The effect of different super absorbent polymer and animal manure ratios on some morphological characteristics and production of fennel essential oil under drought stress conditions

In order to evaluate the effect of manure and super absorbent polymer on some morphological characteristics and fennel essential oil production under drought stress conditions, an experiment was conducted as spilt-plot in a randomized complete block design with three replications in 2015 at Shahrekord University. The main factor was different levels of drought stress including three levels: control (50 mm), moderate stress (100 mm) and severe stress (150 mm) evaporation from class A pan and sub-factor was considered different animal manure and super absorbent polymer ratios in six levels including: (D1: lack of manure and super absorbent polymer, D2: 25 percent manure percent super absorbent polymer, D3: 50 percent manure percent super absorbent polymer, D4: 75 percent manure percent super absorbent polymer, D5: 100 percent manure and D6: 100 percent super absorbent polymer). The results showed that the maximum number of umbel, grain yield, harvest index and essential oil yield from control treatment and D6, the maximum number of lateral branch, floret and plant dry weight from control treatment and D4 and the maximum thousand seed weight and plant fresh weight, from control treatment and D3 and D2 were obtained, respectively. The maximum essential oil percentage was obtained from severe stress and D5 treatment. The maximum plant height and number of main branch were achieved from D6 and D4 treatments and under control conditions, respectively. In conclusion, the super absorbent polymer meanwhile reducing the effects of drought stress caused increasing in fennel grain yield, harvest index and essential oil yield.