Precipitation is the most important problem under dry land condition agriculture. However, soil water amount is a better parameter to decide the hydric stress level in crops. The main objective of this study was to determine a statistical model to decide if planting or not under dry land condition. This model used soil water amount condition as the most important parameter. Two experiments were established in the summer of 1995 and 1996, respectively at the Ejido Feo. Villa, Durango, México. Two corn genotypes (Blanco Hualahuises and H‑412) were used and the soil water amounts were measured since the beginning of the experiment in each plot. Also, grain yields were weighed for statistical analysis, wich consisted on using 2*2 contingency tables and X² interaction to estimate soil water amount for planting. The results indicated that the range optimum soil water amount for planting varies from 6.5 to 7.8 cm, for Blanco Hualahuises and 6.5 to 8.3 cm for H‑412 in 1995; and 6.5 to 7.8 cm for Blanco Hualahuises in 1996. As main conclusion is that the X² interaction is a good tool to determine soil water ranges at the beginning of corn planting. Thus, farmer can decide if planting or not.