L’effet du KNO3 appliqué par voie foliaire, comparé au KCl appliqué dans le sol, sur le rendement du coton a été évalué dans le cadre d’une étude Beltwide de trois ans. Les rendements ont été calculés en moyenne sur les sites d’étude du potassium foliaire dans 12 États de la Cotton Belt aux États-Unis. Dans les traitements à faible teneur en K du sol, le potassium a été appliqué sous forme de KCl selon les analyses de sol effectuées avant la plantation et pour les traitements à forte teneur en K du sol, cette dose recommandée a été doublée. Le taux foliaire était de 11,2 kg/ha/ pulvérisation de KNO3 appliqué quatre fois à des intervalles de 10 à 14 jours après la première fleur. Tous les traitements ont montré des augmentations de rendement par rapport au contrôle (Figure 1).
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Figure 1. Augmentations moyennes du rendement du coton, calculées sur 12 États de la Cotton Belt.