Effects of slope aspect on altitudinal pattern of soil C:N:P stoichiometry in alpine forest of Tibet

Abstract

Knowledge of altitudinal patterns in soil C, N and P distribution is important for understanding biogeochemical processes in mountainous forests, yet the influence of slope aspects on soil stoichiometry has been largely neglected in previous studies. In this paper, a total number of 150 topsoil samples at four altitudes (3700, 3900, 4100, 4380 m a.s.l.) on sunny and shady slopes of Sygera mountains in the Southeastern Tibet were collected. Soil C, N and P contents, and pH, were measured. Soil temperature, moisture and richness of plant species were investigated at each sampling site. The results showed that: 1) in sunny slope, soil C, N and P concentrations increased with the increase in altitude, whereas soil C:N, C:P, and N:P decreased along the altitudinal gradient on s. Soil moisture was the main regulator of soil nutrition and stoichiometric ratios. 2) In shady slope, soil C and N contents had no significant difference along the altitudinal gradient except the higher values at low altitude, whereas soil P increased first and then decreased. Soil C:N increased with the increase in altitude, whereas C:P and N:P decreased first and then increased. Soil temperature and species richness were the main factors influencing soil nutrition and stoichiometric ratios. 3) Decoupling of soil C:N:P stoichiometry was observed in shady slope owing to changes in soil pH and temperature. 4) The rich contents of soil C and P were observed at two slopes along the altitudinal gradient, and high capacity of N supply existed at the topsoil in shady slope. These results suggested that slope aspect plays an important role in shaping the altitudinal pattern of soil C:N:P stoichiometry in mountainous forests.

Impact of Elevation Change on the Physicochemical Properties of Forest Soil in South Omo Zone, Southern Ethiopia

“…In this study, the EC value of the soils ranged from 14 mScm −1 to 630 mScm −1 . Following the soil EC rating suggested by Seifu et al [37], the EC content of the soils in the study area was within the range of moderately saline (8)(9)(10)(11)(12)(13)(14)(15)(16) to strongly saline (>16). Te result indicated that there is no signifcant (P < 0.683) diference in salt accumulation along with increasing elevation.…”

“…Diferent factors signifcantly infuence the physicochemical properties of the soil. Climatic variations such as increasing rainfall and decreasing temperature along the elevation gradient are the most important factors that have signifcant efects on soil properties [14,15]. Te other most critical forms of soil degradation are depletion of soil quality and soil erosion by water, loss of soil organic matter and reduction in soil biological activity, and increased toxicity due to acidifcation and salinization.…”

“…Kumar et al [25] and Ambade et al [26], indicated that the concentration of PAHs was higher in the winter season than in the summer season, and the health risk issue is higher in the winter season than in the summer season [27]. Various studies addressed the impact of elevation on soil physicochemical properties [3,14,15,[28][29][30][31][32][33], but there are limited data from forest ecosystems.…”