Water scarcity is an important obstacle to the development and expansion of the urban landscape in the arid and semi-arid regions of the world. Nowadays, organic and artificial materials can be used to reduce water consumption without impairing the quality and quantity of urban landscape. In order to study the effect of mulch type on reducing irrigation interval for a popular seasonal plant in the Middle East, African marigold, an experiment was carried out in Mashhad, Iran during 2016-2017 in which two treatments were applied including mulch type (typical soil as control, palm fiber mulch, plastic mulch, and superabsorbent) and irrigation intervals (3, 6 and 9 days). Some morphological, biological, physiological and biochemical traits were evaluated. Results indicated that the superabsorbent could significantly increase most recorded traits. The palm fiber mulch also improved plant height, flower number, and dry shoot weight. In most traits, the 3-day irrigation interval indicated a significant increase versus the 6- and 9-day intervals, but plant height, flower number, and photosynthetic rate did not differ significantly between the 3-day and 9-day irrigation intervals. The findings show that superabsorbent and at the next level, palm fiber mulch with 9-day irrigation intervals can be suggested for African marigold in the arid and semi-arid climates.

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