Response of Tobacco to New Fertilizer Blends Containing Polyhalite in Comparison to Conventional Blends in Tanzania.

Polyhalite (K₂SO₄.MgSO₄.2CaSO₄.2H₂O), POLY4®) can potentially expand the options of low chloride potash sources for tobacco. A trial was carried at at the Tobacco Research Institute of Tanzania (TORITA) at Tumbi, Tabora in 2015-16. The treatments were different fertilizer blends i.e. a) 10-18-24 – Poly b) 10-18-24 – Standard c) 10-18-24 – Synthetic Poly d) 8-14-19- Poly and e) 8-14-19 synthetic poly and different rates of K₂O i.e. 80, 120 and 150 kg ha^-1. Treatments effect on green leaf yield, dry matter yield, leaf quality, leaf value, leaf area, nicotine content and reducing sugars was measured. Exponential relationships for cured and leaf indicated greater yields at 80 kg K₂O ha^-1 with 10-18-24 - Poly when compared to other treatments. Similarly, 10-18-24 – Poly blend resulted in significantly higher fresh leaf yield than other tobacco fertilizer blends. Significant difference between blends was not observed for leaf , N, P, K, Ca, and Mg nicotine and reducing sugar concentrations.