Predictions of 30-year average moisture deficits (MD30) were carried out by means of kriging and co-kriging, using simulations for 500 point observations in an area of 404 ha of sandy soils in The Netherlands. From the above point observations 100 points were selected at random to function as an independent test set. Attention was focused on improving the precision of kriged and co-kriged MD30-maps, as characterized by two error measures, the mean variance of the prediction error and the mean squared error of predictions. To do so the survey area was stratified by means of soil-map delineations according to soil type and water-table classes based on the groundwater table. In unstratified maps the standard deviation of the prediction error largely depends on the observation pattern. Stratification resulted in an increase of precision of predictions in strata with low MD30 variability and an apparent decrease in strata with high MD30 variability. Major soil-map delineations, as distinguished by a soil survey, had significantly different internal variability. Use of co-kriging resulted in an average increase of precision of MD30-maps of about 10%. This study illustrates the use of available soil-survey information for stratifying a survey area so as to enhance precision of predictions when using kriging and co-kriging of point data.