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

Abstract Biofunctool ® is a new framework for assessing the impact of land managementon soil quality– defined as the capacity of the soil to function. Biofunctool ® uses a set of twelve indicators to monitor changes in three key soil functions: carbon transformation, nutrient cyclingand structure maintenance (part A). Information from all the indicators is integrated in a Soil QualityIndex using multivariate analysis (PCA) weighting. We used Biofunctool ® to assess the impact of land use, land use change and agricultural practices on soil quality. The Biofunctool ® 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 ® index provides an aggregated synthetic soil functioningscore that is sensitive to land managementand 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-cropson soil functioning. Thirdly, it highlighted a trend of improving soil qualitywith increasing age of rubber plantations, in contrasted pedo-climatic contexts. It is concluded that the Biofunctool ® index is a reliable and relevant descriptor of integrated soil functioning(i.e. soil quality) that could be useful for environmental impact assessmentat regional to global scales.