EFFECT OF DIFFERENT LEVELS OF SALINITY ON GROWTH PERFORMANCES OF FOUR SELECTED TREE SPECIES

Abstract

Salt affected soils are widespread in different parts of the world. In recent years significantamount of land extent were affected due to salinity rendering them biologically unproductive.The use of specific techniques for tnc amelioration of these lands for agriculture is taking placecontinuously. Reforestation of salt affected soils is possible given proper site preparation, choiceof suitable salt tolerant species and their proper nursery and cultural practices are achieved. Thepotentials of these soils for growing trees and woody vegetation have not been fully exploredyet.

Therefore, four different pot experiments were conducted by using four selected tree speciesmainly available in the salt affected areas (i.e, Tamarind (Tamarindus indica), Katuandara(At:acia /eucop/oea), Castor (Ricinus communis) and Wood apple (Feronia /imonia) at theFaculty of Agriculture, University of Ruhuna Mapalana, Kamburupitiya during April to October200 1 to assess the influences of different levels of saline water (i.e. 0.13,2,4,6,8 and 12mmhos/cm) on growth and development of above four tree species. All the experiments wereconducted by using a Randomized Complete Design with four replicates. One month oldseedling raised in 6"x8" size polythene bags were used for the experiment. Seedlings weretransferred to lager Polythine bags (lO"x 12") at 2 months after planning without damage to theroot system to ensure enough space for root development. Plant height, shoot and root biomassyield were measured at every 2 weeks interval.

The result revealed that the plant height, shoot and root biomass yield were not affectedsignificantly by different levels of saline water up to 12 mmhos /cm compared to the controlwhere normal water (O.13mmhosl em) is applied in all crop species. Therefore all four-treespecies, which were used for the experiment, may be recommended as salt tolerant tree speciesup salinity to the level of 12rnmhos/cm.