Dr. Larry Cihacek Soil and Range Science Department NDSU School of Natural Resource Sciences Fargo, ND

 All soils are created equal? T/F ◦ False  All soils are suitable for drainage? T/F ◦ False  Drainage always works in Iowa? T/F ◦ True  Cihacek is opposed to drainage? T/F ◦ False

Saline soil (photo by Jay Goos) Sodic soil (photo by NRCS)

 Subsurface soil drainage: ◦ Reduces salinity ◦ Lowers water table ◦ Warms soil ◦ Allows for earlier tillage and seeding ◦ Increases soil productivity

 While most soils are suitable for drainage, some are not.  Some soils have subsurface properties that may prohibit economical drainage practices.  Some soils may have subsurface properties that may result in drainage failure.

(From PNW 601-E )

High EC Low EC

Golf ball (K + ) vs. Tennis ball (Ca ++ ) vs. Baseball (Mg ++ ) vs. Softball (Na + )

1. Identifying Soil Series – Knowledge of Soil Series. 2. Evaluating Soil Chemical Characteristics or Drainage Properties 3. Verification of Soil Properties

 Soil Drainage Suitability Rating will not provide is a comprehensive site evaluation, determination of wetlands and flooding issues, address social or environmental issues, or soil productivity or design information.

 Accuracy is dependent on population of soil chemical characteristics available for the soils found in in the survey area.  Soil series may have significant inclusions of soils that are of greater or lesser hazard.  Soil survey information should be used for only delineating potential problem areas.

 If SAR is <6 or SDSR is <0.15 no further action is needed.  If SAR is >6 but <10 or SDSR is 0.15 to 0.80, verify soil properties by soil sampling.  If SAR is >10 or SDAR is >0.80, DO NOT DRAIN – Permanent cover?

 In areas to be sampled: ◦ Sample 3 to 8 points (depending on area size and soil variability) - minimum of 1 sample per 5 acres. ◦ Sample each point separately. ◦ Sample in 1-foot increments. ◦ Analyze soil for pH, EC, cation composition. ◦ Estimate sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) ◦ Consult with a soil scientist to evaluate hazard.

 Hydric soils and hydric soil regulation compliance.  Potential for developing an interpretation index for “Tile Drains and Underground Outlets” (dropped from national Soil Survey Manual in late 1990’s). ◦ 0 to 1 rating scale.

DepthE.C.SAR -cm-- mS/cm Sand Clay Sand Clay Sand

 Springer, A. G Water-dispersible clay and saturated hydraulic conductivity in relation to sodicity, salinity and soil texture. M. S. Thesis. North Dakota State Univ., Fargo, ND.

 Illustrations (Horneck, D. A., J. W. Ellsworth, B. G. Hopkins, D. M. Sullivan, and R. G. Stevens Managing salt affected soils for crop production. Pacific Northwest Extension Publ. No. PNW 601-E. Oregon State Univ., Univ. of Idaho, Washington State Univ.  State NRCS Staff.  NDSU Soil and Range Science and Ag and Biosystems Engineering Faculty and Extension Personnel