How plants acquire nutrients is a fundamental life process. Some plants have developed beneficial associations with bacteria and fungi to help them access essential elements such as phosphate and nitrogen.
Indeed, microorganisms can affect plant nutrition and may form the backbone of fortification strategies ensuring high nutritional values of agricultural crops such as grains and vegetables. However, to date it remains hard to harness this power.
Various mechanisms impact plant growth, all intertwined in the soil microbiome. Nutrient mineralization, enzymes and siderophores; nutrient mobilization, for instance, arbuscular mycorrhizal fungi (AMF); manipulation of plant nutrient uptake by plant hormones; and manipulation of plant nutrient translocation.
Is there anything left to discover on nutrient uptake by plants? For Leon Kochian, PhD, who started his career as a plant transport biologist, studying uptake and translocation of nutrients, he notes that “the more we learn, the more we find out how little we know.” Today, Kochian is a research leader with the Global Institute for Food Security and Canada Excellence Research Chair in Global Food Security, as well as a professor at the University of Saskatchewan in Saskatoon, Saskatchewan, Canada.
“I think the advances, particularly from about 1990 on when molecular biology was being employed and integrated with research in plant physiology and plant genetics, has been especially impactful,” he says. “Hundreds, maybe thousands, of genes for different plant mineral transporters have been identified. And that opened up a lot of ways to look at things in much more detail. Subsequently, as the field of molecular biology matured and genomics, the study of plant genomes and large numbers of genes in those genomes emerged, the findings from investigations of multiple genes made us begin to realize how interconnected different plants processes related to nutrient acquisition and mineral homeostasis are. This more sophisticated understanding of how complex these processes are is helping us to better develop crops that can use inputs more efficiently, i.e., maximize yields using the fertilizer and water we apply as important crop inputs, while minimizing environment impact.”
The processes involved in nutrient uptake have been happening for millions of years, with plants absorbing nutrients from the soil. “In nature, that’s nothing new,” notes soil scientist and agronomist Tom Jensen, PhD, who is a sessional soil science instructor and adjunct professor with the University of Lethbridge in Alberta, Canada. “But there’s a lot more knowledge of what exactly is happening now. And to a certain degree, the more science learns what’s happening, they have more questions they don’t have answers for.”
That’s the way science works – you learn a little bit, and you have ideas of how it’s working. Then studies are done and knowledge increases.
“For example, we used to think nutrients mostly came along with soil solutions through mass flow and diffusion; they get close to the root and then they’re absorbed into the root,” says Jensen. “It was all pretty simple. Well, it turns out it’s not quite that simple because the plants actually regulate what comes in and what goes out of the roots a lot more than we realize.”
Tom Jensen, PhD, sessional soil science instructor and adjunct professor, University of Lethbridge in Alberta, Canada
Jensen points to a simple explanation by Professor Greg Taylor with the University of Alberta, who described root cell membranes as having pores or “little doors”, and certain nutrient ions fit through certain doors. So, the roots can let ions in when needed, and keep them out when they’re not needed. “We’re learning a lot on how these nutrient ions get absorbed into the plant roots, and how the plant uses energy to do that,” says Jensen. “The plants have to expend energy from photosynthesis to let certain ions in, keep certain ions out, and regulate things.”
Today, it’s well known there are a lot more effects of the microbes that live in the rhizosphere, defined over 100 years ago as the zone around the root where microorganisms and processes important for plant growth and health are located. Over the past decade, studies show that the diversity of microorganisms associated with the root system is enormous. This rhizosphere microbiome extends the functional repertoire of the plant beyond imagination.
“There’s a lot of microbes that live in there,” notes Jensen. “The roots leak sugars from photosynthesis, and this is prime food for these microbes that, in turn, help the plants out.”
Jensen notes that in early soil science, researchers would take a sterile wire and touch soil and then spread it on an agar plate and certain microbes would grow in the petri dish. Researchers used to think those were soil microbes. But scientists eventually discovered that 95 percent of the microbes in the soil won’t grow on agar plates. “They’re in the soil, and now they know they’re there because they do DNA analysis of the soil around the root,” says Jensen. “They’re finding there are thousands of different bacteria and fungi and archaea that live around the roots and have relationships with the plants that we didn’t know about before. It’s a huge area of research. They’re trying to collect microbes they can make inoculants with to improve plant growth.”
But it isn’t as easy as using any old microbe. “They’re taking these isolated organisms and throwing them into the wild west of the soils and then they have to compete with everything else that’s there, but they don’t do as well,” adds Jensen. “But I think down the road we’re going to have some home runs, and there’s going to be some fantastic advances coming in the next couple of decades.”
Kochian expands on his own research. “What we’re learning about now is signaling, how one part of the plant talks to another part of the plant. We never realized how interconnected everything is.”
In his work on developing world agriculture where the soils are less fertile, Kochian says he and colleagues are studying ways to make crops take up fertilizer more efficiently. This research is useful for
soils in Canada and in soils in tropic regions which may be acidic and have low levels of phosphorus (P).
