Home / Successful Farming / Farm Production / How to know when you need a preplant N test

How to know when you need a preplant N test

Agriculture.com Staff 07/06/2010 @ 5:21pm

Nitrogen costs are high this spring, a situation that has many farmers looking for ways to apply only the nitrogen their crops really need as a way to maximize the economic benefit. A preplant N test could help you answer the question of how much nitrogen to apply this spring.

In an Extension factsheet, University of Missouri Agronomists John Lory and Peter Scharf say as a supplement to the standard soil test, a preplant N test at a depth of two feet will measure the fertilizer value of inorganic N (nitrate N + ammonium N) in the soil.

They note the preplant N test is not recommended under typical weather conditions on cornfields receiving all nitrogen as spring applied fertilizer. They do recommend it in springtime in the following situations:

- On fields that have received manure anytime since the previous summer.

- On fields that have a history of heavy manure applications.

- Following a drought year on fields with a high potential for carryover of fertilizer N.

- Following fall and early-spring fertilizer applications where excessive rainfall may have caused losses of fertilizer N.

Learn more

Complete recommendations and a formula for interpreting the preplant N soil test for cornfields are available in a University of Missouri Extension factsheet Preplant Nitrogen Test for Adjusting Corn Nitrogen Recommendations

A Soil Nitrogen Test Option For N Recommendations with Corn is available from University of Minnesota Extension.

Do you have an agronomy question? Email cheryl.rainford@meredith.com. We'll send some of the most common questions to professionals in the industry and see what they say. Look for answers in upcoming Agro-Connect Ask the Experts columns.

Nitrogen costs are high this spring, a situation that has many farmers looking for ways to apply only the nitrogen their crops really need as a way to maximize the economic benefit. A preplant N test could help you answer the question of how much nitrogen to apply this spring.

CancelPost Comment
MORE FROM AGRICULTURE.COM STAFF more +

Farm and ranch risk management resources By: 07/07/2010 @ 9:10am Government resources USDA Risk Management Agency Download free insurance program and…

Major types of crop insurance policies By: 07/07/2010 @ 9:10am Crop insurance for major field crops comes in two types: yield-based coverage that pays an…

Marketing 101 - Are options the right tool… By: 07/07/2010 @ 9:10am "If you are looking for a low risk way to protect yourself against prices moving either higher or…

MEDIA CENTERmore +
This container should display a .swf file. If not, you may need to upgrade your Flash player.
Holiday Profit Taking Pressures Markets