Diffusion pressure deficit measurements as a means of timing irrigation for tomatoes

Abstract

The diffusion pressure deficit (D.P.D.) of leaves of tomato plants was measured in three groups of plants by Shardakov's dye settling method to show the effects of three different spacings of irrigations on their values. The change in D.P.D. as irrigation was delayed was not sufficient to distinguish between different irrigation treatments although the difference in D.P.D. between frequently and infrequently watered plants did increase significantly during this time. The diurnal range in D.P.D. was correlated with the evaporation conditions during that day.