“Plant minerals are interconnected; for example, we’ve recently discovered that iron is really important in regulating P nutrition. Too little P causes plant roots to accumulate a lot of iron to possibly toxic levels, and this might be part of the reason why P deficiency ultimately inhibits root growth,” he says. “When we started looking at the gene expression of thousands of genes in a plant, we saw that there’s a lot of interconnectedness between different transporters which we wouldn’t normally expect to be connected. For example, you might impose potassium deficiency on a crop plant, and you would then see increased expression of genes that encode potassium transporters go up, but there was often also a connectedness to transporters for other mineral nutrients, as well as other genes that had nothing to do with transport or mineral nutrition, such as genes associated with response to plant disease.”
One complicated area of signaling Kochian says they’re starting to discover involves the phloem. Known for about 200 years, the phloem’s main role is to function as a living long-distance pathway to move sugars from photosynthetically active mature leaves to the plant growing points, such as the roots and shoots, developing flowers and young leaves – areas that all need carbon to grow. But what’s been discovered more recently is that the phloem is a kind of information superhighway – it’s loaded with unique proteins and different kinds of RNAs that act as signals. As an example, if a plant starts becoming deficient in a particular nutrient, the shoots can inform the roots to make changes in their root systems to take up more of that nutrient.
“One example discovered in the last 10 years: under phosphorus deficiency, the mature leaves make this type of RNA called microRNA399, which the leaves load into the phloem where it moves to the roots. There, it turns off a gene that degrades the phosphate uptake transporter that absorbs phosphate from the soil into the roots. So, when you need P, you don’t want the phosphate transport proteins to be degraded, you want them to be functioning and sticking around longer to increase root P uptake,” says Kochian.
Leon Kochian PhD, research leader with the Global Institute for Food Security and Canada Excellence Research Chair in Global Food Security, as well as a professor at the University of Saskatchewan in Saskatoon, Saskatchewan, Canada.
“And there’s many of these signals in the phloem. We’re studying some of them now, and we have found a whole set of proteins that move from the leaves down to the roots, and some of them also move up to the growing shoot tips. Under the early stages of P deficiency, the abundance of some of these proteins in the phloem changes a lot. We have overexpressed the gene for one of these proteins in transgenic canola, and the preliminary data looks like this increases plant development, resulting in a larger plant that produces more seed more quickly, shortening the growing season. These plants may also acquire P from the soil more efficiently. We don’t know yet how these signals work, but we do know some of them are quite special for plant function.”
The importance soil pH Does soil pH make a difference when it comes to nutrient uptake? According to Jensen, a lot of the bacteria “do really well” from about 6 pH to 7.3 pH – “that’s the sweet pH zone where they do quite well.
“Sometimes it’s not so much that it affects the plants, but it affects the microbes that are interacting with the plants,” says Jensen. “If you go down from pH 6 to pH 4, it’s 100 times more acidic. That’s why pH has a big effect.”
Historically, most of the soils in Western Canada tended to be slightly alkaline. Jensen says that every time an ammonium-based nitrogen (N) fertilizer, such as urea or anhydrous ammonia, was added, the soils were gradually being acidified. And with higher rates of N, the faster that has happened.
A team at the University of Lethbridge (UofL) is currently evaluating soil pH and its effect on plant nutrient uptake. A graduate student is conducting studies on three research plots in Western
Canada – at Shaunavon, Saskatchewan, and at Skiff and Strathmore, Alberta.
“Those are areas where we used to say, ‘most of these soils are of an alkaline pH’, but they’re not anymore,” notes Jensen. “There are patches that are getting rather acidic, and that definitely has an effect on plant nutrient uptake.”
Going the other way, to a higher pH soil, has its own challenges, says Kochian. “We know that with higher pH, a lot of micronutrients like iron are less soluble and have to be chelated,” he says.
But overall, the problem of acidic soils is more of a concern. “I do a lot of work on the fundamental aspects of tropical agriculture where a lot of the soils are highly acidic,” notes Kochian. “Aluminum (Al) is the most abundant metal in soils, as it’s an important component of clay minerals. If the soil pH level stays above pH 5.5, the Al remains incorporated into the clay minerals. However, if the soil becomes more acidic than pH 5.5, a soluble and ionic form of Al is solubilized into the soil solution and is very toxic to plant roots. This results in a stunted and damaged root system that has trouble acquiring water and nutrients for the plant. This is a major problem in the humid, tropic and subtropic regions, and about 40 percent of the potentially arable lands in the developing world are highly acidic.”
Kochian spends a lot of his time working with researchers in Brazil identifying genes that confer tolerance to Al and then going through molecular breeding to integrate the best versions of those genes into crop varieties.
“I’ve worked with sorghum and maize, and interestingly, on these acid soils, not only is aluminum toxicity a problem, but also manganese and iron toxicity because they get solubilized at low soil pH levels,” he says. “Working with Dr. Jurandir Magalhaes, my long-time colleague at Embrapa in Brazil, we have identified several sorghum and maize aluminum tolerance genes. These genes
encode transporters which are not mineral transporters; instead, they are organic acid transporters localized in the root outer cell membrane. When the roots are exposed to Al, the genes that encode these organic acid transporter proteins are turned on and make the protein, which mediates the transport of either citrate or malate out of the root into the soil, where they effectively bind and detoxify the Al.”
Root structures Plant roots themselves are a very structured niche for microbes to live in and colonize, and there’s feedback mechanisms from the plant to the microbial community and back. With the development of scanning electron microscopes and DNA technology, scientists are getting a better idea of how roots are structured and how different plant root membranes and microbial membranes interact.
