SIMULATED AND MEASURED SPATIAL CONTRASTS OF SOIL-WATER RELATED PROPERTIES AT FIELD SCALE

Abstract

The assessment of the hydraulic properties of soils is an important aspect to consider when dealing with the soil-water phenomena, particularly its behavior at field sente when data coverage is needed for the feeding of integrated modeling purposes, or if any aspect of water management is treated. At field scale, it is importam to knowyhe spatial behavior of water transfer/retention conditions and related soifparameters as well as the ones that should be sampled for soil-water description. Difficulties for "in situ" determination brings simulation of hydraulic parameters as a natural choice for data coverage in large arcas (at least approximated data, since they have, in most cases, a complex behavior). An experiment was carried out in Angatuba, Sao Paulo, Brazi I (23°33'S; 48°.18'W; 670m) and intensive soim sampling was done in a regular grid, covering a 40 ha field, in order lo study spatial contrasts of hydraulic properties and related easy-measured soim parameters. Simulations for soil-water were done based upon the pore size distribution model and pedrotransfer functions. Results from the field scale observations have shown poi nt-by-point differences in the characteristics of soil permeability, particularly near saturation. Spatial anal ysi s h as shown low coefficient of variation values and lack of strong spatial autocorrelation, for ali soim properties analyzed.