Dairy Channel: St. Paul was educational


I had the privilege of traveling to St. Paul Minn. on July 24 to attend the Soil and Water Conservation Society Annual Meeting and “Headwaters of Conservation” Conference.

Conservation professionals. The Soil and Water Conservation Society is the professional organization of soil and water conservationists from across the U.S. and is usually attended by more than 500 USDA Natural Resources Conservation Service (NRCS) professionals.

My purpose in attending was to present results of manure application and nitrogen utilization research that Gary Graham, the natural resources specialist for the North Extension Center at Wooster and I are doing here in Columbiana County.

Technical topics. Most of the workshops conducted at this meeting were technical in nature, designed to provide information and improve the skills of local conservationists and technicians who design drainage projects, erosion control systems, manure storage and handling facilities and the many other projects covered by EQIP funds and the other programs of NRCS.

Flow of nutrients. The session in which I presented our research also included a presentation on design of grass filter strip systems to manage feedlot runoff from small feedlots in dryland areas such as Montana and Wyoming, a paper on monitoring ground water for nutrient movement under cotton fields in Georgia, and a study of a large manure digester on a Minnesota dairy farm.

By the way, the dairy farm manure digester in Minnesota had not become profitable as expected after five years of operation, despite the use of the methane from the digester to operate electrical generators, the use of the digested manure on the farm as fertilizer and the sale of the digested manure as a fertilizer and soil amendment to local gardeners.

I presented our research results from two years of experiments on the Myron Wehr Farm near New Waterford.

In case you haven’t heard, we are comparing surface application of liquid dairy manure with incorporated applications made in spring and fall, followed by no-till corn.

Measuring benefits. Our 2003 results show a benefit of from 16 to 24 bushels of corn per acre from incorporating manure (either in spring or fall) before growing no-till corn, compared to surface application of the same quantity of manure.

Yields from plots utilizing incorporated manure as the only nitrogen (N) source averaged about seven bushels per acre more than those utilizing liquid 28 percent N, while plots utilizing surface-applied manure averaged 10 to 14 bushels per acre less than liquid 28 percent plots.

Similar research is ongoing in 2004. Please contact me if you need more information about this research.

Utilization factors. The most interesting things I saw in St. Paul were two poster presentations by Dr. Alfred Blackmer and Associates of Iowa State University, concerning the utilization of fertilizer and manure nutrients on crop fields in Iowa.

Blackmer and his colleagues conducted experiments on dozens of Iowa farms to find out how much manure farmers were applying and how well the nutrients were utilized, compared with the use of chemical fertilizers on nonmanured fields.

Calculating responses. The results were very interesting. They applied either 75 or 125 pounds of actual N in alternating strips across 10 to 20 acres on 34 fields in 17 Iowa counties over a four-year period and calculated yield responses to the two rates of N.

The average yield increases resulting from application of 125 pounds N instead of 75 LB N were only enough to pay for the additional N applied (four to six bushels per acre).

The higher rate of N application was profitable at 14 of the 34 sites, but the overall average yield increase over the 34 sites for four years was four bushels per acre.

Blackmer suggests that 100 LB N per acre is usually adequate for corn following soybeans in Iowa.

In another study, Blackmer and his colleagues evaluated the profitability of applying fertilizer N after applying animal manure.

The researchers conducted this research to find out why most Iowa livestock producers do not give the recommended credits for N applied as manure, and end up applying more fertilizer N than recommended on previously manured fields.

Diminishing returns. In these studies, manure application rates varied from 70 to 299 LB N per acre. Where manure was incorporated at application, the average response to fertilizer N was three bushels per acre, which was not enough to pay for fertilization (materials and application).

A late spring test for soil nitrate N identified the responsive fields. Where manure was not incorporated at application, the average response to fertilizer N was 13 bushels per acre, which was profitable on six out of eight fields.

Reliability compared. The researchers concluded that incorporation of manure makes the manure N a more reliable source for corn, while unincorporated manure was not a reliable N source for corn.

This explains why producers are reluctant to give the recommended credits for N applied as manure. Blackmer and associates conclude further that manure can become a more reliable source of N for corn, resulting in a reduction of unnecessary applications of fertilizer.

Furthermore, they suggest that incorporation should reduce losses of manure N before crops are growing.

For more information on the Iowa nitrogen and manure research, contact ablackmer@iastate.edu .

Favors injection. You should draw your own conclusions from these studies, but I think the results are applicable in Ohio, too. Manure injection not only reduces odor dramatically, but it results in better nutrient utilization and reduces nutrient runoff.

Environmental benefits. Equipment and technology exist to incorporate manure into no-till fields. The extra time and cost could be offset by reduced fertilizer costs. The environmental benefits could be the biggest reward.

(The author is the northeast Ohio district dairy specialist with OSU Extension. Send comments or questions in care of Farm and Dairy, P.O. Box 38, Salem, OH 44460.)


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