Supplemental Application of Potassium Acetate Increased Yield of Mesa Russet Potatoes in Sandy Loam Soil with High Potassium Levels

Abstract Potato responses to potassium (K) fertilizer have sometimes been reported in high K soils. This study was designed to investigate the effects of supplemental application of K acetate, a new potassium fertilizer source, to KCl, on the production of Mesa Russet potatoes at the San Luis Valley of Colorado, USA. Treatments included (1) the control treatment where no K fertilizer was applied, (2) application of KCl pre-plant (KCl PP), (3) application of K acetate pre-plant (KAc PP), (4) foliar application of K acetate (KAc F), (5) K acetate pre-plant and foliar (KAc PP + F), and (6) foliar application of K acetate twice (KAc 2 F). KAc PP and KAc F treatments increased total tuber yield and marketable tuber yield (> 114 g) compared to KCl PP treatment in both years. Measurements of tuber quality (tuber dry weight, specific gravity, cracks, knobs, and hollow heart) and plant growth (tuber bulking, aboveground biomass, stem number, and tuber number) showed no consistent treatment impacts. Supplemental application of K acetate (pre-plant or foliar) improved tuber yield of Mesa Russet potatoes; however, the mechanism through which K acetate achieved these yield gains remains unclear and warrants additional research.