THE EFFECT OF DIFFERENT IRRIGATION RATES ON KIWIFRUIT GROWTH AND CROPPING
Irrigation experiments using micro-sprinklers were carried out to determine the effects of water status on fruit development and crop load. Three irrigation treatments of 36, 63 and 100% evapotranspiration (ET) were applied in young kiwifruit vines, using a dry treatment as a control. Pre-dawn leaf water potentials (LWP's) were used as the index of water stress, using a pressure chamber. Volumes of labeled fruit were measured by water displacement in a graduated cylinder. Fruit development was directly related to water availability. There were significant differences (p<0.05) among the rates applied in the LWP's and in the fruit volumes, since the sixth week after full bloom. However, there were not significant differences (p<0.05) between the dry and the 36% ET rates. Pre-dawn LWP from water stressed vines was <-0.1 MPa, whereas the 100% ET irrigated vines was -0.02 MPa. These vines gave higher yield and fruit size. According to these results and the climatology of Asturias, it is recommended to irrigate with the 100% ET. Special care must be taken concerning the water requirements in the period beginning six weeks after full bloom, in order to optimise the final fruit size.
Ciordia, M., Díaz, M.B., Coque, M. and Gómez Aparisi, J. (1993). THE EFFECT OF DIFFERENT IRRIGATION RATES ON KIWIFRUIT GROWTH AND CROPPING. Acta Hortic. 335, 235-240
Kiwifruit, irrigation, leaf water potential (LWP), crop load, fruit weight