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
SynergyAG

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)

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
SynergyAG

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.

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
SynergyAG

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: http://www.soilcc.ca/soilyourundies/2017/Soil-Your-Undies-Protocol.pdf

-Ikenna Mbakwe, PhD, PAg
Head of Research
SynergyAG

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.

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
SynergyAG