Tolerance of Trees to Soil Sodicity

Abstract

Tolerance of six tree species (Casuarina equisetifolia, Eucalyptus hybrid, Acacia nilotica, Dalbergia sissoo, Pongamia pinnata and Araucaria cunninghamii) to soil sodicity was evaluated under pot culture conditions at varying artificially created exchangeable sodium percentage (ESP) levels on an alluvial silty clay loam soil (Fine loamy mixed hyperthermic Typic Ustochrept) by addition of NaHCO3 salt. All the species failed to grow at and above 61.4 ESP. However, the successful growth of Acacia nitotica, Eucalyptus hybrid and Casuarina equisetifolia at 30.6 ESP and Dalbergia sissoo, Pongamia pinnata and Acaucaria cunninghamii at 15.2 ESP was Observed. Height, girth, fresh weight and dry weight of plants decreased with increase in ESP. Uptake of Na+ by plants increased progressively with increase in ESP levels. whereas uptake of Ca++, in general, decreased and Mg++ and K+ were unaffected. The values of Na/K, Na/Ca and Na/Mg ratios in plants increased with increase in ESP. Relatively lower uptake of Ca++ due to high concentration of exchangeable Na+ appeared to increase the adverse effect of sodium on plant growth in sodic soils. Since these observations were recorded under pot culture conditions, further freid studies are suggested to confirm these results.