Sugarbeet Quality as Related to KCl Fertilization1

Abstract

AbstractExcessive available soil N decreases sugarbeet (Beta vulgaris L.) quality. The chloride‐nitrate uptake antagonism offers a possible mechanism for reducing the amount of NO3− absorbed by sugarbeets. The objectives of this study were to evaluate the potential of KCl fertilizer applications for reducing plant absorption of NO3− and its subsequent effect on sugarbeet production parameters, especially quality.Experiments using six rates of KCl (up to 896 kg/ha of K and 814 kg/ha of Cl) were conducted on five farm sites in northeastern Colorado during 1977. The experimental sites were chosen so they were high in residual soil NO3− or had a history of producing low‐quality sugarbeets. All soils tested high in available K+.Fertilization with KCl had only minor and occasional effects on depressing NO3− concentrations in petiole samples taken on three dates during the season. Root thin juice Cl− content was increased at three locations; effects of fertilization on other quality components (K+, Na+ nitrate, α‐amino N, sucrose, and purity) were mostly not significant (P≤0.10). Initial levels of soil K+ and Na+, and soil Cl− plus irrigation water Cl− were positively related to these constituents in the root thin juice. Sucrose was inversely related to soil NO3−. Fertilizer treatments did not significantly (P≤0.10) affect yield, sucrose, purity, or recoverable sugar of the crop at any location. The lack of appreciable treatment effects is attributed, at least in part, to high levels of available soil K+ and Cl−, plus a large Cl− contribution from the irrigation water.