That is a theme I frequently use in my grazing management presentations around the country. I often say I have learned more about grazing management by working the last dozen years in the extremes of irrigated and desert environments of Idaho than I did in 23 years of the high natural rainfall environment of Missouri.
We had a situation develop this summer on the pivots here at Circle Pi-Patterson that really brought the lesson home. The three pairs of pre- and post-grazing pasture pictures are from the same paddock, just at different distances from the pivot center.
To set the stage. We were having poor water flow on the upper pivot (150 acre) for some unidentified reason. Remember these are gravity flow water pressure, no pumping. Historically the lower pivot (300 acres) has run at about 80 psi & puts out tremendous amount of water. We shut the lower pivot valve to half-open. Water pressure should have been adequate. The output ‘looked’ good.
After a month of hot weather from mid-July to Mid-August, it was time to move the cattle onto the higher side of the lower pivot and I got a shock when we were grazing there. I had missed doing one of my biweekly pasture inventories and hadn’t been out to that part of the pasture for a month.
The pictures and graph tell the rest of the story.
This is between towers 9-10. Grass is only 6-7″ tall and dried out.
Post-grazing residual is under 2″ & no green leaf at all. Remember, this is the same paddock with the same herd of cattle for the same length of time. All we are looking at is inadequate water flow as we get farther away from the pivot center.