Effects of animal grazing on vegetation biomass and soil moisture on a typical steppe in Inner Mongolia, China

Abstract

Grasslands play a very important role in the water and carbon cycle of arid and semi‐arid areas, where they are the main type of steppe globally. With this said, research into grassland ecological processes mostly consists of single‐factor controlled experiments such as precipitation, temperature or grazing, and few studies have investigated the effects of synergistic interactions between multiple factors on grassland hydrological, soil and vegetation processes. In this study, we set up a prohibited grazing area in a typical area of the Xilingole Steppe in Inner Mongolia, China. Vegetation (species richness (SR), above‐ground biomass (AGB), below‐ground biomass (BGB), etc.), precipitation and the soil moisture of 5 cm, 10 cm, 15 cm and 30 cm depths were observed continuously from 2015 to 2018. The results indicate that the species number in areas where grazing is prohibited is higher than where it is grazed, and the number and species of dominant species changes with grazing prohibition time. The AGB and BGB of prohibited areas is higher than grazed areas, and the variance rate of AGB increased rapidly (20% and 45%) at the first 2 years and then stabilized (52% and 55%), but BGB's variance rate increased slowly from 12% to 20%. The soil moisture content in the study area is higher in the surface layer than in the deeper layers. In the grazing prohibition zone, the above ground biomass (AGB) and belowground biomass (BGB) were both significantly correlated with volumetric water content (VWC) at the 0.01 level. In grazing areas, there was no significant correlation between AGB and soil moisture, and the coefficient of determination between BGB and VWC was 0.6127 (p < 0.01). SR did not have a significant relationship with soil moisture but indirectly response to it through BGB, especially in prohibited site. These results are important for understanding water cycle processes, grazing management and address food security issues across steppe in arid and semi‐arid regions.

Grazing lowers soil multifunctionality but boosts soil microbial network complexity and stability in a subtropical grassland of China

“…All finally depleted the soil water content ( Hao and He, 2019 ; Tang et al, 2020 ). The returns of ACa and AMg in form of dung and urine ( Saunders, 2012 ) and accelerated soil weathering by grazing ( Lin et al, 2021 ) could elevate the availability of calcium and magnesium, which, in turn, are conducive to improving soil pH ( Figure 1C ). Decreases in plant biomass and coverage ( Wang and Tang, 2019 ; Lin et al, 2021 ) and removal of aboveground biomass by buffalo eating and treading, and root biomass ( Wade et al, 2022 ) due to the depletion of soil water content, and increased bulk density ( Lin et al, 2021 ) and soil hardness ( Figure 1A ), generally reduced the C inputs, which, in turn, commonly reduced the bioavailable soil C ( Ravhuhali and Moyo, 2021 ), aggravated C limitation ( Goenster-Jordan et al, 2021 ) as indicated by the increased investment in C-capturing enzyme (ßGC, Figure 1H ), which can hydrolyze sugars and release labile C. The vector angle under ungrazed was <45, indicating that the soil microbial communities were limited by N; the vector angle under grazed crossed with 45, indicating that the soil microbial communities were under N and P co-limitation.…”

Ecological restoration and rising CO2enhance the carbon sink, counteracting climate change in northeastern China

“…This is most likely due to prohibition of grazing and enclosure implemented in grassland due to ERPs (Wu et al 2013. Prior research has already found that light grazing and enclosure would alter the composition of vegetation species, improve grassland productivity and reduce soil respiration to promote the carbon sink (Deng et al 2017, Lin et al 2021. Another important cause is rising CO 2 .…”

Impact of years of grazing exclusion on surface soil temperature and hydrothermal relations in arid and semi‐arid grasslands

“…Grasslands are of great global economic and ecological importance, covering approximately 40% of the earth's surface (Lin et al, 2022).…”

“…Grasslands are of great global economic and ecological importance, covering approximately 40% of the earth's surface (Lin et al, 2022). Furthermore, grasslands are the largest terrestrial ecosystem type in China and play a critical role in the country's national ecological and environmental protection planning (Ren et al, 2011).…”