REDESIGNING FORAGE GERMPLASM AND PRODUCTION SYSTEMS FOR EFFICIENCY, PROFIT, AND SUSTAINABILITY OF DAIRY FARMS
Location: Dairy Forage and Aquaculture Research
Title: Renovation and Management Effects on Pasture Productivity Under Rotational Grazing
Submitted to: Forage and Grazinglands
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 21, 2009
Publication Date: February 2, 2010
Citation: Brink, G.E., Jackson, R.D., Bleier, J.S., Chamberlain, S.K., Jakubowski, A.R. 2010. Renovation and Management Effects on Pasture Productivity Under Rotational Grazing. Forage and Grazinglands [online]. Available: http://www.plantmanagementnetwork.org/sub/fg/research/2010/rotational/rotational.pdf
Interpretive Summary: Grazing-based livestock producers wishing to utilize improved grass varieties to improve pasture productivity must consider how productive and persistent the new grass variety will be compared to grasses already growing on the farm under his or her farm management. Although new varieties may be superior under controlled evaluation, they may lack the ability to compete and persist with existing species under typical farm management. After establishing a mixture of two improved, cool-season grasses (meadow fescue and orchardgrass) on five Wisconsin grazing-based farms having diverse climate, soil types, and management systems, we found that introducing improved grasses increased pasture yield, but not nutritive value, compared to existing grasses. However, the increase in pasture yield resulting from renovation was greatest on farms where introduced grasses replaced unproductive existing grasses. This information will help grazing-based livestock producers decide whether or not to renovate pastures with improved grass varieties by first considering the composition and productivity of existing pasture grasses.
Renovating permanent pasture to replace existing cool-season perennial grasses with improved varieties has potential risk and reward. Improved grasses may increase long-term productivity, but these increases should offset costs associated with replacing an existing stand. We eliminated existing perennial grass stands with tillage and herbicides and sowed a mixture of improved orchardgrass and meadow fescue in 2006 on five Wisconsin farms that used a range of rotational grazing systems. Paddocks were also subject to either typical producer management or recommended agronomic management. Despite considerable farm-to-farm variation, annual forage yield of improved varieties was greater than that of existing grasses the next two years. The yield advantage of improved varieties was greater when managed according to recommended agronomic practices in 2007, but management had no effect in 2008. Forage nutritive value was not influenced by grasses or management at any time during the growing season. Our results suggest that renovation with improved grasses increases pasture productivity, but producers should also consider their management and pasture production goals before renovating.