Author(s)

Y. Périard, J. Caron, S. Jutras, J. A. Lafond & A. Houlliot

Abstract

Lettuce is an important crop in Canada, mainly grown in South West Quebec muck soils. Lettuce is sensitive to water stress during periods of high crop water requirements, which result in important yields decrease mainly due to tip burn. This physiological disorder can be controlled by adequate irrigation, which is affected by spatial distribution patterns of water needs at different field scales. Such patterns result from spatial variability of soil properties and water drainage, and from evapotranspirative processes affecting local crop water needs at a given time. This study aimed at evaluating irrigation management performances (water and energy consumption, leaching and yield) for Romaine lettuce in a Histosol at two spatial scales, local and global (0.5 and 7 ha). Three field experiments were performed during summers 2010 and 2011 at two sites of 7 ha presenting a high spatial variability in available water (AW). The set up was divided into three zones equipped with wireless tensiometers. The critical irrigation threshold for initiating irrigation was −30 kPa for a low (< 4mm) potential evapotranspirative (ET) demand and −15 kPa for a higher ET (> 4 mm) [1]. Results indicated that local irrigation management has resulted in marketable yield increase of 16.5 to 18.2% depending on years, but resulted in 21.2 to 23.6% more water (and consequently energy) use with respect to global management. Higher frequency

Keywords

precision irrigation, available water, Romaine lettuce