This article appeared in the Fall 2016 issue of Pulse Crop News.

Neil Whatley, Alberta Agriculture and Forestry

In preparation for growing lentils in 2017, field selection, fall weed control and residue management should be top of mind in the fall of 2016.

While land rollers, flex headers, higher podding varieties and improved lodging resistance have allowed producers to grow lentils on less than ideal fields, it continues to be important to select fields with fewer rocks. Lentil plants have a very low tolerance to waterlogging and are susceptible to root diseases, so avoid poorly draining soils as much as possible. Lentils grown on sand and loam soils turn out better in soil zones with customarily higher precipitation or during growing seasons with higher than average rainfall. If lentil is grown on canola or mustard stubble, be prepared to consider a fungicide application for sclerotinia white mould.

Lentil has a thin canopy at the onset of the growing season, making it a poor competitor with weeds. Wild oat, as well as volunteer wheat and barley, are important weeds to control because they are difficult to clean from the smaller seeded lentil varieties. Given that some wild oats are resistant to Group 1 (i.e.: Poast Ultra) and Group 2 (i.e.: Odyssey) herbicides, a wider herbicide rotation slows their resistance development. Therefore, it is important to consider a fall-applied ethalfluralin (Edge) or trifluralin product application, which use Group 3 mode of action.

Edge and trifluralin products suppress wild oat, volunteer barley and volunteer wheat. These Group 3 herbicides can also help control other weeds resistant to other herbicide groups. For example, Edge controls kochia which can be resistant to both Group 2 (i.e.: Odyssey) and Group 9 (i.e.: glyphosate) herbicides. Edge and the trifluralins are only registered for fall-application as granular formulations and must be incorporated at least once in the fall.

Grow your lentils in fields where plant available nitrogen levels are low due to high extraction rates from the previous crop. Planting lentils in fields high in nitrogen prevents the plants from effectively forming nitrogen fixing nodules, increases disease pressure on a wet year due to an increase in vegetative growth and delays maturity. Although newer lentil varieties are generally more determinant than older varieties, excess nitrogen in the soil continues to heighten the risk of excessive vegetative growth instead of adequate seed set if rainfall continues in July and August.

Lentils are sensitive to some herbicide residues in the soil. Check cropping restrictions of chemistries applied over the past few years to determine if it’s okay to plant lentils. Some residues do not break down for two or more years, especially under dry growing conditions. If you are unsure about a field, submit soil samples to a lab for a bioassay.

Root rots have been more problematic on the Prairies in pulse crops over the past few years, with the same root rots affecting both pea and lentil. Leave three years between field pea and lentil crops or between lentil and lentil crops; six years if aphanomyces is present.

Ensure a uniform lentil stand next spring by evenly spreading residue or straw from the previous crop. Good residue management not only prevents variable crop emergence, but also provides maximum efficacy of the pre-seed herbicide application. Further to this, lentils seeded into heavy crop residue are more susceptible to spring frost injury. Additional bare soil absorbs the sun’s heat during the day, releasing it at night, minimizing potential frost injury.

Avoid market class contamination by not growing red and green lentil varieties in rotation on the same field for at least four years. Experienced producers assign specific fields for only red or only yellow cotyledon lentil.