Rehabilitation of alkaline wasteland on the gangetic alluvial plains of Uttar Pradesh,India, through afforestation

A few species of fuelwood trees were established on highly alkaline wasteland at Aligarh (27°5′ N., 78°4′ E.) in a tropical environment. Of these Prosopis juliflora produced maximum biomass (12.05 t ha⁻¹) and had an energy content of 242.11 GJ ha⁻¹ after 3.5 years growth period. The survival percentage of Terminalia arjuna was highest of those the species tried, but their growth and biomass production were inferior to that of Prosopis juliflora and Acacia nilotica. Some of the fuelwood tree plantations were raised without adding any soil amendment but suffered heavy mortality and could not produce any significant quantity of biomass. In another experiment Leucaena leucocephala was identified as a most promising species for afforestation on substandard soils; also it was found that a relatively high population density (of about 7,500 plants per hectare) is required to rehabilitate such land. Of the soil amendments tried, gypsum with farmyard manure and sand in equal proportion gave the better response (gypsum alone was also tried). Two species of shrubs: Sesbania sesban and Tamarix dioca have shown good adaptability in difficult habitats. After five years of afforestation the soil properties of the sites improved significantly, showing marked reduction in pH, EC and ESP values and an increase in organic carbon content.