Published May 17, 2013

Spring Cover Crop Data Collection

By Marc Strobbe

Several staffers from Practical Farmers of Iowa and Iowa Learning Farms traveled to fields across the state this spring to conduct field research. Their task was to measure and document the in-field effects of growing cover crops. Farmers active in both organizations graciously gave access to their fields and often joined the crew to offer insights and at times, directions.

Cover crop biomass samples were collected with a one square foot sampling quadrat. Many other sampling quadrats were distributed so farmers could mail their own biomass samples to Practical Farmers. Back in Ames PFI staffer Tomoko Ogawa is amassing the samples to be tested for total Nitrogen and Carbon at Iowa State University’s Soil and Plant Analysis Laboratory. Thanks to Tomoko for organizing the trips and sharing her office with mounds of forage sample bags. 

At some locations other testing was done as well, underground. Soil samples and bulk density cores were taken to gauge conditions below the surface. These also go to the lab to determine soil type, structure, and compaction.  Cornell University’s Sprinkle Infiltrometer was used to collect soil hydrology data. The infiltrometer simulates rain, in this case about ¼ inch per hour. The volume of runoff can be measured as well. At these sites “time to runoff” ranged from about a minute to almost an hour.

Some sites have been sampled for many years and others were sampled for the first time. The data collected will help gauge the long-term effects of cover crops and different management practices on various factors of soil quality. The combination of above ground biomass, below ground soil conditions, and overall hydrologic performance tells a complete story farmers can use to make their own decisions about cover crops. 

The results of this research will be analyzed then shared and distributed in typical Practical Farmers of Iowa and Iowa Learning Farms fashion. For more information contact Tomoko Ogawa at Practical Farmers of Iowa. 515.232.5661 &