Drought unmasks soil-type impact
Last fall, Scott Lasater received a view of how soil types impact yield without leaving his combine cab. The Gaston, Indiana, farmer works fields containing a mix of soil types. They range from peat soils with head-turning 45% organic matter levels to sticky clay soils that quickly dry out during droughts like 2012.
Last year, one field had both types.
“I watched the yield monitor in one field go from 13 bushels per acre to 298 as I rolled across one field,” he says. “In that particular field, the mucky peat soils didn't run out of water, but clay hills did. I had never seen nearly a 300-bushel difference occur in a field.”
Those differences likely will be magnified in this drought-stressed area of east-central Indiana this year.
“The variability in hybrids is exaggerated in a high-stress year,” he says. “This year, there is an extreme difference in hybrids of similar maturities. Some are handling the stress better; others are not handling it as well.”
That's why hybrid selection continues to reign as one of the top corn production factors that Lasater considers.
“The single biggest thing for growing corn is picking the right genetics and planting them on the right soils,” says Lasater. “When I'm evaluating hybrids either for high- or medium-to-low-producing soils, I use unbiased university data and company-provided data to make those selections. I have seen a hybrid that handles stress tolerance well give up 20 bushels per acre in highly productive soils.”
Besides matching hybrids with soil types, factors like disease resistance, nitrogen utilization, and drydown rank high.
“I planted one hybrid in the early 1990s that had a good balance between yield and drydown, but it was susceptible to gray leaf spot,” he says. “It was a popular hybrid, but getting caught by severe gray leaf spot taught me not to plant hybrids highly susceptible to disease.”
Certain genetic lines also are wetter than others, he says. In some cases, though, the increased moisture at harvest time can be worth it. One hybrid he's planted can be 1.5 points wetter than hybrids in the same relative maturity.
“In that case, I thought the extra yield punch was worth it,” he says.
“From a return-on-investment standpoint, you're often better off having wetter grain and drying if you get more yield,” says Bruce Battles, Syngenta crop specialist. “More and more farms are set up with grain-drying capabilities.”
Lasater normally plants hybrids with relative maturities of 105 to 114 days. He varies populations between soil types, pushing populations on high-organic matter soils up to 37,500 plants per acre from his normal 36,000 plants per acre. “On hills, I cut them back to 30,000 or 32,000 plants per acre,” he says.
For 2013, Lasater plans to continue the following five steps.
1. Applying starter fertilizer
Lasater applies liquid starter fertilizer at planting. “It does slow me down, and it is not convenient,” he says. Still, an eye-popping on-farm comparison in 2011 found starter applications netted an extra $49 per acre.