The effect of rock content on nutrients in a Sierra Nevada forest soil
2012
Johnson, D.W. | Walker, R.F. | Glass, D.W. | Miller, W.W. | Murphy, J.D. | Stein, C.M.
The effects of rock content on nutrient concentrations and contents (kgha⁻¹) in a skeletal soil derived from andesite were investigated. Rock content to a 60cm depth ranged from 8 to 69% among 20 quantitative soil pits within a 10ha area. On average, rocks contained 9% of total soil C, 19% of total soil N, 3% of total ecosystem C, and 12% of total ecosystem N. Percent rock content also appeared to cause increases in organic matter concentrations: rock content was significantly, positively correlated with total C and total N concentrations in the fine earth (>2mm) fraction. Soil C was organic; no carbonates were present. Percent rock content was also significantly, positively correlated with fine earth C:N ratio, suggesting that organic matter in rockier soils was in an earlier stage of decomposition at any given depth. Other consistent correlations with rock content included Bray P (positive) and exchangeable Mg²⁺ (negative). The decrease in fine earth mass with increasing percent rock content offsets the increase in C concentration such that there was no correlation between percent rock content and either fine earth or total soil (fine earth plus rock) C content (kgha⁻¹). Percent rock content was significantly negatively correlated with total N, Bray P, inorganic N, exchangeable K⁺, Ca²⁺, and Mg²⁺ contents, however. The results of this study show that high rock content can affect soil C and nutrient pools not only because of the contributions of the rocks themselves, but also because high rock content appears to cause higher concentrations in the fine earth fraction.
Mostrar más [+] Menos [-]Palabras clave de AGROVOC
Información bibliográfica
Este registro bibliográfico ha sido proporcionado por National Agricultural Library