On farm grain storage creating value for the business

Author: | Date: 28 Jul 2016

Introduction

On-farm grain storage has been increasing during the past 10 years for a variety of reasons. These include harvest buffer, feed storage for livestock and marketing purposes. The key to getting successful is to know the target outcome for the grain and to match the storage system to that end. For example, it is pointless storing grain long term in a system that is intended for short-term storage. The other major consideration is increasing levels of resistance to the contact treatments used in unsealed storage is making insect control more difficult. Investing in gastight sealed storage or having at least a proportion of storage as gas-tight sealed storage enables successful fumigation to kill insects.

Growers will typically use and have a variety of storages at their disposal. While each should work well for their intended purpose, it is worth considering the pros and cons of each; particularly in regard to the ease of insect and quality control for the expected period of storage.

Plan for success

Having a plan is essential to ensure successful grain storage. Know where your grain is, determine suitable protection periods for specific storages, record treatments, determine quality specifications and know when to check the grain.

Often a storage site will increase in size over time and planning for expansion is essential (for example, to ensure access to power for future aeration). Also ensure any storage facility is easy to access and use. When considering new storages, plan for the end goal.

Thinking about storage periods

For short-term storage growers can use ‘ground dumping’ and silo bags. Clearly, grain stored on the ground should be moved or used as quickly as possible (within six weeks). Silo bags offer better protection from the elements and are particularly good for managing harvest pressure.

For medium-term storage growers can use unsealed silos, sheds, silo bags and gas-tight sealed silos. The longer the storage period required, the greater the potential for infestation. It is difficult to control insects in sheds (even when the grain is treated) and options for killing insects if grain becomes infested are limited. Silo bags are typically not treated and require nil insect levels when loaded.

Although we presume there are no insects in grain when being loaded into storage, we generally treat the grain using protectants, or fumigate in gas-tight sealed storage. When using protectants always read and follow label directions, calibrate, mix and apply chemicals correctly and always wear the recommended safety gear.

Unsealed storage, when managed well, can yield clean grain; but always treat grain in unsealed storages with a protectant. Aeration is increasingly common and also can help manage insects and quality in unsealed storages.

Increasingly growers are storing grain for up to 12 months. To do this the storage system needs to be able to kill insects effectively and maintain grain quality. Gas-tight sealed and aerated storage is the best way to do this. Fumigating the grain kills any insects present and the aeration maintains grain quality.

In a gas-tight sealed silo grain can be fumigated effectively providing quick, inexpensive and long-lasting insect control. Market flexibility is greatly enhanced because grain is stored residue-free. When considering new storage, consider gas-tight sealed storage as an option. Like any piece of equipment on the farm gas-tight sealed silos need to be well maintained to work efficiently. Check seals before each filling and replace if worn or damaged. Always pressure test the silo to ensure it is sealed.

Keep it clean

Whatever the system there are always basic principles to follow, the most important is to have excellent grain hygiene; prevention is better than cure. Clean up any grain spills immediately wherever they may be, but particularly around the storage area. To help this process, spray out or remove any weeds around the storage area. Silos mounted on a slab are easier to clean and keep clean.

Clean up all grain spills around the farm and storage area, ensure all harvesting and storage equipment is clean and treated with a structural treatment. Inert dusts (for example, Dryacide®, Absorba-Cide®, Cut ‘N Dry™ and Perma-Guard®) can be used to treat the header, storages and handling equipment for residual control. Always read and follow label directions.

Keep grain safe

If using grain protectants, it is highly likely one of two new products should be used, due to lesser grain borer resistance to Methoprene. Dow Agro Sciences has a product called ConserveTM on Farm and Bayer has a product called K-Obiol®Combi. Both have different chemical actives to control the lesser grain borer. For this harvest Dow is releasing a new formulation which is used in conjunction with Fenitrothion for use on malting barley and maize (where accepted by end markets). K-Obiol®Combi is registered for use on cereal grains where accepted by end markets. Both these new products have strict application requirements which must be adhered too, always read the label to ensure correct use. Insect infestations are not evenly distributed throughout a silo. Insects seek out the most favourable places, such as the grain peak and around hatches where moisture can get in. If insects are found, or damage is detected it is important to treat the infestation.

