1. Predicting a suitable period trafficability using DRAINMOD Mohammed Salahat Guillermo Carrillo Supervised by: Dr. Mohtar, R.

2. Problem statement High water table affects trafficability Trafficability is important for timely seedbed preparation, planting, harvesting, and other field operations Predict best time for trafficability

3. Site of study Southeast Purdue Agricultural Center (SEPAC) Clermont silt loam soil, very poorly drained Corn was planted from 1984 through 1993 with tillage Three years of measured water table (from 1987 through 1989) were used to test the performance of DRAINMOD

4. Objectives Perform evaluation analysis Predict the best trafficability periods

5. Methodology Obtain the data DRAINMOD Run sensitivity analysis, fixed drain spacing and depth Perform calibration and validation analysis Determine the best trafficability periods Good trafficability if water table is deeper than 60cm

6. Sensitivity analysis ParametersDegree of sensibility SpacingSensitive Saturated KSensitive Actual distance from surfaceLight sensitive Thickness of the restricting layerLight sensitive Drainage coefficientNo sensitive Initial depthSensitive Drain depthSensitive Effective radiusNo sensitive Vertical conductivityHighly sensitive Thickness of the restricting layerLight sensitive

7. Results: Calibration

8. Validation

9. Results continued… DRAINMOD predicts acceptable trafficability periods Recommended trafficability period is May-7 to Nov.-5 for the dry year, 1988 Recommended trafficability period is June-29 to Nov.-14 for the wet year, 1989

10. Conclusions DRAINMOD doesn’t work efficiently for frozen conditions DRAINMOD works better in dry years More data and work is needed

11. Acknowledgements Dr. Frankenberger, J. for providing the data

12. Results Sensitivity analysis