scholarly journals Variations in Soil Enzyme Activities and Microbial Communities along an Altitudinal Gradient on the Eastern Qinghai–Tibetan Plateau

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 681
Author(s):  
Shiyu Fan ◽  
Hui Sun ◽  
Jiyuan Yang ◽  
Jihong Qin ◽  
Danjie Shen ◽  
...  

The Qinghai–Tibetan Plateau is the highest plateau in the world and is sensitive to climate change. The dynamics of soil enzyme activities and microbial communities are good indicators of alpine biochemical processes during warming. We collected topsoil (0–10 cm) and subsoil (10–20 cm) samples at altitudes of 3200–4000 m; determined the activities of β-1,4-glucosidase (BG), cellobiohydrolase (CBH), β-1,4-N-acetyl-glucosaminidase (NAG) and acid phosphomonoesterase (PME); and performed Illumina 16S rRNA high-throughput sequencing. We found that the soil carbon (total organic carbon and dissolved organic carbon) and nitrogen (total nitrogen and dissolved organic nitrogen) fluctuated with altitude in both the topsoil and subsoil, whereas the dissolved phosphorus continuously decreased with the increasing altitude. BG and CBH decreased from 3200 to 3600 m and increased from 3800 to 4000 m, with the lowest levels occurring at 3600 m (topsoil) and 3800 m (subsoil). NAG and PME showed similar fluctuations with altitude, with the highest levels occurring at 3400 m and 4000 m in both the topsoil and subsoil. Generally, the altitudes from 3600 to 3800 m were an ecological transition belt where most of the nutrients and enzyme activities reached their lowest levels. All of the alpine soils shared similar dominant phyla, including Proteobacteria (32.7%), Acidobacteria (30.2%), Actinobacteria (7.7%), Bacteroidetes (4.4%), Planctomycetes (2.9%), Firmicutes (2.3%), Gemmatimonadetes (2.0%), Chloroflexi, (1.2%) and Nitrospirae (1.2%); Gemmatimonadetes and Verrucomicrobia were significantly affected by soil depth and Planctomycetes, Firmicutes, Gemmatimonadetes, Nitrospirae, Latescibacteria and Armatimonadetes were significantly affected by altitude. In addition, nutrient availability, enzyme activity and microbial diversity were higher in the topsoil than in the subsoil, and they had more significant correlations in the subsoil than in the topsoil. Our results provide useful insights into the close linkages between soil nutrient cycling and microbial activities on the eastern Qinghai–Tibetan Plateau, and are of great significance for further assessing the long-term impact of environmental changes in the alpine ecosystems.

2014 ◽  
Vol 998-999 ◽  
pp. 1504-1507
Author(s):  
Zhong Mei Wan

To understand the influence of vertical dynamics of soil enzyme activities on the active carbon pool in Calamagrostis angustifolia wetland, the vertical distribution in 0-30cm depth of soil cellulase and amylase activities and active organic carbon fractions (microbial biomass carbon /MBC, easily oxidizable carbon/EOC) were measured and the relationship between soil enzyme activities and active organic carbon were analyzed. The results show that the enzyme activities and EOC and MBC contents in topsoil are the greatest. The soil cellulase and amylase activities and EOC and MBC contents show descending trends from surface layer to 30cm. The soil enzyme activities are significantly positive related to EOC and MBC contents. Therefore, with the increase of soil depth, the activities of cellulase and amylase obviously affect the soil active carbon pool. Furthermore, the cellulase activity of marsh soil has the strongest influence on soil active carbon pool.


2020 ◽  
Vol 22 (4) ◽  
pp. 1045-1056
Author(s):  
Lina Lin ◽  
Minling Gao ◽  
Xuewei Liu ◽  
Zhengguo Song

The effects of Fe–Mn–La ternary oxide-biochar composites on arsenic fractionation, soil enzyme activities, and microbial communities in arsenic-polluted soils were determined.


2018 ◽  
Vol 15 (4) ◽  
pp. 1217-1228 ◽  
Author(s):  
Zhiwei Xu ◽  
Guirui Yu ◽  
Xinyu Zhang ◽  
Nianpeng He ◽  
Qiufeng Wang ◽  
...  

