In preparation for growing lentils in 2017, field selection, fall weed control, and residue management should be top of mind this fall, says a provincial crop specialist.
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, said Neil Whatley.
“Lentil plants have a very low tolerance to waterlogging and are susceptible to root diseases, so avoid poorly draining soils as much as possible” he said.
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. But if lentils are grown on canola or mustard stubble, consider a fungicide application for sclerotinia white mould, he said.
Lentil has a thin canopy at the onset of the growing season, making it a poor competitor with weeds.
“Wild oats, as well as volunteer wheat and barley, are important weeds to control because they are difficult to clean from the smaller-seeded lentil varieties,” said Whatley.
Given 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. Consider a fall-applied ethalfluralin (Edge) or trifluralin product application, which use Group 3 mode of action. Edge and the trifluralins are only registered for fall application as granular formulations, and must be incorporated at least once in the fall.
Whatley also advises producers to grow lentils in fields where a lot of nitrogen was extracted from the soil by 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. Whatley recommends checking cropping restrictions of chemistries applied over the past few years to realize if it’s OK 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 rot pathogens generally affecting both pea and lentil.
“To help prevent root rot from occurring, leave three years between field pea and lentil crops or between lentil and lentil crops, and six years if the aphanomyces pathogen is present,” said Whatley.
Good residue management is also key for even emergence and getting the best results from pre-seed herbicide application, he said. As well, lentils seeded into heavy crop residue are more susceptible to spring frost injury because the soil doesn’t heat up as much during the day.