Storing pulses

Author: | Date: 19 Jul 2017

Department of Agriculture & Fisheries, Queensland

Take home messages

  1. Storage conditions for pulses such as chickpea, mungbean and faba bean has a large impact on the visual appearance e.g. colour.  Visual appearance is often crucial to their market value.
  2. A high standard of storage hygiene, aeration cooling and regular monitoring of pulses in storage is the foundation for successful pulse storage.
  3. Take particular care with grain moisture contents at harvest time. Low moisture contents can lead to excess ‘splits’ during harvest and handling.
  4. Weather damage to pulses prior to harvest not only increases grain splits, but reduces the storage life and germination quality of planting seed.

Storing pulses

Well-managed on-farm storage facilities with aeration cooling and effective hygiene can overcome the majority grain quality and insect pest problems with chickpeas, mungbean & faba bean.

When planning to store pulses on farm keep in mind that the visual appearance is a crucial focus point for export markets. Preserving the light colour in chickpeas or the bright green colour of mungbean and the integrity of the pea is a priority.

Avoid harvesting pulses at very low moisture content. For chickpea, harvesting around 13 to 15 per cent moisture content levels reduces the risk of the peas splitting when handling.

Not only do higher levels of splits reduces the market value, split chickpeas are also more attractive to storage pests such as the rust red flour beetle.

A. Storage type used

Ideally pulses are best handled and stored in cone-based, aerated and sealable silos.

Despite the handling advantages of cone-based storages, in some cases the increasingly popular, large, aerated, flat-bottom silos are also an efficient storage for pulses.

Cone-based silos are easy to clean, allowing for a high standard of hygiene to be achieved and typically there is effective aeration cooling in this style of storage.  It is also valuable if the silo is sealable, gas-tight for when fumigation for pest control is required.

B. Hygiene

It is crucial when planning ahead to store pulses, good hygiene is a high priority as there are strict limitations in terms of the use of insecticides for control of grain storage pests.  None of the grain protectants used on cereal grains can be applied to pulse grains.

Clean all grain residues from equipment such as harvesters, field bins, augers and silos, then follow-up with a diatomaceous earth (DE) product such as DRYACIDE® as a structural surface treatment.

DE has the advantage of being a natural insecticide, which makes it particularly safe for treating storages for cereals, oilseeds and pluses.

C. Aeration

Aeration cooling is a critical part of ensuring pulse quality is maintained and an important aid to reducing insect pest problems during storage.

If possible, only store pulses long term in facilities with cooling aeration equipment. Ensure aeration maintenance and operational checks are undertaken prior to harvest.

Effectively managed cooling aeration will dramatically improve storage conditions for chickpeas, mungbeans and faba bean.  Aeration is more reliable when managed with an automatic controller, with fans turned on during the best ambient temperature & humidity conditions. Fans should be on as soon as the first truck load goes into the silo at harvest time.

Aeration cooling is run in three phases. Initially fans run continuously 24 hours per day for approximately five days from harvest time. This is followed by seven days of the coolest 9 to12 hours per day, typically during the night. Finally select the best 100 hours of ambient air each month. A few models of automatic controllers (e.g. Grainsafe 5000®) will now allow these three functions to run progressively, automatically when you are busy concentrating on other tasks on farm.

Aerated chickpeas and mungbean should aim to be stored at less than 23 oC and preferably around 20 oC during summer.  This inhibits moulds, insects and preserve the quality of the pea.

Aeration cooling will not eliminate the need to fumigate pests, but it dramatically slows insect development and reduces the number of years where insects are a problem.

D. Monthly pest & quality checks – with records

All grain in storage should be monitored monthly and records kept of pests, fumigation treatments, grain quality notes and grain temperatures.

When it comes time to sell pulses that have been in storage, the last thing you want is a nasty surprise by finding the product is infested with insect pests or the quality is not what it should be.

The checking process involved taking approximately one-third of a bucket of grain out of the bottom of the silo to sieve, as well as using an insect probe trap in the top of the silos.

Monthly checks are an efficient method of ensuring you detect any insect infestations early. At the same time use a simple grain temperature probe to check the aeration cooling system is operating effectively.

Building your reputation with grain buyers, as a producer who can manage their storage system and grain quality will be valuable in the long term. It also maintains the pulses industry’s reputation with export markets. Keeping up-to-date storage records for each silo is important. It gives grain buyers confidence that you are professional with both pulse production and your management of on-farm storage.

Chickpea & other pulses – storage tips

  • Avoid storing chickpeas in silo bags. Plan ahead in terms of harvest storage and avoid where possible storing pulses like chickpeas in silo bags, or under tarps. Silo bags are easily damaged and water ingress will results in serious discoloration (black) and loss of value.
  • Harvest chickpeas with moisture levels at around 14% to 15%.  Exercise caution when handling pulses with augers and other machinery. Where possible use a tubeveyor rather than an auger to reduce additional damage.
  • If grading out splits or weed seeds from chickpeas and other pulses, don’t leave ‘gradings’ close to the storage facility. Gradings are very attractive for pests to breed in and can become a source of insects for grains stored nearby.  Sell or use these gradings quickly.

Pulse storage - research information gaps

Australian grain storage research has for many years been directed at the cereal grain industries, in particular stored wheat and barley. This has provided these industries with a sound scientific base to develop recommendations and best practice strategies for: monitoring pests, storage hygiene, aeration cooling and fumigation of pests. Combining these strategies correctly produces reliable results for both grain quality and pest control in stored cereal grains.

Today throughout Australia’s cropping regions, pulse crops are considered an essential and profitable component of our sustainable cropping systems. For pulses there is a valuable export focus. Export grains must fulfil a list of requirements: phytosanitory, grain quality specifications, nil chemical contamination and nil live stored grain insects.

Unfortunately our pulse storage research knowledge has large information gaps are clearly evident.

With critical postharvest storage knowledge gaps remaining, there is uncertainty when attempting to provide advice.

So growers, handlers, processors and advisors are often making decisions based on cereal grain storage research.

This postharvest storage information vacuum impacts on many industries with valuable export & domestic markets

Further reading

Acknowledgements

The author wishes to acknowledge the significant contributions of Grain growers partnership in on-farm research, silo manufactures, storage equipment suppliers and DAF Qld’s Postharvest research team. The author would also like to thank GRDC, and GRDC’s national grain storage extension team for their continued support.

Contact details

Philip Burrill
Department of Agriculture & Fisheries, AgriScience Qld.
Hermitage research facility, 604 Yangan road, Warwick Qld. 4370
Mobile:  0427 696 500 or 1800 WEEVIL
Email: philip.burrill@daf.qld.gov.au

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