Unlocking paddock potential through soil tests

“It’s all about boosting our productivity by getting a better feel for what we have in terms of soil types and fertility,” said Hassad Australia senior agronomist Scott Ceeney.

“Because the farms are aggregations, our Coonamble, NSW, farm is an aggregation of 19 properties you can get a massive variation in what you find in the soil tests just according to the paddock history,” he said.

“Paddocks that have been cropped are generally a lot more fertile than those have been unimproved grazing country or other paddocks have had a much stronger fertiliser history than others, all of which creates variability.”

“When we decided to embark on this program of extensive soil testing it was because of this desire to really get a handle on what we had.”

Mr Ceeney, based in Dubbo, said from here the business wanted to identify productivity gains, primarily through understanding the capabilities of the various soil types present across the farms.

“For instance, in the Central West of NSW there are areas we have found with high chloride levels, which can be a constraint for cropping so we are investigating as to whether these areas would be better utilised under perennial pasture.”

“In other cases, we’ve changed crop rotations because the soil profile and crop type weren’t compatible. We’re also targeting a larger range of fertiliser products and seeing some promising responses.”

He said in some cases the soil tests had revealed obvious solutions and in others more research work was needed, but overall he felt the program was a worthwhile investment.

“As an investment, we’re confident it will pay for itself over time with increases in long-term productivity.”

Mr Ceeney said down the track the company would investigate concepts such as zone management, where inputs are put out in line with areas of similar soil types.

“Water holding capacity, fertility, productivity potential, they’re all things we’re going to be looking at.”

The soil tests were conducted in locations recommended by Precision Cropping Technologies (PCT) who worked with Hassad Australia to map changes in soil profile conditions using electromagnetic (EM) and gamma radiometric surveys.

Collecting the data involved PCT staff driving up and back across the properties on 36 metre widths, continuously taking readings with the electromagnetic and gamma radiometric sensors.

The recordings from the survey were used to create surfaced maps of each of the four depths of sensitivity from the DualEM and four bands from the gamma radiometrics.

The maps indicate changes in the soil profile conditions which can be driven by both physical and chemical soil characteristics, including changes in texture, depth of soil and subsoil constraints like excessive sodicity and chloride.

Michael Wells from Precision Cropping Technologies said PCT’s agCloud soil sensor maps were an excellent guide to soil variability.

“When we’re working with customers like Hassad Australia, we’re helping them learn more about their farms and the nature of variability, and how it affects production and profitability,” he said.

With Hassad Australia, for example, the initial scanning and mapping process provided a very clear guide for testing.

PCT provided Hassad Australia with a detailed prescription for soil sampling, down to individual GPS points for each soil core.

“It showed how many samples we needed to take for each test to be representative and exactly where they should be taken from,” Mr Ceeney said.

Hassad and PCT are using Incitec Pivot Fertilisers’ Nutrient Advantage laboratory for soil testing on the east coast, a National Association of Testing Authorities (NATA) accredited laboratory specialising in soil, water and plant tissue testing for farmers.