Cotton Response to Polyhalite Fertilization.

Potassium deficiency is contributed to a number of factors, including higher yielding and faster maturing varieties. Fertilization of potassium (K) has been shown to have a positive impact on plant growth, osmoregulation within the plant, drought tolerance, disease resistance, cotton yield, and fiber quality. Traditional and more utilized sources of K fertilizer include KCl, K₂SO₄ , and KNO₃, with the majority being broadcasted-preplant KCl. Polyhalite, K₂SO₄.MgSO₄.2CaSO₄.2H₂O, is emerging as a potential multi-nutrient fertilizer that has not been evaluated in Texas soils. Polyhalite will be compared with KCl (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. The cotton was periodically sampled throughout the growing season and prior to harvest for total plant nutrient content, as well as growth and reproductive measurements. The post-harvest analysis consisted of lint yield, seed cotton yield, and lint quality.