Barclay Crop Protection

Dock control in grassland

Farmers frequently ignore weeds that may well be decreasing the yield of otherwise productive grassland mainly because they often do not appear to be causing any damage and they can be both mown and harvested by modern machinery when making hay or silage. If they were bright blue or maybe even pink they would be far more obvious!

The best example of these is probably docks of which there are two primary types, curled docks (Rumex crispus) and broadleaved docks (Rumex obtusifolius) although there are many others which also belong to the family Rumex.

Unlike many other grassland weeds docks are very responsive to nitrogen fertilisers which is why they seem to thrive in intensively managed grassland and why dairy farms often have a particular problem with them. In addition the seeds are almost entirely indigestible by ruminants and they pass through the gut and survive for some time in manure heaps until they are given the right conditions to germinate.

Most plants compete by either growing above others or by spreading their leaves over their neighbours and shutting out light which then allows them to steal nutrients and water.

In addition to this, the feed value of docks is about one third less than the grass they replace so assuming that grazing stock eat these weeds a 15% dock infestation reduces the feed value of a 10 acre grass field is reduced to that of a 9 acre one. In essence farmers are reducing their grazed fields by some 10%. Imagine that you have to pay rent on 10% more than the fields you graze. Ask yourself the rentable value of your fields which may be as much as 100 Euros (£85) per acre per year AND THAT FOR EVERY 9 ACRES YOU RENT YOU ARE FORCED TO PAY FOR ANOTHER ACRE!

The best way to avoid this is to control these invasive weeds and the best way is to use a well timed effective herbicide like Hurler.

The timing of any application is critical and the optimum is when the weeds have a large leaf area but before they start to produce a seedhead. Unfortunately weeds will germinate over a period of time so it is usually only possible to control a the majority of them which is why I prefer using a series of applications possibly at as little as half rate (1lt/Ha) and combine these with topping which will help stop plants producing seed. Where a forage crop is taken an application of Hurler some four to six weeks after mowing can be particularly effective.

Other techniques include being careful not to spread manure containing dock seeds until the material has been given a chance to break down properly or where there is a severe infestation sowing a cereal like wheat or barley which will act as a break crop and allow the use of Hurler (or another herbicide) to best effect.

Successful control of these weeds can be compared with the secret of great comedy. It's all in the timing!

J.A. Harrington
Barclay Crop Protection,