Growers face fertility challenges this fall as they plan a big winter wheat crop, much of it on saturated soil.
The crop has a voracious appetite for nitrogen, but many farmers are often tempted to streamline the process by applying all nitrogen in the fall.
However, too much nitrogen early in the plant’s life contributes to excessive vegetation growth, winterkill and lodging the following summer.
Excess nitrogen and fall growth prevent young plants from hardening off properly, which results in winterkill.
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Agrium’s environmentally smart nitrogen (ESN) is designed to solve this problem.
The poly coating applied on granular nitrogen controls the rate at which water-soluble nitrogen feeds the roots.
Research in southern Alberta gives winter wheat a 3.5 bushel per acre advantage when nitrogen has the ESN coating, compared to non-coated urea.
The coating slows the transfer of nitrogen in cold soil, which is ideal for fall seeded winter wheat.
As winter approaches and soil becomes colder, ESN prevents nitrogen losses either by encapsulating the nitrogen or by causing it to be stored as ammonium nitrate. Nitrogen release speeds up again in the spring as the soil warms.
“ESN performs best on winter wheat when applied in the fall at seeding,” Agrium says.
“For fall applications, ESN is recommended as a single N source to provide controlled feeding during the fall establishment period and rapid growth the following spring.”
Applying 100 percent of the nitrogen in the fall with the ESN poly coating also means farmers don’t have to top dress fields in the spring, which can be a tough job if conditions are muddy or operations get behind schedule.
Three years of research conducted at three sites in southern Alberta show that winter wheat plant counts were consistently higher when fall applied nitrogen was ESN coated.
The trials were conducted by Alberta Agriculture at Bow Island, Lethbridge and Spring Coulee. Researcher Ross McKenzie compared urea with and without ESN in both side band and seed placed applications.
He found there were moderate benefits in side banded applications and more significant yield advantages when ESN was placed with the seed.
Seed placed ESN yielded an average of 6.4 bushels per acre over uncoated urea, while the ESN advantage dropped to 1.4 bushels per acre on plots where nitrogen was side banded.
ESN winter wheat averaged 90 bu. per acre in the seed placed and side band applications.
ESN by itself is not recommended as a spring application on winter wheat because cooler spring temperatures prevent it from releasing enough nitrogen on time for the young crop. In spring it can be applied in conjunction with a non-inhibited nitrogen source, and later applications call for a lower ration of ESN to uninhibited nitrogen.
Agrium cautions that ESN should not be applied on winter wheat after October.
