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Seasonal High Tunnel Systems for Crops Update on interim standard 798. NRCS Idaho October, 2010 . Technical and Program guidance National bulletin: 190-10-10 National Bulletin: 190-10-12. Seasonal High Tunnel. Definition:
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Seasonal High Tunnel Systems for Crops Update on interim standard 798 NRCS Idaho October, 2010 Technical and Program guidance National bulletin: 190-10-10 National Bulletin: 190-10-12
Seasonal High Tunnel Definition: A seasonal polyethylene covered structure that is used to cover crops and extend the season in an environmentally friendly manner • Practice lifespan: 4 years Currently (2011) only available under the Organic EQIP payment schedule.
Purposes - Improve plant quality - Improve soil quality - Improve water quality from reduced nutrient and pesticide transport - Improve air quality through reduced transportation input - Reduced energy use through local consumption
Condition Where Practice Applies • Cropland where the growing season extension is needed due to climate• Crops grown in natural soil profile –Specialty crops like vegetables and small fruits• Raised beds allowed, but not crops on benches or in pots
Criteria • Tunnel shall be constructed of metal, wood, or durable plastic and be at least 6 ft in height • The seasonal tunnel structure must be planned, designed, and constructed in accordance with manufacturer’s recommendation
Elements of a High Tunnel • Shape• Ground Posts and Bows• Purlinsand Truss Supports• Sidewalls and Endwalls• Ventilation and Access • Covering (Polyethylene Plastic)
High Tunnel Shapes Qounset (Round Hoop) Typically 14 to 34 ft wide, 28 to 150 ft long Gothic (Peak) Require additional bracing 12 to 16 ft at peak Photos: Farmtex.com Photo: Danny McBride NRCS, Utah
Criteria • “In climate conditions where snow loads may damage the structure, the tunnel cover shall be removed at the end of the growing season” • As a minimum, a 6-mil greenhouse-grade, UV resistant polyethylene cover will be used •Standard from most manufactures
• Maximum 2,178 square feet for a farming operation • Idaho NRCS has two payment rates: • 1. Up to 1,000 square feet • 2. More than 1,000 square feet Payment Rate Payment rate cap – Tunnel can be larger, but only pay up to 2,178 sq ft – Can have multiple tunnels – Can already have a tunnel
Installation Considerations • Orientation • NS for main season, EW for off season, maximize airflow crosswise • • Distance from structures/shade • –2x height of nearest structure • • Quality soil • • Access to water for irrigation • • Drainage
• Runoff shall be directed away from tunnel to avoid ponding • – Surface or underground outlets • – Protected ground surface • – Critical area planting • Grassed waterways • • If runoff empties onto ground surface, a detention basin, storage reservoir, or stable outlet shall be provided Criteria
• Surface or ground outlets such as rock pads, rock filled trenches with subsurface drains, concrete and other erosion-resistant pads, or preformed channels may be used • Seeding and vegetation shall be established on all disturbed earth surfaces Criteria
Considerations • • Plan appropriate measures to address: • – Conservation crop rotation • – Irrigation water management • – Nutrient management • – Pest management • – Runoff from the structure • Rotate location of the tunnel to reduce disease build up.
High Tunnel Sources For general information and suppliers of high tunnel systems see web sites: hightunnels.org University of Idaho http://www.extension.uidaho.edu/homegard.asp Utah State University https://extension.usu.edu/yardandgarden/htm/vegetables-fruits-herbs