Effect of Thinning on Stand, Yield, and Plant Height in Maize1

Abstract

We conducted experiments at two locations for 4 years to determine the effect of thinning on stand, yield, and plant and ear height of maize (Zea mays L.). We included a control (no thinning) and over‐planting and thinning at three stages of plant development (2 to 3, 5 to 8, and 9 to 11 leaf‐stages) in all experiments. Average stand improvement was 8% over the control regardless of the stage of thinning. Thinning at the 5 to 8 and 9 to 11 leaf‐stages resulted in significantly lower yields than thinning at the ''. to 3 leaf stage. Yields of the control plots were not significantly different from the yields obtained on the plots thinned at the 5 o 8 leaf‐stage, the latter having 8% higher stands. Plant and ear height also decreased with the later stages of thinning. The experiments showed that over‐planting and thinning was justified for improving stands, but that thinning at different sages did affect yield of grain significantly.