Using deficit irrigation with treated wastewater to improve crop water productivity of sweet corn, chickpea, faba bean and quinoa

Plusieurs essais ont ete conduits dans le sud du Maroc (IAV-CHA, Agadir) durant deux saisons 2010 et 2011 dont le but d’evaluer l’effet de l’irrigation deficitaire par les eaux usees traitees sur plusieurs cultures (quinoa, mais doux, feve et pois chiche). Durant la premiere saison (2010) trois cultures ont ete testees, quinoa, mais doux et pois chiche en appliquant 6 traitements d’irrigation deficitaire durant tout les stades culturaux en alternant 100% d’ETm comme condition de confort hydrique et 50% d’ETm comme conditions de stress durant le stade de croissance vegetative, floraison et remplissage des grains. Pour toutes les cultures, le rendement et la productivite d’eau les plus eleves ont ete obtenus lorsque l’irrigation deficitaire a ete appliquee durant le stade de croissance vegetative. Pendant la deuxieme saison (2011) deux lignes du quinoa, la feve et le mais doux ont ete cultivees en adoptant 6 traitements d’irrigation deficitaire (bour, 0, 25, 50, 75 et 100 d’ETm) appliques juste pendant le stade de croissance vegetative, tandis que durant le reste du cycle cultural les cultures ont recues une irrigation complete sauf pour le traitement bour. Pour le quinoa et la feve, appliquant 50% d’ETm durant le stade vegetatif a permis d’obtenir le rendement et la productivite d’eau les plus eleves, tandis que pour le mais doux le traitement optimal qui a enregistre le rendement et la productivite d’eau les plus eleves est celui qui a recu 75% d’ETm. Abstract Several experiments were conducted in the south of Morocco (IAV-CHA, Agadir) during two seasons 2010 and 2011 in order to evaluate the effect of deficit irrigation with treated wastewater on several crops (quinoa, sweet corn, faba bean and chickpeas).  During the first season (2010) three crops were tested, quinoa, chickpeas and sweet corn applying 6 deficit irrigation treatments during all crop stages alternating 100% of full irrigation as non-stress condition and 50% of full irrigation as water deficit condition applied during vegetative growth, flowering and grain filling stage. For all crops, the highest water productivity and yield were obtained when deficit irrigation was applied during the vegetative growth stage. During the second season (2011) two cultivars of quinoa, faba bean and sweet corn have been cultivated applying 6 deficit irrigation treatments (rainfed, 0, 25, 50, 75 and 100% of full irrigation) only during the vegetative growth stage, while in the rest of crop cycle full irrigation was provided except for rainfed treatment. For quinoa and faba bean, treatment receiving 50% of full irrigation during vegetative growth stage recorded the highest yield and water productivity, while for sweet corn applying 75% of full irrigation was the optimal treatment in terms of yield and water productivity.