Using common PA tools and GPS livestock tracking to examine the variability in soil nutrients across grazing landscapes

Precision Agriculture (PA) is changing how producers manage their land. PA involves the use of sensors and management strategies that target the spatial and temporal variability that occurs across a landscape. The introduction of PA has increased profitability and resource use efficiency across many agricultural systems and is now widely applied in cropping and horticultural enterprises. However, development of PA strategies for grazing systems has largely been ignored, possibly due to the complex relationships that exist when considering soil, plant and animal interactions across variable pastoral landscapes. There is a growing interest in the potential of PA management strategies, for example Site Specific Nutrient Management (SSNM) to assist in increasing the fertiliser use efficiency in grazing systems (Simpson et al., 2011). Technologies such as soil EM38 mapping and plant vigour sensors (Crop Circle - Active Optical Sensor) have been extensively used in PA cropping operations and these tools offer some ability to monitor the soil and plant systems in a pasture. The more recent development of GPS livestock tracking has now unlocked the ability to monitor the spatial and temporal variability of the animal component of a grazing system. The integration of these technologies holds significant potential in providing an understanding of how grazing systems vary and how this variability can be managed, particularly through SSNM. This study aims to investigate how common PA tools such as soil EM38 and plant vigour sensors along with GPS tracking information from livestock can be used to understand the spatial distribution of soil nutrients in grazing systems. It is anticipated that this information will lead to an understanding of how producers can zone pasture paddocks to apply SSNM strategies in a similar way to what is currently applied in cropping systems.