Mineral N uptake efficiency and internal distribution in ‘Conference’ pear trees

About the ProjectConference peren

The objective of this project is, by means of fertilization schedules conducted with 15N labelled calcium nitrate, to achieve an optimized fertilization schedule for pear trees, which results in maximum N utilization efficiency, fruit yield and quality, balanced growth of the trees and minimum environmental impact. Specific objectives are: 

  1. Determining the temporal evolution of the N fraction originating from calcium nitrate fertilization in organs of newly produced biomass (sampled organs include twigs, leaves, flower buds, fruit, bark, fine roots),
  2. Determining the N use efficiency of calcium nitrate fertilization schedules during 
    one complete growing season, and
  3. Determining the temporal dynamics of the N fraction from calcium nitrate fertilization in the xylem sap flow.

In order to accomplish this, eight-year-old pear trees are grown in pallet boxes (built as zero tension piezometers) and subjected to different fertilizer application regimes whereof at least one fraction of calcium nitrate is labelled with 15N (excluding the control group which receives no calcium nitrate). Additionally, this project aims at determining the ecophysiological response of pear trees exposed to the different fertilization schedules by using both continuous measurements (i.e. radial stem growth and sap flow) as well as discrete measurements (i.e. photosynthesis, transpiration and N distribution via spectral data).