WITH rising fertiliser cost and more expensive cereal prices, now is the time to plan how to maximize the amount of hay and silage produced from grassland for next year's winter feed.
Controlling broad-leaved weeds is one area to focus on. A 20% infestation of docks in a silage crop will hold back grass yields by 20% - so for a field that normally achieves 11t DM/ha/year, as much as 2.2t DM/ha could be lost each year. This could be worth as much as €150/ha (using Teagasc costing on the value of grass)
TIPS FOR SUCCESS
Chris Maughan, Technical Manager with TP Whelehan, gives the following tips for successful dock control with Doxstar.
Apply when docks are actively growing. For example, in first cut silage, apply three to four weeks before silage harvesting. If applying after silage cutting, wait until docks are growing vigorously and are 15cm high
Use a minimum of 300 litres water/ha (30 gals/acre) to overcome shading by dense grass or dense weed population.
Apply Doxstar at a rate of 3 litres/ha as a single application or two applications of 1.5 litres/ha six to 12 months apart.
In grazing ground, keep livestock out of treated areas for seven days.
Its very important to use product which have no effect on the grass. Older products, like CMPP and 2,4-D which give a temporary kill only, also have the big handicap of severely depressing grass growth. Doxstar is safe on the grass and will not affect the yield of your silage.
SILAGE SWARDS MOST VULNERABLE TO DOCKS
The open nature of silage swards after cutting favours the establishment of docks
This is further compounded by the application of slurry to bare stubble which leads to a temporary setback to the grass and an ideal seedbed for dock seedlings.
Also high soil potash levels are more suitable to dock growth. Cattle slurry is rich in potash and, when combined with chemical potash application, can lead to high levels of potash.
Docks are a major weed of intensive grassland. One mature dock plant can produce up to 60,000 viable seeds per year. From July onwards, given favourable conditions, about 80% of these seeds will germinate. Dock seeds can remain viable for 50 to 70 years if buried in soil. These seeds will germinate when conditions of light and soil temperature are suitable. Docks seeds do not survive in well-preserved silage but do survive in hay.