Effects of Deficit Irrigation with Saline Water on Yield, Fruit Quality and Water Use Efficiency of Cantaloupe in an Arid Region

High groundwater salinity, a high water table and secondary soil salinization are dominant conditions in eastern Isfahan Province, Iran. This region has a low annual rainfall, high annual evaporation demand, saline soils and limited fresh water supplies. To investigate the effects of irrigation deficit and salinity on cantaloupe (Cucumis melo L. var. cantalupensis) production, a field experiment was performed at the Salinity and Drainage Research Station of Rudasht, ۶۵ km East of Isfahan. Irrigation treatments were T۶۵, T۸۰ and T۹۵ (irrigation after ۶۵, ۸۰ and ۹۵ percent of cumulative evaporation from Class A pan, respectively), each having three replicates. EC of irrigation water was ۵.۲۵ dS m-۱; irrigation water depth for the whole growing period was ۳۰۰, ۳۴۲ and ۳۸۴ mm, for T۶۵, T۸۰ and T۹۵ treatments, respectively. The results showed that T۶۵ and T۸۰ irrigation treatments significantly reduced fresh yield, number of fruit, fruit weight per plant and water use efficiency. Fresh-fruit yield was ۳۱.۷۳, ۳۸.۴۸ and ۵۴.۳۴ ton ha-۱, and water use efficiency was ۱۰.۵۸, ۱۱.۲۵ and ۱۴.۱۶ kg m-۳ in T۶۵, T۸۰ and T۹۵ irrigation treatments, respectively. A second order polynomial equation was fitted (R۲= ۰.۹۹) for production function (yield vs. irrigation water depth). The relationship between water use efficiency and irrigation water depth was also a second order polynomial equation (R۲= ۰.۹۷). Nitrogen and potassium content of fruits in T۶۵ treatment was higher than T۸۰ and T۹۵ treatments. Effect of irrigation regimes was not significant on P and Na content of fruits, but was significant on Cl- content (P< ۰.۰۵). Overall results showed that cantaloupe is a crop sensitive to soil moisture stress.