Deep soil nitrogen: A resource for sustainability in the mid-Atlantic using early cover crops

Deep soil nitrogen: A resource for sustainability in the mid-Atlantic using early cover crops

Summary

We had an exceptional response to our call for collaborators, with farmers at 31 sites interested in participating. In August- September, 2014, we took deep (210 cm) soil cores in transects on 14 farms, six in the Eastern Shore region of Maryland and eight in the Piedmont region of Maryland and Pennsylvania, in order to assess the N content throughout the soil profile. Twenty farmers set-up replicated plots of cover crops; the number of treatments and species varied by farm. Among those experiment sites, we were able to collect biomass samples at 11 farms and take deep soil cores within replicated treatments at 7 farms. In addition, in order to investigate methods of establishing cover crops earlier in the season, two farms employed aerial seeding of cover crops, one farm experimented with irrigating after planting, and 8 farms experimented with using low rates of N fertilizer after planting. In fall 2014, presentations discussing cover crops and these experiments were given at the Cover Crop Solutions Fields Day in Holtwood, PA, the Agronomy Society of America annual meetings, at the Mid-Atlantic crop school, at a cooperating farmer’s field day in Lancaster County, PA, and at an extension research projects meeting in Franklin County, PA.

Objectives/Performance Targets

250 farmers plant 25,000 acres early radish/rye covercrops reducing N leaching by 2,000,000 Lbs; 100 of them also reduce N application by 50 lbs. on 10,000 acres, saving $0.5 million annually. 20 advisers recommend early covercrops and 2 state Agriculture Departments include them in their N load reduction programs.

Accomplishments/Milestones

-1000 dairy, 250 grain and 100 vegetable farmers managing 250,000 acres will learn through newsletters, field days, farm newspaper stories and extension meetings about early cover crops to reduce N fertilizer needs and prevent water pollution. Presentations were made at Cover Crop Solutions field day (approximately 300 attendees), a Lancaster County farmer’s field day (approximately 15 attendees), the Agronomy meeting at the Mid-Atlantic crop school (145 nutrient management professional in attendance), and an extension research projects meeting in Franklin County, PA (80 attendees).

-In the first year, 20 farmers (10 dairy and 10 grain or vegetable each year) will collaborate by permitting us access to designated areas on their farms for us to assess deep N under their fields. Deep soil cores were taken on 14 farms by 9/22/15. Time and labor restricted us from sampling more farms. Tractor mounted probes were unable to penetrate the soil below approximately one meter deep; therefore cores were taken using hand-driven Veihmeyer probes.

-In each of three years, 10 farmers will collaborate by planting replicated strips with and without cover crop (2 trts) on their farms so we to access the N uptake and/or soil profile N depletion by one selected species of early planted, deep-rooted, non-immobilizing covercrops.

-In each of two years, 5 farmers will collaborate by planting replicated strips with 4 covercrop treatments to evaluate N uptake by 2 species and a multi-species cocktail of early planted, deep-rooted, non-immobilizing covercrops. The majority of farmers were interested in planting replicated strips of at least two cover crop treatments. In 2014, 17 farms had a radish treatment, 15 farms had a winter cereal treatment, and 15 farms had a cover crop mix treatment combining two or more species.

-In each of two years, 2-3 farmers will help us design and conduct spring N response trials superimposed on late summer cover crop treatments. These response trials will take place in spring 2015. We anticipate at least 2-3 farmers will participate.

-8 of the collaborating farmers host and speak at field days on their farms. Two participating farmers hosted a field day on their farms, October 29-30, 2014 and November 12, 2014.

-200 dairy and 50 grain or vegetable farmers will plant 25,000 acres of early covercrops reducing N leaching by 2,000,000 lb. (avg. 80 lb N/acre reduction)

-100 of these farmers will also reduce fertilizer N use by 50 lb on 10,000 acres, saving 500,000 lbs N or $1.0 million (cost of N = $0.70 to $9.00/lb; avg. $1.00/lb N, includes some high priced N for organic and vegetable farms).

-20 crop advisers will make early covercrops part of their recommendations.

-2 state Departments of Agriculture will include early covercrops in their N load reduction programs.

