Farm Progress

Think Different: Rethink Agronomics 2013

Kurt Lawton

February 22, 2013

2 Min Read

As with most farm business decisions, very few escape without some type of tradeoff, be it labor, time or money. Our cover story may challenge your beliefs if you're sold on 30-in. row soybeans, because you lose yield (range from 2.9 to 4.5 bu./acre) compared to 15-in. – according to a three-year, six-state university trial.

But as farm size grows and 30-in. corn drives the decision to buy a 90-ft. planter to get acres done in a narrow planting window, this tradeoff for speed and optimum corn seems to overpower a soybean yield boost. Numbers tell the tale, as 30-in.-row soybeans occupy 29% of the total in Illinois, up from 18% five years ago. In both Iowa and Minnesota, more than 40% of soybean acres favor 30-in. rows.

However, the cover story cites economics that overturn this tradeoff to make a narrow-row planter pay its way. A 2008 Iowa State study shows that a 1,000-acre farm only needs a 1 bu./acre increase to justify the added expenses of narrow rows, including new planter costs. A 2,500-acre farm only needs a half-bushel increase.

Perhaps, like Wells Fargo ag economist Michael Swanson points out in his management story, this narrow-row planter purchase (like his suggestion of added irrigation) could be your ticket to find that cost-effective way to boost current production?

Another agronomic decision that merits some rethinking, especially given dry Midwest soils, is the need for intensive tillage that robbed valuable moisture and damaged soil structure last fall. A recent research paper published in the Journal of Soil and Water Conservation (pdf) authored by 10 Iowa State University researchers who studied the impact of the drought in Iowa, cited major issues that stressed crops beyond the lack of rainfall and excessive heat.

In fact, lack of soil surface cover in winter 2011/2012 caused deterioration of soil aggregates that allowed cementation to occur. This negatively impacted the soil-water-plant relationship that reduced above-ground biomass and grain yields.

This journal paper cited key lessons of the 2012 drought:

  • Tillage of dry soils damages soil structure that reduces subsoil moisture necessary for higher yields.

  • No-till or minimum till retains more water in soil profile, and surface residue decreases surface erosion.

  • Cover crops guard against erosion, improve soil structure, increase organic matter and significantly reduce nutrient loss. They also accumulate residual soil nitrate to decrease loss from the root zone.

  • Corn following corn suffered much greater yield loss than corn after soybeans during drought.

  • Soil sampling in spring following drought improves accuracy compared to fall sampling.

  • Drought revealed increased rootworm feeding on corn genetics, even those with Bt RW traits.

  • Planting a range of adapted hybrid maturities will help spread risk during drought.

I sincerely thank you for reading and for being willing to Think Different.


About the Author(s)

Kurt Lawton

Kurt Lawton of Eden Prairie, Minn., is a writer and owner of Stellar Content LLC. He is the former editor of Corn+Soybean Digest, a Farm Progress publication.

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