Study of Aloysia citrodora Growth as an Ornamental-Medicinal Plant in Substrates Containing Natural and Synthetic Superabsorbents

In this study, we investigated the effects of organic waste and moisture superabsorbent on the amount of available water and delay in moisture equivalent of permanent wilting point (PWP) in soil. In the first phase (soil incubation phase), 12 treatments were studied in a completely randomized design at the Soil Science Laboratory of Science and Research Branch, Tehran. The treatments consisted of 5 and 10% compost (mixture of municipale waste compost and cow manure); 5, 15 and 30 g/kg soil of zeolite and 2, 4 and 8 g/kg soil of moisture superabsorbents (A200). In the second phase (greenhouse phase), three treatments with the highest delay in permanent wilting point with a control treatment were selected as planting media and in a factorial experiment based on randomized complete block design, we studied the effect of planting substrate (four substrates) and irrigation period at three levels (48, 72 and 120 hours) on Aloysia citrodora growth. The results showed that the highest amount of FC moisture equivalent was related to the treatment with 8 g superabsorbent per kg soil. The highest delay in the permanent wilting point was for 8 g superabsorbent per kg of soil with a delay of 682 h. The highest total fresh weight of plant was observed in the treatment of 10 g of zeolite per kg of soil and 48 hours irrigation round with a mean of 9.47 g. In the superabsorbent treatment, leaf dry weight was higher than the control in 3 irrigation rounds. In general, the results showed that the addition of superabsorbent to the soil by delaying the plant’s wilting point could save water use by increasing irrigation rounds.