'SCAMP' AND 'SAFEGAUGE FOR NUTRIENTS': TWO NEW DECISION SUPPORT TOOLS FOR MINIMISING OFF-SITE MOVEMENT OF NUTRIENTS

MINIMISING THE off-site movement of nutrients from sugarcane blocks is a priority management issue both from a productivity and an environmental viewpoint. The Six Easy Steps approach to nutrient management in the sugar industry makes soil-specific nutrient recommendations and identifies appropriate management strategies by taking account of differences in key properties of individual soil types. SCAMP (Soil Constraints and Management Package) is a decision support framework that systematically derives soil-specific management strategies. SCAMP uses basic soil properties such as texture, pH, organic carbon content, structure, consistence, drainage and permeability to identify soil constraints to productivity and to provide strategies for managing these constraints. SCAMP also identifies the likely pathway(s) of nutrient loss from the soil (runoff, drainage, denitrification) and suggests management strategies for minimising these losses. SCAMP is configured as an Access database, and printed soil/site reports of constraints and management options can be produced. SCAMP has also been interfaced to GIS software, and risk and hazard maps can be produced for issues such as nutrient loss pathway and soil acidification risk. To obtain a qualitative assessment of the risk of off-site nutrient movement from different fertiliser management strategies (fertiliser form, rate, placement and time of application), SCAMP has been interfaced to the decision support tool, SafeGauge for Nutrients (SfN). SfN is a user-friendly package with an interactive front-end that utilises site-specific soil and rainfall information embedded in the package together with user-entered fertiliser management details to display visually the risk of off-site nitrogen (N) and phosphorus (P) movement to surface water (by runoff), groundwater (by drainage) and the atmosphere (by denitrification) over the crop cycle. A printed report on the risk of individual fertiliser management strategies is produced. A powerful application of SfN is in awareness-building because different fertiliser management scenarios can be compared for their effects on qualitative risk of off-site nutrient movement. These two science-based tools provide the sugar industry with capacity-building packages and the capability to produce reports that demonstrate appropriate and responsible nutrient management at the block scale.