GlobalSoilMap.net - From planning, development and proof of concept to full-scale production mapping

The GlobalSoilMap.net project aims to produce predictions of nine key soil properties at continuous depth intervals at a spatial resolution of 90 m for the entire world. These maps of soil properties will be produced by a participants working under the coordination of regional node leaders with responsibility for organizing and delivering results for eight defined geographic regions of the world. This paper identifies and discusses the technical impediments to moving towards commencement of operational production mapping. These are: i) agreement on specifications for all products, ii) location, digital capture and harmonization of legacy soil data, iii) assembly of covariate databases, iv) documentation of prediction methods, v) specification of data model(s) to use to capture, store and disseminate maps and data, vi) selection of cyber-infrastructure to support map production and dissemination vii) end user surveys assessment and verification, and vii) identification of methods for assessing the uncertainty and accuracy of predictions. Actions undertaken to date to address these challenges are presented and progress is evaluated. There are no significant technical reasons for not moving towards planning and implementing operational production mapping

Inverse meta-modelling to estimate soil available water capacity at high spatial resolution across a farm

Geo-referenced information on crop production that is both spatially- and temporally-dense would be useful for management in precision agriculture (PA). Crop yield monitors provide spatially but not temporally dense information. Crop growth simulation modelling can provide temporal density, but traditionally fail on the spatial issue. The research described was motivated by the challenge of satisfying both the spatial and temporal data needs of PA. The methods presented depart from current crop modelling within PA by introducing meta-modelling in combination with inverse modelling to estimate site-specific soil properties. The soil properties are used to predict spatially- and temporally-dense crop yields. An inverse meta-model was derived from the agricultural production simulator (APSIM) using neural networks to estimate soil available water capacity (AWC) from available yield data. Maps of AWC with a resolution of 10 m were produced across a dryland grain farm in Australia. For certain years and fields, the estimates were useful for yield prediction with APSIM and multiple regression, whereas for others the results were disappointing. The estimates contain ‘implicit information’ about climate interactions with soil, crop and landscape that needs to be identified. Improvement of the meta-model with more AWC scenarios, more years of yield data, inclusion of additional variables and accounting for uncertainty are discussed. We concluded that it is worthwhile to pursue this approach as an efficient way of extracting soil physical information that exists within crop yield maps to create spatially- and temporally-dense dataset