On-Farm Study Answers Questions on Deep Tillage

Paul Kassel, Crops Field Specialist, Northwest


The in-line ripper was promoted as a new tillage tool for area farmers in the fall of 2002 and 2003. Yield claims were made showing a benefit of deep tillage (16 to 20 inches) with an in-line ripper.  Some farmers used the in-line ripper on a large number of acres to reduce compaction problems and/or increase rooting depth of corn and soybean crops.  However, other farmers raised the question of the economic benefit of this tillage tool to corn and soybean production. 

Studies were started in the fall of 2003 to study the effect of in-line ripping on farmers farms and research farms.  Twelve comparisons were set up in Palo Alto and Sac counties with four different cooperators.  The farmer comparisons were side by side comparisons.   A replicated study was set up at the Northwest Iowa Research Farm at Sutherland and at the Clay County Growers plot near Spencer.
Results from the farmer comparisons in 2004 on corn yields showed a range of results from a negative 6.4 bu/a to a positive 24.4 bu/a response.  The average corn yield increase was 4.0 bu/a.  The results from the replicated trial at the Clay County Growers plot showed a 7.5 bu/a response when compared to shallow tillage.  Soybean yields were evaluated in 2005.  The soybean yield increase was 0.5 bu/a averaged across all the plots.  A cost and benefit analysis of deep tillage showed a profit of $4.50 per acre if labor and depreciation costs were not included.

One cooperator had done deep tillage on his fields in 2003 and 2004, but discontinued the operation in 2005 due to the cost/benefit analysis.  The other cooperators reduced the number of acres where they used this practice to areas in their fields with compactions problems.
The information from this study was presented to the 2005 Integrated Crop Management (ICM) conference.  About 600 persons attended the two sessions. 
Attendees at the ICM conference were asked to please list one or two things you learned at this program and how those items will benefit you and/or your clients?  There were 232 responses to this question.  Seventeen commented on things they learned at the deep tillage presentation.  Comments included, I learned about the cost effectiveness of ripping, deep ripping for yield increase is questionable, and results of deep tillage study help answer clients questions to rip or not.  Other comments were more specific and included, deep zone tillage works best for higher clay content soils, so look at soil map before zone tillage, and deep tillage may benefit plantings bean early something to consider.

January 6, 2006
142 - Integrated Pest and Crop Management

Page last updated: July 9, 2006
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