crop nutrient

Early season fertility – Beware of ‘hidden hunger’

Plants need 17 essential elements for growth and reproduction. The main criterion used in designating an element as essential is that it must be required for a plant to complete its life cycle. Elements were accepted into the ‘essentiality’ clique at different times based on when somebody proved they had met the aforementioned criterion. For example, nitrogen was accepted as an essential element in 1804. The newest addition to the family is nickel, determined to be essential in 1987. Crop yield and quality are reduced when plants don’t take up these nutrients in sufficient amounts.

There are 3 ways of diagnosing nutrient deficiencies – soil testing, plant tissue analysis, and visual observation of the plant. Soil testing and plant tissue analysis are quantitative tests that compare nutrient concentrations in soil or plant to the sufficiency range for a particular crop. Visual observation, on the other hand, is a qualitative assessment of indicators such as specific leaf symptoms or stunted growth. Plants can show visual signs when there is a nutrient deficiency. But sometimes they don’t. ‘Hidden hunger’ is a term used to describe a situation in which a crop needs more of a given nutrient but shows no obvious deficiency symptoms. Hidden hunger can only be picked up by tissue or soil testing. If and when visual symptoms do appear, crop yield and quality will already have been reduced and corrective actions may not be effective. If detected early, hidden hunger can be corrected by foliar application of the insufficient nutrient. Foliar feeding normally elicits a quick response from the plant and is particularly advantageous where soil conditions keep nutrients in inaccessible forms.

As seeds become seedlings, it is important to keep the possibility of hidden hunger in mind. One nutrient that is vital at this stage of crop growth is phosphorus (P). Seedlings rely heavily on the P taken up in the first few weeks of growth for crop establishment and yield. Early season limitations in P availability can go undiagnosed but will result in consequences from which the plant will not recover, even when P supply is increased to adequate levels later in the season.

Most soils in the Prairies are low in plant-available P because their high pH and calcareous nature favour the tie-up of P in insoluble compounds. Under this condition, P use will be most efficient when soil contact with fertilizer is minimized by placing the P in a band in or near the seed-row. This allows roots to access and utilize the nutrient soon after emergence. In addition, biologicals containing microbes such as Penicillium bilaii will increase the phytoavailability of P in this kind of soils. Your SynergyAG rep can provide you with a low salt index phosphorus source, as well as natural products that solubilize P from soils.

-Ikenna Mbakwe, PhD, PAg
Head of Research

Dealing with insect pests of seedlings

A termite walks into a bar and asks, “Where is the bar tender?”

This joke right here is a witty reminder that insects love tender plant parts. Seedlings fit the profile perfectly. They are tender, succulent, close to the ground and are easy pickings for a host of insect pests. If left unchecked, these insects have no problem turning our farm into their stomping ground as they feast on our precious crops while singing their version of Weevil Weevil Rock You!

Insects can cause two major kinds of damage to growing crops. First, there is direct injury when insects eat leaves or burrow into stems. Then, there is indirect damage when an insect transmits a disease-causing organism into a crop. Early damage to seedlings produces uneven plant stands, and eventual yield loss. However, the presence of insects in a crop does not mean that there will be significant crop loss. The density of the insects has to reach a threshold that causes major concern. An economic threshold is the insect’s population level or extent of crop damage at which the value of the crop destroyed exceeds the cost of controlling the insect. In other words, if controlling the insect will cost you more money than the damage they’d cause, you should…choose the lesser of two weevils. In canola, for example, treatment is recommended when there is 25% defoliation in the presence of flea beetles.

Keeping insect infestations below significant levels is the goal. Effective control starts with effective monitoring. Every field should be monitored on a regular basis to estimate the populations of specific insect pests. A good understanding of an insect’s behaviour will help to know how best to scout for it. For example, cutworms, can be found first on hilltops because they prefer drier and warmer soils. They will eventually move to low-lying areas when their population increases.

