Measure of Success
What’s the usual measure of success for crops? Yields, crop quality and profitability? Sure, but
increasingly growers – and their buyers – must balance these conventional measures
against commitments to reduce the environmental impact of agriculture, too.
We have to find ways to make crop production more sustainable,” says Mike Williams,
CEO of OMEX® Agrifluids USA. “That means making more efficient use of all the resources used to
grow the crop and making real efforts to reduce our environmental impact.
“Simultaneously, we need to maintain yield and production, with the overall objective of getting more
from less.” Mike’s particularly keen to talk about ‘functional fertilizers’, also known as ‘smart’ fertilizers. These
products lie somewhere between the categories of bio-stimulant and conventional fertilizer, he says:
“Think of it as ‘nutrition chemistry’: if a conventional fertilizer is passive in nature, then a smart fertilizer is
active. These products can boost farm production and profitability. “It’s somewhat counter-intuitive, but these products allow us to apply less of the valuable – and currently, very expensive – resource, while the crop takes up
more of what’s applied.
Plant Energy Used Wisely
“That means a reduction in wasted resources – the leached nitrogen and so on – that is so often the root cause of
subsequent environmental problems for which farming takes the blame.
“Take nitrogen, for example,” says Dr Marks. “Every grower tweaks their N regimes to reflect different crops and end
uses, timing applications to optimize yield and quality. “Yet many growers might express surprise at their crops
utilizing only 25-35 per cent of applied nitrogen. The effects of leaching, microbial action and mineralization can
make three-quarters of that nitrogen inaccessible.” Mike points out that the most used forms of agricultural
nitrogen are usually the recommendations of chemists, not biologists. “Historically, it’s also been about what’s easiest to secure or manufacture in large quantities, rather than what’s good for the plant.”
“Plants absorb three types of nitrogen,” he says, “and respond differently to each of nitrate, ammonium and
amine. Each form demands a certain amount of energy to absorb, transport and utilize it.”
Nitrates stimulate leafy growth, resulting in ‘apical dominance’ – a hormone-induced condition where
lateral growth is suppressed in favor of vertical growth. The result? Open, leggy crops with poor lateral root
production (which would lead to reduced tuber mass in a crop of potatoes, for example).
Meanwhile, absorption of nitrogen as ammonium will yield the same total biomass for a given amount of
nitrogen, but more of the biomass will be found in the roots. “Soil microbes quickly convert any soil-applied nitrogen from ammonium to nitrate,” Mike explains. “The plant has the means to revert it to ammonium, but it’s energy intensive.” Nitrates are processed in the leaf, in cell structures called chloroplasts. Energy is used for transporting nitrate to the chloroplasts and in generating the nitrate reductase enzymes that turn the nitrate into amino acids, from which proteins are built.
We often talk about plant energy usage in terms of ‘carbon’ because the carbon-based compounds created
through photosynthesis are the origin of plant energy. Converting ammonium into nitrate, and into plant protein, takes 12 times more carbon than if the same unit of nitrogen were absorbed as an amine. “For protein synthesis,
the plant can use both amine and ammonium forms immediately,” says Mike. “That allows the plant to use captured and stored solar energy for growth instead, immediately, without any kind of a processing lag. Carbon becomes
biomass: yield.”
What’s more, nitrate accumulation in the leaf also stimulates the production of the plant hormone auxin. Auxin encourages vegetative growth. “Evolutionarily, that’s a sensible approach to having more food available,”
comments Dr Marks, “but a farmer who wants not shoots and leaves, but tubers instead, needs to be able to recognize that.”
Because amine and ammonium are both processed in the roots, there’s no energy expended in transport or enzyme generation. The added attraction is that amine in the roots has a similar effect on production of cytokinin, a
plant hormone that triggers reproductive growth: another score for tuber production.
Levity’s nitrogen delivery technology focuses on finding a means of delivering amine direct to the plant. It uses a complexed form of amine urea – and rather than use polymer coatings, or the urease and bacterial inhibitors that other manufacturers offer, it went one step further by developing a unique chemical approach. The problem with inhibitors is that they can affect the mineralization process.
“It’s technical, but the amine urea technology that’s incorporated in the OMEX® product SizeN® forms a cross-linkage between the NH2 amine and a monovalent or divalent cation.
“Simply, it makes the NH2 form of nitrogen all but invisible to soil bacteria,” points out Mike.
By supplying nitrogen in the amine form, we’re providing the plant with a more efficient type of nitrogen. So, we can apply less nitrogen and achieve the same amount of plant growth, as well as making sure that nitrogen usage inside
the plant is more energy efficient.
Early field trials of the technology proved that SizeN® increased yield. Interestingly, it also created shorter plants with more roots – which meant the crop was more resilient to drought induced stress and lodging. Greenhouse trials
revealed that amine increased levels of leaf chlorophyll, improving photosynthetic activity.
“SizeN® generally averages around five percent more yield over the control, but some varieties respond
particularly well. For example, the common chipping variety FL1867 demonstrated a 28 per cent boost
when SizeN® technology was incorporated into the standard nutrition program.”
Of course, the increase in marketable yield is a clear benefit, as is the reduction – albeit more difficult to
quantify – in the by-products like leached nitrates, and emissions of ammonia and nitrous oxide
associated with field applications of nitrogen. But further field trials with amine revealed another
interesting property.
“By revising the fertilizer schedule while using amine, we’ve shown that farmers can accurately manipulate
tuber size distribution in the field, to meet the requirements of their end market: salad potatoes,
chipping, crisping and so on.
“In potato production, we discovered that early pretuberization amine applications increased the percentage of smaller 1½-2½” tubers. Conversely, excluding that early application and concentrating on a bulking-stage timing increased the proportion of large tubers at the 2½ – 3¼” size.”
Trials carried out in New Zealand in 2020 proved the point. The complexed amine technology was applied
to a crop being grown for seed – an extremely high value end-use, where correctly sized tubers can be up
to three times as valuable as those outside the optimum specification.
“It’s easy to see why it’s becoming a routine treatment, especially in Europe, because of that dual effect of increased yield and consistent tuber size.
“It’s why we’re so excited to able to offer this technology to our customers here in the U.S. If the agricultural supply industry is to be responsible, we need to do all we can to offer growers alternative options for nutrition and crop protection, as with nitrogen in this case.