LENTIL plants’ growth habit and structure could be key to determining their susceptibility to pod drop, trials at Kulpara and Tickera have found.

Findings from the trials were presented to an audience of 85 people as part of the Grains Research and Development Corporation Grains Research Update held at the Bute Sporting Club last Thursday, February 9.

Agronomist Jordan Bruce, of Trengove Consulting, Bute, said data from trials at Kulpara in 2021 and 2022 and at Tickera in 2022 showed a direct relationship between the height of plants and their propensity to drop pods.

“The taller the lentil plant, the greater the pod loss we are seeing,” he said.

It was found pod drop loss in the control treatment was 163 kilograms per hectare at Kulpara in 2021.

“The relationship between plant height and pod drop was reasonably consistent, and for every millimetre increase in plant height, an extra 2.5 kg/ha was lost,” Mr Bruce said.

Mr Bruce said pod drop in mature lentil plants had been a significant issue for growers in most seasons, particularly in windy environments such as Yorke Peninsula.

Grower Tim Millard, who hosted the Kulpara trials, said his area was prone to wind damage and pod loss in lentils.

“We have been losing between 30 to 55 per cent of our crop but it’s hard to quantify,” he said.

“It’s not isolated to my property, others around me agree with those numbers.”

Mr Millard said the open canopy structure of some lentil crops made them more susceptible to wind speed and gusts, resulting in dropped pods.

However, Mr Millard said the atypical nature of the 2021 and 2022 seasons meant they were not ideal for the trial.

Mr Bruce said the trials at Kulpara utilised a range of management strategies early in the season, including varying seeding rates and fertilizer application, to alter plant growth habits.

Mr Bruce said lentil varieties such as PBA Bolt had a very upright growth habit and did not branch out as much as spreading varieties like PBA Jumbo2, which tended to grow into neighbouring furrows and tangle with other plants.

Erect types with minimal canopies had reduced risk of being infected with botrytis grey mould but were more exposed to pod drop caused by wind.

Mr Bruce said stubble retention could protect lentils from weather during the growing season, but also influence plant growth habits and structure.

Sowing into taller stubble, such as stripper stubble, could producer taller lentil plants compared with sowing into shorter, conventional stubble or no stubble.

A trial at Tickera in 2022 found different stubble height treatments had different effects, as measured by the September Greenseeker normalized difference vegetation index, July plant height, harvest canopy height and harvest lowest pod data.

However, Mr Bruce said those effects did not translate into any significant pod loss or yield differences.

A pod protection product was also trialed at Kulpara in 2021 and 2022 through application at desiccation and was found to reduce pod drop by 39 per cent, reducing the loss to 100kg/h.

However, Mr Bruce said the overall yield of the crop was not significantly greater than the control treatment.

“Risk mitigation is difficult, as growers do not know when the wind events will occur in relation to desiccation timing,” Mr Bruce said.

“We have not had any major breakthroughs with lentil pod drop but we will keep investigating.”

The trials were supported by GRDC, Northern Sustainable Soils and the South Australian Grain Industry Trust.