Fermenting straw reduced salt damage and improved the stability of the bacterial community in a saline–sodic soil

Abstract

This study aimed to explore the potential of fermenting straw return for remediation of soil salinity. A sealed–pot experiment was used to evaluate four treatments: CK (0 g fermenting rice straw), T1 (120 g fermenting rice straw), T2 (240 g fermenting rice straw), and T3 (360 g fermenting rice straw). Using 13C isotope tracer technique and molecular biological techniques to detect the physical, chemical, and biological properties of saline–sodic soils. The results showed that a small amount of CO2 was produced upon addition of soda–alkali soil to the soil after straw was applied. Quantitative analysis showed that the proportion of CO32– reduction of total CO32– was peaked (4.90%) in treatment T3. Concomitantly, under this treatment soil pH, SAR and ESP were reduced, whereas soil porosity and K+, Ca2+, and Mg2+ concentrations, and total nitrogen (TN), SOM, and MBC were increased. PCoA analysis showed that the addition of straw significantly changed the community structure of bacteria in a saline–sodic soil, and increased the Chao1 and Shannon indexes. Straw application increased ryegrass shoot and root biomass without allelopathic effects in the saline–sodic soil used. Our results highlighted that rice straw should be collected and artificially decomposed after rice harvest and then applied for the reclamation of strongly saline–sodic soils in the Songnen Plain and other similar areas.