Refining the potential for interseeding cover crops in corn

2012 Annual Report for ONE12-172

Project Type: Partnership
Funds awarded in 2012: $14,703.00
Projected End Date: 12/31/2012
Region: Northeast
State: Pennsylvania
Project Leader:
Dr. Gregory Roth
Penn State University

Refining the potential for interseeding cover crops in corn


In this project, we evaluated the Penn State Cover Crop Interseeder on three farms in replicated trials and on one farm as a non replicated demonstration. The trials were designed to evaluate a legume and Italian ryegrass mixture compared to an Italian ryegrass seeding with or without a seed treatment designed to improve establishment. Establishment in the three replicated trials was less than desired in most cases and the seed treatment had little effect on improving establishment. We interseeded annual ryegrass in border areas of each study and this consistently established better than the italian ryegrass. We also noted significant recovery late in the season at most of the sites which demonstrated that with even low establishment plant counts, significant cover crops can establish in the fall. At the demonstration site, establishment was much better including with some of the alternative species we evaluated such as tillage radish. We conducted several outreach activities in the fall showcasing the trials and the some of the insights we gained into interseeding and are using the results as a steppingstone to future work with the interseeders.

Objectives/Performance Targets

The objective of this study was to assess the potential of a seed treatment to improve the establishment of Italian ryegrass and also to evaluate a mix of clover and ryegrass compared to a single ryegrass intereseeding. We were also interested in identifying any issues that could help to improve the potential of interseeding cover crops in corn.


Replicated trials were established at three locations in Bradford and Counties, PA. These were located on the Ron Kittle farm in Sylvania, the Dan King Farm in Milheim, and the Cinda Corl farm in Pine Grove Mills, PA. Each consisted of four treatments and three replications. Treatments consistent or Green Spirit Italian Ryegrass, Green Sprit Italian Ryegrass with a “Yellowjacket” seed treatment, and the PSU mix from Kings Agriseeds, a mix of red, white, crimson, and yellow sweet clover along with the Green Spirit Italian ryegrass. Seeding rates were 10 lb/acre for all seeds.

Interseedings were done at approximately V6 to V8 at each location in mid to late June. Each plot consisted of four rows, approximately 500 feet long at each location. Stand counts were made at each location in early August and silage corn yields were estimated in early September by harvesting 2 1/1000 acre subsamples from each plot. In early November biomass samples were collected from each location. At two of the locations, soil samples were collected at the same time. At the Kittle location soils samples were not collected then and the field was manured before they could be collected. Soil and plant samples were then analyzed to assess nutrient content. At each location, the borders were seeded to an annual ryegrass, DH3, so that we could make some evaluation of its potential. We also established a fourth demonstration site near the Bradford County site, in Sullivan County, PA so that we could conduct a field day if the opportunity developed. At this location we included some additional species including tillage radish, rye and oats.

Impacts and Contributions/Outcomes

A short term drought occurred across much of the region during late June and early July and this had a negative impact on establishment of the interseeded cover crops at each location. Our stand counts averaged about 2-3 plants/sq. ft. at each location. Establishment was also patchy at each site, with each of the treatments. Ideally we would have liked to have had 8-10 plants/sq. ft. in a uniform stand.

At each of the locations, establishment of the annual ryegrass in the border strips was more successful. Establishment in the demonstration trial of the ryegrass clover and tillage radish treatments was also successful. One of our conclusions was that an annual ryegrass could be more consistent that the Italian ryegrass. The annual ryegrass variety we used, DH3, has performed well as a forage in the mid south where heat and drought are common, so this may explain its performance under the heat and drought conditions common in interseeding environments.

At the end of the trial, our cooperator Cinda Corl, in Centre County grazed the corn stubble and cover crops with an Angus cow calf herd and we were able to obtain some good photographs for future use. We also noticed at the end of the season that the Italian ryegrass had some significant recovery in the fall, as we had seen in the past. Italian ryegrasses have performed better in some of the cooler environments where interseeding has been successful in other regions. At the Sullivan County demonstration, the corn population was lower than the other sites, so this suggests that slightly lower corn populations might improve interseeding success. So despite the inconsistent establishment, we feel we learned some ideas that could be useful for the future.

Because of the less than ideal establishment we decided to forgo the idea of having field days at the sites, except for the demonstration site where we had a small field day with farmers and several industry seedsmen from Cover Crop Solutions. This was a great opportunity to discuss the concept and exchange ideas for future development. We were also invited to the Cover Crop Solutions field day in Lancaster to discuss the interseeder where over 200 folks attended.

We developed a handout on the project and distributed it to participants. This led us to be invited to a meeting with Homestead Nutrition, a Cover Crops Solutions dealer, where we shared the potential of the interseeder with over 150 attendees. We also reported on the interseeder project in the Field Crop News ( , a Penn State electronic newsletter that is distributed to over 1000 farmers and crop advisors. We also tweeted images from each of the sites and at least one of these was retweeted by several others, to more than 400 twitter subscribers. An example of one of the tweets and images can be found here: So despite the inconsistent establishment, we were able to generate some good publicity for the project and NESARE and identify some potential strategies for improving our success with the interseeder in the future.


Cinda Corl

[email protected]
Beef Producer
365 West Pine Grove Road
Pine Grove Mills, PA 16868
Office Phone: 8142388742
Dan King

Dairy Farmer and Store Owner
1234 Paradise Lane
Milheim, PA 16854
Office Phone: 8143495645
Ron Kittle

[email protected]
Dairy Producer
209 Watkins Hill Rd.
Troy, PA 16947-8913
Office Phone: 5702974561