Introduction

Weeds on horse properties are a concern because some species are toxic to horses, such as Salvation Jane. Weeds growing in pastures reduce the amount horses can graze as they take the place of desirable, edible pasture plants. Weeds also do environmental harm if they grow in areas of native vegetation (i.e. choke out native species).
 

Abundant weeds usually indicate that pasture quality is poor, and may also be an indicator of low soil fertility or acid soil. Weedy pastures tend to provide poor soil cover particularly during summer/autumn. Also, weed-infested paddocks will produce poor quality hay containing weed seeds. In the Mt Lofty Ranges for example, weeds which compete with desirable pasture plants include dock, sorrel, wireweed and capeweed.
 

If there are any proclaimed (declared) weeds on the property, then these must be controlled according to legislation (see Proclaimed Pest Plants).
 

Where possible, a range of methods should be used to control weeds (e.g. good weed hygiene on the property, good grazing management, re-seeding pastures) rather than just a single method (such as relying on chemical). An integrated weed control program is an important aspect of property management, and is one of the components of a property management plan.
 

Steps to achieve best practice

Suggested steps are:-

 
Step 1

Regularly inspect the property for weeds and identify which weeds are present. You can get assistance and advice on weed identification and control from rural consultants and advisers, and from your Natural Resources Management Board.

 
Step 2

Carry out weed control programs for any problem weeds, using methods that are recommended for your area (especially proclaimed weeds). You can find this out from your Natural Resources Management Board, rural advisers or consultants. Consider using selective weed sprays in pastures (if required).

 
Step 3

Ensure there is good weed hygiene on the property (see Preventing weeds entering or leaving the property).

• Ensure as far as possible that any hay or feed brought on to the property is free of weeds and weed seeds.
• Quarantine new horses for 10-14 days to prevent seed spread on to the property.
• Clean boots, vehicle tyres etc before leaving properties visited for horse events.
• Designate a carpark area for visitors and entry/exit point for the property for contractors and visitors.
• Speak to contractors about your concerns and provide a cleaning down area for machinery if this is determined necessary.
• Put up signs or use other means to communicate your weed quarantine precautions to visitors.

 
Step 4

Manage pastures well (see Pasture Composition). Good quality pastures that have mostly desirable pasture plants will tend to out-compete with most weeds.

• Maintain good soil fertility and ensure soil pH does not become too acid. Do regular soil tests for fertility and pH, and apply fertiliser and/or lime according to soil test results.
• Consider renovating or re-seeding pastures if the amount of desirable pasture plants is low.
• Where possible, use rotational grazing of pastures (see Maintain groundcover), and don't overgraze pastures because this makes it easy for weeds to proliferate.

 
Step 5

Each year, review your weed control program. Each season, monitor weeds present and numbers of weeds in pasture paddocks. Look at how successful or otherwise your weed control has been, and modify the program accordingly.

 

 
Weeds on horse properties are a concern because some species, such as Salvation Jane and Cape Tulip (above), are toxic to horses.

Links

• Natural Resources Management Boards, including fact sheets e.g. www.mlrapcb.net
• Legislation: www.dwlbc.sa.gov.au/legislation.html or www.parliament.sa.gov.au
• Purple Peril Attack - Leaflet CRC for Weed Management Systems.
• Chemical Users Project: Adelaide and Mount Lofty Ranges Natural Resources Management Board / Torrens Catchment Water Management Board Ph. 8271 9190.
• Spraying Chemicals - how much is enough? - Chemical Users Project: Adelaide and Mount Lofty Ranges Natural Resources Management Board / Torrens Catchment Water Management Board Ph. 8271 9190.
• Accuracy: saving time and money - Chemical Users Project: Adelaide and Mount Lofty Ranges Natural Resources Management Board / Torrens Catchment Water Management Board Ph. 8271 9190.
• The answer's on the label - Chemical Users Project: Adelaide and Mount Lofty Ranges Natural Resources Management Board / Torrens Catchment Water Management Board Ph. 8271 9190.
• Weeds of national significance: www.weeds.org.au/natsig.htm
• Land Management Program advisers based in the Mt Lofty Ranges: www.amlrnrm.sa.gov.au/services.html
• Hoofprints - A manual for Horse Property Management - J. Foyel, Primary Industries SA. Agdex 461/10
• A Legal guide for South Australian primary producers - SA Law Society, available from PIRSA offices, Natural Resource Centres (but note some legislation referred to is now superseded)