Soil physical and hydraulic properties in the Donato stream basin, RS, Brazil. Part 2: Geostatistical simulation

Propriedades físico-hidráulicas do solo na bacia do arroio Donato, RS, Brasil. Parte 2: Simulação geoestatística

ABSTRACT

Geostatistical simulation has been the most promising and used technique for the analysis of uncertainties of soil physical and hydraulic properties, with high spatial heterogeneity. This study carried out a stochastic analysis of saturated hydraulic conductivity (K_sat) and soil water retention curve parameters in the Donato stream basin, located in the municipality of Pejuçara, in the state of Rio Grande do Sul, Brazil, with geographic coordinates between 28º 25’ 34” S and 53º 40’ 30” W, and 28º 24’ 50” S and 53º 41’ 30” W, 590 m of altitude. Soil samples were collected during the period from August to November of 2012. Sequential Gaussian simulation technique was used to generate 100 random fields of each variable. The results showed great uncertainties for K_sat and the parameter α of the soil water retention curve. The uncertainties between the percentiles 5 and 95% for K_sat indicated values from 24 to 44 cm d^-1, and for the parameter α, the uncertainties could be estimated from 0.622 to 1.122 cm^-1.

Key words:
sequential Gaussian simulation; random fields; spatial variability analysis