If insect populations exceed economic thresholds, then it’s a good idea to control them using the appropriate methods. Biological control involves the use of the insect’s natural enemies. The northern field cricket (Gryllus pennsylvanicus), for example, is known to prey on flea beetles. In some cases, cultural control of insect pests using good agronomic practices such as effective weed control and crop rotation will help to manage certain insect pests. Chemical control using a good seed treatment or a post-emergent foliar application will also be effective.  So, take the sting out of problems with insect pests and talk to your SynergyAg rep about scouting and suitable solutions.

-Ikenna Mbakwe, PhD, PAg
Head of Research


soil temperature

Soil temperature and its implications for seeding

In many office settings, a request to adjust the temperature of the shared office space can be met with anything from a cold shoulder, to a lukewarm acknowledgement, or a heated argument. Out in the field, however, nature holds the thermostat and we do not get to make that request. So, when late April or early May arrives, our part of the world warms up and farmers in the Prairies prepare to get out into the fields and start seeding. But we also keep an eye on soil temperature – or we should. We should because although soil temperature is affected by air temperature, it is also influenced by soil moisture, soil colour, slope of the land, and vegetative cover which can vary with different soils.

Planting at the optimal soil temperature helps to ensure the best crop emergence. As temperature increases, germination becomes faster and more uniform. Seeding into cold soils can cause seeds to remain dormant and become more vulnerable to soil pathogens, diseases, and predators. This will ultimately lead to poor or staggered emergence and less-than-ideal plant stands. Reduced plant stands favours weed and pests, and also presents staging issues when timing pesticide or herbicide applications. For most spring-seeded crops, soil temperatures warmer than 10°C are optimum for germination. Various crops, however, will germinate at lower temperatures. The minimum soil temperatures needed for seeds of some common Prairie crops to germinate is shown in Table 1.

Table 1. Minimum soil temperatures needed for germination to begin (source: Saskatchewan Ministry of Agriculture)

Crop Soil temperature (°C)
Mustard 2
Canola 2
Flax 3
Wheat 4
Barley 4
Lentils 5
Peas 5
Soybeans 10

Assessing soil temperature is quite simple. First, you have to know the seeding depth of your crop. Then, using a soil thermometer, measure the soil temperature at this depth in a few areas throughout your field. Take two readings – one in the morning, and again in the evening. Take the average of these two temperatures and repeat this process for two to three days to get a multiple day average.

But should you base your seeding decision on soil temperature alone? Certainly not. Research in Western Canada has shown that early planting leads to increased yield because early-seeded crops will utilize available soil moisture better, avoid heat stress during flowering, and can evade the peak pest and disease period. So, it is important to take other prevailing conditions into consideration and plan to seed early. If you have to seed into colder soils, a good way to lower your risk is to use a seed treatment that can improve emergence in cold soils as well as protect the seed against diseases and pests before emergence. Furthermore, because root growth is slow in cold soils, a seed-placed, low salt index phosphorus product will be ideal in boosting root growth in this kind of environment. Your local SynergyAG rep can help you choose the right products.

-Ikenna Mbakwe, PhD, PAg
Head of Research

Minimizing Nitrogen Losses

If there was a throne meant for the king of plant nutrients, I bet nitrogen will be sitting on it, unopposed. The nutrient is by far the most important in crop production. It’s also the most studied, and the most talked about. I’ve even found several songs dedicated to it, from pop to rap…that’s quite cool. What is not cool, however, is the fact that it is difficult to get nitrogen to stay where you want it to – close to plant roots. It seems to always be on the move, change forms and find pathways to leave the soil.  Knowing these forms and pathways is important in minimizing nitrogen loss.

When nitrogen sources such as urea, anhydrous ammonia or manure are applied to the soil, they rapidly convert to the ammonium form. Ammonium (NH4+) is positively charged and can, therefore, be held tightly to the surfaces of soil or organic matter, which are mostly negatively charged (opposites attract; likes repel). But, under favourable conditions, soil bacteria convert ammonium to nitrites and finally to nitrates (NO3). Nitrate is negatively charged and is repelled by the surfaces of soil and organic matter and therefore susceptible to leaching – movement of nitrate below the plant’s root zone by percolating water. Leaching is more prevalent in coarse-textured soils such as sandy soils because these soils have a lower water holding capacity. Nitrate-containing fertilizers, such as urea ammonium nitrate (UAN) and ammonium nitrate, are susceptible to leaching loss as soon as they are applied.

