Manure matters, so dig a little deeper!

Manure, from horses or farm livestock, is a wonderful soil conditioner and natural fertiliser.
Where it is used and subsequent plant growth is less than ideal then this might be directly linked to the manure or compost or it may be a down to other co-incidental factors such as poor quality seed, unfavorable weather conditions, insect pests, disease or virus.

If the manure is the presumed cause of poor growth then that might be because of a number of factors such as:

  • Too much manure
  • Green manure which typically contains a high component of cellulose that tends to draw in valuable soil nutrients to aid its breakdown process
  • Presence of herbicides which have previously been applied to either grassing grass or to silage or hay that has subsequently been consumed by livestock

Herbicide damage to some sensitive crops has previously been reported in the UK and it is possible the manure used came from farm animals or horses fed pasture or conserved forage from grassland previously treated with a herbicide containing the active ingredient aminopyralid.  These products were sold in the UK between 2006 and 2008 and were known as Forefront®, Pharaoh® and Banish®.  Some resulting manure was unfortunately supplied to a few gardeners and allotment holders and this could have caused damage to some sensitive crops.

These products have been subsequently withdrawn and then re-introduced in 2010 with an amended and more directive label alongside an education program for farmers on its use so as to mitigate against this happening again.

Some key questions

Is aminopyralid dangerous?

No. The Chemicals Regulation Directorate (CRD) , the Government agency responsible for the approval of pesticides in the UK concludes that there are no ill effects to human or animal health from food grown from land that may contain aminopyralid residues.


Weed killers or killer weeds?

Aminopyralid-based herbicides were developed to help grassland farmers control and eliminate a number of troublesome and potentially dangerous perennial broad-leaved weeds from their fields.

Although some people are worried about the use of herbicides, the weeds they eliminate are also a concern. According to the Department for Environment, Food, and Rural Affairs (DEFRA) the Weeds Act of 1959 mandates the control of five 'injurious weeds' that threaten grassland health:

  • Common Ragwort
  • Spear Thistle
  • Creeping or Field Thistle
  • Broad leaved Dock
  • Curled Dock

Of these five weeds, ragwort and dock also pose a potential threat to livestock (especially horses), as do buttercups.  Aminopyralid provides very effective control of docks, buttercups and thistles.

What is the chance that I have bought or supplied manure affected by aminopyralid?

Slim. Of the 12 million hectares of grassland in the UK, only 5% is treated with herbicide each year. Of that small percentage, less than one third of that area would receive a treatment containing aminopyralid.

The label on products containing aminopyralid such as Forefront T state that it can only be used on grazing grassland and that grassland must be grazed by cattle and sheep only. If manure is inadvertently produced and collated from its use then any resulting manure must stay on the farm of origin.

A few incidents of garden or allotment crop damage were reported in 2008 and 2009, to which Dow AgroSciences and the CRD responded immediately.

If you think you may have a suspected case of herbicide damage resulting from an application of manure then click here.

Aminopyralid Fast Facts

The following are general facts about aminopyralid-based herbicides, such as Forefront T. For more detailed information about your particular area of interest, click on the most relevant link on the left.


Aminopyralid is safe for humans and animals.

  • Vegetables grown with affected manure are safe to eat.
  • Milk from cows fed treated silage is safe to drink.

Only a few species of plants are affected

  • Sensitive crops include peas, beans, potatoes, sugarbeet, carrots, tomatoes, lettuce and spinach.
  • Affected manure is safe for use on grassland areas and should only be applied to grassland for grazing by cattle or sheep.
  • Affected manure may pose a risk to flower-rich grassland areas, particularly those designated as Sites of Special Scientific Interest (SSSI) or those under agri-environment scheme management where the aim is to maintain or enhance the diversity of wildflowers, as it could cause damage to wildflowers.

Aminopyralid breaks down in the soil

  • Residues of aminopyralid are broken down by soil micro-organisms.
  • Residues in manure break down if rotovated into the soil and turned frequently.
  • Do not use where sensitive crops are to be grown. (See list above.)

Contact us

If you believe your manure has been affected or you have further questions, email us at UKHotline@dow.com .