It’s time to apply spring nitrogen


By Deborah Reinhart Brown - Ag update



As wheat approaches that Feekes Growth Stage 5, it’s time to apply spring nitrogen: The plants will soon begin a rapid uptake of nitrogen which will reduce the potential for loss. Ohio State recommends the Tri-State guide for nitrogen rates in wheat. This system relies on yield potential of a field.

A realistic yield potential is needed to determine the optimum nitrogen rate. The Tri-State guide recommends 110 pounds for yield goals of 90+; 70 pounds for 75 bushels; and 40 pounds for 50 bushel yield goal (total nitrogen, including any applied in the fall). The Tri-state recommends subtracting from the spring nitrogen application any fall applied nitrogen up to 20 pound/A. A more specific method is using the following equation for those fields with both 1 to 5 percent organic matter and adequate drainage: N rate = 40 + [1.75 x (yield potential – 50)]. Note: No nitrogen credit is given for previous soybean or cover crop; we don’t know if that organic nitrogen source will be released soon enough for the wheat crop.

Nitrogen rate studies at the Northwest Agricultural Research Station have shown the optimum rate varies depending on the year. However, averaged over years, yield data from these studies correspond well with the recommendation equation given above. These studies have also shown that, regardless of the year, yields did not increase above a rate of 120 pounds of nitrogen per acre.

An Ohio River Valley Woodland and Wildlife Workshop will be held on Saturday, April 2, at southeast Indiana’s Clifty Falls State Park. This workshop is to help landowners get the most out of their property. The program, 8:30 a.m. to 3:30 p.m., will feature timely sessions on helping honey bees, controlling a pond’s algal blooms, managing the new deadly thousand cankers disease in walnut trees, making a land plan, fighting invasive species, and providing habitat for reptiles and amphibians. There’s even a session called “Fantastic Fungi” about mushrooms, such as morels.

This program is being presented by speakers from OSU, Purdue, and the University of Kentucky. The Indiana Forestry and Woodland Owners Association is also a co-sponsor. Registration is $55 and includes lunch. A complete list of all 15 sessions and speakers can be downloaded at go.osu.edu/2016OHRiverValley.Online registration is available at go.osu.edu/OhioRiverReg. For more information about registration, contact Liz Jackson, jackson@purdue.edu, 765-583-3501.

This may be a good year to consider early termination of over-wintering cover crops that are not intended to provide forage harvest, especially on areas where you want to plant corn. One of the reasons is the prediction of a drier-than-usual spring and summer. While cover crops have many benefits – and can help pull excess water out of the soils – they also pull that water out even if there’s not an excess. On our CORN calls, it’s been noted that soil moistures across the state are drier than average.

Given that risk for a drier than average spring and summer, it’s recommended that cereal and annual ryegrass cover crops should be terminated in late March/early April. There should be a maximum of six-to-eight inches of growth for either of those crops. The recommended method for early termination is the use of herbicides. Glyphosate should be effective, especially if day time temperatures are above 50o F, and is probably one of the most economical options. Dr. Loux’s recommendation is to use a minimum of 1.5 pounds of acid equivalent/acre of glyphosate for cover crop termination and include Sharpen if marestail control is needed. See the article by Mark Loux about cover crop burndown in the issue of the CORN newsletter: http://agcrops.osu.edu/newsletter/corn-newsletter/2015-06-0.

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By Deborah Reinhart Brown

Ag update

The writer can be reached at the OSU Extension office (937-498-7239) or by email at brown.1522@osu.edu.

The writer can be reached at the OSU Extension office (937-498-7239) or by email at brown.1522@osu.edu.