Response of young fig (Ficus carica cv. Sarılop) trees to different irrigation levels in a semi-arid mediterranean environment

Abstract

Drought scenarios that will be faced in the near future in the Mediterranean Basin will affect sustainable crop production in the region. Even the drought tolerant crops under rain-fed conditions will need supplemental irrigation. The fig tree originates from this region and is grown under semi-arid conditions as a drought-prone crop. The aim of this research is to develop irrigation strategies under various irrigation levels in young fig trees. Five irrigation levels were investigated, covering the rainfed treatment (S0), as well as the fully irrigated treatment S4 (100%) and the S1 (25%), S2 (50%) and S3 (75%) treatments of the full irrigation level. The vegetative growth parameters including plant height, stem diameter, shoot length and number of leaves were evaluated in a two-year field experiment. Additionally, stem water poten - tial (SWP), leaf area index (LAI) and proline content (PC) were also measured. The average seasonal water use values (ET) of young trees ranged from 25.5 to 472.2 mm. Plant vegetative growth parameters were significantly affected by irrigation levels and higher growth was observed in the S3 (75%) and S4 (100%) treatments. Plant physiological responses to different irrigation levels have a significant impact on SWP, LAI and PC measurements. In conclusion, S3 treatment (75% irrigation level) appears to be a good alternative to fully irrigated treatment for growing young fig trees under water-scarce conditions in western Turkey. SWP could be used as a tool in irrigation scheduling of young fig trees. Mean SWP values between -0.82 and -0.86 MPa can be accepted as threshold value for semi-arid regions.