Center for Sustaining Agriculture and Natural Resources

Organic Agriculture

Organic Research Database


Personnel: Kevin Murphy
Cooperators:Lori Hoagland
Keywords:hops, cover crops, carbon sequestration

The recent worldwide hops shortage has led to an increase in the price of hops from $5 to $32 per pound. This has spurred an increase in conventional hop plantings; however, due to agronomic obstacles, organic hop acreage lags far behind. Sales of organic beer have been increasing even faster than the organic industry as a whole at a rate of 30-40% per year, reaching $25 million in 2006. To meet this demand, large companies like Anheuser Busch are currently importing organic hops from Germany and New Zealand. Anheuser Busch and smaller microbreweries including New Belgium and Odell are interested in purchasing locally produced organic hops and are making a concerted effort to recruit local growers and support research into organic hop production. Unfortunately, the availability of organic hops is functionally non-existent. Hops are a perennial, high-value crop that, under current production standards, requires large quantities of pesticides and nitrogen fertilizer to achieve high yields and good quality. In response to increasing demand for organic hops and the rising costs of fertilizer and crop protection chemicals, hop growers in the Pacific Northwest (PNW) have begun to plant organic hops. Hop yields, however, often show dramatic decreases under organic or low-input management due to increased insect and disease pressure. Aphids, mites, weeds, downy mildew, powdery mildew and other fungal diseases can be difficult to control without repeated and expensive application of pesticides and herbicides. Since the accidental introduction of powdery mildew in the late 1990's, conventional growers have spent up to $300/acre controlling mildew diseases. Meeting nitrogen needs can be difficult without high inputs of nitrogen fertilizers, especially in varieties with low nitrogen-use efficiency. Research into organic systems is needed to identify suitable hop cultivars; and develop systems based nutrient management plans that improve soil health, supplement nitrogen fertility needs, suppress weeds, provide habitat for beneficial insects, and improve the productivity and quality of hops. The research described within this proposal is focused on meeting the multiple critical agronomic needs of the organic hop industry.


OBJECTIVES: The long term goals of this project are to: 1) Identify and develop high quality hop varieties optimally adapted to low-input and organic production systems; 2) Develop cover crop management options for hop growers that improve soil health, sequester carbon, supplement nitrogen fertility needs and ameliorate nitrogen loss, suppress weeds, provide habitat for beneficial insects, and enhance the productivity and quality of hops; 3) Evaluate differences in carbon sequestration potential between organic and conventionally managed hop systems; 4) Develop educational materials, training days and tools for Cooperative Extension personnel; and, 5) Increase acreage of low-input and organic hops and provide alternatives to high input conventional growers to use systems approaches to reduce production costs. The objectives of this research are to: 1. Formalize an advisory committee of organic and low-input hop growers and establish roundtable discussions between farmers, extension personnel and researchers; 2. Identify high quality hop varieties optimally adapted to low-input and organic production systems in different regions of the U.S. or identify parental lines carrying important traits that can be combined to develop optimal varieties; 3. Identify cover crop management strategies that suppress weeds, disease and insect pests, improve soil health and nitrogen fertility, and positive hop cultivar interactions; 4. Evaluate the potential for carbon sequestration in organic as compared to conventionally managed hop systems; 5. Use quantitative genetic techniques to determine gene action, heritability and anticipated response to selection of particular traits important to organic hop production; 6. Conduct effective outreach through field days on growers fields in WA, CO, MI and VT, and publish results in a wide range of media; and, 7. Develop an educational product, entitled the Handbook of Sustainable Hop Production, for growers focusing on organic, low-input and biologically diverse hop production. We expect to identify which leading hops varieties will perform best in organic systems. This should have immediate impacts in helping farmers transitioning to organic hop production decide which varieties to plant. In addition, this information will be utilized by breeders in the selection of parents for use in organic breeding efforts. We will identify cover crop management strategies that are optimally suited for suppressing weeds, improving soil health, sequestering soil carbon, supplementing N needs, and providing habitat for beneficial insects. In an emphasis on systems research, we will greatly increase available knowledge of hop varietal interactions with hop yard management options, specifically intercrops and cover crops. We anticipate that these interactions will be significant both statistically and agronomically when measured in terms of the many components necessary to achieve a productive low-input and organic hop growing operation. All these outcomes revolve around increasing grower knowledge, awareness and participation.

APPROACH: Multi-state Variety Trials: Rhizomes of 20 hop varieties will be planted in a lattice square design with three replicates (five rhizomes per replicate) on two farms in Washington. They will be evaluated throughout three growing seasons for resistance to the predominant races of powdery mildew and downy mildew. Significant genotype x location interactions for resistance to either disease will be considered as potential evidence for race specificity. If this occurs, isolates will be purified from each location and tested in greenhouse assays to determine if different races are present and if any of the resistances are race-specific. Aphid and mite resistance will be determined through leaf sampling and subsequent counting of pest levels on the collected leaves. Cone yield will be estimated and results will be analyzed through standard statistical analysis of variance procedure. Spearman's rank correlation will be used to rank varieties for all traits across locations. Breeding Line Evaluation: This research will be conducted on the Perrault Farm in Washington State. Five crosses were made in 2006 by Jason Perrault with the purpose of selection in organic systems. Rhizomes of approximately 60 progeny from each cross were planted in an organic field on Perrault Farms in 2008. We will evaluate the breeding lines for powdery mildew, mite and aphid resistance, growth habit, height, alpha and beta acid content, and cone yield. After harvest, hop cones will be dried to approximately 8% moisture for all chemical analyses. Chemical analyses will be performed using HPLC according to standard methods. Cone yield and quality, percent infection by powdery mildew, and aphid and mite thresholds will be evaluated. Both insect pests and beneficial insects will be monitored by Jason Perrault and the Perrault farm agronomist (both experienced at insect identification and monitoring) on a weekly schedule. Population levels will be determined through leaf sampling and subsequent counting of pest/predator levels on the collected leaves. Predator species are described in the cover crop trial detailed below. Cover Crop Management Trial: This research will be conducted on the Perrault farm in Washington State, and smaller trials will be conducted on one farm in both Colorado and Michigan. Cover crop strategies were chosen by farmers based on previous experience or results using these cover crops in other perennial organic systems, such as orchards and vineyards. Cover crops established in the drive row will need to be perennial, drought and frost tolerant, produce a large amount of biomass and provide a lengthy season of beneficial insect habitat. In-row cover crops will need to be low growing and good competitors against weeds while not out-competing hops, especially during emergence and early growth stages of hops. We will evaluate the impacts of cover crop treatments on soil health, carbon sequestration potential, nitrogen availability, and hop nutrition. Additionally, we will evaluate cover crops for biomass, beneficial insect habitat and weed suppression ability; and evaluate hop varieties for agronomic traits, disease incidence and insect populations.

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