Options open up to lower farm footprint
Words by Richard Rennie, Images by Bryce Sharkie
Like most farmers on the Canterbury Plains Oxford dairy farmer Andrew Mehrtens has been anxiously eyeing the implications of the region’s land and water regional plan when it comes to nitrogen limitations.
By 2022 many farms in the region will be required to further reduce their nitrogen losses by anywhere between 7% to 30%, depending upon farm type.
As a dairy farmer facing the likelihood of having to lose more nitrogen at that higher end, Andrew was keen to explore his options when it came to fertiliser use, particularly if they meant the farm’s nitrogen foot print was lowered but production per kg of nitrogen used could be largely retained or even increased.
After attending an Agrichem field day near Rangiora last year demonstrating some of the company’s liquid fertiliser types, he was encouraged to set up a farm trial on his 330ha dairy unit to compare the nitrogen based liquid product alongside conventional dry urea fertiliser.
“To keep it as simple as we could, we split a paddock in half that had been direct drilled the year before with clover and ryegrass putting Agrichem liquid nitrogen on one half, and urea on the other.”
The 4ha paddocks were grazed one after the other and the products were applied from last October, and both irrigated under the farm’s centre pivot irrigator.
Agrichem is an Australian based company selling its liquid fertiliser products in Canterbury through Ruralco. The company is regarded as a pioneer in the liquid fertiliser industry, and produces a wide range of speciality liquid fertilisers and soluble solid formulas targeted for specific crops and usage situations.
The company has developed an extensive global distribution network over 30 countries across five continents.
Ed Redfern, business development manager for Agrichem says interest is growing in his company’s nitrogen based product with its higher level of utilisation. More farmers are having to come to grips with the implications of regional water plans and nutrient limitations.
“Typically with conventional urea you can have a lot of losses, including to the atmosphere from volatilisation, and from leaching. Targeting the plant foliage with our liquid products instead of the soil with conventional product means you have more immediate uptake.”
Importantly for Canterbury farmers soil temperature can have a significant impact upon how much urea is leached through the profile. When temperatures fall too low, leaching tends to be greater due to less micro-organism activity, causing it to leach through the profile.
“But with the addition of humic acid in our products, less nitrogen is leached through the soil. You can also safely apply our product in winter without that risk being as great that it will leach through the profile.”
Ed helped develop a simple application programme for Andrew to use over the trial, with a nitrogen-micro nutrient blend.
“He was a bit hesitant to start with, but he managed to stick with the trial, and that has meant we could harvest regularly for analysis and comparison.”
Some of that hesitation eased as Andrew viewed the data coming back from the pasture samples taken, measuring energy and dry matter levels.
“When you looked at the grass you might have thought the urea treated paddocks were the heavier crop with more bulk. But, when they were measured, it seems it was the liquid fertiliser samples that actually had the extra bulk in them,” says Andrew.
Ed says in general the pasture may not have looked as lush, but the sward itself was denser on closer examination and sampling.
“And energy levels were generally higher than the urea treated pasture.”
Because the trial was relatively small at two 4ha plots, Andrew hesitates to claim the herd milked any better on it.
However the trial has found him at a cross roads this winter as he considers options including increasing the area devoted to the Agrichem treatment.
“It has a lot of merit in my eyes. If we can grow the same amount of grass with less nitrogen, all the better. For us going forward the challenge is the practical aspects of application – to cover more ground we would need a bigger liquid applicator to do the job.”
Ed said estimates are Agrichem nitrogen is up to 3.5 times more efficient per kg applied, thanks to its liquid combination of nitrogen, humic acid and micro-nutrients.
The company is hoping to conduct more trials in the Canterbury region over the coming years, with plans for up to a dozen trial sites.