“We used to think: water and nutrients, they’re absorbed into the root,” notes Jensen. “And yes, that’s correct. But, but there’s a lot of selectivity going on there.”
The other thing scientists are learning is there is a lot of interaction – not only between roots and microbes, but among nutrient ions as well.
Jensen and his colleagues conducted some research on a field in southern Alberta on which a lot of dairy and hog liquid manure was spread regularly. “One summer, we sampled areas on fields, good areas and maybe not quite as good areas, and then we looked at the nutrient availability from soil analyses and the plant nutrient concentrations; we found a lot of the plants in the not as good areas were low in magnesium, which was surprising. These soils had lots of available magnesium, so why weren’t the plants getting the magnesium? The soil samples showed us there was a very high amount of available potassium from the multiple years of livestock manure applications, and it was interfering with the magnesium uptake.
“It’s like a freeway – you get too many cars on the freeway, then things can’t move like they need to, like a bottleneck. In our case, too much of one ion was interfering. That proves to us there’s a lot of interaction between different nutrients.”
According to microbial ecologist Lori Phillips, PhD, who investigates soil biological processes that maintain and enhance agro-ecosystem productivity and sustainability in her position as research scientist with Agriculture and Agri-Food Canada in Harrow, Ontario, Canada, plants form associations with different soil microbes in the rhizosphere. These associations are affected by the types of compounds the plant is releasing from the roots, e.g., organic acids, amino acids and other sugar compounds. The types of exudates that it’s releasing from its roots is going to encourage the growth of different bacteria and fungi.
“By releasing these compounds into the soil, the plant is essentially selecting for different organisms that are going to be beneficial to the plant,” she notes.
Additionally, while it’s known different crops have different root structures, it’s also true that different root structures exist between different varieties or hybrids of the same crop. It makes sense – two canola hybrids are genetically different, so their root structures are slightly different and, thus, their ability to uptake nutrients differs as well.
Jensen says some plant hybrids can tolerate extremes in soil pH better than others. An example of this is in North Dakota (U.S.) – in poorly drained high pH soils some soybean varieties will develop iron deficiency symptoms. “Even though the soil has lots of iron in it, because of the high pH and the wet conditions, the iron is reduced to another form that the soybeans can’t absorb,” says Jensen. “In those cases, they would just add iron fertilizer in these areas. Well, it didn’t respond either. So, they found out they made a lot better progress by selecting varieties, certain genotypes of soybean, that are still capable of accessing that iron. They found it was more effective to use a high pH wet condition tolerant soybean variety than to use iron fertilizer.
“That’s one of the biggest things we’re learning. Sometimes it’s a lot cheaper to select tolerant varieties
than to rely on fertilizer supplementation.”
Phillips agrees. “It’s interesting that if you have two different cultivars of a single plant, they will promote different communities in their plant roots,” she says. “It’s a really close relationship, and we know very little about how that relationship really happens. We know what happens, but in terms of the mechanisms, we still don’t know very much.”
Kochian’s team has been investigating root system architecture as an important crop genetic trait. “We’ve cloned a few genes for P efficiency. With sorghum and maize, about 80 percent of the genetic variation of P efficiency is root P acquisition efficiency,” notes Kochian. “We’ve been looking at these P efficient lines and they make a lot more lateral roots, which assists in ‘mining’ the phosphate from the soil.”
Kochian adds that a lot of people have developed sophisticated imaging systems in the lab and greenhouse for imaging root systems in 3D, computing these traits, and turning this into a genetic analysis. “We’re doing that, too – looking for crop varieties with bigger root systems that make more, longer and thinner lateral roots to more effectively mine P, as well as other mineral nutrients and water from the soil,” he says.
“Root architecture has become a hot topic in the last 10 years.”
Emerging role of the microbiome The root microbiome is considered probably the most complex ecosystem in the world. Scientists have studied mycorrhizae fungi and plant interactions for over 200 years. What’s becoming very clear is that plants have co-evolved for millions of years with these fungi, and they are absolutely essential for crop health and vigour, such as improving root growth, etc.
What isn’t well understood yet is what promotes good mycorrhizae colonization in a field situation, in particular, mycorrhizal symbiosis.
“People are using a lot of agricultural chemicals, such as herbicides, to spray down weeds before planting, and they’re using different nitrification inhibitors, etc. We know very little about how those agro-chemicals affect the establishment of that mycorrhizal symbiosis,” notes Phillips. “We know they have an impact … there are certain chemicals that we know if they are active in the soil during that really short window of time that the plant root and the fungi have to establish that handshake, that that can interrupt the formation of that symbiosis.
“With respect to rhizobia, we know more about how that relationship can be hindered by ag chemicals. So, if you over fertilize, for example, then the relationship simply won’t happen because the plant is not nitrogen limited and it doesn’t send out the signals that initiate that symbiosis,” she adds.
