Stand, yield, weed biomass, and surface residue cover comparisons between three cropping/tillage systems on a well-drained silt loam soil in Ohio, USA

Systems research is a departure from traditional, controlled factor experiments. Whole system experiments provide information about interactions that affect the success of the system. The objectives of this study were to compare corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] productivity, surface residue cover after planting, corn plant establishment, and weed biomass under three cropping/tillage systems. The systems were continuous corn (C/C) (chisel plowed), corn/soybean (C/S) rotation (no-tillage for corn/chisel plowed for soybeans), and corn/soybean/wheat (Triticum aestivium L.) (C/S/W) rotation (ridge tillage). All phases of each rotation were established in triplicate on 0.4 ha plots on a Huntington silt loam (fine-silty, mixed, mesic fluventic Hapludoll) soil at Piketon, Ohio, USA. The study was conducted for 5 years, from 1991-1995. No differences in yields between systems were detected, except for the first year soybeans on ridges. The 5-year average corn yield was 7815 kg ha^-1, which was 315 kg ha^-1 above the historical regional average. The 5-year average soybean yield was 2969 kg ha^-1, which was 269 kg ha^-1 above the historical regional average. The no-till corn (C/S) had significantly higher residue cover (average of 44.4%) at planting than the other two systems (average of 21.1% for C/C and 33.2% for C/S/W), however all systems had surface residue cover ≤ 30% in at least half of the years studied. In the soybean phases the average surface residue was 23.8% in the C/S treatment and 35.8% in the C/S/W treatment. Differences in plant emergence were only detected in 1995 for corn, with the C/C treatment having the highest plant establishment ratio (95.7%). The C/S corn plant establishment was 83% and C/S/W was the lowest at 60%. Note that this difference in stand did not result in a detectable difference in yield. No differences between systems were detected for early season and end of season weed biomasses. Based on 5 years of field data, any of the three cropping/tillage systems can be adopted on a well-drained silt loam soil without yield reductions in corn or soybean.