When soils are very wet or waterlogged for a couple of days, soil microbes starved of oxygen will strip the nitrate molecule of its oxygen. With the oxygen stripped from the nitrate, the remaining nitrogen is ultimately lost to the atmosphere as nitrogen oxides and dinitrogen gas. The process is called denitrification. Denitrification rates can range from 5 to 20% of applied nitrogen. Denitrification can be significant when nitrogen is applied in the fall, before a wet spring. It most commonly occurs in heavy clay soils because of poor drainage.

Urea-based nitrogen fertilizer products such as UAN, or dry urea are susceptible to ammonia volatilization if surface-applied and not incorporated. Ammonia is an intermediate form of nitrogen during the process in which urea is transformed to ammonium by urease enzymes. The risk of volatilization loss is high in moist soils and increases with temperature, soil pH and windspeed. Up to 64% of applied N can be lost as ammonia.

Plants take up nitrogen from the soil solution mainly as nitrates and ammonium ions. If you can delay or prevent ammonium from converting into nitrate, you will reduce nitrogen loss by leaching or denitrification. Nitrogen stabilizers can help with that. Some stabilizers can also slow down the conversion of urea to ammonium which allows more time for the nutrient to move into the soil, thereby reducing loss through volatilization. Your SynergyAG rep can help you pick out the right products.


-Ikenna Mbakwe, PhD, PAg
Head of Research





herbicide resistance

When weeds refuse to die

Since the 1940s when herbicides were commercially released, their use has revolutionized agricultural productivity. Without them, weed control in large-scale farming will neither be economical nor practical, and yield losses will be massive. But the innovation was unfortunately accompanied by the increase in the dominance of resistant weeds. One of the earliest recorded cases of herbicide resistance was in wild carrot in Ontario, Canada in 1957. Although science quickly stepped in to develop herbicides with different modes of action, there has been a steady increase in the number of resistant weeds (see global trends in the figure below). Weeds have learned to adapt and science is struggling to keep up.

increase in herbicide resistance
Herbicide resistance is the inherited ability of a plant to survive a herbicide application that would kill a normal population of the same species. Herbicide-resistant weeds have developed genetic resistance to certain herbicide groups, or sites of action. It is important to note that herbicides do not cause resistance in weed species, rather they inadvertently favour resistant individuals that naturally occur within the weed population. Resistance proceeds when the same herbicide, or herbicides from the same group, are applied repeatedly to an area that contains resistant weeds. The susceptible plants die while the resistant ones, favoured by the reduced competition, multiply. With time, only these resistant species will remain and any weed control efforts using that herbicide will be ineffective.

The introduction of glyphosate provided relief from herbicide resistance for 15 years until glyphosate resistance was found in 1996 from rigid ryegrass in an orchard in Australia. Subsequently, several additional glyphosate-resistant weed populations have been identified even here in the Prairies. The increasing risk of glyphosate resistance means that we are in danger of losing the efficacy of one of the most potent herbicides ever produced. Tank mixing multiple modes of action is an important step in preventing herbicide resistance in weeds, and the spring burn-off window is a good opportunity to use a tank mix rather than glyphosate alone.

Management strategies important in preventing herbicide resistance include:

  • use herbicides only when necessary, and use them at the recommended rate
  • avoid using the same herbicide or herbicides from the same group in the same field, in consecutive years
  • use herbicide mixtures that include 2 or more herbicide groups that control the target weed
  • practice crop rotation because different crops allow for a wider range of herbicide options.

Herbicides are very important tools for efficient and cost-effective weed management but their efficacy is an exhaustible resource that can be depleted over time. The present challenge is to manage them in such a way that their usefulness is prolonged while science tries to find a way to beat the constant evolution of resistant weeds. The renowned scientist Robert Pyle once said, “…make no mistake: the weeds will win; nature bats last.” For all our sakes, I hope nature slows down a bit.

