Research aims to take guesswork out of pulse storage

Prairie pulse growers could be flushing millions of dollars down the toilet every year by “over-drying” peas and lentils.

Joy Agnew, project manager with PAMI Agricultural Research Services in Humboldt, Sask., says the cost of over-drying pulse crops in the bin can be as high as 20 cents per bushel.

Agnew is leading a two-year PAMI study aimed at minimizing storage-related losses that occur during natural air drying or aeration.

“Given that the three prairie provinces produced over eight million tonnes of lentils and peas in 2016, and that the cost of over-drying can be 20 cents per bu. or more, the potential lost revenue runs into the tens of millions of dollars every year,” Agnew said.

“With this study, we want to give producers confidence they’re making appropriate storage management decisions and reducing their risk of loss.”

In a recent interview, Agnew said prairie pulse growers have been managing stored pulse crops without accurate or updated information on critically important factors such as airflow rates, airflow resistance and equilibrium moisture content (EMC) tables for pulse crops.

The primary purpose of the PAMI study is to provide updated information that will allow producers to make informed decisions about how and when to dry stored pulses using forced air.

In addition to monetary losses caused by over-drying, pulse crop quality can also be negatively affected during aeration, especially in cases where the moisture content of stored pulse crops goes up and down over an extended period of time.

Until now, pulse growers have been basing their natural air grain drying decisions on information that was intended for other crops such as wheat, canola and barley, Agnew said.

“The vast majority of work that was done (on natural air drying) was done in the 1980s and ’90s, when pulses were not really a crop of interest,” she said.

“We’ve been extrapolating that information and applying it pulse crops, but we’re not really sure how accurate it is.”

Specific components of Agnew’s research include:

  •  validation of EMC charts for peas and lentils
  • assessment of airflow rates on natural air drying systems
  • determination of airflow resistance rates in different types of pulse crops

Airflow resistance is a key consideration for growers who use natural air on binned grains.

Different types of crops have different rates of airflow resistance.

In general, large-seeded crops such as peas have lower rates of resistance than small-seeded crops such as wheat and canola. That means aeration on peas can remove moisture more quickly.

If growers remove too much moisture, they will end up selling fewer bushels based on standard bushel weights.

The PAMI study will also collect base line data to determine how repeated wetting and drying cycles can affect seed quality.

“There has been some base line work done over the years to establish drying and wetting characteristics of pulses, but it’s never been validated or widely adopted,” Agnew said.

“Given the amount of pulse crops we see today, it’s critically important updated information is available to producers.”

The study, now entering its second year, also involves Saskatchewan producers who agreed to install gauges in fan-equipped bins and submit data when their fans are running.

Agnew said growers are happy to co-operate in a project that aims to reduce storage-related spoilage and maximize profits.

“We have no trouble finding co-operating producers for this work,” she said.

“Our research at PAMI is always driven by producer need, and they’re very anxious to get these results so they can make sound storage decisions that mitigate any downgrading of their pulse crops.”

An interim report will be completed and should be available in early 2018. A final report is expected in late 2018 or early 2019.

Agnew’s study has received federal and provincial funding through the Growing Forward 2 funding framework.

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