Research at this site is funded by the USDA-Agricultural Research Service (ARS) Project Number 5060-11610-003-00D of the Soil and Air National Program and Project number 5060-21220-006-00-D of the Crop Production National Program in coordination with the Long-term Agroecosystem Research (LTAR) network. This research was a contribution from the Long-Term Agroecosystem Research (LTAR) network. LTAR is supported by the United States Department of Agriculture.