**7. K-efficient cotton cultivars' relation with water use efficiency**

Only limited research work has been done on water use efficiency by using K-efficient cultivars. Our findings suggest that the selection of K-efficient cotton cultivars with adequate K application has the potential to improve nitrogen-use

efficiency and save considerable quantities of fertilizer and irrigation water, up to 35% in cotton, without yield loss under arid climatic conditions [11]. The authors [135], in their experiment, describe the degree of association between K levels and physiological processes implying that a high supply of K must be aimed at under dry land conditions for improvement in drought tolerance or WUE should be explored genetically despite adopting optimum mineral nutrition and water management strategies. The normal dose of potassium fertilizer reduces the impact of stress and improves water use efficiency by up to 30% by reducing leaf evapotranspiration and preventing water losses, and maintaining leaf water potential [11].
