As the retail division of Agrium, Inc., fertilizer has been our strength for years and we offer you access to high quality, performance-driven inputs to increase the quality and quantity of your crops. It’s about providing the right combination of soil nutrients for your crop to flourish and your CPS representative is ready to provide recommendations specific to your fields.

In addition to offering granular, liquid and anhydrous ammonia fertilizer, we offer bulk prescription blends mixed to specific requirements utilizing specialized computer software. By providing an industry-leading selection of cost-effective and performance-driven inputs, we deliver what growers need to optimize their yields and returns. 

Fertilizer facts

The Right N Fertilizer

Many farms in Western Canada rely on anhydrous ammonia (NH3) fertilizer as the main source of nitrogen for their crops.  CPS supplies growers with NH3 from many of our locations, primarily in the northern Prairies. For NH3 to be a good choice of crop nutrition for a farm, it needs to fit within the parameters of 4R Nutrient Stewardship agronomy – the Right fertilizer applied at the Right rate, at the Right time and at the Right place in the soil. 

PLACEMENT

In the spring, we should be thinking about the Right placement of NH3 in the soil.

Consider that NH3 must be placed in a band beneath the soil – that’s the Right place for any nitrogen fertilizer to avoid loss as a gas or leaching and to protect the nitrogen from ‘immobilization’ by bacteria as last year’s crop residue decays.

[106 site years of data in Western Canada. Rennie, Doyle and Cowell, 1993:  Summary of western Canadian research.]

DEPTH

There have been numerous studies to measure depth and movement of NH3 in Western Canada, including the research of Les Henry and Terry Hogg which measured NH3 movement behind farm applicators at rates of 35 to 150 lb N per acre. This study and others determined that nearly all NH3 is contained within a 5 cm radius from the centre of the application band.

[Ammonium (NH4+) levels in field soils at 7 sites in the Black soil zone in radius of an NH3 band (Les Henry and Terry Hogg, Can. J. Soil Sci., 1982).]

Further work with soil cores by Les Henry and Dale Tomasiewicz confirmed that NH3 bands are contained in soil in a narrow radius in both wet and dry soils.

We don’t need to apply NH3 very deep, which is sometimes assumed. For most soils, an application depth of 8-10 cm is enough to prevent loss. Common sense must prevail when selecting a depth to set an NH3 applicator. The soil clay and organic matter will very quickly trap and retain applied NH3, but you still need good soil conditions and closure behind each bander. 

NH3 can be a 4R fertilizer for your farm: the Right fertilizer applied at the Right Rate and Right Time – and the Right depth.

Sulphur (S) is considered to be the fourth major nutrient required by plants. It is often forgotten in the fertility program, yet most crops utilize as much S as phosphorus. Critical to growth, S plays a major role in the formation of proteins, enzymes, chlorophyll and effective nodulation.

Crop symptoms

Typically, S deficient crops are spindly, later maturing and the younger leaves are pale green to yellow in colour. In canola, the leaves may cup inwards and develop a reddish or pink colouration on the underside of the leaf.

Sulphur deficient soils

Generally, S deficiencies occur on soils that are coarse textured (sandy), well drained and/or low in organic matter. Deficiencies are also noted on soils with a relatively long history of canola or alfalfa production in the rotation.

N:S balance

Depending on the crop and its growth stage, optimal nitrogen (N) to sulphur (N:S) ratios range between 7:1 and 15:1. To obtain the optimal plant N:S ratios, soil N:S ratios should be between 5:1 and 10:1, depending upon the crop grown. The ratio in the soil should always be lower than that required by the plant to ensure adequate N:S ratios in the plant.

A soil and plant tissue analysis will help identify the need for additional S and the rate required. When soil testing information is not available and the soil is thought to be marginally deficient in S, N and S should be added in a ratio of 7:1 for canola and 10:1 for wheat.

Forms of sulphur

Plants take up S in the sulphate form (SO4=). Ammonium sulphate supplies a readily available form of sulphate. The elemental form of S must be oxidized to the sulphate form before it is available to the crop. As a result, spring applied elemental S may not supply adequate sulphate to your crop during the growing period in which it is required.

General fertilizer recommendations

CROP AVAILABLE S (lbs/ac)
Cereals 15
Canola 20
Alfalfa 30

Application method

Sulphate-S can be applied pre-plant (broadcast, banded or seed row), topdressed after crop emergence or at seeding.

High residue return may result in a temporary nitrogen (N) deficiency due to soil microbial activity. Returning large amounts of crop residues, especially cereal residues, or poorly distributing these residues can cause temporary N deficiencies and reduce crop growth and yield. These deficiencies are often apparent where swaths were located the previous year.

Soil microbes utilize N

When crop residues are added to the soil, soil microbes utilize the residues as a food source. However, some residues may not contain adequate N to sustain increasing microbial populations. To maintain growth, these microbes use soil and fertilize N for their own growth, thus competing with the plant for available N.

Immobilization & mineralization

Nitrogen used by microbes becomes temporarily fixed within microbial tissues. This process, referred to as immobilization, temporarily decreases the amount of available N. Under low N input situations this leads to a N deficiency. However, the N that is in the residue and/or microbial tissue is eventually released to the crop through a process called mineralization.

Carbon to nitrogen ratio

The amount of carbon (C) in the residue relative to the nitrogen (C:N ration) determines whether N is released from the crop residue or tied up by the soil microbes. The C in the residue provides a food source for the microbes; the N provides a building block for protein production. If the residue’s C:N ratio is high, the residue may not contain enough N to support the microbe’s needs.

C:N Ratio Crop Results
30:1 or more Cereal straw Initial tie up on N
Between 30 or 20:1 Legume residues May be a tie up or release of N
20:1 or less Green manure or legume residues Usually a release of N early in the decomposition process

Summary

Remember, immobilization is relatively temporary and continued addition of residue leads to increased amounts of organic matter and mineralizable N in the soil. Returning residues and a proper fertility program will build and sustain soil quality. Yield reductions caused by immobilization can be reduced by ensuring that there is adequate N available for the crop and microbial use.

 

Without adequate nitrogen (N), canola yield, quality and profitability are greatly reduced. Your ability to prevent a N deficiency plays a big role in determining your crop’s success or failure.

Of all the crops grown on the Prairies, canola is one of the largest users of N. A crop of canola requires approximately 3 to 3.5 lbs of N per bushel of grain produced.

Under severe N deficiencies, canola will exhibit some or all of the following deficiency symptoms:

  • Greenish-yellow discolouration (especially older leaves)
  • Purpling of leaves
  • Reduced leaf and plant size
  • Reduced flowering period
  • Reduced pod formation and yield

Confirming your suspicions

Visual symptoms are often the first sign of a N deficiency. Although these symptoms are good indicators, they may not occur under marginal deficiencies and can easily be mistaken for symptoms caused by other reasons. 

To confirm you suspicions, it is best to conduct a soil and tissue test. Comparative samplings of good and poor areas are strongly recommended. This technique provides additional information that can be valuable when making a diagnosis or recommendation. To prevent unnecessary yield losses, soil test your fields prior to seeding.

Correcting nitrogen deficiencies

When a deficiency is diagnosed early, you can improve the situation by topdressing additional nitrogen fertilizer. The greatest yield benefit will occur when applications are made prior to bolting (before or when the canola is in the rosette stage with four true leaves).

Find out more about our stewardship values and our commitment to the 4R Nutrient Stewardship System, matching the right fertilizer to the crop, delivering the right amount at the right time and ensuring nutrients stay where crops can use them.