Assessment of weathering rates in Dutch loess and river-clay soils at pH 3.5, using laboratory experiments

Weathering rates in 12 horizons of soils developed in loess and clay sediments were measured by means of laboratory experiments. The experiments were carried out by percolating thin columns containing approximately 2 g of soil material. Despite the small amount of sample used, the results were fairly reproducible. Weathering rates in loess soils were 0.8 to 8 times higher than rates measured in sandy soils. The rates in river-clay soils were 4 to 90 times the rates in sandy soils. The weathering rates of the base cations (BC), especially Ca and Mg, strongly increased with clay content. Significant relations were found between the mineralogical composition, total element content and texture characteristics of the samples and the measured weathering rates.