Poster Number 285
Wednesday, 8 October 2008
George R. Brown Convention Center, Exhibit Hall E
The main focus of the experiment is to develop sustainable and profitable cropping systems for north-central
Oregon and south-central Washington. The goal of the research is to replace the predominant conventional winter wheat-summer fallow system that has depleted soil organic matter (SOM) with direct-seed based cropping systems that reduce wind and water erosion and build up SOM. The project is now in the fourth year and two more crop-years are required for all crop rotations to complete a full cycle. Based on the three year average (2004-05, 2005-06, and 2006-07 crop-years) winter wheat following fallow in a 3-yr rotation with spring barley produced the highest yields although these yields were not significantly different from yields of wheat after conventional fallow. The high yield obtained from winter wheat in the 3-yr rotation with spring barley could have been partly attributed to low levels of root-lesion nematode incidences. Yields from the 3-yr rotation and winter wheat-CT fallow rotation were significantly higher than yield of winter wheat following chemical fallow. Under annual cropping, continuous spring barley produced the highest yields followed by winter wheat after winter pea. Continuous winter wheat produced the lowest yields over the three crop-years. An economic analysis was performed by subtracting the costs of all variable inputs (herbicides, seed and seeding, fertilizer, equipment costs) including fallow, from the grain value. The greatest annualized partial net return was achieved in the conventional fallow winter wheat rotation followed by continuous spring barley and then the three-year rotation. The standard deviation of partial net return was smallest for the 3-year rotation of winter wheat-spring barley-chemical fallow.