Soil data cuts farm costs

Changing things up at Pontarelli Farms:

First generation farmer, Tom Pontarelli runs Pontarelli Farms with his wife Michelle and their daughters, just North of Ayr in the heart of Northern Queensland. Tom’s father started the family business in 1969 which revolved around cane production and horticulture until recent years, when the Pontarellis diversified and started farming watermelons.

For Tom, being in control of his costs is crucial to running a viable, successful farming enterprise. He said that running a farm is expensive, so you have to do what you can to ensure your money is being spent to better your production.

Incorporating precision ag technology into their production is nothing new for the Pontarellis, who are always looking to improve their efficiency. Using Trimble Agriculture steering and guidance equipment in their machinery has meant they have been able to enforce a strict controlled traffic regime across their farm to manage compaction. The Pontarellis have introduced a “fixed plant” regime to their paddocks, meaning they plant their seeds in the same row, in the exact same place every year, further limiting their compaction.

 Over the last two years, Tom said he has been looking for ways to make more informed management decisions since they’ve started growing watermelons. Watermelons are a high value crop, producing significantly higher returns than sugarcane. Tom said there was also a lot more risk involved when growing watermelons. “They’re such a high return crop, so I need to look at ways to eliminate as much error as I possibly can when growing them,” he said.

Enter SiS:

The Pontarellis previously used traditional method of “picking random spots in the field” when conducting soil tests on their property. With the opportunity to make significantly high returns from his watermelon crop, Tom said it was crucial that he took the guess work out of knowing where his good soil was, which is why he steered away from using traditional soil testing methods. He got involved with the Department of Agriculture and Fisheries’ (DAF) three-year project, ’Maximising the efficacy of variable rate technology (VRT) to reduce nutrient use and sediment transport in vegetable and melon production.’ DAF agronomist, Sarah Limpus said the project aimed to advance the adoption of variable rate (VR) technology and practices to optimise the placement of fertiliser, amendments and irrigation in intensively cropped and irrigated horticulture in Great Barrier Reef catchments.

As part of the project, the Pontarelli’s watermelon country was mapped by Vantage NEA’s Trimble Agriculture Soil Information System (SiS) last year. 87% of the area mapped was affected by moderate to high sodic subsoils, with more than 6% exchangeable sodium (ESP).

SIS is unlike any other soil analysis solution on the market. The system uses multiple technologies and intelligent targeting algorithms, to determine locations within a field that are substantially different to the rest of the field’s soil. These points are then further investigated with a unique Soil Probe, undisturbed soil cores are collected and sent to a chemistry lab for analysis. The post processed soil maps created from the SiS results provide spatial context and relevance to soil information; treatment prescriptions aren’t made from the assumption that regions of a field are similar, therefore require the same treatment.

The Results:

From the soil map produced by SiS, Vantage NEA precision agronomist, Bryan Granshaw in collaboration with Tom’s agronomist, Sarah Limpus (DAF) assisted Tom with developing a variable rate gypsum prescription map, which ranged from between 2 to 5 tonne a hectare to 10t/ha. This replaced the Pontarelli’s usual flat rate gypsum application of 5t/ha. Tom used Trimble’s input crop control system, Field IQ and his FMX Integrated Display to carry out the VR prescription.

Abiding by the variable rate prescription saved the Pontarellis $708/ha in gypsum costs throughout zones that didn’t require high rates and lead to promising changes with their sodicity levels. In a follow up analysis of the area, of the original 21 sub soil cores taken from the area, 89% returned results of less than 6% ESP. Tom said after just 18 months of following a variable rate prescription, he’s seen significant improvements in yield consistency with his watermelon crop. On top of higher yields, Tom said the VR program saved him money with gypsum costs, as he didn’t use as much as he normally would in the paddock. “The savings have already been great, but they’ll only continue to get better as time goes on,” Tom said.

Using SiS for more:

Tom first started using SiS to tackle a problem he already knew about, sodicity. It wasn’t until he got all of the data back from Bryan that he realised there was so much he could learn about his soil. When you have SiS analysis conducted on your paddocks, you receive over 75 layers of data on your soil’s chemical and physical attributes. Bryan said first and foremost, the SiS data highlights problem areas in soil caused by common issues such as nutrient deficiencies. If you analyse the data further though, Bryan said it can show the more complex characteristics of the soil, allowing you to understand a plant’s environment. “We can understand what the plant has to deal with in order to extract water and nutrients from the soil,” he said. “If you know that, you know what it needs to grow a high yielding, consistent crop.”

With Bryan’s guidance, The Pontarellis used the extensive data they received from SiS to their advantage and looked at ways they could gain more control of their water management.

With water being one of the most important and valuable factors to growing a successful watermelon crop, it was no surprise Tom wanted to ensure his water inputs were efficient. From the data collected, Bryan was able to pull out layers reflecting the varying plant available water and water holding capacity within the Pontarellis’ field. From there, they divided the paddock into different zones which had varying water holding capacity and installed a soil moisture probe into each of them. Tom is now able to monitor soil moisture across his paddock constantly, allowing him to make more informed irrigation decisions.

Monitoring Success/Drones:

After taking extensive steps to ensure he had ultimate growing conditions for his watermelon crop, Tom wanted a way to monitor the success of his management options. He looked to an eye in the sky and had the Vantage NEA team conduct drone flights with their Trimble UX5 Multispectral Unmanned Aircraft System. The UX5 has a 5-band MicaSense RedEdge™ narrowband multispectral camera which captures dependable images used to develop vegetation mapping. Vantage NEA flew the UX5 over Tom’s crop twice: once, at an early stage to monitor plant population and mortality rate and once when his watermelon plants had grown vines. The later drone images allowed Tom to monitor pest and disease risks, as it could highlight areas in the field that were not growing at the same rate as the rest of the crop. Bryan Granshaw said the light spectrum from the drone is more sensitive than the human eye, so it could highlight issues in a paddock well before a grower could spot them from the field. If the drone detected any struggling areas, Tom could check the exact area and conduct sap samples to see whether he needed to conduct targeted foliar nutrition.

Working with Vantage:

Tom said working with Vantage NEA made changing his management options all the easier, as he didn’t need to go elsewhere for equipment, advice, data or technology. The fact that the team worked in well with Tom’s other advisers, such as Sarah Limpus was also extremely beneficial.

Tom said in the future, they’re planning to incorporate variable rate into their spraying regime to further cut input costs. Tom said it would also allow him to use all of the data he has on hand to ensure his crops are given the correct nutrients and treatment during the season, eliminating as much error as possible.

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