Lentil is a management-intensive crop. Before planting lentil, many issues need to be considered, which will often affect the crop you grow before lentil. These issues could also determine whether lentil is desirable in your rotation at all.
- lentil cannot tolerate residues from the following herbicides: Accord®, Ally®, Assert®, Banvel®, Curtail M®, 2,4-D, Lontrel®, MCPA, Muster®, Prevail®, Rustler®, Unity® or Prestige®. If a residual herbicide problem is suspected, check the manufacturer’s label (if the label does not clearly state whether lentil can be grown in the given situation, contact the manufacturer directly)
- lentil has a greater risk of developing sclerotinia stem rot if it follows canola, mustard, sunflower, field pea or faba bean in your rotation, so lentil should follow cereal crops
- volunteers from previous crops can reduce lentil’s yield and quality:
- volunteer canola and tame mustard can be difficult to control with herbicides
- volunteer barley and durum wheat are difficult to separate from large-seeded lentil
- volunteer hard red spring wheat is difficult to separate from small-seeded lentil
- failure to control volunteer cereals can result in reduced lentil grade
- lentil lacks the number of effective herbicide options that some other crops have (for example, no herbicides offer in-crop control of Canada thistle or perennial sow-thistle in lentil) – only fields free from these weeds or fields with sufficient control measures (pre-harvest glyphosate) the previous cropping season are suitable for lentil production
- lentil should not be grown on the same field in consecutive years because of the risk of severe ascochyta blight infection:
- ascochyta can spread from lentil stubble from last year’s crop to adjacent fields containing the current year’s crop
- ascochyta blight can also be spread by infected seed
- anthracnose can be transferred by wind-blown dust between adjacent lentil plantings or lentil plantings and adjacent lentil stubble
- lentil seed is very susceptible to mechanical damage during seeding, harvesting, cleaning and storage operations (especially with dry lentil seed at 14 per cent or less moisture) – although damage is often not visually apparent
- reduced germination and vigour can also result from herbicide residues
- to avoid germination and vigour problems, all samples should be tested for germination, seed vigor and seed-borne ascochyta blight, and use certified seed
- Crown® (carbathiin and thiabendazole) is registered as a seed-applied or drill box seed treatment for control of ascochyta seedling blight and seed rot (highly recommended for zero-tannin lentil varieties) – the product is compatible with nitrogen-fixing bacteria found in lentil inoculant
- Vitaflo 280 (carbathiin and thiram) is a newly registered fungicide for control of seed decay and damping off. This product should not be directly mixed with lentil rhizobium (apply in sequence)
- lentil can satisfy up to 75 per cent of its own N demand if properly inoculated – use single strain inoculant products containing rhizobium bacteria specifically for lentil
- rhizobium are living organisms and must be handled carefully to ensure viability – always consult product labels for handling instructions and application rates
Selecting a Site
Field selection is key when planning for lentil in the rotation. Here are some recommendations for field selection for lentils.
- Choose fields that are level and free of stones or dirt clumps. Because the crop canopy is not very tall, choosing a smooth field will make harvest easier.
- Use a land-roller between seeding and the fifth node stage to level the field and push down stones.
- Avoid soils with high N content prior to seeding, as these soils will inhibit nodule formation and are unsuitable for lentil production.
Excess water in lentil crops can cause problems, including delayed maturity, increased disease, and lower yields. Despite that, lentil is a shallow-rooted plant and, therefore, needs significant soil moisture to produce optimum yields. As such, irrigated lentil production requires careful management because, while lentil requires water, it dies quickly when flooded.
Here are some tips to help you manage irrigation in your lentil crop.
- Choose a variety that is best suited for production under irrigation.
- Don’t let water accumulate on the soil surface, especially at seeding time.
- Apply 0.8 to 1.2 in. (2 to 3 cm) of water in early June to prevent plant stunting and yield reduction, especially if plants are starting to display drought symptoms.
- If metribuzen (Sencor® or Lexone®) is applied to the crop, delay irrigation for at least two weeks after spraying. This will prevent leaching of the herbicide into the lentil rooting zone, which could result in crop damage.
- Discontinue irrigation when flowering begins; moisture stress at this time is desirable and will promote flowering.
- Use approximately 4 in. (10 cm) of water after the stress period. This will encourage pod formation and filling.
Rolling Lentil Fields
Rolling lentil fields can reduce problems at harvest time. Keep these tips in mind when rolling your lentil fields.
- Roll lentil fields soon after seeding and when the soil surface is dry.
- Do not roll lentil fields late (after the fifth node stage), as it can result in bruising of the lentil leaves, stem breakage, and increased disease levels.
- Never roll lentil fields in the morning or when the crops are damp; rolling wet lentil leaves spreads disease.
- Do not roll lentil fields after emergence if a frost has just occurred, as crop stress can result in crop damage and yield loss.
- Water ballast in the roller is not generally necessary.