Abstract
Irrigation experiments on evergreen sedum of Kirinsou were conducted on sloped bed soil in glasshouse. The study was done during summer time. The result can be concluded as follow: 1) Evapotranspiration ratio of Kirinsou was decreasing after irrigation with lapsed day and pF values of the end of the irrigation intervals where ranging between 4.2 to 6.0. However, this ratio increased again at the beginning of each irrigation and Kirinsou plant recovered to the normal growth. 2) Cumulative value of evapotranspiration ratios with square root of elapsed time are forming a good fi t of quadratic curve with correlation coefficient of more than 0.99. 3) Evapotranspiration was affected negatively with soil pF value in which this relationship was passing through three different phases. In first phase, the evapotranspiration was influenced by LAI. In second phase, the evapotranspiration decreased shapely. Whereas, in the third phase, the evapotranspiration was decreasing gradually and gave values of less than 0.1. 4) The stress periods, when soil pF values were over than starting point of the third phase, were correlated negatively with dry shoot weight and LAI of Kirinsou. It suggests that the point of depletion for moisture content of normal growth in Kirinsou is pF4.2.
