What is going on!

With the use of irrigation moisture sensors increasing in Mississippi, growers are reporting that their moisture sensor values are remaining high after an irrigation event.  Growers are confused and frustrated that irrigation water is just not getting in the ground.  Traditional “cotton” soils are classified as  sands to silt loams.  These soils have a tendency to seal and decrease the amount of irrigation water that enters the soil profile.  Here are some things to consider on sealed silt loam soils.

1) Look for the furrow flow rates on your Phaucet or Pipe Planner recommendation.  The acceptable values should be 7 gpm for silt loam soils.  If the stated flow rates are greater than 7 gpm, irrigation water is progressing down the row too fast for penetration.  By fine tuning the flow rate below 7 gpm, you can increase penetration in these soil types.

2) Consider installing a surge value to the irrigation set.  Surge valves are designed to increase infiltration uniformly across a field.  Remember that when adding a surge valve, you will need to rerun your Phaucet recommendation dividing the irrigation set in half.  Once again, don’t allow the flow rate to exceed 7 gpm.

3) Utilize “cutback” irrigation technique.   The objective of  “cutback” is to reduce runoff while allowing infiltration of the irrigation water into the soil profile.  Simply put, a grower would apply water to a set at a faster rate until reaching the tail ditch, then slow things down by decreasing (cutback) the flow rate by approximately 50% (idling the motor back or opening another set) and continue until the tail ditch is reached once again.

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