Relationships of field traffic and tillage to corn yields and soil properties

Esperiements were conducted during the summer of 1979 in which field plots oon s Ste. Rosalie clay soil and a Ste. Amable sandy loam soil were subjected to different levels of compaction by machinery, and subsequently treated by moldboard plowing and discing, chiselling and subsoiling by a winged tool. A silage corn crop was grown on all plots and measurements were made of soil bulk densities, penetration resistance of soils and plant yields. The results indicated that the compaction of the soil, if not subsequently loosened by a tillage operation, caused a marked reduction in plant yields. A nnarrow range of dry bulk density produced the optimum silage corn yields in the two experimental soils. The soil densities in this range were obtained by any of the three tillage treatments, as well as by the rototiller treatment, without machinery traffic.