Systematic comparisons of the effects of cultivation treatments on the growth and yield of soybeans have not been reported. We evaluated the effects of six cultivation treatments on yield, maturity, lodging, and height of four soybean [Glycine max. (L.) Merrill] varieties, (‘Hark,’ ‘Amsoy,’ ‘Hawkeye,’ and ‘Wayne’) in three environments. Treatments were combinations of 64- and 114-mm depths of a standard cultivator half-sweep spaced 152, 229, or 305 mm on each side of the row. We applied the treatments once at developmental stages 2, 4, or 6 and a double cultivation at stages 2 and 6.
Treatment response for yield varied with developmental stage and environment, but no significant treatment ✕ variety interaction was obtained. Low production or stress environments seemed to accentuate the yield loss associated with cultivation. For the average of environments none of the treatments was significantly different in yield than was the check at stages 2 and 4. At stage 6, cultivation 114 mm deep, 305 mm from the row was the only treatment that did not reduce yield. Cultivation 114 mm deep, 152 mm from the row, caused the greatest yield loss. For the 64-mm depth, similar yield reductions were obtained at all distances from the row.
Varietal differences were observed for response to cultivation. Wayne was more resistant to cultivation injury than the other varieties evaluated.
No cultivation effects of practical importance were obtained for maturity, lodging, or plant height.