Agronomic Practices For Reduced Smoke and Nitrate Pollution from Kentucky Bluegrass Seed Production

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Project Title: Agronomic Practices For Reduced Smoke and Nitrate Pollution from Kentucky Bluegrass Seed Production

Date Last Updated: 9/99 Project completed. Summary will not be revised again.

Project Summary:
The current practices of open-field burning of post- harvest residue from Kentucky bluegrass seed fields and potential ground water contamination from nitrate nitrogen application are environmental concerns. Alternative mechanical residue removal practices may have potential to reduce acreage burned. Use of ammonia nitrogen fertilizers less likely to leach may decrease nitrate leaching into groundwater.

Concern over these issues prompted the Pacific Northwest Pollution Prevention Research Center (PPRC) to award a $ 50,000 grant to the University of Idaho and Oregon State University in 1992 to conduct a study to evaluate mechanical residue removal of post-harvest residue and enhanced ammonia nutrition in Kentucky bluegrass produced for seed. The award became a stepping stone for a multi-university collaboration that has received more than $2.8 million in funding to define the parameters for more environmentally sound grass seed production.

The purpose of this study was to test combined economic effectiveness of crew-cutting (one of the most current mechanical post-harvest residue removal techniques), bluegrass variety growth response, and enhanced ammonia nutrition as a production package needed to reduce the need for burning and to improve nitrogen use efficiency of Kentucky bluegrass.

This research is unique from previous work in that it tests the combined effectiveness of current and new technologies of residue removal, nitrogen (N) fertilization, and bluegrass variety for economic seed production. In the past, primary emphasis has been on alternative residue management techniques alone.

The targeted areas of study were Idaho, Oregon, and Washington where bluegrass production is prevalent. During August and September, smoke is generated from open field burning of bluegrass seed crop residue. In addition, nitrate nitrogen used on grass and other crops has the potential to leach into groundwater. The greatest potential contributor of non-point source nitrate groundwater pollution in Oregon, Washington, and Idaho is agriculture, particularly in highly irrigated regions which have shallow aquifers like that found between Coeur d' Alene, Idaho, and Spokane, Washington.

Potential Implications of the Study
1. The results indicate that mechanical residue removal could be an alternative to burning in the second year of seed production if economic methods of removal are found.
2. Ammonia nutrition can be used without adversely affecting seed yield in Idaho and Oregon, thus reducing potential nitrogen losses to underground water supplies. A cost saving may also be realized if ammonium based fertilizers are used.
3. Prolonged use of ammonium fertilizers may lower soil pH. In more basic soils this may not be as critical as it would be in acid soils.

Recommendations
1. Kentucky bluegrass cultivars should be classified for persistence of seed yield with repeated mechanical residue removal treatments.
2. Classify fall floral induction requirements of Kentucky bluegrass to shorten the time required for cultivar classification from five years to two years.
3. More information is needed concerning the timing of fertilizer nitrogen application. It should be determined if growing degree days might serve as a timeline for fertilizer timing, especially for irrigated Kentucky bluegrass.

For more information or a copy of the final report, contact Stephen M. Griffith at the National Forage Seed Production Research Center of the ARS-USDA at Oregon State University at 503-750-8742.

Project Keywords: agriculture, groundwater, water contamination, botany, nitrates, fertilizers, smoke prevention, ecology

Organization Performing Research: University of Idaho

Primary Research Contact:
Dr. Glen A. Murray
Plant, Soil and Entomological Sciences
University of Idaho
Moscow, ID 83844-2339
phone: 208-885-7029
fax: 208-885-7760
e-mail: gmurray@uidaho.edu

Date Research Started/Completed: 4/92 - 11/94

Publications Based on Research: See project description

Approximate Project Budget: $51,000

Primary Project Funder: Pacific Northwest Pollution Prevention Research Center (PPRC)

Funder Contact:
Chris Wiley
PPRC
1326 Fifth Avenue, Suite 650
Seattle, WA 98101
phone: 206-352-2050
fax: 206-352-2049
e-mail: cwiley@pprc.org