Simulated Nitric Acid Rain Aggravated the C and P Limits of Forest Soil Microorganisms

Abstract

With the comprehensive emissions of fossil fuel combustion and transportation waste gas, the concentrations of nitrogen oxides (NOX) in the environmental atmosphere increase significantly, leading to nitric acid rain (NAR) pollution. However, the effects of NAR on soil enzyme activities and soil microbial metabolism are unclear. In this study, the Quercus acutissima Carruth. forest in the Yangtze River Delta of China was selected as the experimental subject, and was exposed to the simulated spraying of NAR with pH values of 2.5, 3.5, and 4.5 to study the response of the forest soil enzyme activities and soil microbial metabolism to NAR. The results showed that compared to the non-NAR treatment, the activities of β-1,4-glucosidase (BG), L-leucine aminopeptidase (LAP), and β-1,4-N-acetylglucosidase (NAG) decreased by 56.48%–42.24%, 44.57%–38.20%, and 56.13%–48.11% under the AR2.5 and AR3.5 treatments, respectively. Moreover, there was no significant change in the Vector Length (VL) under different gradients of NAR. The Vector Angle (VA) increased with the decrease of the pH value and reached the maximum value with the AR2.5 treatment, indicating that the strong acid type NAR had a greater phosphorus-limiting effect on the soil microorganisms. The RDA analysis results showed that the dissolved organic carbon (DOC) was a significant factor affecting the soil enzyme activity and stoichiometric ratio, with interpretation rates of 40.2%. In conclusion, we believe that in the restoration of acidified soil, attention should be paid to the regulation of soil pH, reducing scour.

Restoring Subtropical Forests: Alleviating P Limitation and Introducing C Limitation Using Evergreen Broad-Leaved Tree Species

“…EEA stoichiometric ratios reflect soil microbial nutrient acquisition and limitation status [9]. Numerous studies have investigated forest EEA and its stoichiometry [16,21,[36][37][38]. In our study, soil microbes were co-limited by C and P (Figure 3).…”

Nitric Acid Rain Decreases Soil Bacterial Diversity and Alters Bacterial Community Structure in Farmland Soils

“…Microbial community structure can reflect the quality and health of soil to a certain extent, which is of great value in exploring the functional characteristics of soil and the structural properties of the ecosystem [9]. Previous studies have shown that AR can lead to soil acidification [10][11][12], which can promote an increase in the concentration of hydrogen ions in soil and cause changes in the composition and structure of soil microbial communities [13]. In addition, soil microbial diversity in farmland soil is closely related to soil quality [14].…”