of herbicides and harvestability. Short crops, stones, clods, sticks or stubble clumps all cause harvesting problems. However, rolling lentil after sowing for herbicide safety or harvest efficiency reasons, completely or partially flattens standing stubble, negating the beneficial effect of standing stubble on lentil. The flattened stubble may obstruct sowing and will provide limited support for the lentil plants as they grow. Press wheels on seeders can be an alternative to rolling if the press wheels are wide enough to firm the sowing row without knocking down the standing stubble. Disc planters with narrow sowing slots and minimal soil throw avoid the need for rolling after sowing lentil and so the cereal stubble is kept standing.
On sandy and light soils, stubble retention lessens the risk of wind erosion. Stubble loads are often low on these soils and do not usually present a barrier to minimum tillage seeding or direct drilling. Stubble retention and reduced tillage also provide protection from water erosion on hills and steep slopes, especially during summer rainfall or storms.
Where the risk of wind or water erosion is lower, stubble retention is not necessarily widely adopted. Stubble retention is often not possible in areas where slugs and snails are a major problem at establishment or snails are a concern at harvest, particularly in higher rainfall zones.
In southern Australia, late burning of high stubble loads just before sowing can assist with sowing and control of pests such as slugs and snails. Stubble organic matter and cover is lost with burning, however the soil moisture benefits of having maintained stubble cover over summer and early autumn remain. After a late stubble burn the soil surface is exposed, which creates a risk erosion and for weeds to establish before seeding and during crop establishment, until the canopy closes.
Adequate weed control measures must be taken during the previous year and again before sowing, particularly to address problem weeds. For some soil-active broadleaf herbicides to be fully effective, or to avoid crop damage, application must only occur when there is sufficient soil moisture and the soil surface is level. Herbicides applied before seeding or split between pre and post-sowing can be safer than post-sowing if the soil will be left ridged (e.g. after using knife points).
Retaining stubble or plant residue from previous crops protects the soil from erosion, reduces soil moisture loss and assists in crop growth and height. If rolling is required on sloping ground or hardsetting soils, this may have to be done post-emergent to reduce the risk of water erosion or surface crusting. Rolling will flatten cereal stubble from previous crops
Remove excessively large clumps of stubble, otherwise they will cause seed placement and harvesting difficulties. Surface retention of cereal stubble does not affect lentil germination or growth, and can improve establishment on hardsetting, surface crusting soils. It may affect establishment though if seeding equipment cannot handle the stubble load or place seed accurately.
Where soils are below a pH 5 (CaCl2), lime applications should be considered before growing lentil.
SU injury to lentil due to soil persistence.
Iron deficiency in lentils.
Poor nodulation can cause stunting, yellowing and poor growth.
The roller does not place weight on the lentil plants as would happen on flatter soil.
Lentil dying under waterlogged conditions compared to better drained areas
Lentils can emerge through thick cereal stubble.
Wide row sowing of lentils is becoming more common.
Boron toxicity in lentil leaves showing typical leaf tip symptoms.
Imazethapyr (e.g. Spinnaker®) injury in conventional lentil plants (left) compared to an ‘imi’ tolerant (XT) lentil variety (right).
SU injury to lentil due to soil persistence.
Iron deficiency in lentils.
Poor nodulation can cause stunting, yellowing and poor growth.
The roller does not place weight on the lentil plants as would happen on flatter soil.
Lentil dying under waterlogged conditions compared to bette