The Influence of Climate Warming and Humidity on Plant Diversity and Soil Bacteria and Fungi Diversity in Desert Grassland

Our study, which was conducted in the desert grassland of Ningxia in China (E 107.285, N 37.763), involved an experiment with five levels of annual precipitation 33% (R33), 66% (R66), 100% (CK), 133% (R133), 166% (R166) and two temperature levels (inside Open-Top Chamber (OTC) and outside OTC). Our objective was to determine how plant, soil bacteria, and fungi diversity respond to climate change. Our study suggested that plant α-diversity in CK and TCK were significantly higher than that of other treatments. Increased precipitation promoted root biomass (RB) growth more than aboveground living biomass (ALB). R166 promoted the biomass of Agropyron mongolicum the most. In the fungi communities, temperature and precipitation interaction promoted α-diversity. In the fungi communities, the combination of increased temperature and natural precipitation (TCK) promoted β-diversity the most, whose distance was determined to be 25,124 according to PCA. In the bacteria communities, β-diversity in CK was significantly higher than in other treatments, and the distance was determined to be 3010 according to PCA. Soil bacteria and fungi α- and β-diversity, and ALB promoted plant diversity the most. The interactive effects of temperature and precipitation on C, N, and P contents of plants were larger than their independent effects.

Effects of Nitrogen Application Rate on Rhizosphere Microbial Diversity in Oilseed Rape (Brassica napus L.)

Nitrogen is one of the essential nutrients for rape growth and development, of which the demand is large. In order to reveal the response of rhizosphere microbial diversity on oilseed rape to the nitrogen fertilizer, four nitrogen application rates of N (170 kgN/hm2), N50% (85 kgN/hm2), N70% (119 kgN/hm2) and N150% (255 kgN/hm2) were set. The diversity and community structure of soil bacteria and fungi in seedling, flowering and mature stages of oilseed rape were analyzed based on the high-throughput sequencing technology. The results of rhizosphere soil microbial analysis showed that the dominant bacteria phyla were Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidetes and Cyanobacteria. The dominant fungi phyla were Ascomycota, Olpidiomycota and Basidiomycota. NMDS analysis showed that the community structure of soil bacteria and fungi changed significantly under nitrogen treatment. Cluster analysis showed that the bacteria at seedling and flowering stage had little effect under the condition of less nitrogen application, while the fungi had little effect on the rhizosphere soil microbial flora at flowering stage. At seedling stage, the diversity and richness of bacterial community in the rhizosphere of oilseed rape were lower under low nitrogen application (85 kgN/hm2). Bacteria and fungi in the rhizosphere soil of flowering oilseed rape maintained a higher community diversity under the condition of high nitrogen (255 kgN/hm2). The diversity of rhizosphere bacterial community was higher under conventional N application than under other N application.

Utilization of slurry and mushroom baglog to improve growth and yield on strawberry on degraded volcanic soils

Utilization of slurry under the combination with mushroom baglog could be used a potential source for replacing nitrogen fertilizer and improve soil fertility. The purpose of this study was to evaluate the different combination and the level of slurry application combining with mushroom baglog on total soil nitrogen and organic contents, total soil bacteria and fungi, along with the improvement of growth and yield of strawberry (Fragaria x ananassa). The experiment used a complete randomized design with five treatments and five replications. The treatments were A1 (100% inorganic fertilizer application as control), A2 (50% composted slurry and mushroom baglog + 50% in-organic fertilizer), A3 (100% composted slurry and mushroom baglog), A4 (150% composted slurry and mushroom baglog), A5 (50% composted slurry and mushroom baglog + 50% in-organic fertilizer), A6 (100% fresh slurry (uncomposted)), and A7 (150% uncomposted fresh slurry). Results showed that the treatments significantly affected total soil nitrogen, total soil bacteria and fungi, along with the growth and yield of strawberry. The A6 treatment which used 100% uncomposted fresh slurry, showed the highest total nitrogen in the soil (0.23%) and total population of bacteria (7.1 log CFU/g) and the greatest number of strawberry stolons. In term of the number of leaves and total soil fungi, the A3 treatment was the greatest, resulted in number of leaves and total soil fungi at 19.7 per plant and 4.8 log cfu/g x 104. However, the best yield was obtained from the A7 treatment (150% of fresh slurry) at 15.1 kg/ha.

Soil Bacteria and Fungi Respond Differently to Organisms Covering on Leshan Giant Buddha Body

Soil microbial communities play a key role in the functioning of terrestrial ecosystems, in particular through their interaction with above-ground plants and weathering of rocks. In this study, the chemical properties and microbial diversity of soils covered by different organisms on Leshan Giant Buddha body were analyzed. The results showed that the concentration of soil total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) increased significantly with the change of above-ground organisms from lichens to bryophytes and vascular plants. TOC, TN, TP, C:N, and C:P were significantly correlated with the composition of microbial community. Bacterial and fungal diversity responded differently to the change of organisms, and the diversity of bacterial communities changed significantly among different sites. The settlement of Embryogenic plants increased the α-diversity indices including Sobs, Shannon, Ace and Chao indices, which were highest in sites covered with Ferns. The relative abundances of Chloroflexi, Acidobacteria, Nitrospirae and Planctomycetes increased with the order of Bryophyte, Fern, Grass and Shrub, and Cyanobacteria was opposite, with the highest in samples covered with lichens. These results improve understanding of plant–fungi–bacteria interactions during the early stages of soil development, and provide a scientific basis for protection of Leshan Giant Buddha.