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Crop Crac07.05.11
By Wendy Fearon
Losses in grass yield often go unnoticed because farming practice tends to focus on livestock output rather than the actual output of the grass. The productive capacity of grassland depends on a large number of factors but in the main is dependant upon the climate and the soil. Mild temperate weather with deep rich soils is the most favourable. Other factors such as the topography of the land, species mix, and sward damage can be important, but generally to a lesser extent. Grass fields are looking exceptionally well but those known to be deficient in either phosphate or potash will show appearances of stress more than those with the right balance of NPK.
The recent dry spell will undoubtedly cause stress as grass struggles for moisture and this may cause a reduction in the uptake of the herbicide applied. Weed infestations can impact significantly on the yield and quality of grass for both grazing and cutting with trial work confirming a 10% weed infestation will cause a 10%yield loss. FOREFRONT is the most effective herbicide available to grassland farmers for the control of docks, chickweed, thistles, dandelions, nettles and buttercups. It is the longest lasting weed control product in grassland to date with a single well timed spray giving control up to 18 months so whilst it may appear expensive it really is good value for money.
Docks
The unusually dry conditions during March and April have allowed all fields to be treated with slurry or fertilizer. The problem with docks in grassland is that they are well adapted to modern farming techniques. They germinate throughout the year and grow from seed as well as root stocks. They compete strongly with the grass but have only 65% of the feed value of grass. They are also unpalatable to stock.
Docks are ideally suited to the conditions created in intensively managed grassland and particularly cattle regimes. Ideal conditions for grass growth are also ideal for docks: moist, fertile soils with moderate to high levels of nitrogen. Dock and chickweed seeds can pass undamaged through silage, the stocks’ digestive system and slurry. They are therefore spread very effectively by modern farming practices. In the slurry the seeds are effectively coated in nutrient ready to germinate and grow. Lax/open swards resulting from poaching, over-grazing, winter kill, pest damage and lack of tillering in shorter term leys all provide space for seeds to germinate and become established.
Where clover is not important: FOREFRONT can be applied to established swards more than 1 yr old. Aminopyralid is very rapidly translocated throughout the plant; much faster than fluroxypyr and will give long-term control of chickweed, buttercup, thistle, dandelion, nettle and dock with a minimum 7 day grazing interval. DOXSTAR may be used in both established swards and new leys from 3 fully expanded leaves.
GRASSLAND can be applied to established swards and new leys from 3 fully expanded leaves and contains dicamba giving root control of seedling & established docks also controlling thistles, chickweed, buttercup, nettles & rushes. Where clover is part of the mixture then a clover safe product must be used. In recent years ALISTELL was the only product available, giving reasonable results. Its current label however has been revoked and the product therefore is temporarily unavailable. TRIAD is a new SU type herbicide that is safe to clover when used correctly. This product has been available for a number of years in the UK but with a very restricted label, spring barley undersown only with italian ryegrass and clover. It has also been available in ROI with a much wider label including direct reseeds. As a result of ALISTELL not being available, a SOLA (specific off-label approval) has been granted by CRD, allowing TRIAD to be used in cereals undersown with various grass and clover mixtures, and in direct reseeds (albeit as is the case with all SOLA’s, at the user’s own risk). As well as controlling a wide range of BLW’s TRIAD appears to be better than ALISTELL on chickweed.
Leatherjackets
Leather jacket damage in grassland has reached an all time high this season. All areas of the country seem to be affected. Prompt action on leatherjackets gives the most economic return so swards should be inspected now, as high numbers of leatherjackets can cause economic loss in grassland even before physical damage in the form of dead patches in the field are observed.
Spray treatment is the only option and it is important to remember that the soil is the target not the plant. Therefore high water volumes and a coarse spray quality are necessary to ensure good penetration and contact with the pest.
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