Extensive areas of eastern Oregon, eastern Washington, and Idaho are well suited to dryland production of small grains and legumes. Commonly, over this area, winter wheat is planted in rotation with either annual legumes or summer fallow.
Even slight terrain inhomogeneities can cause large horizontal variations in the clear, stably stratified, nocturnal boundary layer largely through cold air drainage. By early morning the valleys and depressions can be several degrees cooler than the adjacent slopes and plateaus. As surface heating begins in the morning, these horizontal variations...