Farmers are looking closely at their fertilizer applications in light of the need to be more cost efficient as prices continue to rise. Crop nutrients in the form of bio-solids from animal manures or from municipal waste treatment facilities are a valuable and beneficial amendment when utilized correctly.

When fertilizers were relatively inexpensive, as compared to the cost today, farmers applied the manure to just get rid of it. They usually did not take into account the nutrients in the manure when determining how much fertilizer to apply to the next crop.

In fact, I remember an extension specialist in the late 1970s telling a group of farmers that it cost more to spread the manure than the value of the nutrients in it were worth. How times have changed.

Municipal bio-solids have been applied to fields here in Butler County for more than 25 years. Current EPA regulations have resulted in the production of high quality product well suited for application to agriculture land. If the municipality manages the product properly, processing it thoroughly and incorporating it immediately, there is limited odor problem associated with land application. If the product is handled properly there is usually less odor than from an application of animal manure. If the product is not totally digested at the plant, is stockpiled on the edge of the field for a period of time and is not incorporated, it can stink to high heaven.

Using organic nutrients requires special considerations. You can balance the needs of the crop with the nutrients in the bio-solid or manure by testing the soil and the product prior to application. The analysis of the bio-solid from a wastewater treatment plant can vary from month to month. There is even more difference in the analysis of the product from plant to plant. It is not possible to use an accurate example of what the analysis might contain to show the value of the nutrient. In general a bio-solid is going to contain much more phosphorus than nitrogen. It contains very little potassium.

If your phosphorus levels in the soil are low to moderate, more bio-solid can be applied. If you are planting corn next year, it would be nice to apply enough bio-solid to meet the nitrogen need of the crop. If the bio-solid contains 30 to 40 pounds of plant available nitrogen per ton, and the field was in soybeans this past year, you could meet the nitrogen need of the crop with a yield goal of 150 bushels per acre with an application of 4.5 tons per acre. This would apply 450 pounds of P205 per acre if the analysis of the product contained 100 pounds of P205 per ton. This would meet the needs of your crop and increase the soil available Bray P2 phosphorus by approximately 14 ppm.

If you applied 4.5 ton per acre, the nutrients in this hypothetical bio-solid would replace approximately $73 worth of nutrient used in next year’s crop plus build up your soil with phosphorus. If you would like more information on using bio-solids on your farm to replace purchased fertilizer, or if you would be interested in seeking a permit from Ohio EPA to apply them to your farm, give me a call at 513-887-3722 or 513-424-5351.

This Ohio Farm News was published in the November 2, 2005 issue of Farm World.