Victorian innovator sets sight on N efficiency
GroundCover™ Issue: 122 | Author: Alistair Lawson
Robert was among the early adopters of no-till farming in Australia, which progressed to a nine-metre, controlled-traffic, zero-till system on three-metre wheel spacings 14 years ago.
Farming with his wife Wendy, son Justin and daughter-in-law Katie, Robert grows cereals, pulses and canola on 381-millimetres row spacing, which doubles to 762mm for some pulse crops.
Robert cites zero-till farming as one of the most important changes to happen in his family business, ‘Glenvale Farms’, at Kewell in the Wimmera, and is a strong advocate for promoting soil health through minimal cultivation.
“There is less soil disturbance and therefore less upsetting of soil biology and you can retain residue on the soil surface for longer,” Robert says.
However, in recent years, Robert noticed that with soil cover increasing, crops were not taking up as much nitrogen as he had hoped. He estimated they were losing about 60 per cent of the nitrogen they topdressed in the residue.
For that reason, the Ruwoldts imported a specialised machine from the US to help improve nitrogen use efficiency in their crops.
The machine, a Fast liquid fertiliser applicator, has coulters and water jets set up on 762mm spacings with a 7000-litre tank, giving Robert the opportunity to side-dress liquid nitrogen both pre-planting and in-season. The coulters cut through the residue and water jets deliver the fertiliser about five centimetres below the soil surface.
“I had been toying with the idea of side-dressing nitrogen for about six or eight years and finally started doing it in 2015 after we imported the machine,” Robert says.
Side-banding liquid fertiliser is common in maize and other crops in the US, but little work has been done in Australia to quantify its potential benefits.
However, not ones to shy away from the prospect of change, the Ruwoldts dived head-on into side-banding to test for themselves the effectiveness of the treatment.
They performed several trials in their wheat, barley and canola crops, with different rates ranging from nil to 15 to 25 units of nitrogen.
“We pre-drilled urea ammonium nitrate (UAN) two weeks before sowing and then followed up with some in-season applications with several different products at varying rates and timings,” Robert says. “What we found from that is there is not too much difference between products – nitrogen is nitrogen. There was only a small difference in rates between products.
“We got a particularly good response from the full rate, especially in barley, which showed up on the yield maps when we were harvesting. The yield increases were about 20 per cent greater with a full rate versus nil and even then there was a big difference between half rate and nil.”
Robert says they did not broadcast any urea in granular form during the season, but he believes there would have been a big difference between that and side-banding, given there was minimal in-season rain to wash granular urea into the soil.
“By using the side-dressing method, we are putting the nitrogen into the soil where the plants will get it and to that end I think we are getting at least 50 per cent better efficacy,” he says.
“The crops didn’t struggle in the early growth period and we saw responses in less than a week after application, so I see side-banding liquids as a huge advantage to us.
“I think it is best to feed the plants regularly in small amounts and we have seen better results by doing that, rather than in big amounts at one time.”
The Ruwoldts use data generated from two soil moisture probes installed on their property to make decisions on when to fertilise, but Robert would like to expand that number by another two or three probes to better represent different soil types.
“Soil moisture probes are like a fuel gauge for the crop,” Robert explains. “We know when they are running out of water and hence not to fertilise.”
While side-banding in-season may seem like a challenge, Robert says new technology has made the practice much easier.
“The bar has high clearance so we can get through standing crops easily and controlled traffic allows us to stick to permanent wheel tracks,” he says. “GPS and implement-steering on the bar means we can do it in the inter-row accurately.”
In coming seasons, the Ruwoldts will continue to do more work on rates to see what works best without over-fertilising or compromising yield.
“We have got to be smarter about what we do, keep our costs down and still grow crops, which is the same with every business,” Robert says.
“We will continue to look at rates and do the numbers to calculate the leanest rates without losing yield so we can minimise expenditure.”
0428 348 205,