The purpose of this project was to investigate the effect of irrigation and two mulching methods on yield and net revenue of hops. We conducted a two-factor experiment to examine the impact of irrigation (irrigated or not) and cover between plants (summer alfalfa or straw), using two and three yield old Nugget, Cascade, Centennial, and Willamette hops. Drip irrigation was established on half the rows and either straw or summer alfalfa was established in a 1 meter strip surrounding the hops hills. Wet hops mass, labor, and all costs were measured in order to determine both yield and cost-effectiveness of the four approaches. Soil samples were also taken. Even in a growing season with 9” more rain than average, the yield and net revenue benefits of drip irrigation were unequivocal. Three-year old Nugget plants produced over 3 times the yield as non-irrigated plants, resulting in a revenue increase of $1,610 per acre. We strongly recommend other farms utilize drip irrigation. Summer alfalfa did have, in some but not all cases, a measurable and statistically significant effect of increasing yield and soil nitrates. However, given the extra cost of planting summer alfalfa, plus potential competition with hops growth, straw is more favorable as a summer mulch.
After preliminary research and on-farm trials using green manures, composted cow manure, and tilling practices, we sought a Northeast SARE to examine the effectiveness of cover cropping methods and irrigation on increasing yield and decreasing labor. We conducted a two-factor experiment to examine the impact of irrigation (irrigated or not) and cover between plants (alfalfa or straw) on yield and net revenue. We measured hop yield in four common commercial varieties (Nugget, Centennial, Cascade, and Willamette) and three planting ages (1, 2 and 3-year old plants). We also conducted soil testing in each treatment/age/variety category to investigate the effect on soil quality of using summer alfalfa as a cover crop. Our goal was to make recommendations to small-scale hops farmers about the cost-effectiveness of investing in irrigation and cover cropping.