RESPONSE OF HIGH DENSITY ENERGY PLANTATION OF <em>EUCALYPTUS</em> <em>TERETICORNIS</em> TO BASAL NITROGEN SOURCE, DOSE AND PHOSPHORUS APPLICATION ON AN ALLUVIAL SOIL

Abstract

On a sandy loam alluvial soil (Udic Ustocrepts) of the foothill of north India, response of high density fuelwood plantation (10,000 ha^-1) of Eucalyptus tereticornis to three levels of basal N (0, 25, 50 g per plant) from two sources, prilled urea (PU, 46% N) and super granules (SG, 1 g of urea briquettes, 46% N) was studied for one rotation of 3.5 y. Phosphorus and zinc sulphate at 25 and 10 g per plant respectively were uniformly applied to all the treatments. There were no significant growth responses to the nitrogen source. The application of 25 N-PU and 50 N-PU increased air dry pole biomass by 22.2 and 43.0% and annual discounted (12% rate of interest) cash returns by 36 and 64% over control at 42 months of age. The plantation accumulated 373, 17 and 241 kg ha^-1 from the available nutrient pool of 1340, 201 and 1015 kg ha^-1 of N, P and K initially present in 0-300 cm soil depth. The soil profile indicated a deficit of 98 and 204 kg ha^-1 of available N and K but a gain of 59 kg ha^-1 of available phosphorus. Although the leaf litter turnover and other probable additions narrowed down the overall nutrient deficit created by Eucalyptus harvest, it was unlikely that such nutrient-poor soil can support additional rotation without balanced fertilization. As such, tree farming was economicaly more viable than rainfed agriculture under moisture and nutrient stress conditions of this tropical region.