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Home > Protecting Our Lands & Waters > Clean Water Fund > Clean Water Research Program > Cover Crop Establishment > Research Methods and Data Collection

Water quality enhancements in corn cropping systems through optimization of cover crop establishment technologies


Methods

Three-year project at:

University of Minnesota’s Research and Outreach Centers in Lamberton and Waseca

Experimental Design: Split-plot design with six replications. Main plot treatments will include establishment technologies, while sub-plot treatments will be cover crop species/mixture. The experimental check 'corn without cover crops ' will be incorporated into the treatment structure.

Cover crop establishment techniques:

Cover crop drill with modified drags

 Direct Broadcast + light incorporation

  • A modified high-boy with drop seed tubes- without soil disturbance
  • A modified high-boy with drop seed tubes and soil disturbance for seed-to-soil contact
  • Direct-drilling cover crop seed between com rows using a custom built 3-in-1 inter-seeder

Cover crop species to be evaluated:

  • Winter rye (Secale cereal L. 'Rymin')
  • Winter Oilseeds Camelina [(Camelina sativa L. 'Joelle') and Pennycress (Thlaspi arvense L. 'Beecher Farms')]
  • Winter hardy mixture (Winter rye + Hairy vetch)
  • Non-winter hardy mixture (Oats + Field pea + Tillage radish)

Often used in Minnesota, a non-winter hardy mixture will be compared to the no cover crop (control) to check for durability and water quality impacts.

Data Collection

Data will also be collected to quantify cover crop success, corn performance and water quality impacts.

  • Established cover crops (i.e. ground cover) using a combination of photography and Sigma Scan software
  • Early-season cover crop stand counts (percent of establishment)
  • Cover crop biomass and nitrogen uptake (measured at both corn maturity and prior to cover crop termination in spring)
  • Corn population, corn nitrogen uptake and corn grain and silage yields (will be measured annually)

Soil samples will be collected to a depth of four feet (one-foot increments) immediately after corn harvest in the fall and also in the spring prior to cover crop termination. These samples will be analyzed for soil nitrate-nitrogen concentration.

Soil water content will be measured in increments of 0-to 8-inch depth starting at the establishment of cover crops and continue bi-weekly (FieldScout TDR 300 Soil Moisture Meter). Residual soil nitrate-nitrogen content and soil water content will provide needed information to calibrate the Nitrogen Loss and Environmental Assessment Package (NLEAP) model (NLEAP-GIS 4 .2); and to use this model to assess N pools and pathways for N losses (USDA-ARS , 2010).

Soil water data loggers (WatchDog Waterscout, Spectrum Technologies) will be installed at a 24-inch depth to monitor soil water status on four-hour intervals at both locations. Soil loss reduction will be estimated through the Revised Universal Soil Loss Equation (RUSLE2).

Necessary parameters to estimate Soil Loss Ratio (SLR) are: canopy coverage, ground cover, soil roughness, ridge height, soil biomass, soil consolidation, and antecedent soil moisture. Measurements will be collected at the V8 com stage, in late fall, and in the spring before termination of cover crops and planting of corn.

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