Any grain with holes in it indicates that primary pests, such as the lesser grain borer or the rice weevil have infested the grain. Correct insect identification is important to determine a suitable control tactic.

If grain is found to be infested the only way to eradicate them is by fumigation. It is imperative that any system has some gas-tight sealed storage which meets a standard pressure test. When purchasing new storages they must meet Australian Standard AS 2628 – 2010 to be confident they are gas-tight.

It is also important that new storages can meet this standard for the expected life of the storage, provided it is maintained correctly. If silos lose their gas-tightness because of structural failure and not from maintenance they are not what you want. Always apply the same decision making principles when purchasing silos and storage equipment as you would any other piece of machinery; it must be fit for purpose.

In sealed gas-tight storage, phosphine will control all pests when used at correct label rates and fumigation periods.

Making phosphine last

Phosphine resistance is a serious threat to the grain industry. While resistance is right in our face, it really is a symptom of a larger problem such as phosphine use in structures that are not gas-tight, or use of phosphine at off-label rates and/or insufficient fumigation periods.

Ensuring phosphine is used only in gas-tight structures at label rates and for recommended fumigation periods will enable the industry to prolong the use of this important insect-control tool. The first step for growers is to ensure existing and new storages are gas-tight. Gas tightness is determined by a standard pressure test (Figure 1).

The Australian Standard for gas-tight sealed grain storages provides growers with a benchmark for testing existing silos and a reference point when buying new ones. The standard is based on a five-minute half life pressure test. For a storage unit to comply with the new national standard for sealed silos the oil levels in the pressure relief valve must take at least five minutes to fall from 25mm to 12.5mm. After the silo has been tested and has met the pressure test it is important to follow label directions when using phosphine.

Diagram illustrating silo pressure differences

Figure 1: Testing the pressure relief valve.

Correct dose rates are essential as are the correct fumigant exposure periods. The fumigant exposure periods are determined by temperature and are:

  • Recommended minimum exposure period:
    • Seven days when temperature is greater than 25 degrees C.
    • 10 days when temperature is between 15 degrees and 25 degrees C.
  • Ventilation period:
    • 24 hours with fans, and;
    • Up to five days without fans.
  • Withholding period:
    • Two days after the ventilation period (human and/or stockfeed).

Maintaining quality

High moisture and temperature can affect grain in many ways; insect activity increases, spoilage can occur due to moulds and fungi and seed viability can be affected. Always aim to store grain at a moisture content level of 12 per cent and at 25 degrees C or less. Harvest temperatures are often 30 degrees C or higher and during summer, temperatures in silos can exceed 40 degrees C. This makes keeping grain cool a challenge.

When harvesting, target cool grain to be stored on-farm. This may mean harvesting when moisture can be high. A moisture meter can be used to ensure moisture limits are not exceeded. Installing an aeration system will further assist in cooling grain.

What should you consider now?

In most cases it would be impractical to replace all storage with new sealed storage. You should have a proportion of sealed storage in your system to fumigate grain. Where storage is to be increased, good quality sealed storage should be purchased. Existing unsealed storage can be fitted with aeration and grain fumigated in sealed storage can be transferred to aerated storage, monitored and confidently stored until needed. Careful planning, understanding your market’s needs, and investing in good quality storage will allow growers to have a quality product. When growers can manage their on-farm storage system in this way, on-farm storage can be a valuable marketing tool.

Keep the market in mind

Above all it is important to work with grain end users to ensure any delivered grain meets receival expectations. When the decision is made to store on-farm, the system becomes a part of the supply chain and growers need to manage the grain with the understanding that it is a food product in most cases. A system that allows easy grain storage while maintaining quality will ensure growers can deliver grain that meets market expectations.

For further grain storage information go to Stored Grain website

Acknowledgements

The research undertaken as part of this project is made possible by the significant contributions of growers through both trial cooperation and the support of the GRDC, the author would like to thank them for their continued support. 

Contact details

Peter Botta
PCB Consulting
0417 501 890
pbotta@bigpond.com

GRDC Project Code: PRB00001,