By Glen Arnold
Dairy and swine manure sidedress plot research has shown livestock manure to be an excellent replacement for purchased sidedress nitrogen. For the study below, 28% UAN nitrogen rates and manure nitrogen rates were 200 units of nitrogen per acre each year. The swine manure application rate was 5,000 gallons per acre to get 200 units of nitrogen. The dairy manure application rate 13,577 gallons per acre to get 130 units of nitrogen per acre. The dairy reps received additional nitrogen as incorporated 28%UAN just prior to the manure being applied to reach the 200# goal. Manure was applied using a manure tanker and Dietrich injection units with covering wheels attached.
| | 2011 Yield (Bu/ac) | 2012 Yield (Bu/ac) | 2013 Yield (Bu/ac) | 2014 Yield (Bu/ac) | 2015 Yield (Bu/ac) | Average Yield (Bu/ac) |
| Pre-emergent Treatments | | | | | | |
| Incorporated 28%UAN | 138.1 | 111.5 | 187.6 | 145.1 | 130.8 | 142.0 |
| Incorporated swine manure | 191.9 | 128.6 | 191.8 | 146.5 | 161.9 | 164.1 |
| Surface applied swine manure | 180.9 | 109.5 | 175.7 | 137.2 | 110.3 | 142.7 |
| Incorporated dairy manure + 28% UAN | 190.1 | 132.0 | 185.4 | 166.1 | 146.3 | 164.0 |
| Surface applied dairy manure + 28% UAN | 184.5 | 97.0 | 166.0 | 141.9 | 106.4 | 139.2 |
| Zero nitrogen | 74.4 | 62.6 | 82.0 | 67.0 | 40.2 | 65.2 |
| Post emergent Treatments | | | | | | |
| Incorporated 28% UAN | 132.7 | 116.0 | 181.9 | 140.9 | 140.1 | 142.3 |
| Incorporated swine manure | 180.8 | 138.4 | 196.7 | 139.9 | 158.5 | 162.9 |
| Surface applied swine manure | 178.0 | 116.4 | 188.0 | 115.6 | 114.6 | 142.5 |
| Incorporated dairy manure + 28% UAN | 180.0 | 138.8 | 192.0 | 156.9 | 167.5 | 167.0 |
| Surface applied dairy manure + 28% UAN | 170.5 | 101.6 | 181.5 | 125.3 | 111.6 | 138.1 |
Pre-emergent manure applications were made within five days of the corn being planted. Post-emergent manure applications were made at the V3 stage of corn growth. The 2011, 2012 and 2014 growing seasons experienced periods of drought. The 2013 growing season was very good with adequate moisture through July. The 2015 growing season was very wet.
Stand populations were approximately 31,000 plants per acre across all treatments. The manure did not appear to reduce the plot stands in any year. All manure was applied with manure tanker and Dietrich tool bar. The incorporated manure applications were approximately 20 bu/acre higher than the 28%UAN treatments over the five-year study. The moisture from the manure was beneficial to the crop in the dry years.
The surface applied manure treatments were similar in yield to the incorporated 28%UAN treatments but this is mainly due to the results of year #1. In subsequent seasons, the surface applied manure treatments were well below the incorporated 28%UAN treatments.