In her lab, Phillips and her colleagues conduct work to understand soil microbiomes. These are the organisms that cycle nitrogen, for example. “So, if you’re adding on a fertilizer N, it has to be processed through a biological pipeline to produce a form of nitrogen that the plant can take up,” she says. “There’s a large body of research on those mechanisms right now. In order for that nitrate to be produced, you have to have the right microbial community present in the right place at the right time. The rate at which nitrate is produced from your fertilizer N is very much going to depend on the type of microbiome and the activity of the microbiome present near where that fertilizer has been applied.”
While farmers today can add a physical barrier onto the N that’s being applied, such as nitrification inhibitors, what isn’t known yet is if it’s possible to add another compound that directly targets microbial activity. For instance, is there a way to reduce other aspects of that nitrification cycle or denitrification cycle and thus reduce greenhouse gas emissions? Or are there other pathways that can be targeted with agronomic management, whether it’s a chemical application or physical disturbance of the soil, that can allow us to increase those processes?
“If we understand how and when the different bacteria are active in performing these processes, that then opens the door to developing new methods to control the rate at which those processes happen,” says Phillips. “And that’s purely a biological process, so we need to understand those biological mechanisms in order to come up with those new tools.”
Besides AMF and rhizobia, there are all sorts of bacteria and fungi that live within the plant root. They’re not on the surface of the plant root, but they’re actually in the plant root, called endophytes. Phillips maintains these endophytes might be increasing the ability of the plant to take up N or water, might be providing stress resilience, might be providing a barrier to pathogens. “If you have a healthy endophytic and rhizosphere microbiome, you’re less likely to suffer serious disease consequences, because those niches are occupied, you have those defenders in place so to speak. It’s a ridiculously complex system. It’s almost like an extension of the plant’s immune system,” she notes.
Phillips says N mineralization is something she gets asked a lot about, and an important point as today’s fertilizer prices keep increasing. With a lot of N tied up in organic matter in soils, how can farmers better access that?
“This is a bacterial and to some extent a fungal process,” says Phillips. “If we could better predict N mineralization, that would be a massive stride forward. There are different ways we use to predict it, including potentially mineralizable N measurements. But the reality is, farmers cannot rely on that to predict their N needs for the year. What happens in the lab doesn’t match up in the field, and that’s mostly because we don’t understand enough about how the soil microbiome is functioning.”
When Kochian arrived at the Global Institute for Food Security in Saskatoon in 2016, he was aware of several researchers who had identified several fungi that grow on and in plant roots, but don’t grow out of the roots like mycorrhizae. He says that some species of these fungi seemed to stimulate, under some conditions, increased drought resistance and salt resistance, as well as enhancing other related crop traits.
“Now when you see all these biofertilizers and biostimulants coming on the market, I realize we should be able to employ them much more effectively by understanding how they work,” he says.
“And the more we learn about fertilizers – from fundamental research in the lab all the way to research and crop production in the field – and also discover how to increase crop yield with more efficient fertilizer uptake and use, the more I believe we will achieve higher quality yields and agricultural sustainability. It’s complex, because you’ve got multiple genomes – the plant genome, and the genomes of the thousands of different bacterial and fungal species living in and on the root. But it’s all very interesting and very exciting.”
Going forward, changes in the developmental program and root structure to better “mine” the soil for limiting nutrients, induction of high affinity transport systems, and the establishment of symbioses and associations that facilitate nutrient uptake, are all on the horizon. Together, these mechanisms will allow plants to maximize their nutrient acquisition abilities while protecting against the accumulation of excess of some nutrients, which can be toxic. It will be game-changing to better understand the ability of plants to utilize such mechanisms that will result in better crop yields as well as plant community structure, soil ecology, ecosystem health and biodiversity. ●
The role of soil and plant microbiome in mobilizing nutrients for use by plants. Source:
… scientists eventually discovered that 95 percent of the microbes in the soil won’t grow on agar plates.
...if a plant starts becoming deficient in a particular nutrient, the shoots can inform the roots to make changes in their root systems to take up more of that nutrient.
It’s interesting that if you have two different cultivars of a single plant, they will promote different communities in their plant roots.
In April, New AG International spoke to a number of individuals in the agribusiness sector in Ukraine, including an adviser to the Minister of Agrarian Policy and Food, to find out how the invasion by Russian military impacted the country’s agriculture sector, the availability of inputs, and what it means for the growing season and the all-important export trade. There were stories of support from agribusiness for the Ukrainian army – not just giving food and fuel, one company said it had given its drones to the military. (NOTE: “interviewee” used to protect identities of sources.) Luke Hutson writes
“We don’t speak about productivity, we speak about surviving,” said Alex Lissitsa CEO of IMC, one of Ukraine’s large agribusinesses and board member of Ukrainian Agribusiness Club (UCAB).
With land in Chernihiv and Sumy regions, his company had some of their lands occupied by Russian forces. By the end of March, the territory was back in Ukrainian hands, but he was quick to point out this does not mean it is safe to farm. In some previously occupied regions, there are mines in fields as well as along the roads.
Lissitsa’s agribusiness was planning to sow around 70,000 hectares (ha); the latest date for sowing in North Ukraine is 20 May.
Another source said the compaction caused by tank tracks also made farming some fields difficult.
Estimates for the amount of arable land lost vary and will continue to vary as the situation evolves. An estimate from one source was that 30 percent of farming land was either currently occupied, unsafe or unable to be farmed.
