Biofunctool®: : a new framework to assess the impact of land management on soil quality. Part B: investigating the impact of land management of rubber plantations on soil quality with the Biofunctool® index
Résumé
Biofunctool (R) is a new framework for assessing the impact of land management on soil quality - defined as the capacity of the soil to function. Biofunctool (R). uses a set of twelve indicators to monitor changes in three key soil functions: carbon transformation, nutrient cycling and structure maintenance (part A). Information from all the indicators is integrated in a Soil Quality Index using multivariate analysis (PCA) weighting. We used Biofunctool (R) to assess the impact of land use, land use change and agricultural practices on soil quality. The Biofunctool (R) index was measured for soils in Thailand within rubber plantations, forests and intensive cash crops (cassava and sugar cane). The results demonstrate that the Biofunctool (R) index provides an aggregated synthetic soil functioning score that is sensitive to land management and is robust in various pedo-climatic contexts. Firstly, the index revealed the impact on soil of land conversion from annual cropping to rubber plantations and ranked the effect on soil with respect to a natural forest reference. Secondly, it showed the positive effect of legume cover-crops on soil functioning. Thirdly, it highlighted a trend of improving soil quality with increasing age of rubber plantations, in contrasted pedo-climatic contexts. It is concluded that the Biofunctool (R) index is a reliable and relevant descriptor of integrated soil functioning (i.e. soil quality) that could be useful for environmental impact assessment at regional to global scales.