Temperature Variation Within and Between Rooting Media in Plant Growth Chambers¹

Abstract

Controlled environment chambers are commonly used to study influence of microclimatic variables on plant processes. An often neglected variable in these studies is temperature of the root zone. Diurnal temperature patterns of soil at 2 and 5 cm and sand at 5 cm in a cool regime (16.8C day/12.8C night) and of soil at 2 and 5 cm and nutrient solution in a warm regime (37.8C day/31.2C night) were measured. Root zone temperatures in the cool regime were higher than air temperatures during the day and cooler at night. Temperatures of the root zone in the warm regime were lower than air temperature during both day and night periods. These data call attention to diferences in root zone and air temperature which can occur during temperature controlled environmental studies.

A Study of Irrigation, Fertigation and Plasticulture in Burley Tobacco Production with a Focus on Yield, GRI and TSNA Concentration

“…The convective heating resulting from plastic mulch is expected to not only keep plant roots in optimal temperatures longer, but it is also expected to allow roots to avoid temperatures which are detrimental to development. Kneivel (1973) reported that root temperatures influenced nutrient availability, uptake, and significantly affected plant growth. An experiment by Osmond and Raper, comparing the importance of root zone temperature, ambient air temperature and soil nitrate concentration, from weeks 2-5 after transplanting, determined that temperature of the root zone had the greatest effect on plant growth.…”

Growth and Nitrogen Accumulation in Tobacco Plants as Affected by Nitrate Concentration, Root Temperature, and Aerial Temperature1

“…The resultant growth reflects the integration of the temperature effects on shoot and root. Further complications arise because root-zone temperature does not necessarily reflect shoot temperatures (6). Temperatures of the root-zone in a growth chamber may be either greater or less than aerial temperatures depending on whether aerial temperature is high or low.…”