John Selker

Ground Water

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Content by John Selker

Field Measurements of Nitrogen Leaching Below Willamette Valley Row and Mint Crops

Discusses the results of a study that measured nitrate concentrations in water percolating below root depth on vegetable and mint fields in Lane County, Oregon. Describes the nitrate leaching process, data from the study, and how nitrate concentrations change throughout the year. Also discusses how...

By John Selker | OSU Extension Catalog

Groundwater and Nitrogen Management in Willamette Valley Mint Production

Describes impacts of nitrogen overfertilization and uneven irrigation on groundwater in Willamette Valley, Oregon. Recommends that mint crop growers use stem testing to gauge nitrogen needs more closely and advises growers on how to improve irrigation system efficiency.

By John Selker | OSU Extension Catalog

Irrigation System Maintenance, Groundwater Quality, and Improved Production

Describes connection between poor irrigation practices and poor groundwater quality. Recommends ways to improve irrigation management and irrigation system efficiency, both to save water and money and to protect groundwater.

By John Selker | OSU Extension Catalog

Western Oregon Irrigation Guides

Set of irrigation guides for farmers in the Willamette Valley, covering the primary field, row, and orchard crops. Gives an overview of the decisions and factors that go into irrigation system design, operation, and maintenance. Includes 16 crop-specific fact sheets that cover all of the major crops...

By Bernadine Strik, John Selker | OSU Extension Catalog

Pesticides in Southern Willamette Valley Groundwater

Reviews recent studies of nitrogen contamination of groundwater in the southern Willamette Valley of Oregon from pesticide use. Finds no violation of drinking water standards, though many water samples contained traces of pesticides. Includes details of studies, a map of sites sampled,...

By John Selker | OSU Extension Catalog

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