il is moist. Its purpose is to flatten any ridges and clods caused by sowing and to press any rocks or sticks into the soil. Soil that is left ridged from narrow points and press wheels at sowing may not press down to being completely level as the roller will tend to ride on the ridges and put less pressure on the plant rows.
Ideally the resulting flat surface will allow the harvester to operate at near-ground level, picking up the short crop and harvesting pods close to the ground. Having a flat surface reduces harvest losses, harvester wear and contamination in the seed sample.
Rolling may not necessarily flatten all of the standing stubble present. However, after summer or harvest rains, cereal stubble and in particularly barley stubble, tends to be more brittle and does not stand as well after rolling. Some of the lentil crop growth and erectness benefits of standing stubble may therefore be lost. Use of some disc drills in standing stubble may eliminate the need to roll lentil crops.
If the soil is prone to hardsetting or crusting, is sandy or on sloping country prone to erosion, rolling may have to be delayed until the crop has emerged. The safest time to roll lentil post-emergent is when the plants are at the 3–5 leaf stage. Avoid rolling lentil plants that are just starting to emerge because the emerging shoots can be broken off. Roll post-emergent lentil crops under warmer conditions when the plants are limp, and not brittle from cold or frosty conditions. Crop damage is minimised if rolling is done in the afternoon or on the morning of a warmer day. Avoid rolling two weeks before or after applying a post-emergent herbicide. Rolling a crop affected by leaf disease may increase the spread of disease within the crop.
A well-nodulated lentil crop should be self-sufficient for nitrogen (See also ‘Pulse inoculation techniques’), however rates of 5–10 kg/ha of ‘starter’ nitrogen may be useful on slightly acid or infertile soils.
Phosphorus removal is about 4.2 kg per tonne of grain. An application of 50 kg of single superphosphate per ha for each tonne of target yield is typically required to maintain soil P levels. Using superphosphate also ensures adequate sulfur for the crop.
Lentil crops may respond to zinc, manganese, iron or molybdenum in soils that are deficient in these trace elements. Use liquid injection or solid fertiliser during seeding to correct any likely deficiencies.
Irrigation of lentil is possible, but good drainage is essential because lentil plants do not tolerate waterlogging, particularly during early flowering. Even short periods of waterlogging can result in severe losses. Management requirements for irrigated lentil are the same as for dryland crops, with a greater emphasis on disease control as irrigated crops are more prone to the spread of foliar diseases due to the dense canopy and potentially prolonged leaf wetness after irrigation.
Salinity levels in irrigation water or the soil to be watered must be low. Lentil is one of the more sensitive field crops to salinity—almost as sensitive as green beans (Phaseolus vulgaris), which require irrigation water < 0.7 dS/m for nil yield reduction. A 10 per cent yield reduction is expected if the irrigation water measures 1.0 dS/m.
Some experienced lentil growers in the eastern Mallee regions of Victoria successfully use overhead irrigation. Flood irrigation of lentil crops is not widely practiced in Australia because the risk of yield loss to waterlogging is considered to be high. Nevertheless, irrigation may be economical if the irrigation system allows adequate drainage, there is good quality water available and the rotation with other winter and summer crops is managed well to reduce the risk of disease pressure.
Good weed control is essential because lentils grow slowly during winter and compete poorly against weeds. Weedy lentil crops lose yield, are difficult to harvest and contribute only minimal rotational benefits to subsequent crops.
Avoid sowing lentil in paddocks with a history of severe broadleaf weed problems. Vetches, tares, medics, 