The Northwest Crops Project was a 6-year on-farm testing project in the intermediate rainfall area (14 to 18 inches annual precipitation) of eastern Washington. It compared a low-risk 3-year crop rotation with a high-risk 4-year rotation, all under direct seeding without irrigation or field burning. The 4-year rotation was spring wheat - winter wheat - warm season grass (corn) - broadleaf crop (cooperator's choice). The 3-year rotation was winter wheat - spring barley - chemical fallow or broadleaf crop (cooperators' choice). The second rotation was similar to a conventional rotation for the area, substituting chemical fallow for tillage fallow. The cooperators used crop varieties that best suited their farm conditions.

The variables considered were crop yield and net economic return (gross revenue minus the sum of fixed and variable costs, from grower data). In comparisons of 3 sites with the most consistent data, we did not see significant differences in performance between crop rotations. This confirmed current farmer decision-making strategies that are based on current commodity prices, climatic conditions, and local farm situations.

We did see statistical differences between some crop sequences within the rotations. Broadleaf crops and chemical fallow in a rotation benefited the subsequent wheat crop. Dryland corn provided residue management benefits but tended to lose more money than did barley in rotation.

A quantitative analysis of soilborne pathogens showed that including a warm-season grass in the rotation did not affect the level of Rhizoctonia and Fusarium species.

A full report for the Northwest Crops Project will be available on the STEEP website under the On-Farm Testing section at http://pnwsteep.wsu.edu/index.htm This will include Microsoft Excel spreadsheets that show rotation management costs. Farmers may use these spreadsheets to calculate the economics of various direct seed rotations on their own farms.