Species Selection for Afforestation of Sub-Standard Soil Sites with Particular Reference to Biomass Production and Soil Rehabilitation

Abstract

Performance of three, evenaged leguminous tree species (Acacia nilotica, A. auriculiformis and Pithecellobium duke) was evaluated on sodic soil sites (pH 9.6) at Biomass Research Centre, Banthra, Lucknow (north India). Species differed significantly in respect to plant survival, growth and productivity since beginning of its growth as observed at the age of five, 10 and, 15 years. Acacia nilotica had highest average girth at breast height (60.5 cm) and stand biomass (161 Mg ha-1) in spite of its lowest plants survival after 15 years of growth. A. auriculiformis ranked next to it with 131 Mg ha-1 productivity. Basal area ranged from 12.8 to 23 m2 ha-1 in different species. P. duke performed poorly as it had only 71 Mg ha-1 of biomass. Average leaf area per hectare in different species ranged from4,129 m2 ha-1 to 16,090 m2 ha-1 after 15 years of growth. A. nilotica also showed superiority in respect to energy content in woody biomass (2,467 GJ ha-1) and fuel wood value index (1694) as compared to the other two species. At the age of 15 years, litter accumulation over the soil surface resulted in marked reductions in soil pH, electrical conductivity, bulk density and sodium content, and increase in soil porosity, organic carbon and nitrogen content, particularly in the uppermost layer of the mineral soil (0-5 cm). A. nilotica exhibited greater efficiency in terms of soil amelioration followed by A. auriculiformis. The relative ranking of three species was A. nilotica > A. auriculiformis > P. duke, respectively. This indicated greater promise of A. nilotica for biomass production, energy harvest, and soil amelioration on degraded soil sites. Matching tree species to soil conditions needs serious considerations in order to expand site specific afforestation programs and to ameliorate vast tracts of degraded soil sites.