Publication Summary

This is the quality assurance project plan for the study Groundwater, Soil, and Crop Nitrogen at a Field where Dairy Waste is used as Fertilizer in Whatcom County.

Dairy manure is often applied as a fertilizer on grass fields in Western Washington. This study will evaluate the effectiveness of recently adopted Dairy Nutrient Management Plans in protecting the quality of the Sumas-Blaine Aquifer by documenting the sequence of changes in nitrogen that can be readily measured at a typical grass field. Manure, soil, grass, and groundwater will be sampled over 2-1/2 years at a 22-acre grass field where manure is applied near Lynden, Washington. Seven monitoring wells will be installed in the field where monthly to every six weeks ammonia N, nitrate+nitrite-N, total N, total and ortho phosphorus, chloride, total organic carbon, and total dissolved solids will be sampled as well as depth to water. Soil, manure, and crop samples will be collected and analyzed by the Washington State University Nutrient Management Program. Soil samples will be collected weekly during the fall and monthly during the rest of the year for nitrate and once annually for phosphorus and potassium. Samples of manure will be collected and analyzed for ammonia N and total Kjeldahl N each time manure is applied, and the volume recorded. Grass samples will also be collected and analyzed for dry weight and nitrogen content. Precipitation data will be recorded and used to observe the influence of rainfall on the movement of nitrate from soil to groundwater in the fall. The NLOS (NLEAP UoUn UStUella) model will be used to compare observed to predicted concentrations of nitrogen in the soil.

Link to EIM data for User Study ID bcar0003