Some investigations into soil and vegetation relationship associated with alkaline-saline soil surfaces in the Walcha area, Northern Tablelands, New South Wales
1995
Kreeb, K.H. (Bremen Univ. (Germany). Dept. of Plant Ecology) | Whalley, R.D.B. | Charley, J.L. (New England Univ., Armidale (Australia). Dept. of Botany)
Soil parameters measured at 23 points along a 200 m transect were highly correlated with the pattern of vegetation. Of overriding significance was soil pH, which varied from a high of over 10 on bare areas delineated by Critesion marinum and Cynodon dactylon to a low of less than 5 on grazing land supporting the growth of a wide range of pasture species. The bare areas were characterized by alkalinity. While they were sodic at all depths measured, they were only marginally saline and then only at the soil surface. The chemical composition of the groundwater collected from 3 piezometer tubes varied quite markedly over the site. It is hypothesized that the presence of alkaline bare areas is the natural result of alternating wet and dry periods which have induced accumulation of carbonates and bicarbonates of the alkali cations, notably Na. Drainage of the original perched swamps by the early landholders, tree clearing and the grazing of domestic livestock would have accelerated the process since European settlement. However, tree planting would appear unlikely to have any impact on the reclamation process in the short term. A more viable option would be the recreation of the original swamps in suitable situations, although this solution would create problems for grazing management.
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