ABSTRACT
The aim of the present work was to evaluate the spatial variability of hydro-physical characteristics and available water of an alluvial soil, keeping in view adequate irrigation management. Disturbed soil samples (0 - 0.20 and 0.20 - 0.40 m layers) were collected in the Capoeira Project, São José do Bonfim, Paraíba state, Brazil. Systematic scheme was used on the regular grid (10 x 15 m) in all 90 points. Descriptive analyses were performed to identify spatial structure of the following variables: sand, silt, clay, field capacity (FC), permanent wilting point (PWP) and percent available water(AW). Mean variability was found for studied variables, with coefficient of variation (CV) between 17.43% (clay, 0.20 - 0.40 m layer) and 46.48% (sand, 0.20 - 0.40 m layer). The quarter interval showed decreasing sequence of variability: sand > silt > clay > FC > AW > PWP. The studied variables presented spatial dependence, with range varying between 25 m (silt, 0 - 0.20 m layer) and 60 m (silt, 0.20 - 0.40 m layer). The isohypsas map, constructed with estimated AW value by kriging, was observed to be an important tool for the irrigation management.
Key words:
variability; available water; spatial dependence; geostatistics