Response of soil bacterial community to agricultural reclamation in the Tengger desert, northwestern China

Abstract

Given the conditions of scarce soil water availability, high UV exposure and huge temperature fluctuation, plant growth in desert is extremely limited. In the last three decades, reclaiming desertified land for agricultural use via the application of solar greenhouse has been developing in the arid regions, northwestern China. However, the soil microbiome shift driven by the transformation of land use remains largely unexplored. To this end, we examined the diversity and composition of the bacterial community in the vineyard soil at the edge of Tengger desert, using the high-throughput quantitative 16S rRNA gene sequencing. Two types of agricultural managed soils, including those near the plant (PLT) and the others on the fertilization furrow (FTL), were collected. Soils from the open desert land without agricultural practices were used as the control (CON). The results showed that agricultural reclamation significantly (p < 0.05) reduced the desert soil bacterial diversity while promoted the total bacterial abundance from 106 copies up to 108 per ng of DNA, which increased up to 90 folds. Among the dominant bacteria Firmicutes, Proteobacteria, Actinobacteria, and Acidobacteria, Bacilli and Actinobacteria were found to be the keystone taxa responding to the agricultural practices especially to the nutrient inputs from fertilization. The functional prediction of the microbiome suggested that amino acid and carbohydrate transport and metabolism were the most important metabolic pathways differed between the three types of soils. Overall, our findings provide deep insights into the understanding of desert soil microbial responses to agricultural reclamation on the processes of human urbanization and reversion of desertification.