Two soil profile reconstruction techniques

This paper presents two different soil profile reconstruction techniques; the fitting of equal-area quadratic splines (EQS) through bulked horizon data and the use of Tikhonov regularisation (TR) on layered apparent electrical conductivity readings measured from an electromagnetic induction instrument. A Red Kurosol was used to demonstrate the two techniques. The results revealed some problems with both. For the spline reconstruction problems occur when the morphological horizons do not reflect accurately the depth function of a particular soil attribute. For TR a major problem is choosing the regularisation order without a priori information. Both methods are useful in different situations, the spline reconstruction when horizon data are available and TR when no or little soil information is available as the reconstruction relies only on instrument readings from an electromagnetic induction instrument.