Fourier Transform Infra Red Spectroscopy to investigate soil leachates

A series of artificial plant communities were set up to study the interactions between grasses and legumes and to assess the viability of Fourier-Transform infrared spectroscopy (FT-IR) in analysing the community soil leachates. FT-IR measures the absorbance of a sample over the mid-infrared region and successfully discriminates the chemical changes in samples with appropriate chemometric data analysis. A randomised block design with 24 blocks and 15 plant communities (varying proportions of Lotus corniculatus and Lolium perenne) was used. Regression models related the biomass of an individual to the density of its own and the other (companion) species. Soil leachates were collected and analysed by FT-IR. The chemical differences in leachates reflected the changes in plant community structure. The biomass analysis suggested facilitative interaction, as the mixture yield was greater than monocultures due to reduced intra-specific competition. Thus FT-IR is useful to investigate plant community interactions and soil leachate chemistry.