Mohammad Ali Shahrokhnia and Hamid Zare
Agricultural Engineering Research Department, Fars Agricultural and Natural Resources Research and Education
Center, Agricultural Research, Education and Extension Organization (AREEO), Shiraz, P. O. Box : 71555-617,
Iran
*(e-mail : mashahrokh@yahoo.com; Mobile : + 98 9177109159)
(Received : January 19, 2021; Accepted : March 16, 2021)
ABSTRACT
Rainfed fig growers in Estahban plains, Iran, apply supplementary water without following an appropriate method for irrigation scheduling. To reduce the effects of drought stress on rainfed fig trees and also save water, different timing of irrigation was investigated using the empirical Crop Water Stress Index (CWSI). The experimental treatments were defined as applying irrigation at different levels of CWSI including 0.0, 0.2, 0.4, 0.6 and 0.8. The experiment was designed as randomized complete block with four replications. Results indicated that fig trees reached the maximum CWSI of 0.6 that occurred in late July. As the number of irrigation practices increased, the tree fruit yield increased from 3.1 to 9.8 kg per tree. However, water productivity decreased from
1.73 kg/m3 in the rainfed treatment to 0.60 kg/m3 in the full irrigation treatment. The maximum water productivity of 2.16 kg/m3 was achieved at CWSI = 0.6 where it was irrigated only once during the season. Therefore, only one irrigation at the end of July would be enough to preserve rainfed fig
trees from severe drought damage.
Key words : : Rainfall, soil moisture, water productivity, Estahban