Assessment of multi-scale soil-plant interactions in a poplar plantation using geostatistical data fusion techniques: relationships to soil respiration

Background and aims: An adequate sampling strategy for the estimation of soil respiration depends on spatial heterogeneity in soil and plant characteristics. The objective of this work was the assessment of the spatial soil-plant interactions to define a sampling strategy of soil CO2 efflux.Methods: In a long-term poplar plantation in Italy, a joint analysis of spatial variability of soil and plant properties was performed using geostatistical data fusion techniques. Soil samples were collected at 64 points and analyzed for pH, organic carbon, nitrogen, available phosphorous and texture. Trunk diameter was measured for 446 trees.Results: The analysis of the whole data set (soil and plant properties) revealed the presence of three main scales of variation: a nugget effect (micro-scale), 30 and 100 m.Most spatial variation (71 %) was observed at the longer range scale; soil spatial variability was reflected in the differences in plant growth and affected soil CO2 emissions significantly.Conclusions: The joint analysis of soil and plant properties allowed to model their spatial scale-dependent relationships. A map of a synthetic indicator of joint soil-plant variation can be used to choose the most representative plots for soil respiration monitoring.