Scale‐dependent effects of environmental factors on soil organic carbon, soil nutrients and stoichiometry under two contrasting land‐use types
Qing Zhu, Kaihua Liao, Xiaoming Lai, Ligang Lv
Abstract
Abstract Variations in and control of soil total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) and their stoichiometric ratios (C:N, C:P and N:P) are critical in agricultural nutrient management. This study examined the scale‐dependent effects of environmental factors on these soil properties under two contrasting land‐use types (tea versus. bamboo) at plot scale (70 × 70 m) and landscape scale (2 × 2 km). Results showed that at both scales, the tea garden generally had higher TOC and nutrient concentrations and lower stoichiometric ratios than the bamboo forest, because of fertilizer and green manure applications in the tea garden. Influences of topography and soil texture on TOC, nutrients and stoichiometric ratios were scale‐dependent. In the tea garden plot, as scale increased, influences of topography and soil texture on TOC, TN and C:N ratio increased, whereas their influence on TP, C:P ratio and N:P ratio decreased. Similar patterns were observed in the forest plot. At the landscape scale, the effects of influences of topography and soil texture on TOC and nutrients were not obvious. The spatial variations in TOC, nutrients and stoichiometric ratios were controlled by both topography and soil texture at the plot scale but were mainly influenced by soil texture at the landscape scale. The influences of topography and soil texture on TOC, nutrients and stoichiometric ratios were generally weaker at landscape than at plot scale. This study confirmed that the effect of scale must be considered when predicting the spatial variations in TOC and nutrients.