This column started in the spring, when I was visiting a neighbor, and we had to move a couple of old traveling big gun sprinklers to get to another piece of old machinery. “I will never, ever use those things again,” my neighbor said, noting that he had installed several center pivots for supplemental irrigation since our 2012 drought and had no more desire to drag the sprinkler, hoses and portable pump around.
These famous last words haunted us both during the third week of June when there was insufficient soil moisture in his nonirrigated field to start a corn or bean crop following recently chopped triticale. Literally next door, I was having similar dryland anxiety due to thirsty newly planted alfalfa and pasture in adjacent fields. We had gotten no real rain since before Memorial Day, and as it turned out, we didn’t get any more measurable rain until the second week of September. By then it was too late for a lot of corn producers.
But in late June, I had two thoughts: One was wishing for rain and the other recalling a column I wrote for Irrigation Today a few years ago addressing this exact issue (see October 2017 issue). Thinking to myself about what academic baloney I may have offered at that time, and suddenly becoming sensitive to the term “walk the talk,” I did a bit of self-reflection on irrigating in a transition area between predominately dryland and irrigated crop production. Reviewing the article, it appears assumptions about yield impacts (significant in some years), crop prices (low) and per acre costs matched actual 2020 condition. Overall, I had concluded, with some caveats, that supplemental irrigation in Southwest Iowa made economic sense even under relatively low crop prices. And, having the chance to use my own and neighbor’s operations as case studies, I’ll stick with that story.
Of course, the dreaded traveling big gun units, hose and portable diesel-powered pump were pulled out and readied for operation after nearly a decade. Travel lanes were cut through the corn field, but my hay fields were wide-open for a poorly navigated big gun. Despite a host of leaks, everything worked, and we were in the irrigation business for the first time on these fields. Lacking well capacity, we drew water from an adjacent creek and managed to irrigate his corn field and half of my pasture. We would stop at night for fear the unsupervised gun would take off on a path of its own, which it did, so we ended up irrigating 16 hours per day for about 10 days. We calculated we added about four acre-inches to the corn and pasture. We probably should have done it again in August but didn’t because of unrealized expected rain and concerns about impacts to the diminishing creek.
Despite the haphazard nature of the operation … it has allowed me to see a side-by-side comparison of irrigated vs. dryland pasture yield in an extremely
Despite the haphazard nature of the operation, it allowed my neighbor to get some form of corn crop rather than nothing, and it has allowed me to see a side-by-side comparison of irrigated vs. dryland pasture yield in an extremely dry year. There is still a portion of the year left to go, and I’m still not settled up with my neighbor for diesel fuel, so the final impact of irrigation is not yet known, but I look forward to the results. I may be in the market to buy some used traveling big guns.