Getting the best from your grass

UK - February 05, 2010



Analysis of farm accounts shows that cattle and sheep farmers who feed more grazed and conserved grass make more money.  As input costs continue to rise, producing more meat or milk from grass has never made more economic sense.  Optimising grass growth and utilisation can help livestock enterprises make a positive contribution to the bottom line.

Grass offers opportunities to every meat or milk business, whether it is those brave enough to embrace low-cost milk production based on grazing, or those producing the highest quality beef and lamb on species-rich pastures, and all those operating in between.

Managing grass is not easy, but the benefits of improved grassland management include:

• Increased grass quality and yield leading to higher:
  • Intakes
  • Stocking rates
  • Liveweight gains
  • Milk production
• Lower concentrate feeding
• Extended pasture life and overall
• Higher margins from each hectare of forage.

Realising the full potential of existing pasture depends on many factors.  These include soil type, pH and structure; stocking rates, nutrient supply from fertiliser, manures and soil reserves, sward composition and not least, weed content.

Deep rooted and difficult weeds such as docks, thistles and nettles reduce sward yields and downgrade the quality of fresh grass and conserved forage.  Also in dry conditions weeds will outcompete grass for what little moisture there is.  This is an unnecessary waste of low-cost home-grown feed resources.

Controlling these weeds is an effective and relatively simple way to start improving grassland production and use.

Welcome to the Grass Bites Farm

To help livestock producers understand the options for effective control of a wide range of grassland weeds, herbicide company Dow AgroSciences has developed a model farm to make the job of identifying the best course of action simpler.

Grass Bites Farm is a livestock enterprise running to 200ha.

Situated in the west of the UK, it is owned and managed by farmer Jock Field.  The farm carries herds of dairy and beef cattle and a flock of sheep.  His daughter Mary has just set up a DIY livery business.

The fields are a mixture of short to medium cutting and grazing leys.

One of the steeper fields has a high proportion of bio-diverse species.

Maize is grown for silage and the six metre margins surrounding this are in an environmental stewardship scheme.

Grass Bites Farm can be viewed on-line at www.grassbites.co.uk. 

Solutions for every situation

Dock control in silage ground

Docks are bad news in cutting leys.  They compete for light, nutrients and moisture which all reduce grass yields.  This means that more concentrate feed than is necessary may have to be bought to get livestock through the winter.  Independent trials have shown that a 10% infestation of docks will cause 10% loss of grass yield.

Docks are also unpalatable with only 65% the feed value of grass.  Their presence can also affect silage fermentation which will reduce feed quality further.

Doxstar was developed specifically for long-term control of all types of dock, and can be applied at any time of year, as long as the weeds are at the correct growth stage and actively growing.

Unlike older products, treating pre-first cut with a grass-safe herbicide like Doxstar, will not check delicate early spring grass growth.  Thus docks can be tackled early without reducing fist cut yield of high quality forage.

If it is not possible to treat before first cut - leaving the aftermath for two to three weeks to allow sufficient re-growth before spraying will give very good control.

Delaying second cut for at least three to four weeds after application allows the herbicide to move deeper into the long tap roots, giving more effective and longer lasting control.

Although the treatment window between cuts is tight, with good timing, it produces excellent results on the uniform dock re-growth.  With all the plants actively growing treatment is idea at the perfect rosette stage, with foliage 150 to 200 mm high or across and no seed heads visible.

Dock control in grazing pastures

Docks are unpalatable and livestock only eat them as a last resort.  They can also cause dietary upsets particularly in young animals.  By taking up space where grass could be growing, docks also reduce the available grazing area,which drives stocking rates and/or grazing days down below a field's full capacity.  Doxstar can be applied once at the full 3 litres/ha rate or in two half rate doses during the year.  The split treatment is useful on established infestations to effectively control regrowth.  Livestock need only be kept out of treated areas for seven days.

Thistle control in grazing pastures

A 10% infestation of thistles (i.e. just ten plants in 35m²) will reduce grass production by 1.1 t/ha of dry matter per hectare.

As well as lost grass production, thistles also pose a hazard to lambs.  The spikes can act as dirty hypodermic needles to animals brushing past them - breaking their skins and spreading diseases such as orf within the flock.  Controlling thistles on sheep pasture not only protects lambs, but also cuts the cost and labour of inoculating lambs against infection.

Lasting thistle control above and below ground requires a translocated herbicide such as Thistlex applied to young and actively growing weeds with little stem.  Spraying in May or June is ideal provided thistles have reached the rosette stage.  If they have gone beyond 6 cm in height, it is better to top the pasture and spray the re-growth 6-8 weeks later.

Trials indicate up to 80% control is still achieved 12 months after application.  This saves time and money on follow-up treatments.  Thistlex is also safer to grass than other conventional herbicides.

Dock, thistle and nettle control in grazing pastures

In fields where a range of different weed species are causing problems, using a broad spectrum herbicides may be the solution.  Pastor offers long term control of docks, nettles and thistles in one product.

Pastor can be applied at any time of year provided weeds are actively growing so that the herbicide can be carried freely to all parts of the plant.  Weeds should also be at the correct growth stage and not suffering from stress due to cold or drought.

Pastor can be applied as an overall spray at 4 litres/ha or split into two applications where docks are the main target.  Fields should not be cut for 28 days after application to allow the herbicide to fully translocate into the root systems for full effect - although stock can be re-introduced after seven days.

Weed control in flower-rich meadows and environmental margins

For a more targeted approach to weed control, spot treatment using Grazon 90, applied through a knapsack sprayer is the most appropriate option.  It will also take out unwanted species such as buttercup, and even scrub weeds like gorse and bramble.

Grazon 90 works very quickly on target plants without any harmful effect on grass.  Once dried onto foliage - usually within two hours, it cannot be dislodged e.g. by wildlife or dogs walking through treated areas.

Again for best results target weeds should be actively growing and not stressed by extreme hot or cold weather.  An interval of seven days must be observed before re-introducing grazing livestock and of 14-28 days after spraying, to allow the herbicide to translocate throughout the weed, before cutting for hay or silage.