Evapotranspiration, irrigation water applied, and vegetative growth relations of young apricot trees under different irrigation regimes

Abstract

This study was carried out between 2004 and 2008 to investigate effects of different irrigation regimes on crop 
water use and vegetative growth of drip-irrigated young apricot trees. Six different irrigation treatments were 
used: five of which (S1, S2, S3, S4, and S5) were based on adjustment coefficients of Class A pan evaporation 
(0.50, 0.75, 1.00, 1.25, and 1.50). The other treatment (S6) was regulated deficit irrigation treatment that was 
irrigated by applying 100% of Class A pan evaporation until harvest, but not irrigated after harvest in all the 
years of study. The greatest irrigation water and evapotranspiration values were observed in the S5 treatment 
while the smallest values were observed in the S6 treatment. A linear relationship was found between 
irrigation water applied and evapotranspiration in the experimental years (R2 = 1.00). Both the crown diameter 
and trunk diameter values showed statistically significant differences among treatments in the experimental 
years. The S5 and S4 treatments showed the highest crown and trunk diameter values, while the lowest crown 
and trunk diameter values were found for the S1 in 2004, 2005 and 2006, and for the S6 treatment in 2007 and 
2008. Furthermore, it was found that there was a positive polynomial relationship between both the crown 
diameter and trunk diameter and evapotranspiration (R2 = 0.89 and 0.96). When considering irrigation 
treatments and vegetative growth parameters as a whole, the best developments were obtained at S5 and S4. 
However, taken into consideration relationships between tree development and evapotranspiration, the S4 
treatment has been more productive.