Starter Boost

Applying fertilizer at planting ignites corn growth but doesn't always translate to higher yields and profits.

Matt Wilde
By  Matthew Wilde , Progressive Farmer Crops Editor
Neal Wikner, Farmersburg, Iowa, uses a custom blend of starter fertilizer to help seedlings thrive. (Progressive Farmer image by Matthew Wilde)

Watching corn quickly grow in late May solidified Neal Wikner's plans to continue a family tradition of using starter fertilizer.

His father, Clark, first put nutrients near corn seed during planting about 25 years ago. He wanted to give young plants a boost because cold and wet soils--a common early-spring occurrence in the Upper Midwest--slows root development and nutrient uptake.

Persistent rain this year delayed corn and soybean planting, and emergence throughout much of the Corn Belt by several weeks, according to government crop reports. Plant development also fell behind.

It took the Wikners, who farm near Farmersburg, Iowa, five days to plant 580 acres of corn in mid-May. Emergence occurred in about 10 days because of cool, wet conditions. Corn was slightly yellow initially, but stands were uniform. Plants quickly turned a healthy dark green and reached the V4 to V6 stage by the third week in June with no signs of stress.

The 3 1/2 gallons per acre of 8-13-0-1-1 liquid fertilizer--nitrogen, phosphorus, potassium, sulfur, zinc and boron--placed in-furrow at planting spurred early development in less-than-ideal conditions, Neal believes. He hopes that translates to good yields at harvest.

"We feel placing fertilizer by the seed will help corn in the early stages until it can reach the anhydrous [ammonia] layer," Neal says. "Every infant needs extra nutrition.

"I can't say for sure what starter equates to in extra yield, but it's reasonable to expect 5 bushels [per acre]," he adds.

Studies from several universities and companies indicate a similar yield bump associated with starter fertilizer.


Research proves pop-up and banded nutrients at planting jump-start corn growth, being especially beneficial in certain soil types and environmental and agronomic conditions.

But, starter fertilizer doesn't guarantee more bushels or a return on investment (ROI), agronomy experts agree.

"It's certainly a good practice to get corn off to a good start," says Joe Lauer, an agronomy professor at the University of Wisconsin and state Extension corn specialist. "The economics, though, are mixed at best."

Some growers question whether starter fertilizer is necessary given the resiliency of modern hybrids and recent low crop prices, Lauer explains.

To provide some answers, the university is in the last year of a three-year starter fertilizer study at 11 locations throughout Wisconsin. It's evaluating the agronomic response of corn with 4.1 gallons per acre of seed-placed liquid fertilizer (10-34-0-1 with zinc) and 200 pounds per acre of fertilizer (9-11-30-6 with sulfur and zinc) banded 2 inches to the side of the row and 2 inches below the seed at planting compared to untreated checks.

In 2017 and 2018, on average, corn with in-furrow and banded fertilizer outyielded the untreated check by 1 bushel and 5 bushels per acre, respectively. Five of 11 locations had a significant response to fertilizer treatments; others didn't.

"The bottom line is that in states like Wisconsin, where there is a lot of manure applied, we don't see a lot of response to starter fertilizer," Lauer concludes. Soil with high to adequate phosphorus levels is less likely to see a yield response from the practice.


There are circumstances when starter fertilizer aids corn development, which can translate to additional bushels and profit, Lauer and other experts say.

During growth stages V1 to V5, it's important to prevent stress that can stunt corn and possibly reduce yield potential. Starter fertilizer provides easily accessible nutrients to developing plants to enhance seedling growth until they establish larger root systems to better access water and nutrients.

Planting conditions that may benefit from starter fertilizer include:

> soils that test low in phosphorus

> soils that test high or low in pH

> cool soil temperatures that are associated with early planting

> continuous corn

> high residue cover associated with conservation tillage and no-till

> northern Corn Belt locations

> coarse-textured (sandy) soils low in organic matter

> poorly drained soils

> locations prone to substantial drought stress.

Starter fertilizer improved corn yields by 4.1 bushels per acre on average in more than 50 on-farm trials conducted by Growmark the last three years. The tests are part of the Bloomington, Illinois-based agricultural supply cooperative's MiField Applied Research.

Prior to adding in last year's aggregated results, the average increase was 5.9 bushels per acre.

"What we're seeing from starter is a highly variable response … the data reflects that," explains Brendan Bachman, Growmark senior agronomy and technology manager.


The local environment, individual management and cropping systems will likely dictate if starter fertilizer provides an ROI, Bachman adds.

Growmark MiField Applied Research last year revealed liquid starter fertilizer applications lost $3.40 per acre, on average, under relatively good early growing conditions where studies were conducted. Several different products were applied at a rate of 5 gallons per acre at an average cost of $15.

This year may be a different story since adverse weather delayed planting throughout much of the Corn Belt. Corn prices are also higher. A 5-bushel bump per acre at $4 per bushel could net farmers a $5 ROI.

"In these tough economic times, growers are looking at every application and management practice. They're evaluating ROI to minimize risk and boost productivity," Bachman says.

The Wikners did. Their corn yield goal is 200 to 240 bushels, depending on the field, to feed 2,000 sows and have 25% of the crop left over to sell. To help reach that goal, they upgraded their John Deere 1750 8-row planter with Precision Planting Keeton Seed Firmers with in-furrow fertilizer application.

Several years of low crop prices and extreme weather events dictated the move, Neal Wikner says.

"These are challenging times, especially the recent cold and wet years," he continues. "The extra nourishment of starter helps the corn get through."

Recent Purdue University research found corn starter fertilizer increased plant height and dry matter by an average of 49 and 140%, respectively. Plants reached tasseling and silking faster, and grain moisture at harvest was up to 1.7 percentage points drier, which can save in drying costs.


University of Minnesota studies show starter fertilizer increases corn yields by 4 to 5 bushels per acre in low-phosphorus soils. Yield benefits tend to decrease as soil test value increases or in situations where phosphorus is broadcast at recommended rates.

Daniel Kaiser, University of Minnesota Extension soil specialist, urges farmers to consider the nutrients applied with a starter in their overall fertility program.

"If you need nutrients, you will see some yield increase," Kaiser says. "Really, it's more of an insurance policy. Growers that use it generally stick with it."

Farmer Brad Theis, of Le Center, Minnesota, has used 10-34-0 starter with zinc for 25 years. He has no plans to quit.

Theis added a new liquid fertilizer system to his John Deere DB80 planter as part of a $125,000 retrofit. The Precision Planting vApplyHD automatically controls rate and flow of nutrients.

"Starter gets the corn to pop up quick," Theis says. "In the north, we need to do everything we can to help it right away.

For more information:

> University of Wisconsin Corn Response to Banded Fertilizers Study:

> University of Minnesota Extension Corn Starter Fertilizer Guide:

> Follow Matthew Wilde on Twitter at @progressivwilde.


Matt Wilde