Abstract. Soil microorganisms play an important role in regulating nutrient cycling in terrestrial ecosystems. Most of the studies conducted thus far have been confined to a single forest biome or have focused on one or two controlling factors, and few have dealt with the integrated effects of climate, vegetation, and soil substrate availability on soil microbial communities and functions among different forests. In this study, we used phospholipid-derived fatty acid (PLFA) analysis to investigate soil microbial community structure and extracellular enzymatic activities to evaluate the functional potential of soil microbes of different types of forests in three different climatic zones along the north–south transect in eastern China (NSTEC). Both climate and forest type had significant effects on soil enzyme activities and microbial communities with considerable interactive effects. Except for soil acid phosphatase (AP), the other three enzyme activities were much higher in the warm temperate zone than in the temperate and the subtropical climate zones. The soil total PLFAs and bacteria were much higher in the temperate zone than in the warm temperate and the subtropical zones. The soil β-glucosidase (BG) and N-acetylglucosaminidase (NAG) activities were highest in the coniferous forest. Except for the soil fungi and fungi–bacteria (F/B), the different groups of microbial PLFAs were much higher in the conifer broad-leaved mixed forests than in the coniferous forests and the broad-leaved forests. In general, soil enzyme activities and microbial PLFAs were higher in primary forests than in secondary forests in temperate and warm temperate regions. In the subtropical region, soil enzyme activities were lower in the primary forests than in the secondary forests and microbial PLFAs did not differ significantly between primary and secondary forests. Different compositions of the tree species may cause variations in soil microbial communities and enzyme activities. Our results showed that the main controls on soil microbes and functions vary in different climatic zones and that the effects of soil moisture content, soil temperature, clay content, and the soil N ∕ P ratio were considerable. This information will add value to the modeling of microbial processes and will contribute to carbon cycling in large-scale carbon models.


2021 ◽  
Author(s):  
Chengjiao Duan ◽  
Yuxia Mei ◽  
Qiang Wang ◽  
Yuhan Wang ◽  
Qi Li ◽  
...  

Abstract Although some studies have reported an important role of rhizobia in mitigating heavy metal toxicity, the regulatory mechanism of the alfalfa-rhizobium symbiosis system to resist copper (Cu) stress through biochemical reactions in the plant-soil system is still unclear. Hence, this study assessed the effects of rhizobium inoculation (i.e., Sinorhizobium meliloti CCNWSX0020) on the growth of alfalfa and soil enzyme activities under Cu stress. Our results showed that rhizobium inoculation markedly alleviated Cu-induced growth inhibition by increasing chlorophyll content, height and biomass and the contents of nitrogen and phosphorus in alfalfa. The content of malondialdehyde (MDA) was increased in both shoot and root of alfalfa under Cu stress. The application of rhizobium alleviated Cu-induced phytotoxicity by increasing the activity of antioxidant enzymes and soluble protein content of tissues and inhibiting the level of lipid peroxidation (i.e., MDA level). In addition, rhizobium inoculation improved soil nutrient cycling, increased soil enzyme activities (i.e., β-glucosidase activity and alkaline phosphatase) and microbial biomass nitrogen. Both Pearson correlation coefficient analysis and partial least squares path modeling (PLS-PM) identified that the interactions between soil nutrient content, enzyme activity, microbial biomass and plant antioxidant enzymes and oxidative damage could jointly regulate plant growth. This study provides comprehensive insights into the mechanism of action of the legume-rhizobium symbiosis system to mitigate Cu stress and provide an efficient strategy for phytoremediation of Cu-polluted soils.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Parul Chaudhary ◽  
Anuj Chaudhary ◽  
Heena Parveen ◽  
Alka Rani ◽  
Govind Kumar ◽  
...  

Abstract Background Since the World’s population is increasing, it’s critical to boost agricultural productivity to meet the rising demand for food and reduce poverty. Fertilizers are widely used in traditional agricultural methods to improve crop yield, but they have a number of negative environmental consequences such as nutrient losses, decrease fertility and polluted water and air. Researchers have been focusing on alternative crop fertilizers mechanisms to address these issues in recent years and nanobiofertilizers have frequently been suggested. “Nanophos” is a biofertilizer and contains phosphate-solubilising bacteria that solubilises insoluble phosphate and makes it available to the plants for improved growth and productivity as well as maintain soil health. This study evaluated the impact of nanophos on the growth and development of maize plants and its rhizospheric microbial community such as NPK solubilising microbes, soil enzyme activities and soil protein under field condition after 20, 40 and 60 days in randomized block design. Results Maize seeds treated with nanophos showed improvement in germination of seeds, plant height, number of leaves, photosynthetic pigments, total sugar and protein level over control. A higher activity of phenol, flavonoid, antioxidant activities and yield were noticed in nanophos treated plants over control. Positive shift in total bacterial count, nitrogen fixing bacteria, phosphate and potassium solubilizers were observed in the presence of nanophos as compared to control. Soil enzyme activities were significantly (P < 0.05) improved in treated soil and showed moderately correlation between treatments estimated using Spearman rank correlation test. Real time PCR and total soil protein content analysis showed enhanced microbial population in nanophos treated soil. Obtained results showed that nanophos improved the soil microbial population and thus improved the plant growth and productivity. Conclusion The study concluded a stimulating effect of nanophos on Zea mays health and productivity and indicates good response towards total bacterial, NPK solubilising bacteria, soil enzymes, soil protein which equally showed positive response towards soil nutrient status. It can be a potential way to boost soil nutrient use efficiency and can be a better alternative to fertilizers used in the agriculture.


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