Precision ag tools go under spotlight

The project was a collaboration with the SA Murray-Darling Basin Natural Resources Management Board and received funding from the federal government’s National Landcare Program.

Its key objective was to examine the potential for five different PA tools to improve resource use efficiency in intensive dairy farming operations by providing additional timely information about soil types, plant growth, fertiliser requirements and water availability.

Of the five tools tested, two stood out for their potential to support pasture decision-making for farmers – electromagnetic soil mapping and Greenseeker.

EM mapping works by creating a magnetic field and measuring reflectance from the soil in the form of an electrical current with the results reflecting soil variations and also showing water table levels.

It has the potential to provide a quick and cheap method of understanding soil variation provided ground-truthing is adequate.

Two different EM tools were tested at Mount Compass – the EM38 and the Veris EC Mapper, with the latter proving slightly more accurate.

The other standout technology tested was the Greenseeker.

The hand-held Greenseeker is a relatively cheap tool that emits brief bursts of red and infrared light and then measures how much is reflected back. The strength of the reflectance is considered a direct indicator of a plant’s vigour.

Greenseeker has the potential to estimate pasture biomass and replace a plate meter or visual estimates, making the job easier and potentially more accurate, ensuring the right amount of feed is available when a paddock is grazed.

Precision soil pH testing was also evaluated, successfully identifying areas of the paddock with different pH levels, but given the difficulty of spreading different rates across one paddock, the low cost of lime and the presence of subsoil acidity in the Mount Lofty Ranges, this technology is probably not as relevant as the EM soil mapping and Greenseeker tools.

Also tested was Pastures From Space and soil carbon mapping.