“From our land bank at the moment, there is no access to an area of about 5,000 hectares – agricultural trials are cancelled,” Inter, an agribusiness with 30,000 ha, told New AG International (NAI) in a statement in late April.
Another farm owner speaking to NAI said they had lost one-third of their land, equating to around 1,000 ha. This land was still occupied at the time of writing.
Government support To help farmers, the government gave the country’s banks 9.3 billion hryvnia (USD$308 million) to lend to farmers, Markiyan Dmytrasevych, adviser to the Minister of Agrarian Policy and Food of Ukraine told NAI. The loans are at a zero percent interest rate, and 80 percent guaranteed by the government.
“But we still have a problem with the small farms, those with around 10-30 hectares. Often, they are not registered, work with cash and no accounts, and that’s a problem for our banks to lend money to them,” explained Dmytrasevych. “That’s why we asked the EU Commission for direct cash grants – 200 euro per hectare – so small farmers can buy seeds, fertilizer. That’s the best to support these small farmers.”
A decision is still pending on the cash grants. More immediately, Dmytrasevych said the Food and Agriculture Organization (FAO) is rolling out its programme by supplying seeds directly to these small- and medium-scale farmers.
In its rapid response plan (RRP), the FAO stated it requires USD$115.4 million, increasing its initial request of USD$50 million, to support 376,660 households (979,320 people) in Ukraine from March-December 2022. Support includes vegetable and crop seeds.
“The FAO plans to use multi purpose cash (MPC) transfers in combination with other assistance, or on their own, as part of its response,” says the RRP document. The FAO provided seed to farmers in eastern Ukraine during 2017.
Estimates of spring sowing In early April, the UCAB estimated that 70 percent of usual spring area, equating to 14 million ha, will be planted in 2022. Dmytrasevych agreed with the figure of 70 percent of the usual spring planting, and said overall the ministry was projecting to harvest around 50 percent of the yield compared to last year, which was approximately 100 million tonnes of grains and oilseeds.
The UCAB said the biggest land losses were in the northeast, east and south of the country.
One interviewee estimated that sowing in the southern oblast, or region, of Kherson would be around 50 percent of the usual area.
As of April 2022, farmers were planning to seed less corn, and more soybean and sunflower, according to the UCAB.
Corn has been a major growth export for Ukraine in recent decades (see NAI country report here) with around 33 million tonnes. Without the ability to export, there is a disincentive to plant and spend resources on this crop.
Damage to infrastructure The estimates of land lost is just the starting point. There were reports from interviewees of the destruction of farming equipment, buildings, storage silos, and even the theft of farm vehicles. One interviewee claimed a Land Cruiser 200 had been stolen from their land; using GPS, they located it in Belarus.
There are also reports of a loss of livestock. One interviewee said they lost 300 cattle in the first month of the war because of a lack of fodder. Egg production is threatened in the country. One of the country’s leading producers, Avangardco, has sustained losses and up to three million chickens are at risk according to its parent company UkrLandFarming.
In terms of fertilizer plant infrastructure, some nitrogen plants are understood to be running. Cherkasy Azot, part of Ostchem Holding, is reportedly still producing as of April. This plant is Ukraine’s largest producer of ammonium nitrate. One interviewee said that because of the shortage of fuel, inputs such as fertilizers in some regions were available only by collection.
The ammonia pipeline that carries ammonia from Russian territory had not been damaged as of April, according to one interviewee. He thought there was probably little sense in destroying it, not only because it takes ammonia from the Russian fertilizer plant of Togliatti but also it cannot be exported from Odesa, where the pipeline ends.
Problems to overcome From the conversations there were a number of core problems that needed to be overcome. From an inputs’ perspective, farmers were looking to reduce the number of fertilizer applications due to limited availability and a surge in prices. In April, UCAB estimated availability of fertilizers at 80 percent.
One interviewee planned to make only two fertilizations on their wheat. They had sown 600 ha.
Another interviewee said they had bought extra fertilizer volumes at the end of last year as a precaution. His business farms 2,000 ha in Kyiv region, mainly soya and rapeseed.
Another grower said they would reduce fertilizer usage by 30-40 percent. In the past, a lot of their fertilizer had come from Belarus, he noted.
Seeds appear to be one of the least disrupted inputs. Although UCAB put availability at 75 percent, the agribusiness leaders speaking to NAI felt that supply levels were sufficient. One interviewee explained there is seed production in Ukraine, so there is less reliance on imports, compared with pesticides. The availability of pesticides was pegged at 60 percent by UCAB for the spring planting campaign.
The frequently cited problem was fuel. Availability can depend on location, and according to one interviewee, prices increased by 30 percent in some areas. Some farms in the north gave their fuel to the Ukrainian army in the early days of the occupation.
Fuel for the planting season is a concern, estimated at 40 percent by UCAB, and one interviewee was even more worried about the situation for the harvest period.
Fuel storage tanks were hit by missile strikes. One interviewee thought most fuel storage facilities along the Belarus border had been hit by missiles.
One idea that is being explored to overcome a persistent fuel shortage is to turn some of the rapeseed oil into biofuel.
Farm workers In the early stages of the invasion, some farm workers were conscripted into the Ukrainian army. There were negotiations, according to one interviewee, between the government and various large-scale companies, and a consensus was reached whereby a certain level of farm workers was needed to grow the necessary food for the population and army.
