Modelling sustainable salt water management under deficit irrigation conditions for melon in Spain and Brazil

BACKGROUND In water scarcity areas the use of saline water for irrigation is a common practice. In this study, experimental data from two two‐year melon tests were collected for the calibration (2004 ‘Yellow Melon’ (YeMe) type) and validation (2002 YeMe, 2005 and 2006 ‘Piel de Sapo’ (PiSa) type) processes in melon crop simulation under deficit irrigation conditions using salt water. The simulations were carried out for Castilla‐La Mancha (Spain) and Ceará (Brazil) using the MOPECO model, which includes optimized regulated deficit irrigation (ORDI) methodology. The objective was to determine the most suitable irrigation strategy for both areas. RESULTS Under fresh water conditions, ORDI may increase yield by up to 20% (PiSa) and 7% (YeMe) compared with constant deficit irrigation. Higher water deficit should be induced during the vegetative development and ripening stages. The rainfall between irrigation periods is able to leach the salts supplied by the irrigation water. CONCLUSION The combination of ORDI with different strategies for managing saline water may increase water use efficiency. In these areas it may be of interest not to apply the leaching fraction (saving up to 67% of irrigation water). However, leaching of the soluble salts accumulated before starting the most sensitive periods may be suitable. © 2014 Society of Chemical Industry