Silage - Trading by Weight

This Topic Includes:
What the law says
What the Ministry is doing

The issue

• The silage trading industry is a multi-million dollar industry and growing.
• Silage has traditionally been bought and sold on the basis of some agreement on the size of the farmer's paddock. This method increasingly led to disputes as the silage industry grew.

• The silage industry recently decided to switch to trading by weight. The method adopted uses the total weight adjusted against the dry matter percentage of a sample of the silage.
• Industry representatives have told the Ministry that many different types of weighing equipment are being used by contractors to determine the weight of silage being bought and sold.
• In many cases the type of equipment being used to determine the weight of silage was not approved for trade use and did not bear the mark of verification ( a "stamp") as required by the Weights and Measures Act 1987.

What the law says

The Weights and Measures Act 1987 requires that, where goods are bought and sold by quantity, that quantity, must be correct. The Act also provides that any weighing or measuring instrument used to make that determination must be approved and verified as required under the Act.

The criteria for approving weighing equipment for trade use involves testing the equipment to ensure in meets a variety of technical performance requirements. The equipment may also have conditions imposed to ensure that when it is in use it does not facilitate fraud.

Once a type of weighing equipment has been approved each piece of equipment of that type must still undergo verification testing to ensure it meets the requirements of the approval certificate and is accurate and suitable for its intended purpose.

What the Ministry is doing

The Ministry is pro-active and wants to work with industry representatives such as Federated Farmers and contractor representatives to ensure that silage sales are conducted using only approved and verified weighing equipment.

The Ministry is looking at various weighing systems currently being used in the silage trading industry to see if they can be approved under the Act as suitable for trade use.

A recent survey the Ministry conducted in the Waikato and Canterbury showed that the range of weighing equipment being used included:

• weighbridges
• portable weighbridges
• wheel weighers
• axle weighers
• live weigh systems fitted to equipment such as trucks and loaders.

If you are a buyer or seller of maize silage you should ensure that the equipment used to determine the quantity of the product is approved and verified. If you have any doubts contact the Measurement and Product Safety Service.

If you would like to discuss getting some weighing equipment approved please contact our Approvals Officer on 04 568 4737.