Description & Adaptation
Lentil (Lens culinaris L.) is a pulse crop that is part of the Leguminosae family.
Lentil plants are typically short but can range from 20–75 cm or 8–30 inches in height, depending on growing conditions.
Lentil seed undergoes hypogeal germination, meaning the cotyledons remain below-ground. The first two nodes on the stem develop at, or below the soil surface and are known as scale leaves. Scale leaves provide points for possible re-growth, should the plant sustain injury from conditions such as frost, heat canker, wind damage, or defoliation. The third node on the stem has two leaflets and is called the first true leaf. Lentil seedlings can produce a new node every four to five days under good growing conditions. Leaves are about 5 cm long with nine to 15 leaflets. Stipules, much smaller than leaflets, occur in pairs on either side of the leaf axis where it joins the stem. Just prior to flowering, new leaves will develop a short tendril at the leaf tip. At this time, usually around the 12 node stage, the first flower clusters can be seen developing at the base of the leaves.
Lentil seed undergoes hypogeal germination, meaning the cotyledons remain below ground. The first two nodes on the stem develop at, or below the soil surface and are known as scale leaves. Scale leaves provide points for possible re-growth, should the plant sustain injury from conditions such as frost, heat canker, wind damage, or defoliation. The third node on the stem has two leaflets and is called the first true leaf. Lentil seedlings can produce a new node every four to five days under good growing conditions. Leaves are about 5 cm long with nine to 15 leaflets. Stipules, much smaller than leaflets, occur in pairs on either side of the leaf axis where it joins the stem. Just prior to flowering, new leaves will develop a short tendril at the leaf tip. At this time, usually around the 12-node stage, the first flower clusters can be seen developing at the base of the leaves.
Lentil plants have an indeterminate growth habit. Plants continue to flower until they encounter some form of stress, such as lack of moisture, high temperatures, or nutrient deficiency.
Flowers are self-pollinated. Flower stalks produce one to three flowers, which develop pods. Pods are less than 2.5 cm in length and usually contain one or two seeds. Vigorously growing lentil plants with adequate space will produce two or more primary shoots from the base of the stem. However, the main contribution to seed yield is made by secondary (aerial) branches that arise from the uppermost nodes of the main stem just below the first flowering node. Flowers that form after the first week of August may not produce filled seeds by harvest.
Lentils are a cool-season crop with a relatively shallow root system (0.6 metres or 1.97 feet) and is moderately resistant to high temperature and drought. Lentils require at least moderate moisture—15 to 25 cm during the growing season to produce a full seed set. Due to its indeterminate growth habit, lentil will often continue to flower as long as growing conditions remain favourable for vegetative growth. Therefore, low moisture or low nitrogen stress is required to encourage seed set and hasten maturity. Excess moisture before the plant is in full bloom promotes vegetative growth, thus delaying and reducing seed set and promoting fungal infections. Lentils grow best on well-drained soil with pH levels of 6.0–8.0. It will not tolerate flooding, or soils with high salinity.
In Saskatchewan, lentils are best adapted to the Brown and Dark Brown soil zones but can be grown successfully in the Thin Black and Black soil zones in years with moderate moisture. The development of more determinate red and small green varieties allows the opportunity to expand lentil production into less traditional lentil-growing areas of the province such as the moist Dark Brown and Thin Black soil zones.
Related Resources
Varieties
Lentil varieties produce seeds ranging from size small, averaging under 40 grams per 1,000 seeds (g/1,000 seeds), to large, which average over 50g/1,000 seeds.
Seed coat colours range from clear to green, tan, brown, grey, blotched green and black, or black. Cotyledons may be yellow, red, or green, with various combinations of seed coat and cotyledon colours determining specific market classes.
Varieties typically have yellow cotyledons with green seed coats and seed size is described as large, medium, and small. About 75% of the green lentils are large-seeded and about 25% are classified as small greens. Green lentils are consumed whole seed. Most large green varieties require early seeding because of their relatively late maturing, indeterminate growth habit. The tall stature of these varieties can make them prone to lodging, and susceptible to Botrytis (grey mould) and Sclerotinia (white mould) infection in high moisture conditions.
Varieties typically have red cotyledons with grey seed coats. Although sometimes consumed whole, red lentils are typically dehulled and/or split to increase palatability. Red lentils are divided into large, small, and extra small market classes. Small red varieties tend to be earlier maturing and shorter than green varieties.
