Research by the Northern New York Agricultural Development Program has helped develop two tests for use in determining soil nitrogen requirements for a following year’s planting.

As farmers approach corn harvest time, they are already thinking about next year’s crop. Northern New York Agricultural Development Program-funded research conducted on regional farms by the Cornell Nutrient Management Spear Program and its Cornell Cooperative Extension, W.H. Miner Agricultural Research Institute, and farmer collaborators has developed recommendations for using two testing tools to help farms optimize nutrient use over time with their corn crops. Those tools are the late-season Corn Stalk Nitrate Test (CSNT) and the Illinois Soil Nitrogen Test (ISNT).

Research was conducted in northern New York as part of a 2008-2011 statewide project to determine to what extent on-farm manure resources can replace the need for purchased starter nitrogen fertilizer for corn production. The results evaluate how best to apply the CSNT and ISNT to better use manure resources, conserve soil value, reduce costs, and enhance agricultural stewardship.

Certified Crop Advisor Peg Cook routinely encourages the farmers she advises to implement NNYADP research results into their cropping and dairying practices.

“One of the farmers who has applied the results of the manure value studies has said that were it not for the recommendations based on that research he would not be in business. He has not purchased fertilizer in four years and that adds up to thousands of dollars of savings,” Cook says.

St. Lawrence County dairy farmer Mary Kelly agrees, “We use soil testing on every field. What we learn from that can add up to significant savings.”

The late-season CSNT evaluates the success of nitrogen (N) application decisions over the course of that growing season. The ISNT is a soil analysis that estimates if there is enough potentially mineralizable nitrogen in the soil to feed a new corn crop. While the soil can be sampled for ISNT-N at any time of year except within five weeks of manure application, the recommendation is to test right after corn harvest for results to guide the following year’s decision-making.

Due to the dry weather, CSNT results may be slightly higher this fall. Educators caution that 2012 CSNT data and growing season weather conditions should be viewed in tandem with ISNT-N results before farmers decide whether the farms’ manure supply can replace, or eliminate, the need for the purchase of starter nitrogen fertilizer for 2013 corn crops.

“During seasons with serious drought conditions, plants stressed by lack of water are not able to take up nitrogen to the full potential of a crop grown under more optimal conditions. If it rains later in the season, this nitrogen can still accumulate in the lower portion of the corn stalk resulting in high CSNT values without causing a yield increase in the crop,” says Lawrence.

Cornell Cooperative Extension of Jefferson County Field Crops Educator Mike Hunter cautions, “Growers need to be careful with CSNT in a dry year as results can be skewed due to the accumulation of nitrogen in the corn stalk in abnormally dry years. The CSNT is meant to be used over multiple years on the same field to fine tune nitrogen management, not as a one-time indicator.”

Agronomist and Soil Scientist Eric Young at W.H. Miner Agricultural Research Institute, Chazy, praises the project identified by the farmer-driven NNYADP for research, saying, “The starter N project offers convincing evidence that we can substantially improve nitrogen use efficiency on dairy farms by proper soil testing and manure management.”

Links to Cornell Agronomy Fact Sheets on the CSNT and ISNT-N, how to fine-tune N use on corn crops, and “Can Manure Replace the Need for Starter N?” are posted in the Field Crops: Manure Management section of the NNYADP website at www.nnyagdev.org.

The Northern New York Agricultural Development Program is a farmer-driven small grants program that funds on-farm research promoting the long-term viability of the Northern New York agricultural industry. Farms in northern New York contribute nearly $600 million in farm product value to the regional economy. Approximately 4,200 farms support a regional payroll of $52.9 million in jobs.

More info: www.nnyagdev.org.