Variable rate spreading is based on a simple concept: Apply fertislier only where you need it. Northland contractor Ben McLennan is based at Mata, south of Whangarei. He started applying variable rates of fertiliser last year and finds it as straightforward as regular spreading.
“We just push a button and we become a variable rate spreader”
– Ben McLennan, McLennan Groundspread LTD
Ben and his father Alex run McLennan Groundspread and, to date, have two clients who want variable rate applications – one dairy and one sheep and one beef farmer.
“We’re not doing a lot of it but I am hoping this is just the start,” Ben says. “For us, it was absolutely simple.”
“Our trucks are already set up with the software, so we just push a button and we become a variable rate spreader. I initiated the trial as I am interested in the new technology but Dad soon became involved and we realised how simple it was.”
The McLennan’s spreader runs on TracMap GPS guidance system, which enables the variable rate application. “I’ve got a button on a truck that says ‘wireless.’ I push that and it searches for the maps on the internet. They’re sent to the truck and appear within seconds. It’s that easy.”
TracMap released a simple on-line mapping system at National Field Days in June. It is cloud-based and makes it easy and makes it easy for people to design variable rate maps or to upload maps or to upload maps made in other systems.
One of McLennan’s clients is working with his Balance rep, who is especially interested in varibale rates and is spearheading the up-take in the area. The rep carries out the soil tests and, alongside the farmer establishes management zones i.e. areas of land with similar properties.
These zones are grouped together, based on soil, fertiliser, slope and aspect – not just where the paddock boundaries happen to be. The management zones then receive the fertiliser they need, rather than a blanket amount of spread across the entire farm.
While Ben must be in the reception area to download the maps, once they are loaded, they work anywhere. “Gullies and things won’t affect it. We only need four satellites to work and we can always find four.”
A recent job involved applying super and selenium to a 200ha steep hill country property. “We went from 1000 kg/ha at the bottom to 67 kg/ha at the top, where the cattle camp. It changed three times going up the hill – from 1000 to 600 to 300, and then to 67.
It was interesting to see where it changed rates. I wouldn’t have picked the places that need more or less.”
This article originally appeared in Rural Contractor and Large Scale Farmer Magazine May 2015.