**Pinnara Ket 1,2,\* ID , Sarah Garré 3, Chantha Oeurng 1, Lyda Hok <sup>4</sup> and Aurore Degré <sup>2</sup> ID**


Received: 19 March 2018; Accepted: 16 May 2018; Published: 21 May 2018

**Abstract:** Setting up water-saving irrigation strategies is a major challenge farmers face, in order to adapt to climate change and to improve water-use efficiency in crop productions. Currently, the production of vegetables, such as lettuce, poses a greater challenge in managing effective water irrigation, due to their sensitivity to water shortage. Crop growth models, such as AquaCrop, play an important role in exploring and providing effective irrigation strategies under various environmental conditions. The objectives of this study were (i) to parameterise the AquaCrop model for lettuce (*Lactuca sativa* var. *crispa L.*) using data from farmers' fields in Cambodia, and (ii) to assess the impact of two distinct full and deficit irrigation scenarios in silico, using AquaCrop, under two contrasting soil types in the Cambodian climate. Field observations of biomass and canopy cover during the growing season of 2017 were used to adjust the crop growth parameters of the model. The results confirmed the ability of AquaCrop to correctly simulate lettuce growth. The irrigation scenario analysis suggested that deficit irrigation is a "silver bullet" water saving strategy that can save 20–60% of water compared to full irrigation scenarios in the conditions of this study.

**Keywords:** crop growth; lettuce; AquaCrop; water saving; water productivity; deficit irrigation
