Different Responses of Soil Bacterial Communities to Nitrogen Addition in Moss Crust

Abstract

Bacterial communities in soil serve an important role in controlling terrestrial biogeochemical cycles and ecosystem processes. Increased nitrogen (N) deposition in Northwest China is generating quantifiable changes in many elements of the desert environment, but the impacts of N deposition, as well as seasonal variations, on soil bacterial community composition and structure are poorly understood. We used high-throughput sequencing of bacterial 16S rRNA genes from Gurbantünggüt Desert moss crust soils to study the impacts of N addition on soil bacterial communities in March, May, and November. In November, we discovered that the OTU richness and diversity of soil bacterial community dropped linearly with increasing N input. In November and March, the diversity of the soil bacterial community decreased significantly in the medium-N and high-N treatments. In May, N addition caused a substantial change in the makeup of the soil bacterial composition, while the impacts were far less apparent in November and March. Furthermore, the relative abundance of major bacterial phyla reacted non-linearly to N addition, with high-N additions decreasing the relative richness of Proteobacteria, Bacteroidetes, and Acidobacteria while increasing the relative abundance of Actinobacteria and Chloroflexi. We also discovered that seasonality, as characterized by changes in soil moisture, pH, SOC, and AK content, had a significant impact on soil bacterial communities. Significant variations in the makeup of the community were discovered at the phylum and genus levels throughout the various months. In May, the variety of soil bacterial community was at its peak. Further investigation showed that the decrease in soil bacterial diversity was mostly attributed to a drop in soil pH. These results indicated that the impact of N deposition on the soil bacterial community was seasonally dependent, suggesting that future research should evaluate more than one sample season at the same time.

Biochar Addition Alters C: N: P Stoichiometry in Moss Crust-Soil Continuum in Gurbantünggüt Desert

“…On the one hand, the effect of biochar addition on plant growth varies with type and dosage of biochar [ 16 ]. On the other hand, the community structure is directly associated with soil chemical properties, such as C or N levels [ 45 ], the addition of biochar increased the plant absorption of phosphorus by influencing the rhizosphere microorganism and increased the supply of available phosphorus in soil [ 4 , 46 ]. Other studies also found the content of soil C, N, and P in the whole growing season were 2.65–44.4, 0.02–0.32, and 0.3–0.80 g/kg after biochar addition [ 47 ].…”

Snow-cover loss attenuates the effects of N addition on desert nutrient cycling and microbial community

“…Snow-cover (6–16 cm) is during winter ( Hui et al., 2022 ), mainly from November to March (Stable snow period: 100-150 days) ( Zhang et al., 2022b ). The vegetation in China’s largest fixed and semi-fixed desert is dominated by Haloxylon ammolondren , Haloxylon persicum , Ephedra distachya and Ceratoides latens , with well-developed BSCs widely dispersed, moss crusts distributed under the plant canopy and in plant gaps, some algal crusts distributed on the bare ground, and only a few lichens distributed ( Huang et al., 2021 ).…”

“…The distance between each sample area was greater than 20 m. Besides, the split-plot experiment involved two snow treatments in main plots: (1) snow-cover (natural snow cover) (S), and (2) Snow-uncover (covered with tarpaulin before snowfall and removed after snowfall) (UnS). According to the 3.6 g N·m −2 ·year −1 atmospheric N deposition during the past decade ( Huang et al., 2015 ), each application with a three-level N addition of 15 NH 4 15 NO 3 solution (dissolved in 100 ml non-ionized water) in sub-plots, which was added and sprayed evenly on the sample square with a sprinkler on November 1, 2018 ( Huang et al., 2021 ): (1) high N (7.2 g N·m −2 ·year −1 ) (H), (2) moderate N (3.6 g N·m −2 ·year −1 ) (M), (3) light N (1.8 g N·m −2 ·year −1 ) (L), and each application had three replicate plots. A portion of the collected soil samples was quickly packed on dry ice, brought back to the laboratory, and kept in a freezer (−80°C) within 12 h. The other portion of each uniform sample was divided into several parts and air–dried for analysis of soil nutrients and enzymes.…”

“…The Gurbantunggut Desert has a large distribution of BSCs and more potential sources of N from agricultural and industrial activities ( Fan et al., 2013 ; Huang et al., 2021 ), yet studies on the effects of snow-cover and N addition on nutrient cycling and microbial communities of BSCs are lacking. Here, we performed a split-plot experiment with snow-cover and N addition to examine the following questions: (1) how snow-cover altered the nutrient status of BSCs under different N additions, (2) how are soil enzyme activities related to N acquisition in BSCs response to snow-cover under different N additions, (3) effects of snow-cover on bacterial structure and function under different N addition levels, and (4) address the underlying mechanisms that drive soil nutrient dynamics and microbial communities.…”

Long-Term Wheat-Soybean Rotation and the Effect of Straw Retention on the Soil Nutrition Content and Bacterial Community

“…Soil microorganisms play an essential role in the soil ecological and biogeochemical processes, including carbon and nitrogen cycling for plant nutrient uptake [18]. The complexity of the microbial network increases significantly with straw return [19].…”