Moisture distribution within a maize crop due to dew

Abstract

With the Bowen ratio energy balance technique the total dewfall from above the canopy was measured. By estimating the soil characteristics and measuring the soil moisture and temperature gradients of the top soil, an assessment of the dewrise from the soil could be made. To estimate the distribution of free water within the crop, the liquid water profile was measured with Leick plates at 5 levels. Dewfall proved to contribute most to the total dew deposition. As an average for the experimental period, nearly 5% could be attributed to dewrise and 95% could be attributed to dewfall. On the 10 occasions, the total amount of dew ranged between 0.01 and 0.41 mm per night. To obtain a simple but rough indication for the amount of dew, the difference between the minimum and midday dew point temperature could be applied, or, if the soil was well-watered, the top soil temperature gradient could be applied. -from Authors