Polyhalite for Cotton Production in Texas

Fertilization of cotton with K has been shown to positively impact plant growth and development, water management within the plant, disease tolerance, yield, and fiber quality.  Traditional K sources include KCl and KSO₄, with the vast majority being KCl sources that are broadcast and incorporated prior to planting the cotton crop.  Magnesium, Ca, and S are other macronutrients essential for plant growth and reproduction. While these elements are not often limiting for plant growth in Texas, there is a potential benefit. Polyhalite, K₂SO₄.MgSO₄.2CaSO₄.2H₂O, is emerging as a multi-nutrient fertilizer that has not been evaluated in Texas soils.  Polyhalite will be compared with KCl (aka muriate of potash or MOP), polyhalite+KCl, and KCl+MgSO₄+CaSO₄ (i.e., polyhalite equivalent), and a no K or S treatment under irrigated and non-irrigated conditions. Cotton was evaluated periodically through the growing season and at harvest for leaf nutrients as well as growth and reproductive assessments and at harvest for lint yield, seed cotton yield, and lint quality.  Soil test were conducted pre- and post-production.