A lot depends on the moisture you receive during the growing year.   It definitely needs more rain to grow that first crop.   In our area of ND we've always gotten 2/3 to 3/4 of what my other soybean fields yielded that first year and I've been pretty lucky that it was usually a wet summer.   I've never tried corn, and it was direct planting of the beans into land that was hayed the previous year and burned down.    After the first year yields always improved.