What was it all about?

This innovative project as the first of its kind in Australia to explore variability within potato production fields and the impact on crop yield. An understanding of how crop production varies spatially within a field lets growers detect any problems, with the aim of applying inputs at variable rates. The technique has the potential to raise on-farm efficiency and maximise profits with a lower environmental impact.

Researchers surveyed potato fields in the duplex soils of the Tasmanian Midlands and the Ferrosol loams of northern Tasmania, using in-crop sensing from both aerial and ground-based platforms. Electromagnetic induction instruments were used to measure the ability of the soil to conduct electricity, as higher apparent electrical conductivity generally means better fertility and yield potential.

Aerial imaging of the crops during the growing season proved a useful way to track variation in crop development and monitor crop stress for irrigation purposes. A first generation on-harvester yield monitoring system was also used to successfully map changes in yield within a field to quantify the extent of production variability.

Substantial within-field and between field variation in soil physical and chemical properties, elevation and crop yield were found using the technology.

Potato yields were found to vary substantially between fields in both Tasmania’s north and the Midlands. There was extensive variation in soil type and texture, with the topsoil found to be more variable in soil physical properties than the subsoil.

The researchers also demonstrated relationships between yield and soil-borne diseases including Lesion nematodes, northern root-knot nematode and powdery scab.

Increasing the average stem length of plants within a three metre length of row was found to boost crop yield.

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Read more about the findings on p22 of the April/May 2015 edition of Potatoes Australia