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Cut Costs Strategically: Look at Seeding Rates, Fertility

If there’s one theme from this winter’s meetings, it’s cut, cut, and cut yet more crop inputs. Just be careful which inputs you cut, because not all cuts are created equal.

A method called intelligent intensification can safeguard your most productive inputs like planting rate, fertility, and targeted pest control, says Mike Gunderson, Purdue University agricultural economist. They disproportionately influence your yield and profit.

Cutting inputs that sacrifice yield can backfire. The chart below shows that reducing your projected crop yield can increase a $295-per-acre cash rent to between $1 and $2.36 per bushel, depending on where your projected yield lies between 120 and 300 bushels per acre, Gunderson says. A 160-bushel-per-acre crop translates to cash rent of $1.84 per bushel in this example. A 230-bushel corn crop translates to $1.28-per-bushel cash rent, he says. 

Seeding rates
Fred Below, University of Illinois crop physiologist, ranks plant population (seeding rate) as the fifth-most influential yield influencer behind weather, nitrogen (N) rate, hybrid selection, and previous crop.

“Of the various production factors, seeding rate has changed the most over the last 50 years, increasing from an average of 18,000 plants per acre in 1965 to 32,000 plants per acre today. It’s going to have to go even higher to achieve 300 bushels per acre.

“To reach 300 bushels per acre with roughly the same size and number of kernels per plant as 200-bushel corn, you need to increase population from 32,000 to 45,000 seeds per acre,” says Below. (Realize that your better ground responds the most to intelligent cutting.)

The table below shows if reducing corn seeding rates by 6,000 seeds per acre lowers yields by 6¢ bushels per acre, profits fall by 4¢ per bushel.

This is because the 9¢ per bushel of savings from reducing seed costs is more than offset by increases in per-bushel machinery costs (3¢ per bushel) and land costs (5¢ per bushel). Total net result is an increase of 2¢ per bushel.

Fertility is key, too
High plant populations pay only when you fertilize accordingly, Below says. Those extra plants compete with one another for nutrients. Also, weather determines which inputs have the largest sway over yields in a given season.

For example, extra phosphorus (P), a premium balanced nutrition formulation, or banding paid off the most (+17 bushels per acre ) in 2011 in Below’s Illinois high-yield trials.

In 2013, narrow rows and high population (45,000 vs. 32,000 plants per acre) paid off the most (+27 bushels per acre). In 2014, fungicide and narrow rows paid off the most (39 bushels per acre).

Obviously, since the weather has such a large impact on yield, it’s not surprising that each year’s most influential production factor reflects that season’s weather.

“Assuming you keep up with your soil test, know the amount of nutrients that your crop removed,” he says.

Fertility factors
Here are other fertility factors to keep in mind.

  • Pay attention to when and how the corn plant uses each nutrient, especially those where most of what the crop absorbs ends up in the grain, or those with a high harvest index, Below says.
  • Nutrients with high harvest index (nitrogen, phosphorus, sulfur, and zinc) are most important for high corn yield, Below says.
  • Phosphorus (P) has the highest harvest index of all nutrients. More than half of P uptake occurs during grain fill. Below sees “an enormous boost in emergence uniformity and early growth” from banding or placing in-furrow P, an immobile nutrient in the soil. Bands should be 4 to 6 inches directly under the crop row, or a minimum of 3 inches horizontally from the crop row, he says. If it doesn’t occur, “you might as well broadcast it,” he says.
  • The plant absorbs more than 7 pounds of nitrogen (N) per day for 21 days from roughly June 21 to July 14 as it creates a stalk and leaves, Below says. That’s 150 pounds per acre of N that you can’t make up for later.
  • Potassium (K) has to be absorbed by the corn plant before flowering to be useful, Below notes.
  • Boron plays a huge role in pollination, Below says. It’s immobile in the plant except during flowering.
  • More than half of sulfur (S) and zinc (Zn) uptake occurs during grain fill. This explains the logic behind chelated micronutrients (plant-available formulations), Below says.

Beyond agronomics
Intelligent cutting extends beyond agronomy to these fixed costs from Ann Johanns, Iowa State University Extension management specialist.

  • Propose a flexible cash rent or crop-share arrangement.
  • Check out custom farming agreements. They can postpone costly equipment outlays or bridge a transition to a new tillage system.
  • Own machinery jointly with another producer to lower your fixed costs.

Plant populations
Of all the yield-shaping variables, plant population has changed the most in farmers’ careers, says Fred Below, University of Illinois crop physiologist.

“Since 1965, U.S. corn yields have increased by 242%, while populations have increased by 178%,” he says. “The highest you can go in 30-inch rows is 38,000 plants with today’s technology. At a certain point, plants compete with one another, root systems shrink, and feeding the plant becomes way more important. In 1965, we planted 18,000 seeds per acre, on average, and yielded 70 bushels per acre. Today, we average 32,000 plants per acre and average 170 bushels per acre.”

On the horizon
These concepts, products, and technologies hold promise for future yield increases, says Fred Below, University of Illinois crop physiologist.

  • Chelated nutrient formulations, including micronutrients for in-furrow applications. 
  • Nutrient coatings that prevent P and micronutrient tie-up in the soil. This may include physical barriers or formulation chelations that prevent positively charged nutrients from being tied up by negatively charged nutrients or being locked up by negatively charged soil particles.
  • Fertilizer catalysts that increase N mineralization (N release from the soil’s stores).
  • Narrow rows that increase plant population (but ones with more space between plants within the row).
  • New soil-test technologies or algorithms may be required to fertilize accurately for yields above 300 bushels, Below says. “Today’s soil tests were calibrated to yields and production practices of the 1960s and 1970s.”

Written by Susan Winsor

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