Molecular Soil Biology 2024, Vol.15, No.3, 109-117 http://bioscipublisher.com/index.php/msb 111 release during snowmelt. In Arctic ecosystems, increased snow depth and later snowmelt have been linked to improved soil and vegetation nutrient status, as well as higher soil moisture levels (Figure 1) (Moriana-Armendariz et al., 2022). Conversely, in temperate forests, shorter snow cover duration and reduced snow depth due to climate change can lead to increased soil freezing and lower soil moisture levels during the growing season. Figure 1 Comparison of estimates between gradient studies (based on snowmelt time) and experimental studies (based on snow depth) (Adopted from Moriana-Armendariz et al., 2022) Image caption: (A) Soil moisture content as a percentage of soil moisture capacity. (B) Dissolved organic nitrogen (DON-N), (C) ammonium (NH4-N) and (D) nitrogen concentrations in the form of nitrate (NO+ 3−. N) is expressed as μgN per g of dry soil. The concentration of nitrogen in the leaves of (E) Bistorta vivipara and (F) Salix polaris is expressed as a percentage of leaf dry matter. TheNof (G) B. viviparaand (H) S. polaris leaves is shown in ‰ (Adopted from Moriana-Armendariz et al., 2022) The study by Moriana-Armendariz et al. (2022) showed the effect of snow cover duration and depth on soil moisture content (Figure 1A). In general, the deeper and longer the snow cover, the higher the moisture content of the soil. This suggests that the depth of snow cover and the time of snowmelt play an important role in regulating soil moisture, especially when the soil moisture content increases significantly at deeper or later snowmelt. This conclusion is further supported by the agreement between experimental data (Exp) and gradient studies (Grd). 3.4 Comparative analysis of soil moisture in snow-covered vs. snow-free periods Comparative studies have shown that soil moisture levels are significantly higher during snow-covered periods compared to snow-free periods. In a study conducted in a temperate grassland, deepened winter snow cover was found to increase soil moisture in the early growing season, which in turn enhanced net ecosystem exchange of CO2 and stabilized plant community composition and productivity (Li et al., 2020). In contrast, snow-free periods are often associated with lower soil moisture levels and increased soil freezing, which can negatively impact soil biogeochemical processes and plant growth (Chen et al., 2020). 4 Impacts on Plant Growth 4.1 Influence of snow cover on soil temperature Snow cover acts as an insulating layer, significantly affecting soil temperature during winter. Increased snow depth can raise winter soil temperatures by approximately 3 ℃, as observed in the Canadian Low Arctic mesic shrub tundra (Christiansen et al., 2018). This insulation effect can protect plant roots from extreme cold, thereby influencing plant survival and growth. Conversely, reduced snow cover can lead to lower soil temperatures, increasing the risk of frost damage to plant roots and affecting overall plant health (Drescher and Thomas, 2013; Chen et al., 2020).
RkJQdWJsaXNoZXIy MjQ4ODYzMg==