Laj Ahuja's Contributions to the Development of Pedotransfer Functions.

Recognition of the need in developing reliable pedotransfer functions arose as the hydrologic modeling in soil science and agronomy was becoming an accessible tool for research and application. It is difficult to overestimate Laj Ahuja’s  contribution to this field. He was the first to show how addition of one or more measured water retention data drastically enhances pedotransfer. The first application of scaling in pedotransfer work has been developed by Ahuja. His contributions to class pedotransfer function development created opportunities of using soil survey data in agronomic modeling. He was the first to note that class pedotransfer functions (PTFs) require a smaller number of parameters to be predicted as compared with PTFs with continuous inputs.  Ahuja was also the first to emphasize the need and the feasibility of introducing the temporal component in pedotransfer work, as well as uncertainties related to the absence of such components. Explicit inclusion of management parameters in pedotransfer opened new opportunities of using pedotransfer at coarser scales, particularly in remote sensing.  All these and related ideas have appeared to be most fruitful and have found development and applications during last 40 years. The talk will illustrate the progress made thanks to the remarkable contributions made by L Ahuja - the stalwart enthusiast and the major driving force of the agronomic modeling, and agronomic science as a whole.