In April, Dmytrasevych said they had 200,000 workers on farms and was confident this would be sufficient given the smaller area being worked. Typically, around 500,000 workers would be employed, he said. The broader number for workers in agriculture is much higher – around 17 percent according to the National Investment Council of Ukraine, which is roughly 7.5 million of Ukraine’s population of 44 million before the conflict.
As well as workers on the actual farms, there are also employees working across the various inputs. BTU-Center, a leading producer of biofertilizer and soil remediation products in Ukraine with a total staff of around 500, told NAI they had closed their head office in Kyiv.
“For those people who needed evacuation, BTU-Center provided free accommodation in Vinnytsia region. BTU-Center tries to save jobs and financially support team members who have been particularly hard hit by the fighting. As at the end of April, 90 percent of the staff are comparatively safe,” the company stated.
There are also curfews in some regions. Inter stated in April that in the Chernihiv region, “they are not allowed to work around the clock, which means that the sowing period will be delayed.” Another interviewee made a similar point that typically during the sowing period, farms would operate non-stop and work through the night.
Finance and domestic prices Farm credit is a major issue, and particularly for smaller farms as outlined above. One interviewee said they had debts still to pay on a farm that was now occupied.
Banks are reluctant to lend to farmers. “There’s no insurance in case of war,” one interviewee noted. But loans still need to be repaid.
The economics for farms are particularly challenging given that the domestic prices for some crops, such as soybeans, have declined. However, soybean meal has actually increased, and this is a problem for dairy farmers who use it as a feed. As one dairy farmer explained on a UCAB webinar 21 April, the price of soybean meal had increased but the price they receive for milk had decreased. So, while the prices of their products were declining, input costs were going up.
The domestic corn price was reduced by 40 percent. Farmers cannot easily export, and so the surplus is weighing down on prices. One interviewee said they would try to sell their stocks to air purification end-users or keep and sell next year.
Some input suppliers maintained their prices. “BTU-Center has not changed prices for its products to actually support agricultural producers,” it noted in April. “The payment procedures are maximum flexible. For those agrarians who suffered the most, BTU-Center provided biologicals for free.”
Export options Low domestic prices make the need to export even more acute, but there are several obstacles. The first obstacle is that major export routes for Ukraine’s agricultural output is via three ports in the Black Sea – Odesa, Mykolayiv and Mariupol. In April, there was no export from these ports and they were blocked.
Another key problem is there are still large volumes of stocks to be exported, before the new crop is even harvested. Estimates in storage are 15-17 million tonnes, with UCAB putting an even higher estimate of 20 million tonnes of grains still to be exported, as of April. Typically, Ukraine would export around six to seven million tonnes of grain and oilseeds per month. So even in normal circumstances, the current volume in storage would take several months to clear.
One interviewee who grows rapeseed was concerned about storage, saying it was hard to store, with moisture needing to be controlled below 10 percent.
Railway option? Exporting via railway is not as easy as first seems. Around 200,000 tonnes was exported in March 2022 via railway, according to one interviewee.
Rail exports could be expanded to between 600,000 tonnes to one million tonnes, but as UCAB noted, at this rate, it would take 18-24 months to clear the current inventories, and that’s before any new crop has been added.
“Honest to say, it’s a disaster,” one interviewee told NAI in April. Not just because it could lead to Ukrainian companies defaulting on bank loans, but also for those countries who rely on importing Ukrainian grains and oilseeds, he explained.
When discussing how non-seaborne trade could be expanded, one interviewee did say they were looking at road haulage to Poland and the Baltics. The critical physical problem is the different railway gauges from Ukraine to other European countries. Any exports need to be re-loaded at the border.
One interviewee said that when working as an adviser in the Ministry of Agrarian Policy and Food, there was a proposal to make a railway hub in Poland for quick re-loading, and then being moved on to Germany and Netherlands. But it never made it past the drawing board.
But that might have changed – discussions were taking place to export out of the Baltic ports. One option is the Lithuanian port of Klaipeda. This port has lost the volumes from Belarussian potash prior to the Russian invasion, due to sanctions on Belarus by the U.S. from December 2021. However, moving grain via rail from Ukraine to Poland to Lithuania would involve two changes due to different gauges – wide in Ukraine, narrower in Poland, wide again in Lithuania.
“We will increase exports,” says Dmytrasevych in April. “If we were exporting five million tonnes per month by the Black Sea ports, by railway in the best situation we can reach 1.5 million tonnes per month.”
Another problem is the need for phytosanitary checks at the border with Poland. There was a plan to increase inspectors at the Polish border.
Some other options included railing grain to Izmail, a port on the Danube River in Odesa Oblast. Taking by barge to the Romanian port of Constanza is not possible at the moment, according to Dmytrasevych. Not only is Constanza reportedly full of grain, but volume from Romania’s harvest would be arriving in the coming months. A temporary measure was to store grain on vessels.
Outlook When discussing the future with the interviewees, much depends on their type of farm and circumstances. One interviewee has a 3,500 ha no-till farm in the region of Vinnytsa. He felt he was in a better position with less reliance on inputs, although he was quick to point out that no-till formed less than one percent of farming in Ukraine.
