Experiment Title: Investigating differences in photosynthetic traits between species grown in monocultures and multicultures, and their spectral signals for upscaling from leaf-level to canopy scale. Institutions responsible:

Utrecht University (Astrid Ode)
Experiment Description: The aim of this experiment was to investigate differences in leaf photosynthetic and gas exchange traits (C:N, d13C, LMA, LAI, gs, spectral measurements) of species grown in monoculture and multicultures. Focus 1 was on biodiversity (differences mono/multiculture) and focus 2 was on upscaling leaf traits to canopy level using spectral measurements.
Variables being tested: Experimental Details (factorial design, replication, lab/field/ controls, vegetation type): Data availability: Study limitations:
Leaf-level:

  • LMA
  • D13C
  • C:N content
  • Stomatal conductance
  • Spectral signals

Canopy-level:

  • Spectral signals
  • LAI
  • LMA

Drone-level: camera measurements

 This experiment was conducted end of June – start of July of 2024, in the Bioclive experiment at Utrecht University. This long-term experiment uses 352 containers, each with 1000 liters of soil, to precisely construct grassland ecosystems that represent a gradient of biodiversity. The containers have different levels of plant diversity: they contain 1, 4, 8 or 12 species of grasses and forbs.

Four species, consisting of two grasses (Arrhenaterum elatius and Holcus lanatus) and two forbs (Knautia arvensis and Origanum vulgare) were measured at the leaf-level (gs, LMA, C:N, d13C, spectral signals) and canopy level (LAI, LMA, spectral signals).

 Data analysis ongoing.

Preliminary data of stomatal conductance and LAI available on request (unpublished yet).

 Excessive weed growth present in the plots, and plots were weeded during measurement period. Plots with as minimal as possible weed growth were chosen for the measurements. LAI was measured both before and after weeding of the same plots.

Only leaves on the outer edge of the plots could be measured because of the owners of the experiment (Biology department) needing the central part for biomass measurements. Canopy-level spectral signals: noise due to clouds probably.