Prior to planting, in 2012 and 2013, MicroEssentials SZ was broadcast applied as part of the different fertility treatments.
Farm Journal Test Plots conclude high-yield three-year study
What does it take to push fields to the highest yield level? For the past three years, Farm Journal Associate Field Agronomist Missy Bauer set out to answer that with multi-site demonstrations in southern Michigan.
"To increase yields, farmers must identify the weakest link in their production practices," Bauer says. "The goal of the these plots was to push populations and push fertility to understand the lacking component in high-yielding environments—irrigated corn-on-corn fields."
The test plots were set up to compare the traditional fertility program (determined by soil tests) and the farmer’s standard nitrogen sidedress rate as a check to the higher fertility programs.
A granular fertilizer was broadcast before planting at an above-average rate. In 2010, the MicroEssentials S10 (12-40-0-10S) product from Mosaic was applied at 250 lb. per acre.
"In the first year, early season tissue tests showed increased nitrogen, phosphorus and sulfur in the plants that received the MicroEssentials S10 product," Bauer says. "The average yield increase using MicroEssentials S10 in combination with extra nitrogen was 22 bu. per acre across management zones."
In the second and third years, Bauer wanted to isolate the fertilizer components. Zinc was added to the granular product, and the MicroEssentials SZ (12-40-0-10S-1zn) fertilizer was applied at 200 lb. per acre. The MicroEssentials product is formulated so each fertilizer granule contains nitrogen, phosphorus, sulfur and zinc. Additional treatments included increasing the rate applied at sidedress with and without the MicroEssentials product applied. Each treatment was replicated at least three times in the field-sized plots.
Fertility treatments included a regular and increased rate at sidedress to isolate the potential response to more applied nitrogen.
"With each treatment, we are trying to isolate the component that increases yield—or what our limiting factor was," Bauer says.
In 2012, there was not a consistent yield increase to the higher fertility treatments, but early season plant weight and tissue tests reflected higher nutrient uptake.
"I think partly that is due to our warm spring and dry conditions; fertility was not the limiting factor in 2012," she explains. "Those fields averaged 239 bu. and 254 bu. per acre."
In 2013, the same protocol as 2012 was repeated at two locations, one planted in 30" rows and the second planted in twin rows. Fields were planted at two populations—36,000 and 40,000 plants per acre.
"We found as population increased we needed to follow with higher fertility to support a yield gain," Bauer says.
Additional results from 2013 are detailed in the charts below.
In the field planted in 30" rows, the hybrid responded to population and higher fertility treatments. The nitrogen program included dry broadcast; pre-plant weed and feed; starter; sidedress; and fertigation. The treatment with extra nitrogen had 40 lb. more applied at sidedress than the standard rate.
"Particularly in the lighter soils, those zones needed more fertility. When planted at the higher population with increased fertility, we saw yield increase," Bauer explains. "Plant uptake is critical for fertility to make an impact on yield."
- Mid-February 2014