Sidedressing Liquid Manure in Corn

The Greenhouse Gas Mitigation Program was set up to provide funding for projects that work towards reducing greenhouse gas emissions in the Canadian agricultural sector. Best management practices to reduce greenhouse gas emissions are identified. To raise awareness among producers, demonstration plots that emphasize the importance of protecting soil and methods to reduce harmful emissions are set up.

One of the issues being pursued is the management of manure. The effectiveness of manure as well as some of its detrimental effects are greatly affected by how and when the manure is applied. Sidedressing nitrogen in corn is effective in that the nitrogen is being provided to the crop at the time when it most needs it, and it is applied in the root zone making it easily accessible to the crop. Applying inorganic nitrogen fertilizer at sidedress is not uncommon in the corn growing areas of Ontario, but it is less common to find producers sidedressing manure. One of the projects set up under the Greenhouse Gas Mitigation Program involves test plots with manure injected at sidedress, as well as demonstration days for producers to see first-hand how this works and the different configurations possible.

Research & Demonstration Sites

In 2004 and 2005, research and demonstration sites were established to evaluate the feasibility of sidedressing manure into corn. Research plots established in 2004 in northern Wellington County compared sidedressed liquid hog manure applied at either 2000 or 4000 gal/ac to four rates of sidedressed UAN (60, 120, 180, and 240 kg N/ha). Besides corn grain yield, soil compaction and post-harvest soil nitrate levels were also evaluated.

Soil compaction (soil bulk density) did not appear to be significantly affected as a result of traffic by the manure tanker. Soil nitrate levels of both the 2000 and 4000 gal/ac treatments taken post grain harvest were comparable to nitrate levels associated with UAN applications of 60-180 kg N/ha. The following table gives the final grain yield (kg/ha) for each of the nitrogen treatments. Manure application at 2000 and 4000 gal/ac was equivalent to 107 and 215 kg N/ha, respectively. A check was also established for both the manure and UAN.

Equipment Designs

In June 2005 a manure sidedress demonstration day was held in Perth County to allow producers to see this practice working in the field. Several different toolbar configurations were presented by various companies. Opener or injector design varied significantly among the equipment that was being demonstrated. Growers, researchers, and extension agronomists are evaluating the strength and weaknesses of a range of knives, coulters, discs and shanks for manure sidedressing with the aim to increase manure N use efficiencies. Ammonia loss measurements from the various inter-row areas indicated that a relatively shallow covering of the manure with soil substantially decreased N losses from the soil. It was also apparent that a flow control system on tankers which inject the manure out-of–sight is a valuable tool in keeping manure application rates accurate.

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