Trials highlight benefits of lentils in crop rotations

The research, which has been undertaken for five years so far, is being conducted at Wagga Wagga, Greenethorpe, Urana and Condobolin. These years include some of the driest and wettest ever recorded. CSIRO farming systems agronomist Dr John Kirkegaard leads the ongoing study.

Lentils have been an important Victorian and South Australian crop for many years, especially in lower to medium rainfall environments like the Wimmera and Mallee. It is receiving increasing interest in NSW, with researchers like John Kirkegaard believing the crop has great potential to expand dramatically. However, as for all crops, agronomic issues need to be carefully assessed. And like all crops, there are risks associated with diseases, pests, wet harvests and market uncertainty.

Peter Matthews Technical Specialist, NSW DPI Grain Services and Don McCaffery, Technical Specialist, Oilseeds and Pulses, authors of the NSW Winter Crop Variety Sowing Guide, stress that lentils prefer neutral to alkaline soils (pH Calcium chloride method, 6 to 8). This includes through the soil profile, not just the topsoil.

Mr Matthews and McCaffery also advocate choosing soils with high fertility, good water holding capacity and good drainage that are not prone to waterlogging. Hard-setting, dispersive soils should be avoided, as should soils that are sodic in the surface as well as root zone.

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Lentils worldwide are around six to seven million tonnes, with Australia producing around half a million tonnes in most years. As a high-value pulse, food crop, quality is a key issue, and markets can vary dramatically. There are different grades and qualities requiring a good knowledge of varieties suited for agronomy reasons and also for specific markets. Lower-value livestock feed markets suit when grain does not meet market specifications.

Lentils are a relatively short crop. Paddocks that are even soil type are easier to manage. Changes in soil type across a paddock can lead to uneven crop maturation, harvest delays and increased grain losses from shattering. A relatively even soil surface is important for harvest efficiency. Paddocks also need to be free of stones, large clods and sticks. Rolling the seedbed after sowing is often helpful for harvest.

Sowing lentils directly into previous cereal stubble is preferred Peter Matthews and Don McCaffery also stress. Retained stubble commonly enables more timely sowing in the early preferred part of the sowing window. Standing stubble provides crop canopy support and enhances harvest efficiency.

Part of the growing popularity of lentils is the release in recent years of much improved varieties. These commonly have a higher yield, better disease resistance, and improved plant architecture. Some have tolerance to specific herbicides that allow more weed control options.

Examples of recent variety releases include GIA Leader, an imidazolinone (IMI) tolerant red lentil with improved disease resistance (botrytis grey mould and ascochyta blight). It is mid to late maturing. GIA Thunder is a new, broadly adapted, IMI-tolerant, small, red lentil with Group 2 (IMI and SU) herbicide tolerance.

PBA Highland also is a herbicide-tolerant, small, red lentil tolerant to Intercept herbicide, improved tolerance to flumetsulam, plus reduced sensitivity to some SU and IMI herbicide residues and has improved resistance to Ascochyta. GIA Sire is the first IMI-tolerant lentil with improved tolerance to clopyralid soil residues. GIA Sire is suited to early sowing and favourable areas. GIA Metro is a medium to large-sized red lentil and the first to combine IMI and MET herbicide tolerances.

Mid-May is the preferred sowing time in southern and central NSW. In western areas, sowing seven to 10 days earlier is suggested. Lentil inoculant is the same Group F required for field pea. In most situations, a phosphorus-based fertiliser is required. For further information, refer to the NSW DPI Winter Crop Variety Sowing Guide.

Next week: Research confirms soil phosphorus levels build up from previous fertiliser use.