With silage harvest right around the corner, now is the perfect time to test nitrogen uptake in your corn crop using a late season cornstalk nitrate test.

This test will determine whether your corn crop was low, optimal or excessive with nitrogen usage over the growing season. With this information you can determine if weather and management practices played a factor in uptake.

For example, if you applied all of your nitrogen at or around planting and then had heavy rains soon after, you may have a low test result. Another example could be side dressing nitrogen during dry but humid times, which led to significant volatilization.

To collect samples, Penn State has developed Agronomy Fact Sheet 70 which details sampling procedures along with interpreting results.

Gathering samples should be conducted similarly to soil testing, where random plants are collected throughout a field. This should be done between ¼ milk line and black layer formation with 8-inch stalk sections being collected about 6 inches off the ground.

The samples are then cut into 1 inch pieces and overnighted to the analytical lab for analysis. Any corn removed for silage should be followed with a cover crop. Rye or wheat provide good winter cover and give you options for late fall or winter manure applications.

These crops can either be harvested for forage in the spring or burned off and directly planted into. By applying manure to a cover crop, most of the nitrogen is captured and held by the crop versus leaching through the soil in cases where there is no winter cover.

Cover crops should be no-tilled, but can be broadcast and followed up with a cultimulcher pass. However, any tillage operation to plant a cover crop is really discouraged due to timely planting and wasted fuel.

Planting should wrap up by the end of September for both rye and wheat to provide good cover heading into winter. However, with the right weather conditions, small growth is achieved from planting as late as November.

Andy Gaver is a conservationist with the USDA Natural Resources Conservation Service in Butler County.