Alternative nitrogen sources

Remember to take nitrogen credits when you use other nitrogen sources.

There are simple management practices that farms can implement to optimize nitrogen applications, as well as protect groundwater from nitrogen leaching. One of the easiest practices, though not often done, is to adjust nitrogen rates accurately. When determining nitrogen applications, a grower should consider not only soil tests but also any other residual nitrogen sources.

Legumes are a great source for nitrogen. Alfalfa, clover and soybeans are the most common legumes grown. More growers are using legume cover crops to assist in nitrogen production. Hairy vetch is a common cover crop that has the potential to produce a great amount of nitrogen.

Adjusting nitrogen application in correlation to adding manure is another management practice that could have great benefit to the farm both economically and environmentally. To determine the nitrogen value of manure, the best method is to have a sample analyzed. There are book values that can give the approximate nutrient value for manure, but every farm is different so the best strategy is to get a sample from your farm.

Cover crop usage is growing exponentially. Many farms are looking at cover crops as another fertilizer source. The challenge for using cover crops as a nutrient source is in the amount of credit to take, as well timing of the nitrogen release. Nitrogen availability may not correlate with the time the crop needs it. If a farm wants to use cover crops as a nutrient source, cover crop should be considered during the planning process.

There are some book values that can be found on how much nitrogen credit can be calculated, but the best practice is still to use soil samples followed by Pre-sidedress Nitrogen Tests (PSNT) when applicable. Later in the growing season, a petiole sample or a stalk nitrate sample should be taken to further determine if the farm has an efficient and effective nitrogen plan. Michigan State University Extension educators can assist you in planning for nitrogen management.

If you would like to learn more about cover crops, the Midwest Cover Crops Council (MCCC) is holding its annual business meeting followed by a one day conference this year in Michigan. The MCCC conference will be held on March 15, 2017 at the Crowne Plaza, 5700 28th Street SE., in Grand Rapids. The MCCC business meeting will precede the conference on March 14. Event details are available on the MSU Extension website event page. This event is an opportunity for farmers, researchers, educators, agency personnel, NGOs and agribusiness to learn from one another about the latest information in successful cover cropping. The meeting and conference is being hosted by MSU Extension. The theme of this year’s conference is Making Cover Crops Work - Experiences from the Field. In addition to joint sessions on cover crop termination and interseeding of cover crops, three concurrent sessions will feature cover crop use in field crop, vegetable crop and forage and grazing systems. CCA and RUP credits will be offered. Exhibitors providing cover crop and other ag related services will be present. Register online.

The Midwest Cover Crop Council’s goal is to facilitate widespread adoption of cover crops throughout the Midwest, to improve ecological, economic and social sustainability. States and provinces represented in the MCCC are: Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, Ontario, South Dakota and Wisconsin.  

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