Seed Yields of Meadowfoam as Influenced by N, Seeding Rates, and Soil‐Water Table Levels 1

The vegetable oil from meadowfoam, Limnanthes alba var. alba , promises to be an agronomic source of several unique long‐chain fatty acids needed by industry. Studies were made on N fertility, seeding rates, and soilwater levels to determine those cultural practices necessary to maximize the production of oil bearing seeds of meadowfoam. The treatments for N fertilizer experiments consisted of two sources of N, ammonium sulfate and ammonium nitrate, and two rates for each source of N at 56 and 112 kg/ha. Seeding rates of 11.2, 22.4, 33.6, and 44.8 kg/ha were used in the seeding rate experiment. The soil‐water levels used were no drainage, soil‐water level maintained at 30.5 cm, and soil‐water level maintained at 61 cm below the soil surface, by creating hydraulically isolated soil plots. The soils used were Typic Ochraqualfs (Dayton) and Typic Olbaqualf (Concord). Seed from meadowfoam plots for all experiments was harvested with a Hege 125 self‐propelled plot combine. The addition of N increased total seed yields. The use of ammonium sulfate as an N source as compared to ammonium nitrate depressed seed yields. A seeding rate of 33.6 kg/ha in drill rows 15‐cm apart produced highest seed yields. Lowering of soil‐water levels in soils with low permeability rates did not improve seed yields. This study indicates that meadowfoam has the potential for commercial production on poorly drained wet soils in high winter rainfall areas of Oregon.