Varieties are grown throughout Saskatchewan in small volumes. Black-seeded lentil (Indianhead variety), originally intended for use as a green manure or plow-down crop, has been marketed more recently as a Beluga, or black lentil. French green lentils have a green marbled seed coat with yellow cotyledons, small seed size most like small red lentils and retain their shape better than small reds or greens upon cooking. Green cotyledon lentils have a green or marbled seed coat with green cotyledons and small-to-medium seed size. Spanish brown lentils have a grey dotted seed coat with yellow cotyledons, small seed size most like small reds, and are sold primarily to Spain. Varieties with the Clearfield® trait (have CL suffix) have a tolerance to imidazolinone herbicides, such as Odyssey®, Odyssey DLX®, and Solo®. These herbicides, if applied to conventional lentils, will cause injury.
Varieties differ in their height, maturity, and resistance to ascochyta and anthracnose. Ascochyta resistance rated as good is still only considered intermediate resistance and anthracnose resistance is only to Race 1. Integrated disease management practices are important, as the varieties can still be infected with the diseases.
Want to see how different varieties compare?
Visit the Interactive SaskSeed Guide for information on all lentil varieties available to Saskatchewan producers.
Related Resources
Seeding
Lentils are well suited to direct seeding cropping systems. Lentil seedlings tend to be vigorous and can emerge through crop residue and grow from greater depths versus some crops traditionally grown in Saskatchewan.
Studies conducted by Agriculture and Agri-Food Canada at Swift Current demonstrated the benefits of producing lentils on untilled stubble and the influence of the previous crop stubble height. Lentil yield increased significantly as the stubble height of the previous crop increased. While pre-worked fields produced the lowest yields. Seeding lentils into tall standing stubble helped reduce soil moisture evaporation, particularly prior to flowering, resulting in greater water use efficiency (amount of grain produced per unit of water used) by the crop. As stubble height increased, the height of the lowest pod also increased, easing harvest operations and possibly reducing shattering losses.
Fields seeded to lentils are usually rolled with a land roller following seeding or up to the fourth node stage. Rolling levels the soil, protects harvest equipment by pressing most rocks into the dirt, and reduces the risk of downgrading the harvest sample with dirt contamination (earth tag).
Related Resources
Technical
Pre-Seed and Pre-Emergent Herbicide Options for Lentils
Technical
Lentil Seed Treatment Options
Technical
Calculating Seeding Rates
Article
Seeding Tips For Pulse Crops
Article
Tips for Rolling your Pulse and Soybean Crops
Inoculation & Fertility
Lentils inoculated with the proper rhizobium (Rhizobium leguminosarum) strain have the potential to secure up to 80% of its nitrogen requirement through nitrogen fixation.
Nitrogen fixation is a symbiotic relationship, in that it benefits both the bacteria and the plant. Rhizobium enters the root hairs of the plant and induce nodule formation. The plant provides energy in the form of carbohydrates for the Rhizobium living inside the nodules. The Rhizobium, in return, converts atmospheric nitrogen into a form of nitrogen that can be used by the plant. This relationship provides maximum benefit when the supply of available soil nitrogen is low and the soil moisture and temperature levels are adequate for normal seedling development.
Rhizobium leguminosarum strains will nodulate peas, faba beans, and lentils but some strains may be more effective on certain crops or certain varieties. Manufacturers package the inoculant as either a mixed or single strain inoculant.
Once the proper inoculant is chosen, care must be taken to ensure maximum rhizobia survivability. Rhizobium bacteria (either on the seed or in the package) are susceptible to temperature stress, drying out, and damage from direct sunlight. Inoculant must be stored in a cool dark environment prior to use, and expiry dates must be observed. Inoculated seed should be planted as soon as possible.
Inoculants are sensitive to granular fertilizer therefore, banding fertilizer to the side and/or below the seed is recommended. Inoculant should never be tank blended with fertilizer. Inoculants are also sensitive to some seed-applied fungicides. Check the labels of both the inoculant and seed treatment for compatibility. When using a combination of fungicide and inoculant, apply the fungicide to the seed first, allow it to dry, and then apply the inoculant immediately prior to seeding.
Inoculants are available in different formulations: liquid, peat-based, and granular.
Liquid-based products offer convenience and better control of application rate, compared to other forms. However, the rhizobia in these formulations are more susceptible to damage from environmental extremes and direct contact with seed treatments than other inoculant forms. If treated seed is planted immediately into a moist seedbed, liquid formulations perform well.
Peat-based formulations are more durable and less prone to desiccation and damage from direct contact with seed treatments compared to liquid formulations, although care must still be taken. Some peat-based powder inoculants require the use of a sticker. Adhesion to the seed can be enhanced if the seed is slightly damp during inoculation.
