Grassland crop protection

Strategies to combat sorrel, buttercups and similar

After cutting, show courage and take targeted action against problem weeds in grassland between uses.

After cutting is a particularly favourable time to target problem weeds in the grassland. Farmers should take the following into account as they tackle weeds:

  • Mechanical and chemical means can be used to combat weeds
  • After-treatments are required at times – farmers need to be flexible regarding the application period
  • Toxic plants have negative effects on farm animal health and performance
  • Observe waiting times; use Simplex in spring with subsequent grazing only
  • Remove toxic plants such as common ragwort once they have died off since animals lose their aversion to toxic plants when feeding if the plants have been treated

Sorrel is widespread on grassland. A DM yield loss of 5% is to be expected with just one sorrel plant per square metre. Farmers achieve an optimal control time (20% of sorrel flowering stems sprouted) using a full rose across sufficient leaf mass. If farmers declare war on sorrel with Ranger, for example, they will kill chickweed and dandelion at the same time.

Application rates grassland crop protection

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Rough calculation to indicate cost-effectiveness of sorrel treatment

DM yields of some 50 dt DM/ha are expected for the first cut.

  • 5% = 2.5 dt DM/ha loss
  • At 6.5 MJ NEL/kg DM = 1,625 MJ NEL/ha
  • = 518 litres less milk per 1 hectare
  • At 32 ct/kg milk = €165/ha
  • As a comparison: Use of Ranger about €90/ha + application

Grassland areas with sorrel

Poisonous effect of meadow buttercup
Buttercup
Many underestimate the poisonous effect of the meadow buttercup.

Weeds in grassland cultivation not only compete for nutrients and space, but they are also poisonous. Many underestimate the meadow buttercup (Ranunculus acris). It contains the toxin protoanemonin.

Characteristics of the meadow buttercup

  • Slightly poisonous
  • Takes two months to become non-toxic in silage
  • Use in hay reduces toxic load
  • Toxic load is highest during florescence

Symptoms and problems

  • Mucous membrane irritation; can damage kidneys and mammary glands during excretion
  • Effects on the central nervous system leading to paralysis, cardiac arrest, death
  • Damage to the liver which leads to intolerance to sunlight
  • Animals avoid the plant in meadows, but not in silage
  • Symptoms such as loss of appetite, drooling, diarrhoea and a reduction in milk yield are often not associated with intoxication

Overseeding after herbicide has been used

Overseeding after herbicide use is essential to cover patches with high-quality grasses before more grass weeds and other weeds take over such parts. As a plant which requires light for germination, sorrel has no problem spreading across bare patches. Farmers should therefore take preventive action with continuous overseeding to ensure a dense sward and prevent patches. However, patches should only be overseeded after weeds have died off completely to ensure grass seeds come into contact with the soil. Damage to the seedlings is not expected at this time – clover plays a special role in this respect.

Overseeding carried out in early spring has generally exceeded the four-leaf stage and is relatively robust against herbicide use. Farmers should pay attention to suitability for locations and performance of the varieties used to ensure they choose the right seed mixes. The mix is particularly suitable for overseeding Plantinum Intensiv . It contains certified top varieties of late-flowering German rye grass. These varieties ensure a high cutting frequency with maximum harvesting elasticity. The combination between competitive German rye grass and subsequent intensive cutting and pasture use helps grass to become established in the old sward and ensures overseeding succeeds.

Tip from the experts

Farmers can minimise the risks of overseeding by seeding at several different times. An ideal solution is to sow 5 kg/ha of seed in the spring, during use and in the autumn.