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 m1 and fresh water: ec=0.51 ds m1) 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 (r2 = 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 tha1 by surface drip irrigation with recycled waste water and the lowest was 41.4 t ha^-1 by furrow irrigation with fresh water.