BIOMASS AND NUTRIENT-UPTAKE OF AILANTHUS EXCELSA AS AFFECTED BY N-FERTILIZATION AND P-FERTILIZATION ON AN ARIDISOL

A field experiment was conducted on a coarse sand soil having pH 8.8 a nd organic matter 0.06% in Indian arid region, to study the influence of N and P fertilizers on growth, biomass and nutrient content of Aila nthus excelsa, which is an important fodder species of arid and semi a rid regions. Three levels of nitrogen (0, 9 and 18 g N tree(-1) as Ure a) and of phosphorus (0, 3 and 6 g P2O5 tree(-1) as Single Superphosph ate) in factorial combinations were taken in triplicate and the experi ment 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 biomas s 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 y ears of age. Combined application of 18 g N and 3 g P2O5 tree(-1) (N18 P3) 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 improv ed considerably the branching of roots and root length and enhanced ro ot biomass by 2 to 3 folds. N18P3 treatment increased the nitrogen upt ake 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 N 18P3 treatment in 1 year old and 11.37 g tree(-1) due to N9P6 treatmen t in 2 year old plantation.