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The Cook Agronomy Farm (CAF) Long-Term Agroecosystem Research (LTAR) site combines site-specific and regional research efforts to advance sustainable agricultural systems. At the site-specific scale, the Cook Farm was launched as a long‐term, direct‐seed cropping systems research program by a team of USDA‐ARS and Washington State University (WSU) scientists in 1998. Process-oriented and applied research is conducted at plot, landscape and farm scales to advance knowledge of field-scale biophysical and economic processes with the overall goal to advance sustainable agroecosystems and precision agriculture technologies. At the regional scale, research is extended to the dryland cropping region of the inland Pacific Northwest and includes long-term studies as well as crop modeling and other research contributing to sustainable agriculture.

Three major agroecosystem classes (AEC) occur across the region based on the proportion of fallow that occurs within a rotation.  The grain-fallow AEC is defined as a field that is over 40 % fallow.  The annual crop-fallow transition AEC is defined as a field that is between 10 % and 40 % fallow.  And the annual crop AEC is defined as a field that is less than 10 % fallow.