EFFECT OF EXCHANGEABLE SODIUM ON GROWTH AND CONCENTRATION OF IMPORTANT MACRONUTRIENTS IN NEEDLES AND STEMS OF 4 CASUARINA SPP

A greenhouse experiment was conducted to evaluate the effect of increa sing exchangeable sodium percentage (ESP)viz. 11, 17, 35, 58 and 70 on the growth and the concentration of important macronutrients in needl es and stems of Casuarina obesa Mig., C. glauca Sieb. ex. spreng., C. cunninghamiana Mig. and C. equisetifolia Forster and G. Forster. A sig nificant increase in the dry matter was found with increasing soil sod icity. At ESP 70, the percentage increase in dry matter over ESP 11 fo r the first three species was 44%, 35% and 124% in the needles, and 78 %, 37% and 86% in stems, respectively. On the other hand the yields of C. equisetifolia decreased with increase in soil sodicity. Among the 4 species, C, obesa and C. glauca produced comparatively more DM under sodicity than did C cunninghamiana and C, equisetifolia. The effect o f sodicity was more pronounced on needles than on stems. Sodium concen tration in plant parts increased with increasing sodicity, whereas con centration of potassium, calcium, magnesium, nitrogen and phosphorus s howed a decrease.