastal saline soil by regulating soil aggregates and the bacterial community

Soil salinity, poor soil structure and macronutrient deficiencies are three important limitations responsible for poor crop yields in coastal saline soils. Here we used humic fertilizer and vermicompost to ameliorate salt-induced stress by regulating the soil bacterial community and aggregates in different growth stages of winter wheat. Soil salinity, aggregates, nutrient availability, the soil bacterial community from next-generation high-throughput sequencing, and wheat yield were determined in this study. The results indicated that humic fertilizer and vermicompost could efficiently alleviate salt accumulation (by 16.8-41.1 and 13.3-42.7%, respectively) in topsoil by inhibiting resalinization and increase the proportion of soil macroaggregates (by 26.7-85.9 and 31.6-105.5%, respectively) in the wheat growth stages. Skermanella, Arthrobacter and Sphingomonas were the dominant genera in the study soil. Humic fertilizer and vermicompost could improve soil total N (by 4.7-15.6 and 2.4-25.2%, respectively), available P (by 15.9 and 7.3-64.4%, respectively), and exchangeable K (by 3.9-18.4 and 0.7-12.1%, respectively) by increasing the abundance of Arthrobacter and Pedobacter, consequently improving shoot biomass (by 41.1 and 52.8%, respectively) and grain yield (by 45.1 and 60.2%, respectively) of wheat. Therefore, vermicompost and humic fertilizer ameliorate salt-induced stress in coastal saline soil through the integrated improvement of soil physical, chemical and biological properties.