Effect of Early Defoliation on Maize Growth and Yield: an Eleven-year Perspective
- R. Kent Crookston and
- Dale R. Hicks
We previously reported that grain yield of the maize (Zea mays L.) hybrid ‘Trojan TXS 85’ was increased following 100% defoliation at the five-leaf stage. The objective of this study was to extend those observations and to examine the relationship between early defoliation, soil-water use, and yield. Eight additional years of defoliation trials (plants 100% defoliated at the five-leaf stage) were conducted in the field with Trojan TXS 85. The soils at the two experimental sites are a Webster clay loam (Typic Haplaquoll) and a Nicollet clay loam (Aquic Hapludoll). Defoliation decreased grain yield 3 of the 8 additional yr, and had a nonsignificant (negative) effect the remaining 5 yr. Positive yield response to defoliation was associated with low yields and with low end-of-season available soil water. It thus appears that an early reduction in vegetative growth of maize might help avoid drought stress in regions where late-season water stress is common. Early defoliation does not appear to be a practical management approach in high-yielding environments, such as the upper Midwest, where soil-water deficits are infrequent and unpredictable.
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