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A comparison of plant available nutrients on decomposed granite cut slopes and adjacent natural soils
Author(s) -
Claassen V. P.,
Zasoski R. J.
Publication year - 1998
Publication title -
land degradation and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 81
eISSN - 1099-145X
pISSN - 1085-3278
DOI - 10.1002/(sici)1099-145x(199801/02)9:1<35::aid-ldr273>3.0.co;2-v
Subject(s) - topsoil , soil water , nutrient , environmental science , organic matter , revegetation , soil organic matter , soil test , edaphic , soil science , agronomy , phosphorus , chemistry , ecology , biology , land reclamation , organic chemistry
Decomposed granite (DG) slopes are often difficult to revegetate after existing topsoil and vegetative cover have been removed. In this study, naturally vegetated soils and denuded DG cut slopes were evaluated to compare edaphic (soil‐related) conditions that may differ between the vegetated and non‐vegetated states. Potential plant nutrient deficiencies were evaluated by soil nutrient extraction, plant tissue analysis and by greenhouse bioassay methods. The DG cut slopes have approximately one‐quarter to one‐half the clay content, soil organic matter, water‐holding capacity, and total and available nitrogen (N) of the adjacent natural soils. Soil extraction tests for phosphorus (P) availability gave variable results, but a growth response to P amendment was observed in a greenhouse bioassay. The native topsoils and the DG cut slope materials had non‐limiting levels of pH, exchangeable Ca, Mg and K, and total P. Cation exchange capacity and sulfate–sulfur (S) were low but similar between the two soil groups. Principle nutrient limitations are interpreted to be N, P, and possibly S and boron (B), in order of decreasing severity. Based on these results, we conclude that the removal of humified soil organic matter on the cut slopes reduces plant growth directly by lowering several of these essential nutrients, and indirectly by decreasing the soil's water‐retention and infiltration capacity. Soil organic matter is viewed as a critical factor and major contrast between barren and revegetated DG materials. © 1998 John Wiley & Sons, Ltd.