Moisture distribution within a maize crop due to dew.

Abstract

During 16 nights in Sept. and Oct. 1986, the process of dew formation was studied within a crop of maize cv. Vivia. 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 temp. gradients of the topsoil, 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 av. for the experimental period, nearly 5% could be attributed to dewrise and 25% 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 min. and midday dew point temp. could be applied, or, if the soil was well-watered, the topsoil temp. gradient could be applied. (Abstract retrieved from CAB Abstracts by CABI’s permission)