Application of malrstone-based conditioner and plantation of Jerusalem artichoke improved properties of saline-alkaline soil in Inner Mongolia

Soil salinization is a critical environmental issue restricting agricultural production. Inner Mongolia is one of the areas with severe land salinization in China. This study aimed to investigate the effects of conditioning agent (containing marlstone and a range of enzymes) and cultivating Jerusalem artichoke on saline soils in Inner Mongolia. The effects of conditioner (0, 0.06 and 0.18 kg/m2) on soil physical, chemical and biological properties, including soil carbon fractions and microbiota in saline soils planted with Jerusalem artichoke, were characterized. The results showed that soil salinity was reduced significantly after cultivating Jerusalem artichoke and declined also after the conditioner addition. The application of conditioner increased the content of DOC (dissolved organic carbon), HFOC (heavy fraction organic carbon) and the content of aggregates >0.25 mm compared to the soil planted with Jerusalem artichoke alone. The relative abundance of halophilic bacteria such as Thioalkalivibrio and Thiohalobacter was greater in the CK (non-treated control). By contrast, the relative abundance of microorganisms with the carbon assimilation and nitrogen fixation capacities, such as Cyanobacteria and Rhodovulum, was greater in the conditioner-treated and Jerusalem artichoke-planted treatments. The planting of Jerusalem artichoke reduced soil salinity, increased soil organic carbon fractions, improved soil structure, and altered the soil microbial community, with the application of the conditioning agent enhancing these positive changes. The co-occurrence network structure of "Jerusalem artichoke-conditioner-saline soil-soil microorganism" was established, which provided scientific basis for Jerusalem artichoke-conditioner to improve saline soil.