Measurement of Temperature and Humidity in Tobacco Plots in Rhodesia

Small nickel resistance thermometers were tested in variousanti-radiation screens over bare sandy soil in Southern Rhodesia.Satisfactory results were obtained only when the thermometerswere aspirated in small chromed metal shields, based on thedesign of the Mark 3 Assmann psychrometer. The aspirated unitswere compared with an Assmann, at various heights within tobaccoplots during a range of whether conditions, and grave satisfactoryresults when used for continuous periods of several months.Some results are presented illustrating the vertical distributionof temperature and humidity within tobacco plots at differentstages of growth. When plants were small, temperature and humiditygradients appeared to be similar to those that might be expectedover open ground. Later the pattern resembled that of a cropof medium ground cover and density.