Determination And Analysis Of N, P And K Nutrient Elements In The Leaves Of Cinnamomum Camphora, A Street Tree In Shanghai, And A Preliminary Study On Fertilization Strategies

DRIS(Diagnosis and Recommendation Integrated System)comprehensive diagnostic analysis is diagnosis of plant nutrition proposed by Beaufils after more than 20 years of research.This method not only takes the nutrient concentrations in consideration,but also uses the ratio of nutrient concentrations to explain the analysis results.In this experiment,we took the street trees of 58 roads in 17 counties of Shanghai as the objects of the study,and chose three trees whose growth vigour are similarly selected randomly in each road to be a composite sample expected to be measured the concentration of nitrogen,phosphorus and potassium.Trees growing in the green space which has fertile soil and good environment were chosen as the main samples composing reference groups,and the 58 Cinnamomum camphora leaf samples were divided into 10 reference groups and 48 control groups.We got the range of best ratio of concentration of nitrogen,phosphorus and potassium three elements of leaves from reference groups with DRIS comprehensive diagnosis analysis:P/N=0.1648±0.0762,N/K=1.5453±0.4915,K/P=5.8560±1.9075.According to the range of best ratio of concentration of three elements,using graphical method for Cinnamomum camphora respectively to establish nutrition comprehensive diagnostic analysis standard,and to analyse this samples of control groups,getting relative fertilizer sequence of street trees of each road,providing basic technical guidance to improve the urban greening.