IMPACT OF KAOLIN PARTICLE FILM ON LIGHT EXTINCTION COEFFICIENT AND RADIATION USE EFFICIENCY OF PISTACHIO (Pistachia vera)

Abstract

Kaolin application became a common treatment in orchards against different pests like psyllid. After kaolin application a thick powdery layer covers both sides of each leaf. It is a major concern that how much this layer affect light absorbance of leaves and net plant production, although light interception can be altered by changing spacing, tree height, tree shape and/or row orientation. In order to investigate the effect of kaolin spray on light extinction coefficient and radiation use efficiency of pistachio, an experiment conducted on a commercial orchard in khorasan razavi province. Three concentrations (0%, 3% and 6%) of processed Kaolin particle film sprayed on four varieties (Ohadi, Sepid, Kalehghoochi and Akbari) of pistachio as a liquid suspension, which evaporates, leaving white colour powdery film on the surfaces of leaves, stems and fruits. Treatments arranged in a randomized block design with 3 replications. Imaging softwares used to extract canopy structure and light transmission factor. In this case that we could not measure total plant production, only dried fruit production of each tree was used to estimate RUE (Radiation Use Efficiency). The results showed that kaolin film decreased single-leaf light absorbance and increased total light absorbance of pistachio tree. K, the Light extinction coefficient was not significantly different in different concentration of kaolin treatments.