Biomass and nutrient uptake ofAilanthus excelsa as affected by N and P fertilization on an aridisol

Abstract

A field experiment was conducted on a coarse sand soil having pH 8.8 and organic matter 0.06% in Indian arid region, to study the influence of N and P fertilizers on growth, biomass and nutrient content ofAilanthus excelsa, which is an important fodder species of arid and semi arid regions. Three levels of nitrogen (0, 9 and 18 g N tree⁻¹ as Urea) and of phosphorus (0, 3 and 6 g P₂O₅ tree⁻¹ as Single Superphosphate) in factorial combinations were taken in triplicate and the experiment was laid in Randomised Block Design. Application of 9 g N plant⁻¹ improved tree height by 15 to 25%, collar circumference by 30 to 37% and crown diameter by 18 to 26% in the initial 3 years. Total biomass increase due to 9 g N plant⁻¹ was 76% and 59%, respectively, after 1 and 2 years of planting. Application of 3 g P₂O₅ tree⁻¹ increased tree height by 8 to 18% and collar circumference by 17 to 24% during initial three years, and total biomass by 70% at 1 year and 30% at 2 years of age. Combined application of 18 g N and 3 g P₂O₅ tree⁻¹ (N₁₈P₃) was the best treatment which increased tree height by 49%, 85% and 35% and collar circumference by 56%, 10% and 11% at 1, 2, and 3 years of age, respectively. N₁₈P₃ treatment increased the total biomass by 181% at 1 year and 185% at 2 years of age. N and P applications improved considerably the branching of roots and root length and enhanced root biomass by 2 to 3 folds. N₁₈P₃ treatment increased the nitrogen uptake by 304% (4.02 g tree⁻¹) at 1 year and 211% (42.56 g tree⁻¹) at 2 years of age. The P uptake was maximum (290.4 mg tree⁻¹) due to N₁₈P₃ treatment in 1 year old and 11.37 g tree⁻¹ due to N₉P₆ treatment in 2 year old plantation.