Day-Night Temperature Effects on Leaf Expansion and Height of Field-Grown Corn
- G. R. Benoit ,
- A. Olness and
- K. A. Van Sickle
The effect of constant day/night, average daily, or instantaneous temperatures on plant growth has been extensively documented. Little work has looked at how plant growth under field conditions may be influenced by variations in the day/night temperature combinations experienced. Our objective was to evaluate the effect of day/ night temperature differences on daily corn (Zea mays L.) growth. To accomplish this, corn was grown with and without irrigation (four replications of three planting dates in 1983, 1984, and 1985) on a Hamerly clay (Aerie calciaquoll, fine-loamy, frigid) at Morris, MN. Hourly soil and air temperature, weekly profile soil water content, and daily precipitation were recorded. Leaf area and plant height were measured daily from eighth leaf to 100% silking. Only plant size data from consecutive days of complete measurements were used with daily maximum and minimum temperatures to establish temperature-growth rate relations. Leaf area and plant height prediction equations developed from stepwise multiple regression techniques were used to construct percent growth (leaf area and plant height) vs. maximum and minimum temperature response surfaces. Equations were developed for all possible combinations of planting date and irrigation level for each year and all years combined. Combined data showed general relations representative of those shown by individual data sets between percent growth and temperature. Plant height and leaf area predictive equations for combined data have highly significant r2 values of 0.72 and 0.54, respectively. The data shows that percent increase in plant size decreases over time as size at the start of any 24-h-growth period increases and that each daily maximum temperature has a successive apparent optimum night temperature for growth.
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