Alireza Samadzadeh - Department of Agronomy and Plant Breeding, Faculty of Agriculture, University of Birjand, Birjand, Iran
Hamid Reza Fallahi - Department of Agronomy and Plant Breeding, Faculty of Agriculture, University of Birjand, Birjand, Iran
Gholamreza Zamani - Department of Agronomy and Plant Breeding, Faculty of Agriculture, University of Birjand, Birjand, Iran
Shahram Nakhaie - Seed Science and Technology Group, Department of Agronomy and Plant Breeding, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
Mahsa Aghhavani-Shajari - Department of Agronomy, Ferdowsi University of Mashhad, Mashhad, Iran
Amin Amirizadeh - Department of Agronomy and Plant Breeding, Faculty of Agriculture, University of Birjand, Birjand, Iran

Two field and laboratory experiments were conducted to investigate the effects of superabsorbent polymer (SAP) and irrigation management on seed and essential oil yields of Cumin, as well as the impact of water quality on water holding capacity of SAP. Salinity had a negative effect on the amount of water absorbed by SAP (۳۳۵ and ۵۹ g H۲O per g SAP, for distilled water and solution of ۰.۵% NaCl, respectively). SAP application (۳۰ kg.ha-۱) along with three times irrigation at sowing, flowering and seed filling stages increased the amounts of seed and essential oil yields by ۲.۷۹ and ۳.۰۵ times, compared to control. Positive effects of SAP were related to enhancement of soil water holding capacity (۱۲۰ gr irrigation water per gr SAP), leaf area duration (one week) and subsequently grain filling period.

Deficit Irrigation, Leaf area duration, Medicinal plants, Secondary metabolites