ConstraintID: An online software tool to assist grain growers in Australia identify areas affected by soil constraints.

• Persistently poor-growing areas in fields can indicate a soil constraint. • Remote-sensing data with a long history can reveal these areas within fields. • ConstraintID is an online tool to help grains growers reveal persistent patterns. • It can be used to guide soil sampling and help interpret the resulting soil data. • It links soil data with critical values of soil constraints to different crops. Soil constraints, such as soil sodicity, salinity and acidity, are one cause of yield loss for grain growers globally. A first step towards reducing the associated yield gap is the identification of the area affected and the soil constraint/s responsible for the yield loss. Within a single field, persistent spatial variation of crop growth that repeats year after year is likely due to some form of soil constraint. Vegetation indices derived from satellite imagery can provide a valuable alternative to yield maps for assessing these persistent patterns. The variation identified from remote-sensing data can be compared with soil data from the field to help identify which soil constraints are potentially causing yield differences. This application note describes ConstraintID (www.constraintid.com.au), a web-based software tool that makes it easy for growers to use and interact with remote-sensing data to (1) reveal the persistent long-term variation of crop growth within their fields, (2) devise targeted soil sampling plans and (3) interpret the resulting soil data in view of critical values for certain soil constraints. [ABSTRACT FROM AUTHOR]