Impacts and Contributions/Outcomes

The farmer interest in surveying the deep soil N on their land and participating in cover crop trials exceeded our expectations. We collaborated with farmers throughout the Piedmont regions of Pennsylvania and the Piedmont and Coastal Plain regions of Maryland, an area which spanned approximately 300 km. We took deep soil cores in transects on 14 farms during August to September. Our initial intension was to use a tractor assisted Giddings probe to take deep cores; however, with this equipment we were unable to sample below approximately one meter deep. Instead we used hand-driven Veihmeyer probes, with which we could sample up to 210 cm deep on most sites. This sampling method also allowed us to take soil cores in fields with standing crops without disturbing the crop, giving us access to more farms during the late summer sampling period. However, this method was time and labor intensive and restricted the number of farms we could sample. Initial estimates indicate the top 210 cm of soil have from 30-540 kg NH₃-N/ha and from 50-530 kg NO₃-N/ha.

Twenty farmers participated in the cover crop trials through planting replicated strips with and without cover crops. Farmers were given an option to plant one or more species of cover crops. Seventeen farmers chose to plant radish, 15 a winter cereal species, and 15 a treatment that contained a mixture of at least two species. County extension personnel were integrally involved in working with us and the farmers to help set-up these plots. In November through December, we were able to collect biomass samples at 11 farms and take deep soil cores at 7 farms, again restricted from sampling more sites due to the heavy time and labor requirements of taking the deep soil cores. In addition, several farms experimented with methods of establishing the cover crops earlier in the fall. Two farmers on the Eastern shore compared aerially seeded cover crops to drilled and/or broadcast seeded cover crops, one farmer compared post-planting irrigated to non-irrigated cover crops, and on 8 farms, experiments were performed using low rates of N fertilizer after planting. In addition, we set-up replicated plots utilizing 15-N isotope to investigate the N uptake from 100 cm deep and 200 cm deep of two cover crop species (radish, rye), on two soil types (clay, sandy), at two planting dates (August 28, October 1). All late fall biomass and soil samples have been processed and are beginning to be analyzed for N content.

In fall 2014, project personnel gave talks at the Cover Crop Solutions Fields Day in Holtwood, PA, the Agronomy meeting at the Mid-Atlantic crop school, at a collaborating farmer’s field day in Lancaster County, PA, and at an extension research projects meeting in Franklin County, PA.

List of presentations and events:

1. Weil, Ray. 2014. Panel on Innovations in Cover Crops. Meeting of the Minds. Lancaster, PA. October 29, 2014. 100 farmers and agric. professionals and press reporters in attendance.

2. Weil, Ray. 2014 Impacts of Cover Crops of Yields. Invited Keynote talk at the 19^th Annual Cover Crop Field Day at Groff Farm, Lancaster, PA. October 29, 2014. 100 Farmers, professionals and reporters in attendance.

3. Weil, R and N. Lounsbury. 2014. Forty minute field day talks to eight groups of 30 farmers, professional and reporters (~ 240 total). Oct. 30, 2014. Cedar Meadow Farm, Lancaster, PA.

4. Gruber, P. 2014. Getting to the roots of cover crop benefits. Lancaster Farming, Lancaster Farming .com, Lancaster, PA. http://www.lancasterfarming.com/results/Getting-to-the-Roots-of-Cover-Crop-Benefits#.VGEFsPnF-Sp. Press coverage of Weil’s field day talks at Groff Farm. Approximate circulation: 56,000 paid subscribers.

5. Weil, Ray. 2014. Getting Creative with Cover Crops as Tools for Soil Health and Nutrient Cycling. Mid Atlantic Crop Management School in Ocean City, MD. November 19, 2014. Two 1 hour sessions with a total of 145 ag professionals in attendance.

6. Graybill, Jeffrey. 2014. Field day at a Lancaster County cooperator’s Quarryville, PA. November 12, 2014. 15 in attendance.

7. Patches, Kelly. 2015. 2014: Franklin County in Review. Franklin Crops Day. Chambersburg, PA. January 28, 2015. 80 people in attendance.

Collaborators: