ISHS Acta Horticulturae 449: II International Symposium on Irrigation of Horticultural Crops
DAILY STEM RADIUS VARIATIONS AS INDICATORS TO OPTIMISE OLIVE TREE IRRIGATION SCHEDULING |
| Author: | N. Michelakis |
| Keywords: | Stem contraction, stem growth, plant water stress, evaporation, atmosphere water potential, soil water availability, dendrometer |
| Abstract:
The suitability of daily stem radius changes as indicators to optimise irrigation scheduling was investigated in two cv. kalamon olive trees grown each in a cement, 2 m deep and 30 m2 surface area, lysimeter. The maximum Daily Stem Radius Contraction (DSRC), under the formed High (H) and Medium (M) Soil Water Availability (SWA) levels, was highly correlated to the corresponded maximum daily and monthly values of the Class “A” pan" Evaporation (Ep). The H and M treatments of SWA did not seem to affect notably the maximum DSRC. The rate of Daily Stem Radius Growth (DSRG), was affected strongly by SWA. It was increased rapidly after irrigation and declined as soil became drier taking zero or even negative values in extreme drier conditions. It can be inferred that the rate of the DSRG can be a reliable and useful biological indicator to determine the optimum irrigation time for olive tree. The DSRC may be an indicator for the soil water availability existing in the root zone, but attention is required, since small DSRC values may be occurred with either very high or very low soil water availability. Thus, DSRC alone could not be considered as a reliable indicator for olive tree irrigation scheduling. | |
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