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Hawaii Water Quality Extension Program
nps 319 | oahu watersheds | waialua | project 02-211
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Natural Resources Extension

Project Name: Cover Cropping for Reducing Soil Nitrogen Following Seed Corn Production in the Kaiaka-Waialua Watershed
ASO Log No.: 02-211
Start/End Date: March 2002 to July 2003
Federal Funds: $40,000.00
Matching Funds: $43,500.00
Contractor: John McHugh
Hawaii Farm Bureau Federation (HFBF)
2343 Rose Street
Honolulu, HI 96819
Phone: (808) 848-2074
Fax: (808) 848-1921
Non point source pollution from agricultural fertilizers is a concern in the Kaiaka-Waialua watershed, considered a water quality limited segment. Crop production practices in the watershed include bare ground fallow, causing erosion during periods of heavy rainfall. Soil nitrogen residues left from previous crops can move with the soil into nearby water bodies during rainy periods.
Objectives/Goals: To determine if two types of grass cover crops can be effective in reducing soil nitrogen in an agricultural cropping system that currently uses bare ground fallow as a pest management tool.
Methods Employed: • Implement soil nitrate management via cover cropping
• Collect soil samples, analyze soil nitrate, and construct database
• Increase farmer, student and public knowledge of water quality issues and best management practices through technology training and application
Pollutants of Concern: Nitrogen and phosphorous
Watershed: Waialua, Kiikii, Poamoho, Kaukonahua, Paukaulia, Opaeula, Helemano, Anahulu, Kawailoa, Kawaiiki, Loko Ea and Keamanea Watersheds, island of Oahu
Size of Project: 8 field sites
Affected Water Bodies: Kaiaka and Waialua Bay; Paukawila, Kiikii, and Anahulu Streams
Deliverables: • Waialua High School students’ scientific paper located at
• Hard copies of Powerpoint presentations
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Cooperative Extension Service programs, conducted in cooperation with the U. S. Department of Agriculture, are provided to the people of Hawaii without regard to race, sex, age, religion, color, national origin, ancestry, disability, marital status, arrest and court record, sexual orientation, or veteran status. The University is an equal opportunity / affirmative action institution.