Soil properties determine the elevational patterns of base cations and micronutrients in the plant–soil system up to the upper limits of trees and shrubs
- 1State Engineering Laboratory of Soil Nutrient Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
- 2Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou 318000, China
- 3Soil Erosion and Degradation Research Group, Department of Geography, University of Valencia, Valencia, Spain
- 4Sydney Institute of Agriculture, School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
- 5Forest dynamics, Swiss Federal Research Institute WSL, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland
- *These authors contributed equally to this work.
Abstract. To understand whether base cations and micronutrients in the plant–soil system change with elevation, we investigated the patterns of base cations and micronutrients in both soils and plant tissues along three elevational gradients in three climate zones in China. Base cations (Ca, Mg, and K) and micronutrients (Fe, Mn, and Zn) were determined in soils, trees, and shrubs growing at lower and middle elevations as well as at their upper limits on Balang (subtropical, SW China), Qilian (dry temperate, NW China), and Changbai (wet temperate, NE China) mountains. No consistent elevational patterns were found for base cation and micronutrient concentrations in both soils and plant tissues (leaves, roots, shoots, and stem sapwood). Soil pH, soil organic carbon (SOC), total soil nitrogen (TN), the SOC to TN ratio (C : N), and soil extractable nitrogen (NO3− and NH4+) determined the elevational patterns of soil exchangeable Ca and Mg and available Fe, Mn, and Zn. However, the controlling role of soil pH and SOC was not universal as revealed by their weak correlations with soil base cations under tree canopies at the wet temperate mountain and with micronutrients under both tree and shrub canopies at the dry temperate mountain. In most cases, soil base cation and micronutrient availabilities played fundamental roles in determining the base cation and micronutrient concentrations in plant tissues. An exception existed for the decoupling of leaf K and Fe with their availabilities in the soil. Our results highlight the importance of soil physicochemical properties (mainly SOC, C : N, and pH) rather than elevation (i.e., canopy cover and environmental factors, especially temperature), in determining base cation and micronutrient availabilities in soils and subsequently their concentrations in plant tissues.