For the moment, the consumption balance can support the population and war effort. One official from the Ministry of Agriculture speaking during the UCAB webinar on 21 April said that consumption was lower due to the number of people who were displaced by the war and moved to other countries. Out of 100 million tonnes in grains and oilseeds, around 20 million tonnes are typically required for domestic consumption.
On the face it of it, production could fall by some margin to cover domestic consumption, but this would be ignoring two key knock-ons – the reduction in revenue, both for farmers and the government, and the lack of supplies to the usual overseas buyers. The buyers of wheat in North African countries are one reason for maintaining close-to-near normal productivity levels.
Uncertainty abounds since 24 February when Russian tanks rolled over the border. The only certainty is there are more battles to come for Ukraine’s farmers. ●
Nutrien Ltd. is evaluating Geismar, Louisiana (U.S.) as the site to build the world’s largest clean ammonia facility.
Building on the company’s expertise in low-carbon ammonia production, clean ammonia will be manufactured using innovative technology to achieve at least a 90 percent reduction in CO2 emissions. The project will proceed to the front-end engineering design (FEED) phase, with a final investment decision expected to follow in 2023. If approved, construction of the approximately US$2 billion facility would begin in 2024 with full production expected by 2027.
The company stated the new clean ammonia plant would leverage low-cost natural gas, tidewater access to world markets, and high-quality carbon capture and sequestration infrastructure at its existing Geismar facility to serve growing demand in agriculture, industrial and emerging energy markets. The plant is expected to have an annual production capacity of 1.2 million metric tonnes of clean ammonia and capture at least 90 percent of CO2 emissions, permanently sequestering more than 1.8 million metric tonnes of CO2 in dedicated geological storage per annum. The new plant will use auto thermal reforming technology to achieve the lowest carbon footprint of any plant at this scale and has the potential to transition to net-zero emissions with future modifications.
Nutrien has signed a term sheet with Denbury Inc., a trusted partner for nearly a decade, that would allow for expansion of the existing volume of carbon sequestration capability in the immediate vicinity of its Geismar facility, if selected as the final site of construction.
Nutrien has also signed a letter of intent to collaborate with Mitsubishi Corporation for offtake of up to 40 percent of expected production from the plant to deliver to the Asian fuel market, including Japan, once construction is complete. ●
Wetland plants have a high tolerance against flooding due to the formation of “lysigenous aerenchyma,” air channels that help transfer gases to the submerged roots. These channels also help the plant withstand drought and nutrient deficiency.
Now, scientists from Japan investigate the underlying mechanism of aerenchyma formation to understand the phenomenon better, opening doors to the development of crops that are resilient against extreme weather changes.
Floods and droughts are the main environmental disasters responsible for most crop failures. Aerenchyma formation can help crops cope with these environmental stresses. However, it is not commonly observed in non-wetland species like wheat and maize, which are staple food crops in certain areas of the world. Researchers Takaki Yamauchi and Mikio Nakazono from Nagoya University, Japan, have surveyed literature on the topic to get a concrete overview of the various factors involved in aerenchyma formation. “If we can genetically control the timing and amount of lysigenous aerenchyma formation in roots of all agronomically important crops, such as maize, wheat and soybean, the global crop production loss could be dramatically reduced,” says Dr. Nakazono.
Dr. Yamauchi and Dr. Nakazono suggest imagining the lysigenous aerenchyma to a snorkel used to breathe underwater. During flooding, the roots get cut off from oxygen and other vital gases needed for survival. In response, the plant creates air pathways connecting the submerged regions of the plant to the parts above water. Similar to a snorkel, these pathways help the plant “breathe” by transporting gases to the submerged roots. Moreover, the air channels reduce the energy requirement for the breathing process and can help the plant conserve energy during extreme conditions of drought or nutrient deficit.
The researchers found that a phytohormone called “auxin” is required for the formation of aerenchyma during normal root growth, and identified two factors leading to the induction of aerenchyma formation in response to flooding. The phenomenon begins when the roots are submerged underwater in aerobic conditions. The restrictions to gas exchange cause ethylene to accumulate in the roots, which encourage the production of respiratory burst oxidase homolog (RBOH) – an enzyme responsible for reactive oxygen species (ROS) production. As it turns out, the released ROS triggers cell death in the tissues, forming cavities for the passage of gases.
The RBOH can also be activated by the presence of calcium (Ca2+) ions that are transported from the apoplast (water pathways). Certain plants have calcium-dependent protein kinases that use Ca2+ to add phosphates to the RBOH, stimulating it to produce ROS. This effect occurs at later stages as the plants gradually experience oxygen-deficient conditions after prolonged underwater submersion.
While aerenchyma is mostly associated with plants that have adapted to soils with high water content, it can also develop in upland plants under drought and nutrient deficiency. Low concentrations of nitrogen and phosphorus was found to increase the ethylene sensitivity, stimulating the formation of aerenchyma. Moreover, ethylene was also a common factor in triggering aerenchyma in maize, offering a way to improve the crop’s resilience. “The increase in ethylene sensitivity could be an effective strategy to stimulate aerenchyma formation in the absence of restricted gas diffusion,” speculates Dr. Yamauchi.
