Cultivation During Early Season and Irrigation Influences on Corn Production1

Abstract

AbstractEarly season cultivation was shown previously by Cartee and Hanks to influence production of dry bean (Phaseolus vulgaris L.). Preliminary results indicated similar effects on sweet corn (Zea mays L.). Consequently, studies were conducted for another year with sweet corn and later expanded with field corn (Zea mays L.) to include irrigation and variety variables. The “coleoptile” cultivation (seedbed hilling just prior to coleoptile emergence) produced a statistically significant 29 to 40% increase in fresh ear yield in the sweet corn, compared to the “Control” (no cultivation) for 1971 and 1972, respectively. “Coleoptile” cultivation increased yields of dry matter for field corn 6% over the control treatment which was significant at the 0.05 level, but did not affect grain yields. The “blind” cultivation treatment (seedbed hilling at planting time) produced no significant differences in dry matter or grain yields for the field corn. “Blind” cultivation was not used in the sweet corn trial. Ear yields of sweet corn on the “normal” treatment (seedbed hilling when plants are 20 to 25 cm high) were significantly greater than the “control” by 12 to 20% in 1971 and 1972; however, the yields of dry matter and grain of field corn were not significantly greater than the control.An interaction of cultivation and irrigation on dry matter (but not grain) yields of field corn was indicated. Yields tended to be higher for the “coleoptile,” “blind,” and “normal” cultivation compared to the control, only where mild water stress occurred. The effect of cultivation was not evident for the extremely dry or extremely wet irrigation levels.A very high positive correlation (r > 0.95) between evapotranspiration (ET) and yield was obtained during both years of the field corn trial. The relation of relative yields vs. ET was similar for all varieties. Thus, an early cultivation in irrigated sweet corn should result in substantial yield increases. In irrigated field corn, moderate dry matter but little grain yield increases should result from early cultivation. Yield increases due to cultivation appear to be more probable under moderate water stress.