 most other pulses, despite their seed size, but plant growth is slow during winter. If germination coincides with soil temperatures below 5°C, complete emergence may take 30 days.
Lentil crops in southern Australia are increasingly being sown at wider than ‘standard’ (18–25 cm) row spacing, when sown into standing stubble as part of a whole farming system. Wider row and ‘skip’ row lentil crops (30–50 cm) must be part of an overall system.
Standing stubble is essential when sowing on wider rows to avoid moisture loss and prevent weed infestation inter-row. Standing stubble ensures taller, more erect plants with pods higher above the ground, and reduces lodging before harvest. Lift any non-sowing tines so inter-row soil disturbance is minimised, reducing the risk of weeds germinating where there is no crop competition. Reasons for choosing wider rows with lentil and other pulses vary with location, system and operator. Often lentil is sown in narrower rows like some other pulses (e.g. chickpea, faba bean or lupin). Key drivers for using wider row, stubble systems are the combination of:
- better yields and yield consistency
- availability of equipment with better stubble clearance and other sowing practicalities
- improved water use efficiency (drought tolerance)
- delay of canopy closure to minimise disease risk and for easier management
- option to sow early and minimise foliar disease risks with a bigger crop canopy
- better weed control through minimised soil disturbance
- option of shielded sprayers for weed control inter-row
- improved harvesting speeds and efficiency.
Time of sowing is critical for lentil disease control, best yields and to avoid frost or heat damage. Match variety choice with the sowing system because varieties now differ in their growth habit and height, lodging, time to canopy closure, flowering time and disease resistance. Attitude to disease control, row spacing, moisture availability, stubble presence all affect the optimum sowing dates.
Dry sowing can be successful in lentil, provided weeds like medic are not a problem. Rather than waiting for the correct moisture status, many growers sow lentil on a calendar date to ensure that sowing is completed early or to avoid interfering with other operations. Paddock selection is particularly important for dry sowing lentil to be successful.
Choose a seed inoculation method suited to dry soil conditions such as granular inoculants (see more below).
Seed inoculation and treatment
Lentil requires the same rhizobium as field peas (Group E). Inoculation of lentil seed may not be required on some alkaline soils if the paddock has recently grown inoculated and well-nodulated field pea, faba bean or lentil crops. If uncertain about soil types or rotation history and practice, it is best to inoculate and be sure.
Fungal seed dressing can improve seed emergence, especially in wetter conditions. If using inoculum and seed dressing, apply the seed dressing first and then inoculate immediately before seeding. Do not mix inoculants and seed dressing together unless the inoculant label specifies compatibility.
The traditional ‘peat slurry’ method of applying inoculum remains widely used however other methods, such as liquid injection and placing inoculum granules into the seeding row, are also becoming more common practice. Granular forms of inoculum may assist in rhizobial survival, particularly in adverse conditions such as in acid (lower pH) soils or when the crop is sown dry. Given the importance of successful nodulation in lentil on acid soils, growers might consider inoculating the seed in a peat slurry and also using a granular inoculum at seeding. Note that freeze-dried inoculums applied to seed may not provide the same protection to the rhizobia as peat-based inoculums.
See also ‘Pulse inoculation techniques’.
Rolling of the soil surface may be required to protect the crop from residual herbicide damage or to improve harvest efficiency. Rolling is possible from pre-emergent to the 4–5 leaf stage of growth. It is best done with a rubber-tyre roller when so