Evaluation of number and frequency of irrigation on establishment and forage production of Acacia salicina Lindl in climatic conditions of Semnan province

Acacia salicina Lindl is native to Australia. Features such as high forage production, as well as abundant flower production have made this evergreen species a valuable and versatile plant for planting on the edge of agricultural lands. This study was performed with three treatments to study and determine the amount of irrigation on the establishment and growth of this species in Semnan province with three replications in a randomized complete block design at Semnan Natural Resources Research Station. Fourteen acacia seedlings were planted in each replicate. In the third year, the percentage of survival and fresh weight (aerial biomass) of trees were recorded. The results showed that the highest weight growth (6271 g per rootstock) was related to treatment 3 (weekly irrigation), showing about a five-time increase compared to the control treatment (1223 g per rootstock). Treatment 2 (every two weeks irrigation) with 2569 g per base was in the next place. Also, biomass production in treatment 3 (weekly irrigation) was estimated at 62 tons per hectare. The leaf dry matter was 44%, therefor dry (aerial) forage in treatment 3 (weekly irrigation) was 26772 kg/ha, and in treatment 2 (biweekly irrigation) was estimated at 10967 kg/ha. The results also showed that the survival rate of treatment 3 (weekly irrigation) was 63%, treatment 2 (every two weeks) was 50.5%, and treatment 1 (control) was 15%. The survival rate of weekly, once every two weeks, and control (without irrigation) were 63%, 50.5%, and 15%, respectively. According to the results, if water consumption is not limited, treatment 2 (every two weeks irrigation) was proposed to produce forage of this species.