THERE has been a lot of positive news about liquid nutrients this year.
But the question of changing to liquids from granular nutrients remains a moot point.
There’s general agreement in the industry that in-furrow management practices using a range of liquid products, will become the norm over the next five years.
But for now, it’s more a case of staying on the fence while anecdotal evidence is backed up by trial data.
According to Great Northern Rural Services agronomist Owen Mann, Geraldton, there still remains impediments to adoption in the Mid West – an area seen as ripe for change to liquids.
“There are guys up here who have been playing around with different mixes after more than a decade of using liquid nitrogen,” Mr Mann said.
“They understand the benefits of more in-furrow liquid treatments such as wetters, fungicides and macro and micro nutrients, to achieve better plant vigour and health.
“But going liquid requires logistics such as tanks, liquid carts and delivery systems to seeding bars.
“That’s all adds up to more dollars that you’ve got to spend, along with, in some instances, paying more than double for a liquid product, than you would for that same product in granular form.
“And you also could rightly argue that many farmers have been put off changing to a different system because of tank mix compatibility which leads to some mixes blocking up delivery lines or turning to glug in the tank.”
The above remark has been a real experience for farmers considering themselves early adoptees of the system, only to despair that “it’s all too hard”.
Mr Mann emphathises with farmers who have had a go and didn’t achieve what they wanted and said the move from granules to liquids was a leap of faith.
But it’s a safer and less costly leap these days.
“There are a lot more user-friendly liquid products and delivery systems on the market today,” he said.
“And while the cost of liquids is still there, it’s upfront, with arguably a better return on investment as an in-furrow treatment.
“We’re already seeing that with in-furrow fungicides like Uniform being used to reduce early disease pressure, with less emphasis on seed dressings, though you still need seed dressings to protect against smuts and bunts, particularly barley.
“That’s why we’re involved with Primaries CRT which plans to set up trials in 2018 throughout the Wheatbelt.
“So we’ll get more knowledge about the benefits or not of banding liquid nutrients or placing them to the side of the seed and, for example, comparing the effects of wetters in non-wetting soils using granular and liquid nutrients.”
The biggest plus for liquid nutrients is the continuous availability to plant roots as opposed to spatial variation of granular products.
More accurate targeting can lead to faster plant uptake.
The issue of product compatibility in tank mixes still remains, particularly if mixes are not balanced.
This can lead to antagonistic reactions in the soil where, for example, too much nitrogen can reduce molybdenum, copper, potash and boron uptake by plant roots.
And too much phosphate can reduce zinc, copper, iron, potash and calcium uptake.
Similar reactions occur with excess levels of potash, calcium, magnesium, iron, manganese, copper, zinc and molybdenum, reducing plant availability of nutrients that become ‘tied up’.
Happily, an increasing range of products are now on the market that can counteract antagonistic effects.
For example, liquid nitrogen is mixed with liquid calcium to neutralise the effect of the nitrogen on subsoil pH.
“Getting the right balance between nutrients is a key,” Mr Mann said.
“It’s easy to go overboard with liquids.”
Early adoptees of liquids are still using liquid calcium to alleviate subsoil pH issues in the 20-30 centimetre (8-12 inch) profile, to get plant roots through to the “bucket” of deeper-placed nutrients and water, and this practice is growing in appeal.
But where does that leave spreading lime sand?
“It is a good idea to assess the cost comparison and what you think works best for your property,” Mr Mann said.
“Trucking sand has its costs, along with spreading and the result can be variable.
“Research has shown some lime sand doesn’t leach to that 20-30cm depth or has minimal effect on certain soil types.
“With liquids, again there is cost but you can target closer to where the problem is intensifying and from a time consideration, it’s a quicker result (to elevate soil pH).
“Having said that, many farmers are now attaching inclusion plates onto their deep rippers and introducing the topsoil at depth, taking the lime-rich topsoil down to accelerate the process.
“Arguments that liquid only provides strips of treatment are valid but the strips do provide roots with a pathway through that hot zone of subsoil pH.
“This is not a simplistic subject and there are areas of discovery nearly every day.
“It’s constantly evolving, which really reflects the continuing of playing around with liquids to find out what works and what doesn’t, as I said before.
“So while there has not been substantive adoption in the Mid West to liquids as a management practice, I’m encouraged by what I see in new products and delivery systems that will make it more cost effective and hopefully, profitable, for farmers to go that way.
“Realistically, I think it will be the next generation of farmers that takes hold of this.”