Global Maize Project in the United States: Ames, Iowa

The project site was set up in the 2010 crop year. Treatments were not initiated; instead the site was prepared for 2011. This included plot designation and layout, uniform tillage across each crop area, crop planting to begin the corn-soybean rotation, and uniform N application across the corn area. Each plot was harvested for grain yield to investigate any potential underlying effect that might indicate a treatment response when none existed. This was accomplished by statistical analysis of the plot yields as if the treatment structure was already in place. The study design is a split plot. The main plot is management system (MS): 1) farmer practice, and 2) ecological intensification. The split plot is: 1) N application (NAPP) according to the management system, and 2) no N. The treatments are in a randomized complete block, with four replications. An analysis of variance showed no inherent site effect that would influence the 2011 treatment productivity/yield results.

Analysis of collected soil samples will also aid in understanding site variability. The mean corn yield in 2010 was 140 bu/A. The yield was low due to the site having corn following corn and a low N application rate (120 lb N/A). The low N rate was used so as to not influence potential N response in future years and to identify any site history variability that might influence plant available soil N supply. The mean soybean yield in 2010 was 62.2 bu/A. Baseline soil sampling according to the protocol was completed in the fall of 2010 before tillage and fertilizer application. After soil sampling, fall fertilizer application and tillage was conducted according to the treatment protocol and in preparation for the 2011 crop year. In addition to the study area, an area was designated as a non-N limiting reference for active canopy sensing, and areas were set up so treatments could be practiced before implementing in the study plots. IPNI-26