While the mechanism behind aerenchyma formation remains uncertain, suggesting the need for further research, the findings of this study open up the possibility of improving crop resilience and paving the way for better food security in the wake of climate change. ●
Yara has recently established a new Incubator Farm in the Columbia Basin of Washington (U.S.), aimed at exploring how a complete potato crop nutrition program that drives productivity and grower profitability can simultaneously lead to a reduced carbon footprint.
The 260-acre trials will analyze the role of crop nutrition and practices such as 4R nutrient management in supporting the industry’s need to continue to produce high yielding, quality crops, while also implementing solutions to decarbonize the value chain.
“The global food chain continues to be under pressure to produce food for a growing world population, while also being tasked with reducing the environmental footprint. These two missions don’t have to be mutually exclusive, but take investment in research and exploration to find solutions that both improve farmer profitability and have a nature-positive impact,” said Trey Cutts, market development director, Yara North America. “The Incubator Farm network in North America is designed for this challenge, and we are excited to establish a farm that focuses on such a globally important crop such as the potato.”
The farm will enable collaborative research efforts to address sustainability and crop nutrition goals through the latest innovations in digital tools and future focused technologies in the industry. Yara’s partners and other industry stakeholders will be invited to leverage the farm’s research and findings with the opportunity to see firsthand the benefits of the crop nutrition solutions implemented.
“Yara’s new Potato Incubator Farm will bring together findings from large scale trials and innovation-focused small plots – giving us, our partners and the industry valuable insights into the role of crop nutrition in potato production sustainability,” said Erika Wagner, potato crop manager, Yara North America. “We envision the farm being a center to drive collaborative research and foster innovation, while working towards Yara’s global ambition of Growing a Nature Positive Food Future.”
Field scale trials at the farm will include half pivots of Yara’s TopPotato crop nutrition solution and half pivots of grower standard fertility program. There will also be multiple points of data collection throughout the season to evaluate crop performance related to emergence and early vigour, tuber set, resilience to stress, yield, storage and processing quality. On smaller scale plots nearby, Yara will also trial future-focused treatments evaluating nutrient use efficiency, water use efficiency and soil health initiatives as part of a global strategy to advance regenerative soil health insights.
Yara North America has three additional Incubator Farms – two in the U.S., in Modesto, California and Auburn, Alabama; and one in Saskatoon, Saskatchewan, Canada. The farms are instrumental in advancing Yara’s ambition of “growing a nature positive food future” by building solutions to decrease carbon footprint, improve water and nitrogen use efficiency, regenerate soil sources and more. ●
A sand-based mulch could help reduce irrigation on desert farms
A nature-inspired wax-coated sand could help enhance food production in the desert as freshwater resources dwindle.
Many arid countries are facing serious water security problems. In desert regions such as Saudi Arabia, high temperatures and dry winds accelerate evaporation from the soil and increase transpiration from plants, which consequently need extra water to maintain their ideal temperature and absorb nutrients. Farmers rely upon unsustainable levels of irrigation to meet their crops’ increased evapotranspiration needs.
“With over 70 percent of the country’s freshwater resources used for agriculture, groundwater aquifers that supply 90 percent of irrigation water are being irreversibly depleted,” noted Kennedy Odokonyero, a postdoc at KAUST in Himanshu Mishra's team. In some arid countries, plastic sheets are used to curtail evaporation, but the plastic eventually ends up in landfills.
In 2016, Himanshu Mishra and colleagues developed superhydrophobic sand (called SandX), a bio-inspired material comprising grains of sand or sandy soils coated in a nanoscale layer of paraffin wax. The sand’s roughness combined with the naturally impermeable wax created an extremely water-repellent (superhydrophobic) surface.
“A 5-10mm thick layer of SandX applied like mulch over wet soil greatly reduces evaporation,” said Mishra. A four-year field study of SandX mulching of tomato, wheat and barley plants in western Saudi Arabia showed that “SandX significantly improved plant health, size and yield under normal irrigation,” he said, “but the specific physiological factors underlying these results were unclear.”
Further investigation by Mishra's team looked at the effects of SandX on tomato plants (Solanum lycopersicum) grown in controlled, desert-like conditions alongside a group of unmulched tomatoes for comparison. They tracked water use, plant size and the physiological health of the roots, shoots and fruits of the plants under normal and reduced irrigation.
Remarkably, the combined evaporation and transpiration budget remained the same in mulched and unmulched plants. However, SandX mulching reduced evaporation losses by nearly 80 percent, which enhanced transpiration and benefitted the plants under both irrigation scenarios.
“Mulched plants had a significantly wider root xylem, the vessel that transports moisture and minerals from the root through the stem, which improved water and nutrient uptake from the soil,” noted Odokonyero. And just as the team observed in their field tests, the fruit yields of the mulched tomatoes were around 30 percent higher than the unmulched counterparts.
“SandX could offer a sustainable solution for excessive water consumption,” said Odokonyero. Field trials are already underway on different crops and native trees in Saudi Arabia, and the team has begun scaling up SandX production after receiving KAUST’s Innovation and Economic Development grant. “Our technology will contribute to food production and greening projects in arid regions across the Middle East and beyond,” concluded Mishra. ●
Using a highly hydrophobic layer of sand as a mulching material reduces soil evaporation and enhances crop yield significantly.
Photo: Adair Gallo Jr.
