One promising solution to the high costs associated with hi-trellis hops infrastructure is the low-trellis organic hop system. According to the USDA ARS (2008) low-trellis systems can reduce labor costs by 30 percent and, by our calculations, establishment costs by over 50 percent. Like most organic systems, weed and fertility management are the major impediments to economically viable yields in hops production. In conventional hops, weeds are managed by tillage and herbicides. The effects of repeated tillage on soil structure, erosion, and nutrient retention are well documented in the literature. Weeds in organic Michigan hopyards have been controlled by tillage and significant quantities of straw mulch. While effective, these practices are both labor intensive and expensive.
To investigate some of these questions, in 2011 we installed a 3 acre low-trellis hops system with the variety Summit and seeded the understory with leguminous ground cover. Though the growth rate of our hop rhizomes was subpar in 2011, we began filling gaps in 2012, with plants from Yakima, WA that were grown to size in pots in a local greenhouse. In spite of an early March warm-up and severe summer drought, Summit plants yielded 2 lbs./plant on average.
Initial cost/benefit analysis suggests that the low trellis system is 40 percent cheaper as compared to the traditional tall trellis system. On a per acre basis, reduced yields are made up for by increased density in the low trellis system. We hosted a hop tour and field day to provide outreach to farmers, brewers, and potential farmers. Results indicated a very successful learning experience for those involved.
The objectives of our grant were to:
1. Determine the growth habits, yields, quality, and market potential of the hop cultivars Summit and Teamaker on a low-trellis system under Great Lakes growing conditions.
2. Assess the effects of understory nitrogen-fixing cover crops on soil quality, soil nitrogen levels, hop leaf nitrogen, and weed control.
3. Conduct a cost/benefit analysis of low-trellis vs. hi-trellis organic hop production systems.