EFFECT OF EXCHANGEABLE SODIUM PERCENTAGE ON THE GROWTH, YIELD, AND CHEMICAL COMPOSITION OF SUNFLOWER (HELIANTHUS-ANNUS L)

The effect of exchangeable sodium percentage (ESP) on the yield and chemical composition of sunflower was studied in a field experiment with five replications. An ESP higher than 16 delayed the germination and decreased the plant height and stem-to-leaves ratio. Emergence of the flower heads was delayed, but maturity was enhanced at high ESP. The grain yield of sunflower was significantly reduced at ESP 24.8 and higher. There was a slight reduction in oil content of the grain at high ESP, and the oil yield per hectare decreased as ESP increased. The decrease in the yield of the grain was associated with 0.4 percent Na in the upper leaves at the time of maturity. Sodium increased and calcium decreased with increased ESP, and there was no effect on the Mg and P content of the plant parts. Potassium content of the leaves at maturity increased with increased ESP. Zinc decreased and Fe increased and Mn was not affected by soil ESP. © 1979 The Williams & Wilkins Co.