Effect of different levels of nutrients on growth and productivity of clonal eucalyptus

Abstract

Clonal eucalyptus has been adopted by farmers of Punjab on a large scale owing to its fast growth. An experiment was conducted to standardize the nutrient requirement of clonal eucalyptus through six years of growth for getting its better productivity. The treatments comprised of 12 combinations out of 24 factorial combinations of four N, three P (as P₂O₅) and two K (as K₂O) levels varying during different years. Growth parameters of plants (DBH and height) were measured and biomass, timber and firewood (including lops and tops) weight were estimated from these parameters. Economics of eucalyptus plantation was calculated and influence of nutrient application on nutrient content in the soil was also determined. The DBH, height, biomass, timber and firewood weight of eucalyptus were the lowest without the application of nutrients i.e. in T₁ (15.93 cm, 16.32 m, 229 t ha^-1, 171 t ha^-1 and 57.9 t ha^-1, respectively). These parameters were significantly higher in T₄ (17.86 cm, 18.88 m, 329 t ha^-1, 248 t ha^-1 and 81.2 t ha^-1, respectively) than other treatments. The net returns were lowest in T₁ (Rs. 8,94,899 ha^-1) which increased to Rs 12,68,241/ha in T₄. The available N, P and K contents after six years of age were lowest in T₁ (96, 9.8 and 112 kg ha^-1, respectively) and highest (121, 16.1 and 126 kg ha^-1, respectively) at the highest level of nutrient application. Treatment T₄ was better than other treatments for getting higher productivity and better returns from eucalyptus plantations.