Performance of 31 tree species and soil conditions in a plantation established with saline irrigation

Establishing salt tolerant tree plantations utilising the saline ground waters may provide for an economic use of abandoned arid lands but issues related to long-term sustainability of such plantations are unknown. Thus a field trial with 31 tree species was conducted over 9 years (1991–2000) on a calcareous soil in a semi-arid part (annual rainfall about 350 mm) of northwest India. Tree saplings were planted at the sill of furrows and irrigated with saline water (EC 8.5–10.0 dS/m) for initial 3 years (4–6 times/year) and there after, plantations were irrigated once during the winter only. Measurements were made on tree growth, water use and biomass production. Ranking in order of survival, growth and biomass yield showed that preferred choice for tree species in order of persistence and performance should be: Tamarix articulata, Acacia nilotica, Prosopis juliflora, Eucalyptus tereticornis, Acacia tortilis, and Cassia siamea. Water use efficiency in these tree species ranged between 21 and 99 kg/cm of water. The other species can be A. tortilis (hybrid), Melia azedarach and Acacia farnesiana. Tree species like Acacia auriculiformis, Albizzia lebbeck, Bauhinia variegata, Cassia glauca, Syzygium cuminii, Crescentia alata, Samanea saman, and Terminalia arjuna showed satisfactory early growth and survival when these were supplied with supplemental saline irrigation but proved to be sensitive after the cessation of irrigation, thus emphasising the need for long-term evaluation trials. Cassia javanica and C. alata were observed to be very sensitive to frost whereas Casuarina equisetifolia could not survive drought due to the prevailing arid conditions at the site. Salt storage in soil profile increased substantially during irrigation period (5.6–10.4 dS/m) but the added salts got distributed in soil profile as a consequence of seasonal concentration of rainfall during monsoons and some episodic events of rainfall during the following years. The soil was enriched with organic carbon (>0.4% in upper 30 cm) under the promising tree species. Total ionic composition of leaves ranged between 2.8 and 6.8%. Thus, rehabilitation of arid soils with the above recommended tree species using the available saline waters, would not only render these abandoned soils to be productive but would also ensure conservation and improvement in environment for long range ecological security on these lands.