Study on laws of annual nutrient uptake in a paulownia plantation

Abstract

Laws of annual nutrient uptake of 8-yr.-old paulownia (Paulownia Sieb. et Zucc) plantation (spacing in row 6m, row spacing 10m) in Fengqiu paulownia experimental spot in Huanghuaihai plain was studied for 2 years by using scientific methods and became clear. Annual total uptakes of 5 macronutrients (N, P, K, Ca, and Mg) in 1989 and 1990 were 287.3238 and 242.4234 Kg/hm² · a respectively. The study found the following laws; (1) the nutrient uptakes of different paulownia organs came in the following order: foliag> branches> flowers> stems> roots; (2) the uptake of different nutrient elements came in the following sequence: N> Ca> K> P> Mg; (3)paulownia’s uptake rate of nutrient elements was mainly conducted during the period between the beginning of growth and the end of July.