Gutstein, Y., Department of Agronomy, The Volcani Institute of Agricultural Research, Bet Dagan, Israel

The regression of yield components and concentration of sucrose at harvest time on the concentration of nutrient elements in the d.m. of the petiole of 36- and 69-day-old plants was estimated from data of a field experiment carried out on a loess soil. Highly significant interactions between NO3-N and K2O concentrations were estimated and illustrated in response surfaces for the components assessed; the type of interaction changed with the age of the plant. The changing type of interaction between the two elements was in close agreement with the variations in the functional synthesis of the sugar beet in the course of the sampling period. Highly significant positive correlations between yield components and concentrations of Na2O in the petiole at the two dates of assessment were determined and the optimum concentrations of this element required for maximum production of the different yield components were estimated. © 1968 Kluwer Academic Publishers.