Monitoring sugar beet rooting depth irrigated with recycled waste water and different irrigation methods for water savings in an arid climate

A detailed understanding of crop rooting systems will facilitate water use reduction, optimized nutrient uptake and irrigation scheduling more efficiently. A field experiment was conducted during 2005-2006 to investigate sugar beet rooting depth growth, irrigated with three irrigation methods (subsurface drip, surface drip and furrow) and two water qualities (recycled wastewater: EC= 1.52 dS m -1 and fresh water: EC=0.51 dS m -1 ) in order to improve irrigation water management. A local rooting depth model was developed and three empirical models describing the root growth were evaluated. A significant reduction in sugar beet root depth was observed in the plots irrigated with furrows compared to those irrigated with the pressure irrigation methods. However, no significant difference (p<0.05) in root depth was observed for the crops irrigated with recycled wastewater and fresh water. A good correlation (R 2 = 0.99) between root depth and time was observed. The results also showed that using a locally developed rooting depth model to predict the soil water depletion may lead to water savings of between 20% and 34% when compared to the empirical models developed in other regions. The highest root yield obtained was 80 t ha -1 by surface drip irrigation with recycled waste water and the lowest was 41.4 t ha -1