even surface residue affect the soil intake rate. In their research paper titled, “Characterizing Droplet Kinetic Energy Applied by Moving Spray-Plate Center Pivot Irrigation Sprinklers,” Bradley King, PhD, PE, and David Bjorneberg, PhD, PE, had this to say about water droplets, “The kinetic energy of discrete water drops impacting a bare soil surface is generally observed to lead to a drastic reduction in water infiltration rate due to soil surface seal formation.”
You can read the entire paper at
https://eprints.nwisrl.ars.usda.gov/1566/.
The droplet sizes within the sprinkler pattern matters also. As an example, if all of your droplets were consistently a single size, it would create serious limitations to a sprinkler pattern. An intentionally designed variety of droplet sizes and stream radii are important to protect the intake rate of the soil and to help prevent surface sealing.
Find an interesting presentation including six truths of droplet size at:
resources/technicalpapers/2019/sprinkler- drop-characteristics_king.pdf.
Therefore, the sprinkler type chosen, as well as the stream characteristics, velocity and specific energy of the various droplets produced by the sprinkler, will have a direct impact on soil surface sealing and
runoff potential. Silty soils are especially susceptible to surface sealing, so beware if the word “silt” is prominent in the name of your soil type.
If you are uncertain about your soil type
you have is with the free app from the U.S. Department of Agriculture-Natural Resources Conservation Service called SoilWeb. SoilWeb can be downloaded onto your mobile device from the Apple app store or Google Play. Another option is to use the Web Soil Survey website:
https://websoilsurvey.sc.egov.usda. gov/app/
homepage.htm.
Knowing about some of the most impactful influences on your center pivot’s water application package and how they relate to each other is important when making decisions regarding the type of technology and equipment appropriate for your center pivots.
Deep in the canopy of a corn crop, a low-pressure sprinkler on drops can be very effective if not spaced too far apart and if the soil intake rates are adequate.
irrigationtoday.org
Summer 2020 | Irrigation TODAY 17
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