Irrigation Volume and the Number of Emitters per Pot Affect Root Growth and Saline Ion Contents in Weeping Fig

Our knowledge of design and management aspects of irrigation needs to be improved in regions where the availability of good quality water supply is limited. This contribution describes how potted weeping figs were grown in a greenhouse with one, two, or four emitters (1.2 L•h-1) per pot and irrigated with water of 3 dS•m-1 and two irrigation volumes (control or high). The aim was to determine the effect of the number of emitters, irrigation volume, and their interaction on plant growth, water application efficiency and the concentration of saline ions in plants. The horizontal distribution of roots and the concentrations of root saline ions were determined in four quadrants (south, west, north, and east) in the substrate. In the case of the control irrigation volume, the use of four emitters per pot reduced the total of water applied compared with the use of one or two. Irrigation volume increased the leaching fraction, while the number of emitters per pot reduced it. Increasing the number of emitters per pot or/and irrigation volume increased the shoot/root ratio. With the two irrigation volumes applied, the use of one emitter led to a heterogeneous horizontal distribution of roots. The same was true for the saline ion content of the roots. Both behaviors were attenuated as the number of emitters per pot increased. Weeping fig accumulated higher a concentration of chloride than sodium. In relative terms, roots retained about 95% of the sodium and about 76% of the chloride in plants. The data suggest that both irrigation volume and the numbers of emitters per pot should be considered together when developing a water management strategy for container-grown plants.