-Ikenna Mbakwe, PhD, PAg
Head of Research

How water quality affects herbicide efficiency

Recently, I read a chemistry quote that said, “You either have to be part of the solution, or you’re going to be part of the precipitate”. Now, I know that’s a play on Eldridge Cleaver’s famous words (You either have to be part of the solution, or you’re going to be part of the problem), but when mixing herbicides with spray water, it’s a good idea to think about it that way. As far back as the 1990s, research has demonstrated that the solubility and efficacy of some herbicides can be adversely affected by the quality of water used to dilute them.

So, what are the key parameters to watch out for?

The pH measures the level of acidity or alkalinity. A pH of 7.0 is neutral. If the pH is lower than 7.0, it is acidic, higher than 7.0, it is alkaline. Herbicides such as glyphosate, 2,4-D, dicamba, and many others become negatively charged at alkaline pH. In this condition, they are more susceptible to being tied up by positively charged ions such as those of Calcium (Ca2+), Magnesium (Mg2+), and iron (Fe2+, Fe3+), and to form complexes that are not easily absorbed by the plant, thus reducing the effectiveness of the herbicide. Extreme water pH levels can also reduce the solubility of some herbicides or cause the herbicides to break down faster, and not be as effective.

Water hardness is caused by positively charged ions of mostly calcium and magnesium, and sometimes iron and sodium. These positively charged ions can bind to negatively charged herbicides such as glyphosate and 2,4-D amine thereby reducing herbicide efficacy.

Bicarbonate is known to reduce the activity of 2,4-D amine and the “dim” group of herbicides – tralkoxydims (such as Achieve), sethoxydims (such as Poast), and clethodims (such as Centurion and Select). Bicarbonate levels as low as 500 parts per million can interfere with herbicide effectiveness.

Cleanliness/turbidity refers to how much suspended matter is in the water. Soil and organic matter particles can bind onto and reduce the effectiveness of herbicides such as glyphosate, dicamba, diquat, bromoxynil and paraquat. These particles can also block spray nozzles and affect the delivery of the product.

Cost of herbicides can be substantial, and using water of poor quality will reduce the return on investment. Besides, anything that lessens the efficiency of herbicides can lead to poor weed control and significant yield loss.  Moreover, having herbicides tied up by cations in water will result in lower-than-recommended rates of herbicides and possible herbicide resistance. So, it is important to test spray water to determine its suitability for herbicide dilution. Where laboratory services are difficult to access, a good place to start is to test the electrical conductivity (EC) of the water using a conductivity meter. The EC standardized at 25 ⁰C gives a useful approximation of the Total Dissolved Solids (TDS). If EC is less than 500 µS/cm, it is unlikely that the efficacy of herbicides will be affected. Where EC is higher than 500 µS/cm further tests are necessary to confirm the culprit ions.

If your water source is of poor quality, adding water conditioners can be helpful. Some conditioners can modify the pH of the spray water to better suit the specific herbicide. Some of these products can also bind up the problematic cations so that herbicides don’t get tied up. Be sure to talk with your local SynergyAG rep for the right options.


-Ikenna Mbakwe, PhD, PAg
Head of Research



soil health

Digging up the truth about soil health

When the Soil Conservation Council of Canada challenged everybody to ‘soil your undies’, the move sparked a lot of interest as farmers and gardeners buried clean underwear in the soil and then dug them up 2 months later to assess soil health. Those whose soils were healthy dug up little else besides elastic waistbands, while those with unhealthy soils dug up dirty but intact underwear. You could say that’s the soil health story in briefs.

The soil is not a lifeless mixture of sand, silt and clay. It is a living system buzzing with billions of bacteria, fungi, and other micro and macro organisms that are critical to the soil’s functions of providing and recycling nutrients for plant growth, detoxifying pollutants, retaining water for use during drier periods, and serving as a firm structure for agricultural activities. Soil health has been concisely defined as the continued capacity of the soil to function as a vital living system that sustains plants, animals and humans. Two elements in this definition are key. First, ”the continued capacity of” reflects the soil’s resilience and ability to regenerate and function well for future generations. Second, recognition of soil “as a vital living system” highlights the importance of soil biota.
The role of soil biota in the soil system was largely neglected in the past because it was poorly understood and difficult to measure. Today, however, with advanced analytical techniques, soil biota can be better studied, and its importance in the sustenance of life is gradually taking center stage.