Granular formulations offer ease of application and should be applied in the seed row. These formulations remove the risk of incompatibility with seed treatments but care must still be taken to minimize risk of desiccation. Granular inoculants are less affected by environmental stress and seed-applied fungicides than other inoculant forms.
All inoculant formulations will perform equally well if the inoculant is properly applied and if environmental conditions are ideal. Under adverse conditions granular formations tend to perform best, followed by peat, then liquid.
Although Rhizobium bacteria can live in the soil for several years, efficient nitrogen-fixing bacteria may not be among those that survive. This reinforces the recommendation to inoculate each time lentils are seeded. Western Canadian research indicated a significant yield response to inoculation of grain legumes in 30–50% of the cases. For this reason, most experienced lentil producers use an inoculant on their lentil crop every year.
Checking Nodulation
Nodulation efficacy can be verified by examining the pulse crop at early flowering. It may take up to four weeks after seeding for nodulation to reach a point where it can be evaluated. The best way to check for nodulation is to dig up a plant and gently remove the soil from the roots by washing in a bucket of water. Nodules are fragile and readily pull off if the roots are pulled out of the soil.
If the rhizobia are actively fixing nitrogen, the nodules will appear visibly red or pink inside. Nitrogen fixation is synchronized with plant growth, supplying the crop nitrogen during rapid vegetative growth. Nitrogen fixation declines once plants begin pod formation and seed development.
Seed applied inoculant should result in nodules forming on the primary root near the crown. If the inoculant was soil applied (granular), nodules should be found on primary and secondary roots. Lack of nodules indicates rhizobia did not infect the pulse plant. Lack of a pink colour (usually green or cream coloured) indicates the rhizobia are not fixing nitrogen.
Fertility
Soil testing is important. High soil nitrogen levels will adversely affect nodulation and fixation. As the supply of nitrogen from soil and fertilizer increases, the amount of nitrogen fixed by the plant decreases. Nitrogen is necessary for high yields, but generally nitrogen fertilizer application is not required for lentil. Lentils can derive up to 80% of its nitrogen requirements through nitrogen fixation. The remaining nitrogen comes from the soil (available at time of seeding plus mineralized during growing season).
Where combined levels of soil and fertilizer nitrogen reach 28–40 kg per hectare (kg/ha) or 25–35 pounds per acre (lb/ac), development of nodules and nitrogen fixation may be delayed. Combined soil and fertilizer nitrogen levels greater than 55 kg/ha (50 lb/ac) can prevent effective nodulation and nitrogen fixation.
It can take three to four weeks following planting for nodules to become fully functional. Early plant growth may be poor in soils with nitrogen levels less than 11 kg/ha (10 lb/ac), causing plants to appear yellow prior to the onset of active nitrogen fixation due to nitrogen deficiency. This early deficiency can be corrected by adding low levels (10–15 kg/ha) of starter nitrogen at seeding. Although high levels of starter nitrogen may appear to help the crop overcome a nitrogen deficiency during early crop growth stages, final seed yields may not increase. Typical applications levels of monoammonium phosphate (ex. 12-51-0) often provide the small amount of nitrogen needed for early plant growth and, depending on the soil test, may provide the starter nitrogen required.
Lentils have a relatively high requirement for phosphorus. Phosphorus promotes the development of extensive root systems and vigorous seedlings. Encouraging vigorous root growth is an important step in promoting good nodule development. Phosphorus also plays an important role in the nitrogen fixing process and in promoting earlier, more uniform maturity.
Lentils grown on soils testing low in available phosphorus or under cool wet conditions may respond to phosphate fertilizer. However, dramatic yield responses are not always achieved. Even if seed yield increases are not achieved every year, a lentil crop may benefit from improved stress tolerance because of phosphorus application.
The maximum safe rate of actual phosphate applied with the seed is 22 kg/ha (20 lb/ac) with 10–15% seedbed utilization (SBU) under good to excellent moisture conditions. Calculate SBU by dividing seed spread by row spacing. For example, a 2.5 cm (1 in) spread with 25.4 cm (10 in) row spacing, equates to 1/10 or 10% SBU. Rates of seed-placed phosphate should be reduced if less than ideal moisture conditions exist. Higher rates of phosphate fertilizer placed in the seed row with narrow openers like discs or knives can damage the emerging seedling and reduce the stand. If higher phosphate rates are required, band the fertilizer away from the seed (sideband or to the side and below) or increase phosphate levels in the years prior to growing lentils.
