Manure Application Methods, Timing and Nutrient Utilization in No-Till Corn

Ernest Oelker and Gary Graham

Ohio State University

To assess the effectiveness of liquid dairy manure on no-till corn yields, spring and fall applications of 11,800 gal/acre of liquid dairy manure, incorporated and surface applied, were compared to a conventional liquid N program applied at planting. In addition to corn yield, previous crop residue, soil compaction, pre-side-dress total inorganic N, plant tissue N, and Stalk nitrate N were evaluated. A 9-18-9 liquid starter fertilizer was applied to all plots. No additional N was applied to the manure plots.  Data collected during 2003, indicated that application of liquid dairy manure on no-till corn produced yields comparable to liquid 28% N.  Although yields from incorporated manure were significantly higher than surface applied manure, there was no significant difference in yield between spring and fall applications.  However, incorporation during the spring could increase the risk of seed rot and seedling damping off.  To compensate, more seed should be planted or a tool used that places manure below the seed zone.  The manure applicators did not significantly affect soil compaction and residue cover remained well above 33%. 

For additional information contact Ernest Oelker at oelker.2@osu.edu or Gary Graham at graham.124@osu.edu

Discussion:

Rick Wilson (Ohio EPA) asked why there was a difference in soil inorganic nitrogen (N) between incorporated and surface applied manure.  Oelker noted that losses due to volatilization are greater for surface applied.  Cold, wet soil increases denitrification so that more nitrate nitrogen is lost.  Soil nitrate N was higher in 2002, when seasonal rainfall measured 11.25 inches, than in 2003, when rainfall measured 33.1 inches.

Wilson asked whether the increased rain and/or slope had increased runoff of nitrogen.  Oelker replied that although 2003 was very wet, runoff was minimized due to field slopes of less than 3 degree and crop residues greater than 45 percent.  Wilson asked whether measurements were made or visuals were used to evaluate potential runoff.  Oelker responded that the fields were visually inspected but tile drains and waterways were not monitored as the fields were not systematically tiled.  Monitoring will be considered for future trials.  Graham noted that 15-20 foot grass buffers around all fields offer additional protection.

David Munn (ATI) suggested that most of the N was in the organic form which is more difficult to measure.  Thus, it may not have volatilized or runoff.

Wilson asked what regulations require no-till plots to maintain at least 33 percent residue.  Oelker cited the 1985 Farm Bill.  It required that a farm maintain 33 percent crop residue from the previous year to qualify for farm program payments.  Although no longer stipulated, it is still used as a benchmark.

Wilson asked if plans exist to use different instruments to incorporate manure.  Oelker replied that they would continue with the Balzer for 2004.  He also noted that similar research may be conducted for poultry manure in the future.

Duane Wood (Wayne SWCD) asked for a recommended depth for pre-side-dress soil tests.  Oelker said they used 8 inches as it is the method used by the Ag Land Coop.

Wood commended the research, noting the need for good data.  Graham noted that it has been producer driven and that there has been good response during field days.

Munn asked if the grower normally incorporated the liquid N.  Oelker noted that the grower used a knife injector on a planter with a split application on either side of the row.

Notes by Mary Wicks

The OCAMM (Ohio Composting and Manure Management) Program is funded by OARDC/OSU.