By: Diana Roberts, Regional Extension Specialist, Spokane
Innovative, dryland grain farmers in Lincoln and Spokane Counties, WA, want to include a cover crop or companion crop in their rotation to raise soil organic matter levels, break disease cycles, suppress weeds, penetrate soil compaction layers, and improve soil fertility by fixing atmospheric nitrogen.
In addition, they want to make this system work with the winter precipitation (Mediterranean climate) of the area. So far, seeding cover crops in the spring in place of fallow, results in excessive loss of soil moisture so that getting a crop germinated that fall has proven tricky. Consequently, the group is exploring other options.
We have learned the following so far:
• Always inoculate when seeding legume with species-appropriate inoculant
• With companion crops, use seeding rates that won’t “smother” the cash crop
• Use starter fertilizer at least with cover or companion crop seedings
• Legume companion crops may not provide nitrogen to the current crop (only to subsequent crops)
• Cover crops seeded in the spring may reduce moisture availability for germinating the subsequent fall cash crop.
Following is a link to the complete annual report provided to Western SARE (the funding agency for the project).