Consecutive high-efficient water-saving irrigation increase crop yield and decrease soil salinity through reconstructing rhizosphere soil bacterial communities.

Roughly 10 % of the world's arable land is affected by salinization, which significantly reducing crop yields, degrading soil health, and posing a serious threat to food security and ecological stability. High-efficient water-saving irrigation (HEI) technologies have showed positive effects on crop yield, especially with long-term application in salinized soil fields. However, the microbial mechanisms and influential pathways that promote crop yield and reduce salinity under consecutive HEI remain unclear. We conducted a 25-year study of long-term consecutive HEI in typical saline oasis areas, utilizing 16S rRNA high-throughput sequencing and structural equation modeling to analyze the results. The results showed that prolonged application of HEI significantly increased the diversity of soil bacterial community, enhanced the survival rate and yield of cotton, and significantly decreased soil salinity in the cotton fields. Compared with the 1 year application, the diversity indices of soil bacterial communities increased significantly (p < 0.05) by 45.41 %-61.64 %. After 5 years of consecutive HEI, the bacterial network interactions were enhanced. These enhanced interactions significantly (p < 0.005) increased the cotton survival rate by 55.27 % and the yield by 69.99 % after 10 years of application. With the joint positive influence of soil bacterial communities and crop growth after 15-25 consecutive years, soil salinity, the sodium absorption ratio, and the Cl and SO equivalence ratio were significantly (p < 0.005) reduced by 88.01 %-90.00 %, 75.52 %-82.66 %, and 48.39 %-56.66 %, respectively. During the process, Acidobacteriota, Nitrospirota and Myxococcota contributed to higher crop yield mainly via nitrogen fixation, while Bacteroidota and Firmicutes reduced soil salinity primarily via nitrate reduction. Interestingly, Verrucomicrobiota, Nitrospirota, and Desulfobacteria, initially discovered in 5, 10, and 15th years, respectively, reappeared after intervals of 10 years. The diversity, complexity, and stability of the rhizosphere soil bacterial communities continuously improved up to 25 years, significantly (p < 0.005) increasing crop yield and decreasing soil salinity, by 71.55 % and 90.00 %, respectively.