The aims of the PA component of the GRDC Stubble project were to:
• deliver a pilot project to understand how soil parameters, including PAW, vary across a paddock and understand
whether current PA datasets can correlate with PAW
• connect variations in soil moisture with nitrogen supply
• demonstrate the use of NDVI to inform variable rate applications of nitrogen
• determine the economic value of variable rate nitrogen application across paddocks, based on zones
• Electromagnetic (EM) zoning was strongly related to differences in pH at 10–30cm depth in two out of three paddocks.
• All three paddocks showed variability in chemical properties, with the EM zoning showing good separation of chemical properties between zones. This provides confidence that the zoning was suitable.
• Variability in plant growth needs to be examined ‘holistically’ rather than just focussing on one variable. While a paddock may show variation in plant available water (PAW), it may be that sodicity or subsoil acidity is the key limiter in plant performance, not water availability per se.
• Existing precision agriculture (PA) datasets, in conjunction with selected chemistry sampling, can be used to indicate relative change in PAW across paddocks, but not the actual volume of water storage.
|Lead research organisation
|Host research organisation
|Trial funding source
This work was carried out as part of the PA component of the GRDC investment into the Maintaining profitable farming
|Other trial partners
|University of Adelaide, School of Agriculture, Food & Wine; Centre for eResearch and Digital Innovation; Federation University Australia; Australian Precision Ag Laboratory; Precision Agriculture
|Cereal (Grain): Wheat
SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.