Response of Russet Burbank Potatoes to Manganese Fertilizer on Silt-Loam, Calcareous Soils.

High pH, calcareous soils can be low in Manganese (Mn), and potatoes are often produced on these types of soil in southeast Idaho.  Manganese plays a vital role in plant development by influencing photosynthesis and lignin synthesis.   Low soil levels of Mn will reduce potato yield and tuber quality, and potatoes grown in Idaho’s calcareous soils have been observed to be responsive to Mn fertilization. This study is being conducted to observe the response of Russet Burbank potatoes grown in calcareous soils to various Mn fertilizer treatments.  The study included a control and five Mn treatments with six replications in a randomized block design. Each treatment (except the control) included a base fertilizer mix of 635 kg ha^-1 of ammonium sukfate (21-0-0-24S), 172 kg MAP ha^-1 (11-52-0), 93 kg KCl ha^-1 (0-0-60), 2.3 kg B ha^-1, 3.6 kg Zn ha^-1, and 2.2 kg Cu ha^-1.  The treatments were a control (no fertilizer), base fertilizer only (no Mn fertilizer), MnSO­₄ at 0.44 kg Mn ha^-1, MnSO₄ at 6.55 kg Mn ha^-1, GET DRY fertilizer (0.44 kg ha^-1), and Wolftrax fertilizer (0.44 kg Mn ha^-1).  Petiole samples and normalized difference vegetation index (NDVI) measurement were taken during the growing season for determining vegetative differences among treatments. Each plot was 12.2 m long with four rows, spaced 91 cm apart. The middle 6.1 m of the center two rows of each plot was mechanically harvested with tubers weighed to determine yield.  Analysis of NDVI measurements suggested that the GET DRY fertilizer had the highest NDVI levels (0.699) followed by the Wolftrax and high MnSO₄ fertilizer treatments (0.689 for both).  The low MnSO4 and no Mn fertilizer had lower NDVI levels than the control.  These data suggest that the potatoes responded to larger quantities Mn fertilization and the increased efficiency of the GET and Wolftrax fertilizers.  Potato yield and tuber quality have yet to be determined, although, initial sample digs suggest that difference exist among the treatments.