This article appeared in the Winter 2017 issue of Pulse Crop News.

The buzz word for pulse crops in 2016 across Alberta was certainly red lentil. High prices and producer interest pushed acreage up 126 per cent from 220,000 acres in 2015 to over 550,000, acres according to Statistics Canada. Industry representatives feel this number is highly estimated but, regardless of the numbers, there were more red lentil grown in Alberta than ever before.

When prices jump and producers respond in an effort to bring higher revenue to the farm, many times a crop is pushed beyond its agronomic suitability and grown in areas where it shouldn’t be. Unfortunately, the result is a poor crop where yield and quality suffer.

Do lentils grow well in Alberta? The timing was good for research results released in the spring of 2016 answering that question. Funded by the Alberta Pulse Growers and ACIDF, Robyne Bowness, a pulse research scientist with Alberta Agriculture and Forestry finished a four-year project testing Clearfield red lentil at five Alberta locations, showing that red lentil can be successfully grown in certain areas of Alberta with good success.

Ninety per cent of Canadian lentil are grown in Saskatchewan. The climate and soil conditions are very conducive to success. Many areas of Alberta have similar conditions and soil characteristics as our neighboring province, so why are we not growing more lentil here? Could red lentil be suited to your farm? Here are some things to consider:

Soil texture and field drainage

Lentil crops do not tolerate water saturated soils. Avoid fields with high water holding capacity or fields where water tends to pool for prolonged periods. Sandier soils with good drainage in the brown or dark brown soil zones are a good choice. Success has been achieved in the thin black and grey wooded soils as well in drier years and well drained areas. As this crop tends to be fairly indeterminate, drought stress is encouraged after flowering to enhance time to maturity.

Weed pressure

Weed control in lentil is important as the crop does not compete well until canopy closure at flowering. The imidazolinone herbicide resistance present in Clearfield red lentil will help manage annual weeds but will not control perennial and/or winter annual weeds. Heavy infestations will result in yield loss. Perennial weeds that are difficult to manage such as quackgrass, Canada thistle, sow thistle and narrow leaved hawk’s beard need to be controlled in the fall prior to seeding the lentil crop.

Nitrogen and other nutrient levels

High nitrogen levels promote vegetative growth, increase days to maturity and reduce nitrogen fixation in pulse crops. It is not recommended to grow a pulse on fields with high nitrogen levels, but rather choose a crop with high nitrogen requirements. Pulse crops grown on fields that have a recent history ( cattle (solid) > hog (liquid). Summerfallow fields tend to be high in nitrogen as well, and should not be considered.

Crop rotation

Diverse crop rotations reduce the risk of disease, enhance the soil profile and contribute to overall soil health, which in turn increases long term profitability. Seeding a broadleaf crop into cereal stubble is a best management practice. Growing a lentil crop on broadleaf stubble, especially canola, increases the risk of disease.

Disease considerations

As mentioned, it is best to rotate a lentil crop with a cereal crop. Seeding a lentil crop into broadleaf stubble is not recommended. For example, Sclerotinia is common to both canola and lentil and is, therefore, not a good management strategy. As pulse crops tend to be seeded early in the year into cooler, wetter soils, seed treatment is recommended.

With the increase of soilborne root rots showing up across Alberta over the past few years, seed treatments are an essential tool. Fusarium and Aphanomyces root rot have become a problem, especially in wetter soil zones and under high moisture conditions. These diseases can potentially devastate a lentil crop. A seed treatment can help with Fusarium but nothing is registered to manage Aphanomyces at this time. Unfortunately, there is nothing that can be done in-crop.

With these considerations in mind, lentil may be a valid and profitable rotational crop on your farm. If so, you may be thinking you could give it a try, especially if the price remains high. So your next question is: “How do I grow them?” The research trials looked at some basic agronomic factors to address the best management strategies for Alberta soil zones. Here is what we learned:

1. Nitrogen application and inoculation

As a pulse crop, why would you add nitrogen? Anecdotal information from producers who had grown the crop suggested that it may be beneficial for lentil. A trial was conducted testing rates of nitrogen application from 0 to 60 kg ha-1 and combining that with the use of symbiotic rhizobial bacterial inoculant in some treatments and no inoculant use in others.

