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| Title | Quality Assurance Project Plan: Effects of Conventional versus Minimum Tillage on Groundwater Nitrate at a Manured Grass Field | |||
| Month-Year Published | October 2009 | |||
| Online Availability |
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| Short Description |
This is the study plan for effects of conventional versus minimum tillage on groundwater nitrate at a manured grass field. (Also see abstract below) | |||
| Publication Number | 09-03-126 | |||
| Author(s) | Carey, B. | |||
| Print Availability | ||||
| Number of pages | 29 pp. | |||
| Keywords | agriculture, conservation, district, Ecology, grass, groundwater, internet, manure, nitrate, quality, quality assurance, quality assurance project plan, soil, wells, Whatcom | |||
| Subject Waterbodies |
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| Abstract | Long Description |
In cooperation with the Washington State University, Whatcom Conservation District, and Washington State Department of Agriculture, the Washington State Department of Ecology (Ecology) conducted a nitrate study on a 22-acre grass field near Lynden, Washington from 2004 to 2008. One of the study findings was that nitrate concentrations in groundwater reached high levels (maximum of 43 mg/L nitrate+nitrite-N) beneath the field following conventional tillage of the field. This Quality Assurance (QA) Project Plan describes a planned 2009-11 study to compare the effects of conventional tillage with the effects of minimum tillage. During conventional tillage, the soil is disturbed 8 times to a depth of 3 feet, while the minimum tillage method only disturbs the top few inches of soil one time. Because the soil is not completely turned over using the minimum tillage method, there is less opportunity for soil organic nitrogen to oxidize and mineralize to nitrate. The field has been divided in half for the 2009-11 study, with three shallow monitoring wells in each half. One half received conventional tillage, and the other half minimum tillage. Groundwater monitoring will be conducted four times per year for both years. Groundwater results will also be compared with soil nitrate, grass nitrogen uptake, manure nitrogen applied, and climate data. If minimum tillage of grass re-seeded into grass results in less nitrate release to groundwater and produces an equivalent crop, this could become a preferred alternative for maximizing crop uptake of manure nitrogen. Each study conducted by Ecology must have an approved QA Project Plan. The plan describes the objectives of the study and the procedures to be followed to achieve those objectives. After completion of the 2009-11 study, a final report describing the study results will be posted to the Internet. |
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This page last updated October 16, 2009
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