Rye biomass of 5200 kg ha−1 reduced Palmer amaranth emergence by 50%.
Rye biomass of 5370 kg ha−1 reduced light at the soil surface by 50%.
Maximum spring rye biomass occurred when it was planted prior to the middle of November.
50% reduction in spring rye biomass when rye was planted in the middle of December.
Increasing the rye seeding rate did not overcome delays in planting.
Nitrogen increased rye biomass 23–33%, when averaged over all planting dates.