Effects of Alternating Versus Constant Soil Temperatures on Maize Seedling Growth
Walker, John M.
The responses of maize seedlings (Zea mays, L.), which were grown with soil temperatures alternating ± 3C about 20, 23, and 26C means and also at equivalent constant soil temperatures, were compared. Soil temperatures were alternated about the means diurnally in synchronization with 12-hour light and dark periods. Both the alternating and constant soil temperature treatments were applied when seedlings were 7 days old and were maintained for 16 days in a uniform aerial environment (25C air temperature). Alternating soil temperatures about 23 and 26C means yielded more growth than was obtained at the equivalent constant soil temperature. These alternating soil temperature response data could be explained by relating the light, dark, and mean soil temperatures to the optimum constant soil temperatures for growth (leaf length growth was optimum at 20 to 23C, dry weight growth at 23C, and stem growth at 26C). Apparently, soil temperature most strongly influences growth during the light period (daytime) when a plant is photosynthesizing.Show more [+] Less [-]