Evaluation of forest and fruit trees used for rehabilitation of semiarid alkali-sodic soils in India

In India about 3.58 million ha are alkali soils. These soils are characterized by high pH, low organic carbon contents, excessive exchangeable sodium, low fertility, low infiltration rate, and the presence of indurated CaCO3 in the profile. These properties make the soils unsuitable for most vegetation. To find suitable forest and fruit tree species for these areas, long-term experiments were conducted off highly, alkali soil (pH > 10). Thirty forest tree species, 15 strains of Prosopis, and 10 fruit tree species were planted at the Saraswati Range Forest site if? the semiarid region of Haryana in India. To identify suitable and cheap technology for forest tree establishment two methods of planting were used: (1) deep augers piercing the kankar pan, and (2) shallow augers not piercing the kankar pan. After seven years of planting, only, 13 out of 30 species survived, and of the surviving species only. Prosopis juliflora, Tamarix articulata, and Acacia nilotica were found suitable for such soils. Eucalyptus tereticornis showed good survival and height but no meaningful biomass production was observed. Dalbergia sissoo, Pithecellobium dulce, Terminalia arjuna, Kigelia pinnata, Parkinsonia aculeata, and Cordia rothii showed higher than 70% survival but could not attain economically, suitable biomass. Out of 15 strains of Prosopis after six years of growth P. juliflora was the superior species in terms of growth and biomass production. Among the fruit tree species two methods of planting (i.e., auger hole and pit methods) were tested using 5 and 10 kg of gypsum in each auger hole and 10 and 20 kg of gypsum in each pit as soil amendments. After seven years Ziziphus mauritiana, Syzygium cuminii, Psidium guajava, Emblica officinalis, and Carissa caranandus were the successful species for these soils showing good growth and also initiated fruit setting. At the establishment stage there was no significant difference in growth up to two years between the two methods, but later the growth was better in pits. The establishment cost for Pits was almost double that of the auger holes. These studies have helped in selection of most suitable forest and fruit tree species for rehabilitation of these difficult soils.