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Ginny Moore and Jamie Crawford
Using cover crops has the potential to improve sustainability and address a range of production challenges in hemp systems.
Weed management. Hemp producers currently lack herbicide options to manage weeds. Some systems (e.g., CBD production) rely on plastic mulch for weed suppression. Cover crops have been successfully used for early season weed suppression for other crops (e.g., maize) and may be useful for hemp as well.
Soil moisture. Cover crops can improve soil moisture in both dry conditions (by improving water-holding capacity) and wet conditions (by increasing infiltration). The latter may be particularly important for hemp, which does not grow well in wet soils.
Nutrient management. Cover crops are frequently planted for their ability to biologically fix nitrogen (in the case of legumes) or to provide other benefits related to nutrient scavenging and cycling. Cover crops can serve as a source of fertility for subsequent hemp crops.
Research needs. There are many unknowns about optimal cover cropping practices in hemp production systems, including cover crop species, timing, and management needs; optimal practices may also depend on the hemp end use. Some hemp varieties may perform better with cover crops (i.e., genotype x management interaction).
Red clover as a cover crop for hemp production
red clover plots (June 27, 2022)
Experiment Description: Hemp planted into an established red clover stand, with treatments including red clover termination methods and hemp varieties
Location: Freeville, NY
Treatments:
- Termination methods: full tillage (8” row spacing), full tillage (16” row spacing), mowing, tarping
- Varieties: Joey, X-59 (grain types)
Hemp Seeding Rate: 30 lb/acre
Key Dates:
- 3/15/21: red clover planted
- 5/6/22: tarps placed on plots
- 6/13/22: plots mowed
- 6/14/22: plots tilled
- 6/15/22: plots planted with no-till drill
| Tillage Treatment | Hemp Cultivar | Stand Count (per ft) |
| Full tillage (8” row spacing) | Joey | 4.1c |
| X-59 | 7.4bc | |
| Full tillage (16” row spacing) | Joey | 5.2c |
| X-59 | 6.3c | |
| Mowing | Joey | 4.0c |
| X-59 | 4.5c | |
| Tarping | Joey | 10.2b |
| X-59 | 10.2b |
Table 1. Stand counts of hemp (Cannabis sativa) planted into red clover (Trifolium pratense) using different termination methods: full tillage, mowing, and tarping. Tarped plots had significantly better stands than other treatments.
Acknowledgements: Thank you to Betsy Leonard and Steve McKay for their help in setting up this trial.