So, how can we improve soil health? Research has shown that reducing the level of soil disturbance, diversifying the species of plants grown, keeping the soil covered all the time, keeping living plants in the soil as often as possible, and adding organic or biological soil amendments all have beneficial effects on soil health.

Recent studies warning that we are losing topsoil a lot faster than it can be replenished through natural processes should indeed make us pay attention and stop treating soil like dirt. And by the way, if you want to ‘soil your undies’ this year, now is a great time to start. You can find the protocol for the experiment here:

-Ikenna Mbakwe, PhD, PAg
Head of Research

seed treatment

The rise and rise of biological seed treatment

When treating seeds with biological organisms was first suggested many years ago, the idea seemed like something out of a sci-fi comic book. But today, just like how these organisms proliferate in plant systems, the idea has proliferated in the R&D departments of top agricultural companies as research scientists join the race to find the best ways to unleash the powers of these microscopic creatures. Indeed, the future of agriculture is looking more likely to be defined not necessarily by huge machinery, massive satellites and big data, but by the tiny organisms whose potentials we are just beginning to unmask.

There are billions of microbes in the soil around plant roots. Some are friends, some are enemies. The person who said ‘Keep your friends close, and your enemies closer’ wasn’t talking about crop production… not literally anyway. In farming, you’d want to keep your friends close and your enemies far, far away. Keeping the very beneficial soil microbes close is key, and forms the core of biological seed treatment.

But how do these beneficial organisms work? Farmers all over the world are familiar with Rhizobia used to inoculate legumes such as soybean, peas and lentils. These bacteria were discovered more than a century ago. When applied on seeds of legumes, the bacteria penetrate the root, resulting in the formation of root nodules that fix nitrogen from the air and make it readily available to the plant. Another bacterium, Azospirillum brasilense, in addition to fixing nitrogen, also produces plant hormones which help important plant processes such as germination, stem elongation, flower development and leaf and fruit senescence. Penicillium bilaiae, a naturally-occurring soil fungus excretes organic acids that solubilize phosphorus tied up in the soil, making the nutrient available for uptake by plant roots. Some biological seed treatments also contain natural compounds which encourage the colonization of roots by mycorrhizal fungi thereby increasing the surface area of roots and enabling them take up more water and nutrients. There is indeed, a wide range of biologicals and at SynergyAG we are committed to ensuring that growers use the products best suited to their needs.

Science has shown that seed treatments are advantageous. The return on investment will be more apparent when growing conditions are poor. For example, if a treatment is designed to help seeds thrive during periods of moisture stress, its efficacy cannot be assessed if the soil is sufficiently moist. However, treating seeds offers insurance against unexpected crop challenges or when the weather throws us a curve ball – which seems to happen far too often these days.

-Ikenna Mbakwe, PhD, PAg
Head of Research

seed treatment

Staying ahead of the game – Why seed treatment is vital for a successful cropping season

If seeds could talk, they’d probably tell you they agree with Mike Tyson when he said ‘everyone has a plan until they get punched in the mouth’. Every seed has a plan – a plan to push roots down, send shoot up and yield a bumper crop. That plan is the seed’s genetic yield potential. But a seed hardly actualizes its plan. As soon as you put that seed in the ground, it gets…well, sort of punched in the mouth by a host of soil and environmental conditions. That is why protecting your seeds is definitely one of the best decisions you’d make early in the season.

