Shade trees in cacao agroforestry systems: influence on roots and net primary production

This research has the goal to contribute to an assessment of consequences of large-scale conversion from tropical lowland rainforest to transformation systems for carbon sequestration and ecosystem functioning.

This project will investigate changes in carbon sequestration, net primary production above- and belowground and litter carbon fluxes to the soil carbon stock for the study sites in lowland rainforest, jungle rubber, intensive rubber and oil palm plantations within the study region.

• Complementary vertical distribution in the soil profile
  

  For the complementary vertical distribution we will extract volume-based soil samples (30 cm x 30 cm x depth) from 6 soil depths (0-10, 10-20, 20-40, 40-80, 80-120, and 120-160 cm) in order to investigate the abundance of living and dead fine and coarse root mass and to analyze differences in vertical rooting patterns across species and transformation systems.

• Deuterium stable isotope signature in coarse roots
  

  In order to investigate the significance of water uptake by single roots from deeper soil layers of the different transformations systems, we will use a stable isotope (δD) technique (e.g. Dawson et al. 2002).