Lentils have a high demand for potassium. Use a soil test to determine whether additional potassium is needed. Seed-placing potassium may cause seedling damage. As with phosphate, a wider opener may allow for slightly higher safe seed-placed rates. The sum of seed-placed potassium (K2O) plus phosphate fertilizers must not exceed the recommended safe rate of phosphate mentioned previously (22 kg/ha or 20 lb/ac). Most of the potassium taken up remains with soil residue and is not removed with the grain. Most soils are sufficient in potassium. However, deficiencies may exist, especially in sandy Black and Grey soils found in Northern Saskatchewan.
Sulphur is required in a relatively significant amount. A 30 bu/ac lentil crop requires about the same amount of sulphur as a 40 bu/ac wheat crop; approximately 9–11 kg/ha (8–10 lb/ac) as lentils remove about 0.2 lb/bu of sulphur. Soils testing low in available sulphur should have this deficiency corrected by side-banding, mid-row banding, or broadcasting ammonium sulphate, which contains sulphur in a plant-available form. Most research indicates limited yield response from the addition of sulphur fertilizer except in fields testing very low in sulphur.
Micronutrient deficiencies for lentil production have not been identified as a problem through lentil growing areas of Western Canada. If a micronutrient deficiency is suspected, it is advisable to analyze soil and plant samples within the suspect area and compare the analysis to soil and plant samples collected from a non-affected area of the same field. If the analysis confirms a micronutrient deficiency at a relatively early growth stage, a foliar application of the appropriate micronutrient fertilizer may correct the problem.
Related Resources
Technical
Inoculant Options for Pulse Crops
Technical
4R Phosphorus Management in Pulses for Growers
Technical
Safe Rates For Seed-Placed Fertilizer For Pulses and Soybeans
Technical
Assessing Nodulation & Nitrogen Fixation
Clearfield® Production System & Stewardship Guidelines
BASF has revised their requirements for growing Clearfield® lentils. A signed Clearfield® Commitment form is no longer required and has been replaced with the Stewardship Guidelines for Clearfield® Lentil. The Stewardship Guidelines are designed to ensure long-term sustainability of the Clearfield Production System for lentils by preventing or delaying the development of herbicide resistance in weed populations. Please review the guidelines.
Key points:
- Source seed either directly from your local seed grower or use good quality farm-saved seed.
- Get your farm-saved seed Clearfield-Confirm® tested at an independent seed laboratory facility approved by BASF as listed in the guidelines. The use of certified seed and farm-saved seed that has passed the Clearfield-Confirm Test ensures an acceptable degree of herbicide tolerance trait expression in the Clearfield variety purchased and planted.
For growers who opt to participate in the Clearfield Seed Quality Offer Program, BASF will cover the cost of the Clearfield-Confirm Test.
Varieties
There are different seed sizes in lentils. The large-seeded type has a seed size that averages 50 grams or more per 1,000 seeds.
The small-seeded type has a seed size that averages 40 grams or less per 1,000 seeds. Seed coat colours range from clear to green, tan, brown, gray, blotched purple, or black. The cotyledons can be yellow, red, or green. The different combinations of seed coat and cotyledon colours determine specific market classes preferred by consumers.
Green varieties typically have yellow cotyledons with green seed coats and are described as large, medium, and small. About 75% of green lentils are large-seeded and about 20% are classified as small greens. Green lentil is mostly sold as whole seed. Most of the large green varieties require early seeding because they are relatively late maturing and indeterminate. They produce tall plants which can be prone to lodging and are susceptible to botrytis (gray mould) infestations in high rainfall areas.
Red varieties typically have grey seed coats with red cotyledons. Red lentils are sold as whole seeds, dehulled seeds, or as dehulled split seeds, and described as large, small, and extra small market classes.
Specialty varieties are grown in much of Saskatchewan in small volumes. Indianhead is a black-seeded lentil originally intended for use as a green manure or plow-down crop, and more recently has been marketed as a Beluga Lentil. King Red is a specialty red lentil market class with a large seed size. Small quantities of varieties of the French green, Spanish brown, and green cotyledon (Queen Green) market classes are produced.
Varieties with the Clearfield trait are a recent development. This trait allows use of imidazolinone herbicides, such as Ares, Odyssey, Odyssey DLX, Odyssey Ultra, Solo and Solo ADV that would otherwise cause injury to conventional lentils.
Varieties differ in their height, maturity, and resistance to ascochyta and anthracnose. Small red varieties tend to be earlier maturing and shorter than green varieties. Ascochyta resistance rated as ‘good’ is still only an intermediate level and Anthracnose resistance only applies to Race 1. Integrated disease management practices need to be considered as the varieties can still be infected by diseases.