Submitted to: Crop Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/31/2013
Publication Date: 6/25/2014
Publication URL: http://handle.nal.usda.gov/10113/59520
Citation: Hendrickson, J.R., Tanaka, D.L., Liebig, M.A. 2014. Tillage and grazing impact on annual crop yields following a conversion from perennial grass to annual crops. Crop Management. 13(1):1-7. DOI: 10.2134/CM-2013-0081-RS.
Interpretive Summary: Converting from perennial grasses to annual cropping systems is increasing as more CRP contracts are expiring. Scientists at the Northern Great Plains Research Laboratory in Mandan, ND evaluated no-till and minimum-till techniques to convert perennial grass plots, seeded to intermediate wheatgrass, to annual cropping. Prior to being converted to annual crops, the perennial grass plots had been grazed either early, mid or late in their morphological development. The use of no-till resulted in higher yields in two of the four annual crop years. Cattle grazing did not impact yields but did impact weed seed density. If producers are considering converting CRP land or utilizing a perennial phase in their annual cropping system, no-till appears to provide the best conversion option. The use of grazing to change weed dynamics also shows promise.
Technical Abstract: Interest in methods to transition from perennial grasses to annual crops should continue to increase because of expiration of Conservation Reserve Program (CRP) contracts in the USA and a desire by some to include a perennial phase in annual crop rotations. A four-year study was initiated in 2005 at the Northern Great Plains Research Laboratory USDA-ARS in Mandan, North Dakota, USA to evaluate different tillage options for transitioning from perennial grass to annual crops. The study site was previously used to evaluate the persistence of intermediate wheatgrass [(Thynopyrum intermedium (Host) Barkworth & D.R. Dewey] when grazed at the early vegetative (EARLY), mid-culm elongation (MID), or late boot (LATE) morphological stages. We seeded soybean (2005), corn (2006), flax (2007) and spring wheat (2008) into the plots using either no-till (NT) or minimum-till (MT). Tillage type interacted with previous grazing history to impact soybean grain yields (2005), total weed density in flax (2007) and grassy weed density in spring wheat (2008). The use of NT generally resulted in greater yields and lower weed densities then MT. Surprisingly, timing of grazing still had an impact, especially on weed densities; four years after the cattle were removed.