The International Seed Federation describes seed treatment as the ‘biological, physical and chemical agents and techniques applied to seed to provide protection and improve the establishment of healthy crops’. The practice of seed treatment is very old. One of the earliest references is around 470 B.C. when Pliny proposed that seeds be soaked in wine plus a mixture of bruised cypress leaves to protect them from wheat mildew. I imagine it must have been a sweet proposition (for the treater), but these early methods were crude and coverage was poor. Today, modern seed treatment facilities use sophisticated and precise equipment to coat seeds with a host of active ingredients. Seed treatments can include protectants, nutrients and biologicals.

seed treatment

Treated wheat seeds

Protectants (such as pesticides, fungicides, insecticides, and predator deterrents) are designed to guard seeds from predation and infection by pathogens. Applying these products directly to the seed is much more efficient and effective than broadcasting crop protection products. Moreover, using protectants in seed treatments is an environmentally more friendly way of using pesticides because the amounts used are very small. Nutrient amendments used in seed treatment have mainly focused on adding micronutrients, such as zinc, boron, manganese, copper, and molybdenum – important nutrients which can easily become deficient because they are often neglected in many fertilizer programs. Treatment with biologicals can deliver natural compounds or microorganisms which proliferate on the seeds, transfer to the root, protect against soil-borne pathogens, and enhance uptake of nutrients. They can also stimulate plants’ natural biological processes to help them cope with abiotic stresses such as cold, heat, drought and salinity.

Studies evaluating seed treatments have shown positive effect on germination, growth, and yield but it is important to use the right product and technique to achieve full coverage when treating seeds. Incomplete coverage will leave some of the crop unprotected, and reduce the effectiveness of the process.

The full potential of crops lies in the seed. Giving a seed every chance to reach that potential starts with a good seed treatment. Be sure to talk to your local SynergyAG rep about the right option for your needs.

-Ikenna Mbakwe, PhD, PAg
Head of Research

fertilizer salt index

Don’t Let Your Crops Feel ‘Asalted’ – What to Know About Fertilizer Salt Index

Fertilizers are great for boosting crop yield but when someone tries to convince me to add loads of a particular fertilizer to my soil, I take what they say with a pinch of salt. That’s because fertilizers are mostly salts. When they dissolve in soil water, they increase the salt concentration (also called osmotic pressure) of the soil solution. The higher the osmotic pressure of the soil solution, the more difficult it is for plants or seeds to extract the water they need for normal growth.

The fundamental principle is that for plant roots to take in water, the water must pass through the root cell membrane. Water can pass through this membrane only when the osmotic pressure of the solution inside the plant cell is higher than the osmotic pressure of the soil solution outside the cell. If the osmotic pressure of the soil solution becomes higher than that of the solution inside the cell, water cannot enter the cell and may eventually move out of it. With time, the plant tissue dries out and eventually dies. Some people call this phenomenon ‘fertilizer burn’.

Fertilizers differ in their propensity to create salty conditions in the soil. I dare to say that the brilliant scientist who developed the concept of ‘salt index’ to differentiate fertilizers was definitely worth their salt. Salt index is a measure of a fertilizer’s relative tendency to increase the osmotic pressure of the soil solution as compared with the increase caused by an equal weight of sodium nitrate. All fertilizers are compared to sodium nitrate because sodium nitrate is 100% water soluble and it was commonly used when the concept of salt index was developed. A fertilizer with a high salt index has a high tendency to damage crops compared to a fertilizer with a lower salt index. But salt index alone does not predict the amount of material that will cause injury to crops. It only classifies fertilizers relative to each other and shows which is most likely to cause injury.

It’s important to note that crops vary in their tolerance to fertilizer salts. Moreover, salt toxicity will be more serious in dry soils (because there is less water to dilute the salts), in coarse-textured soils like sandy soils (because of their low ability to react with the fertilizers), and in cold soils (because root growth in cold soil is slow and thus the root is exposed to the higher concentration of fertilizer for a longer time). Furthermore, the risk of injury is higher where fertilizer is banded close to seed or plants.
So, if your soil or plants are showing signs of nutrient deficiencies, there’s no need to ‘rub salt in the wound’. Talk to your local SynergyAG representative for guidance on the right products and agronomic techniques.

-Ikenna Mbakwe, PhD, PAg
Head of Research