Grazing and Mowing Affect the Carbon-to-Nitrogen Ratio of Plants by Changing the Soil Available Nitrogen Content and Soil Moisture on the Meadow Steppe, China

Abstract

Common grassland management practices affect plant and soil element stoichiometry, but the primary environmental factors driving variation in plant C/N ratios for different species in different types of grassland management remain poorly understood. We examined the three dominant C/N stoichiometric responses of plants to different land uses (moderate grazing and mowing) in the temperate meadow steppe of northern China. Our results showed that the responses of the C/N ratio of dominant plants differed according to the management practice. The relative abundance of N in plant tissues increased due to increased soil NO3−, with a consequent decrease in plant C: N in the shoots of Leymus chinensis, but the C/N ratio and nitrogen concentration in the shoots of Bromus inermis and Potentilla bifurca were relatively stable under short-term moderate grazing management. Mowing reduced the concentration of soil NH4+, thus reducing the nitrogen concentration of the roots, resulting in a decrease in the root C/N ratio of Potentilla bifurca. Structural equation model (SEM) showed that the root C/N ratio was affected by both root N and soil inorganic N, while shoot C/N ratio was only affected by the soil inorganic N. Our findings provide a mechanistic understanding of the responses of plant C/N ratio to land use change. The species-level responses of plant stoichiometry to human-managed grasslands deserve more attention.

Evaluation of Al Kabeer Al Shamali River's Water Suitability for Drinking, Based on Modeling and Pseudomonas Aeruginosa Detection in Syria

“…As for the tunnel water, no temperature was recorded in the winter due to the lack of pumping into tunnel, and the lowest recorded temperature was 21 C° in May, with the start o f the irrigation season. Studies indicate [30], [31] that the more as the temperature rises, the ratio of carbon to nitrogen (C: N) in surface water increases due to the decomposition of organic matter these approved by our Previous research by [19] showed an increase in the ratio of C: N in the samples of the months of July and September in lake water 23, 22.5, respectively. Along with temperatures of 31.5 and 28.9 C°for the year 2019, respectively, due to the decomposition of plant residues by the existing bacteria, and this is what we will notice later in pseudomonas counts.…”

“…16 th Tishreen Dam Lake site: The Pseudomonas aeruginosa counts decreased in the 16 Tishreen dam lake water to the low values of 1000 cfu/100 mL in August due to the stratification of the lake and the redistribution of Pseudomonas between the surface and deep layers of the lake water and then its release again from the sediments in the deep and dark waters that stimulate the growth of bacteria, as we will notice in the tunnel water. The highest values were recorded in the lake water in autumn, as the counts increased to 19000 cfu/100 mL in October 2019 with a turbidity rise of 13.2 NTU, and the counts recorded in October 13000 cfu/100 mL associated with a turbidity of 3.88 NTU, a decrease in the lake level and decomposition of plant residues, causing an increase in the C/N ratio [31]. On the other hand, the lowest concentration of 420 cfu/100mL recorded in the lake water in May 2019, associated with a relatively low turbidity of 2.27 NTU and the lowest pH value of 7.75.…”

Short-Term Snow Removal Alters Fungal but Not Bacterial Beta Diversity and Structure during the Spring Snowmelt Period in a Meadow Steppe of China

“…In the experimental field, Leymus chinensis (Trin.) Tzvel., Bromus inermis Leyss., and Potentilla bifurca L. represent the dominant plant species [ 26 ].…”

Soil nitrogen and carbon storages and carbon pool management index under sustainable conservation tillage strategy

“…The high input of exogenous carbon is conducive to the growth of roots, which changes the quantity and chemical composition of root exudates, affects the functional groups and quantity of soil organisms, and significantly increases the content of soil EOC (Sun et al, 2013). Under sustainable conservation tillage, Due to the continuous decomposition of straw mulching and the input of carbon into the soil, the content of soil carbon components increased continuously (Wang et al, 2022).…”