It was found that the use of starter nitrogen applied at seeding was, in fact, beneficial as long as amounts were low. Amounts below 30 kg ha-1 had a positive effect on lentil growth, but above that amount there was a negative effect on growth, nodulation and yield. It was also found that the use of rhizobial inoculant is important.

Inoculation with the bacteria resulted in higher yield regardless of nitrogen application at any rate. Relying on the native rhizobia in the soil to work symbiotically to fix nitrogen is not adequate and adding high levels of nitrogen fertilizer does not compensate.

2. Seeding rate

Determining the optimal seeding rate was another focus of investigation. With different soil types around the province and varying climatic conditions within growing regions, the seeding rate could differ. Plant populations ranging from 40 to 200 plants m-2 were tested to determine which rate would provide the best return given seed costs and resulting yield.

In general, the higher the seeding rate, the higher the yield. This was noted for all seeding rates and was significant up to 160 plants m-2. Beyond 120 plants m-2 the yield increased slightly from 120 – 160 plants m-2 and again from 160 – 200 plants m-2 in a few instances but the increase was minimal and depended upon available moisture.

The structure and growth habit of the plant canopy was diverse at different plant populations. The plants seeded at 40 plants m-2 were short, bushy and had thick stems, whereas the plants seeded at 200 plants m-2 were taller, spindly and had thin stems.

At the lower seeding rates, the plants took advantage of the nutrients, water and space available and tried to compensate as much as possible, but given the low population, they couldn’t compensate enough. At the high seeding rates, inter-plant competition was significantly increased. The plants responded by stretching to reach available light but were limited by nutrient and water availability. In years and locations where moisture was not limiting, higher yields were observed at higher seeding rates.

3. Herbicide use

Group 2 imidazolinone herbicides work well at controlling a number of weed issues in pulse crops. The Clearfield tolerance in the new red lentil varieties is very advantageous for producers. However, sometimes the group 2 herbicides can be a little “hot” and the temporary yellow flash we see in pulses after an application can cause some concern until the crop recovers and grows out of it.

The imidazolinone group of products includes a number of active ingredients, so each active was tested to see if there were any advantages or disadvantages among the products for growth or yield. Solo (imazamox), Odyssey (imazamox + imazethapyr), Odyssey DLX (imazamox + imazethapyr + tepraloxydim) and Ares (imazamox + imazapyr) were all applied at the recommended rate and timing to the lentil crop.

The results showed that all herbicide formulations worked well at effectively controlling weed pressure and there was no significant damage to nodulation or yield decrease. The most effective herbicide formation differed depending on the year, amount of precipitation, soil type and other climatic conditions.

Additional factors to consider, that were observed through the research trials, were other nutrient requirements and the occurrence of disease. The recommendation that nitrogen is not necessarily needed does not indicate that fertilizer is not required at all. Phosphorus is an important nutrient for a lentil crop and is required for root development, early plant growth and crop maturity. Lentil is less sensitive to seed row placed phosphorous than other pulses, but levels below 25 kg ha-1 will negatively affect growth and yield.

Sclerotinia can be a problem in wetter areas as well. If lentil is grown in higher moisture areas, soils or years, an application of fungicide is recommended before canopy closure to protect from this potentially devastating disease. It is well documented that pulses are good for the farm and contribute in many ways to long term sustainability. Another pulse crop option on your farm would only add to the rotational benefits and contribute to diversity and potential economic profitability.

If after considering the aforementioned factors you feel lentil may be a good fit for your farm, give them a try. Growing lentil can be tricky but the research has been done and the results prove that success is possible when good agronomic practices are followed.