EVALUATION OF MECHANICAL WEED MANAGEMENT PROGRAMS FOR CORN (ZEA-MAYS)

Eight cultivation programs with several equipment combinations were co mpared with each other and with an atrazine plus pendimethalin herbici de program with and without supplemental cultivation from 1992 to 1994 . In two of the three years, cultivation with a rotary hoe or tine wee der reduced weed seedling density by 39 to 74%. Tine weeding was more effective than rotary hoeing in 1992. Rotary hoeing or tine weeding re duced corn populations by an average of 6%. Weed control by different types of inter-row cultivators varied little, except that an in-row cu ltivator provided better control than a rolling cultivator in two-year s and better control than a shovel cultivator in one year. Weeds estab lishing from seeds were better controlled by herbicides in all three y ears, but weeds establishing from roots, rhizomes, and tubers were con trolled as well or better by cultivation. Weed control was sometimes b etter using herbicides plus cultivation than with herbicides alone, bu t the combination damaged the crop in two of the three years. Cost of mechanical treatments which combined inter-row cultivation with rotary hoeing or tine weeding differed from that for the herbicide treatment by less than 2%. Yields of the best mechanical treatment and the herb icide treatment were nearly equal in all years, but the best mechanica l regime varied between years. Consequently, mean net return was moder ately higher for the herbicide treatment.