Effect of irrigation and Super-absorbent hydrogels on morphological characteristics, yield and essential oil of anise (Pimpinella anisum L.)

Anise (Pimpinella anisum L.) is an annual medicinal plant which belonged to the Apiaaceace family. Grain is the most important organ to produce essential oil of anise. In order to produce medicinal plant it is necessary to determine the environmental factors under which they give higher yields and better quality (23). In medicinal plants, balanced fertilization using chemical and biological inputs has great effect on yield and phytochemicals related to yield production. Management practices and the use of advanced techniques for improvement in soil water-holding capacity are essential. Therefore the pot experiment was conducted to evaluate the effect of different levels of irrigation and superabsorbent hydrogel on morphological characteristics, yield and essential oil of anise.
The experiments were designed as RCBD under factorial plot arrangement with three factors in the Golestan province on 2013. The first factor included four irrigation levels (FC, 80%FC, 60%FC and 40%FC) and the second factor included three superabsorbent levels (0, 100 and 200 kg/ha) on growth parameters of anise plant. The soil was Silty clay loam in texture and its chemical characteristics of the soil were EC; 0.91, pH; 8.1, %O.M; 1.04, %TNV; 17.70, B.D; 1.5, %F.C; 27.3, %N; 0.073, P2O5; 4.2 and some soluble cations were 200, 1, 0.5, 0.6, 0.5 meq L-1 for the K , Fe2, Mn2, Zn2 and Cu2 respectively. Plant height, number of umbels, umbellets, harvest index, one thousand seed weight and plant yield were measured. After planting and harvesting operations and growth performance measurements, essential oil was dehydrated by distilled water method using Clevenger and Sodium sulfate.
The analysis of variance showed that there was significant effect of levels of irrigation and superabsorbent on all studied characteristics of anise. The interaction effects on all traits except harvest index had a significant impact. The highest plant height, number of umbels per plant, the number of umbellets, seed number, seed weight, seed yield, oil percentage in treatment with 100 kg/ha Super-absorbent hydrogel Field capacity (FC) was statistically significantly with irrigation surface Fc 80% and 100 kg/ha were Super-absorbent hydrogel. There was no significant interaction between treatments on yield, but the effect of irrigation levels at 1% and 5% level of superabsorbent polymer showed a significant effect on yield.
The results of this test introduced the treatment, 80% of field capacity and 100kg of superabsorbent hydrogel as the best treatment in terms of economy because with lower consumption of water and polymer.