ddock. Excessive boron or sodic subsoil within the crop root zone can cause plant death and severely limit lentil yields. Soil acidity delays and limits nodulation and hence, reduces yield.
Lentil is well suited to alkaline, self-mulching grey clays (e.g. the Wimmera) and also grows successfully on loamy sands (e.g. in the Mallee).
Lentil is extremely sensitive to some residual herbicides from Groups B and I. Observe maximum plant-back periods on the label and when planning crop rotations, take herbicide residues and plant-back requirements into consideration.
Plant-back on herbicide labels will not change with the new herbicide tolerant lentil varieties, PBA Herald XT and PBA Hurricane XT, but crop safety is greatly improved with these varieties where residual herbicide impacts would otherwise be expected.
See also ‘Herbicide residues and weed control’.
Stubble retention systems
Lentil fits well into stubble retention systems, serving their wider role in crop rotations and farming systems.
Stubble retention implies the stubble of previous crops is left standing, on the soil surface or incorporated (buried) into the soil. Lentil fits well in minimum tillage, direct drilling, no-tillage or zero-tillage farming systems provided the physical seeding process is not affected. Using GPS-guidance and auto-steer systems lentil can be sown inter-row, between standing stubble rows. This aids in stubble clearance during sowing, often reduces herbicide throw and damage, and the lentil crops grow taller and are more erect, achieving greater harvest efficiency.
Stubble that grazing animals have trampled, is lodged or brittle from summer rainfall can present difficulties at sowing, even when sowing inter-row. Lentil crops that follow a drought-affected cereal or a hay cut may not benefit from the limited amount of stubble retained, particularly if the sowing is aggressive, causing a high level of soil disturbance and incorporation of the remaining stubble.
Many pulse crops require a level soil surface for effective application 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 her