100872 Overcoming Tunnel Vision: Incorporating Cover Crops into High Tunnel Rotations to Improve Soil Health.
Poster Number 318-705
See more from this Division: ASA Section: Agronomic Production Systems
See more from this Session: General Organic Management Systems Poster (includes student competition)
Tuesday, November 8, 2016
Phoenix Convention Center North, Exhibit Hall CDE
Abstract:
High tunnels are increasingly used for season extension in the Upper Midwest. However, intensive high tunnel planting, irrigation, and fertilization to optimize high-value growing space can lead to soil health problems, such as increased salinity and compaction, as well as organic matter loss. This project evaluated the use of cover crops as a management tool for high tunnel soil health improvement and nitrogen fertilization. Three cover crop treatments 1) Red clover monoculture, 2) Austrian winter pea/winter rye bi-culture, and 3) hairy vetch/tillage radish/winter rye tri-culture were planted in three replicates and repeated in three high tunnels across USDA hardiness zones in Minnesota, compared to a bare ground control. Treatments were evaluated for their effect on soil quality parameters including cover crop biomass carbon (C) and nitrogen (N), extractable N in soil, potentially mineralizable N, and labile soil carbon (Permanganate Oxidizable Carbon, POX). Cover crops were planted in late August 2015, terminated and incorporated in mid-May 2016, and followed by orange bell peppers. Cover crop biomass, weed biomass, and soils were sampled before cover crop termination/incorporation and soil was sampled again two weeks after termination/incorporation. At one site, biomass %N ranged from a low of 1.2 in rye to a high of 5.9 in vetch, biomass %C ranged from a low of 31.0 in radish to a high of 41.2 in rye, and C:N ranged from a low of 6.9 in vetch to a high of 34.2 in rye. For all treatments at all sites, extractable N ranged from 6.9-22.0 mg N/kg dry soil, potentially mineralizable N ranged from 3.7-29.9 mg N/kg dry soil, and POX carbon ranged from 727-1089 mg C/kg dry soil at cover crop termination and from 741-1137 mg C/kg dry soil two weeks after cover crop termination. Overall POX carbon increased from the first to second sampling.
See more from this Division: ASA Section: Agronomic Production Systems
See more from this Session: General Organic Management Systems Poster (includes student competition)