Lentil field
Paddock Selection
Lentils should not be grown on the same paddock more than once in three years. That means the previous two crops should not have been lentil. In addition, avoid paddocks that have grown a crop of chickpea, faba bean or vetch in the previous two seasons. The paddock chosen should be also at least 500 metres away from the stubble of last years’ lentil, faba bean or vetch crop. Finally ensure that at least two years has passed since sulphonylurea herbicides (Glean, Ally, Logran, Lontril) were applied in the paddock.
These precautions are designed to minimise the risk of fungal disease and herbicide damage.
Lentils are extremely sensitive to sulphonylurea herbicides and will be damaged if residues of these herbicides remain in the soil. These herbicides will break down within one to two years of application depending on soil pH, organic matter content, soil structure, and rainfall. Minimum plant back periods must be observed.
- No more than one lentil, chickpea, vetch or faba bean in the past two years
- At least 500mm away from last year’s lentil stubble
- Free from sulphonylurea residues
- Medium to heavy textured soils with pH greater than 6.0 (CaCl2)
Lentils are best produced on free draining soils with a loamy sand texture or heavier and a pH of at least 6.0 (CaCl2). Good soil type selection is a critical step towards the production of good lentil crops. In the Northern and Central Agricultural Regions there are many loamy sands and clays well suited to lentil production. Lentils are produced on a range of soils from heavy cracking clays in the Dongara area to the red loams throughout the Mid-West and also salmon gum soils in areas such as Coorow and Mukinbudin.
- Lentils have a low salt and boron tolerance, which should also be taken into account when assessing a soil’s suitability. A soil structure and slope that allows good drainage. Waterlogging is an issue because lentils can not withstand even short periods in waterlogged soils.
- An even site with few rocks, and depressions Paddocks should be free of stones, stumps and other debris and the paddock should always be rolled to ensure a smooth harvest.
- Low broad leaf weed population
Lentils are poor competitors with weeds and the optimum for post-emergent control of broad-leaf weeds is limited. Therefore, select a paddock that is relatively free of broad-leaved weeds.
Lentils do have some quite specific soil requirements as outlined above but they are successfully grown throughout the central and northern region on a wide range of soil types. It is a matter of picking the paddocks on your farm best suited.
Other considerations
Stubble from the previous crop may be a problem at harvest time. Ensure it has been cut short, chopped and spread evenly.
Vetch is difficult to control in lentil crops and seeds are of similar size and appearance, and are very difficult to grade out. There is a nil receival tolerance of vetch in lentil. Paddocks that contain vetch should be avoided.
Lentils do not produce a large amount of biomass and hence do not fix as much nitrogen as field pea or faba bean. The nitrogen benefit of a lentil crop to following cereal or canola crops is therefore lower than for field pea or faba bean.
Paddock selection
Sowing date
The ideal time to sow lentils is from early May to mid June, depending on rainfall.
Highest yields will generally be achieved from earlier sowing. Early sowing allows greater dry matter production and more bulk to the crop leading to easier and more efficient harvest. On the other hand, lentils are poor competitors with weeds, and delaying sowing will allow better weed management before sowing.
Don’t sow lentils before the May 1st in low rainfall environments or before May 15th in medium rainfall environments. Lentils are not recommended for high rainfall regions due to their sensitivity to waterlogging.
In general, early sown crops are more prone to ascochyta blight and botrytis grey mould than later sown crops. These diseases have not yet been serious in Western Australia, but to guard against, these diseases don’t sow earlier than the recommended dates, particularly in wetter environments.
Do not sow lentils into dry soil because the crops will not nodulate effectively and weeds will be too difficult to manage. Plant establishment will also be reduced.
When to sow lentil
- Low rainfall(<350mm)1st May to 10th May
- Medium rainfall (350 to 450 mm)
15th May to 15th June - Not recommended for high rainfall areas
Inoculation
Always inoculate lentil seed with Group F inoculum. The seed should be inoculated with rhizobia regardless of the cropping history of the paddock. Even if rhizobia are present in the soil, they are likely to be less effective than the inoculated strain. Seed needs to be sown within 24 hours following inoculation because the viability of rhizobia on inoculated seed deteriorates rapidly with time.
Fungicide seed dressings are toxic to rhizobia. If the seed has been dressed, then double the rate of inoculum and sow seeds into moist soil as soon as possible after inoculating into moist soil. The rhizobium will quickly die if it is applied to fungicide-dressed seed and then sown into dry soil.
It is important to take care when inoculating seed. There are many cases where poor inoculation technique has caused crop failure. Peat sprinkled out of the bag onto seed as it is being augured into the seeder is quick but not effective. Slurry inoculation is the best way to ensure a well nodulated crop. Refer to page xx in the chickpea section for more details on slurry inoculation.
Seed rate and depth
Seed rate and depth
Seed Depth
Sow lentils 4 to 6 cm deep.
Crops sown at these depths are less likely to be damaged by herbicides applied before or immediately after sowing. Soil temperatures and moisture at these depths also tend to be more favourable for the survival of rhizobium.
Lentils will emerge rapidly from the soil when compared to other pulses, but they exert less force. Plant establishment will be reduced if seedlings need to emerge from deeper than six cm or need to penetrate a surface crust.
Sowing Rate
Aim to establish a crop of 120-150 plants/m2. The higher densities in this range should be used where growing conditions are less favourable and individual plant growth is limited, such as in low rainfall and short season environments. The lower densities should be used in the more favourable growing environments where individual plants have a better chance to express their individual yield potential.
Sowing rate is dependent on seed size and germination percentage. Based on an 80 percent germination percentage and allowing a further 10 percent for emergence loss.
Leveling the paddock
Always roll the paddock after sowing lentils. This is essential to ensure an even soil surface so the crop can be efficiently harvested. On most soils it is best to roll the paddock immediately after sowing. On soils that form surface crusts that hinder emergence, it is best to roll after plants have emerged and have reached the 3-5 node stage. When rolling established plants do not roll in the mornings when pants are stiff but wait until mid afternoon, and avoid herbicide application for 2-3 weeks.
If rolling immediately after sowing, paddocks should be levelled with harrows and then rolled with a rubber tyre or steel rollers to flatten the soil surface and push obstacles into the soil.
Rolling the paddock after emergence will weaken the plants. Therefore, as a precaution, don’t roll the paddock within two weeks before or after the application of post-emergent herbicides.
