Effect of controlled irrigation on physiological and biometric characteristics in teak (Tectona grandis) seedlings

Abstract

Effect of controlled irrigation in physiological and biometric characteristics in teak seedlings is monitored at Forestry College in Kerala, India. Six month old seedlings of Teak (Tectona grandis L. f.) were raised in polybags. Irrigation was done once in a week. Daily evapotranspiration was calculated and treatments IW/ET=1, IW/ET=0.6, IW/ET=0.3 were irrigated with 100, 60 and 30 per cent of cumulative evapotranspiration. A control without irrigation (IW/ET=0) was also maintained. Physiological as well as biometric observations were carried out at regular intervals. Canopy air temperature difference (CATD) was measured using a hand held infrared thermometer and it was observed that seedlings from well watered treatments (IW/ET=1 and 0.6) showed negative CATD whereas treatments IW/ET=0.3 and IW/ET=0 showed positive CATD throughout the growing period. Seedlings in the treatment IW/ET= 0 and 0.3 showed a significant reduction in relative chlorophyll content, seedling height, collar diameter, number of leaves, total dry weight and relative growth rate whereas in IW/ET=1 and 0.6 these parameters were higher and there was no significant difference observed between these two well watered treatment. In the case of root shoot length ratio and root shoot biomass ratio IW/ET=0 was superior over other three treatments.

Keywords

• water stress
• Tectona grandis
• physiological characteristics
• biometric characteristics