Briefly (the results are explained in the project report) the key-results from this project so far are:
a) Simulated maximum yield potential for soybean in Iowa of 90 bu/acre
b) The associated yield gap varies with variety choice and date of planting
c) Web-tool: http://www.agron.iastate.edu/CroppingSystemsTools/
d) Optimum plant population varies with date of planting
e) N-fixation experiments successfully completed, the results will be announced later