Weeds

Real Direct Seeding

Traditional seeding method

In Real Direct Seeding, perennial root weeds such as couch grass are killed by glyphosate spraying.
According to users of the method, the best time to control the root weeds is in spring before seeding

Spring spraying before seeding

The weed control in spring must not be started until the growing season has started, the daily heat summation is sufficient and the liquid flux to the plant roots is in progress. In spring, the weeds are most sensitive to control and, if the conditions are favourable, half a dose of glyphosate is enough to kill the couch grass. The weather conditions and temperature often determine the spraying result. In addition to control of root weeds, control of seed weeds must be carried out later in the summer.

The users do not recommend weed control after the seeding. Especially with soils rich in humus, as the seeding coulter tills the soil, part of the weeds become covered and thus avoid the spraying. Weed control after the seeding also involves a weather risk. Rainfall may occur after the seeding and some of the shoots may emerge before the spraying can be carried out. If shoots have emerged or seeds lie exposed on the ground, they will be destroyed by spraying.

Weed control in autumn after the harvesting

The autumn weed control is best suited to the clayey soils of Southern Finland. There the grain ripens earlier and more time is left for autumn weed control. If even a small amount of green weeds is visible in spring following the autumn weed control, it pays to repeat the control in spring as well.

After harvesting

In order to succeed with the post-harvesting spraying it is advantageous if the crop stand is upright and the stubble is left high so that a part of the weed leaves remain visible. The blades of the chaff cutter need to be sharp and the dispersion plate must be adjusted to the side so that the chapped straw does not cover the weeds. It pays to carry out the harvesting so that no straw heaps are left. However, if straw heaps are formed for some reason, it is advisable to spread them out to enable successful spraying.

Leaving the autumn spraying late increases the risk of cold weather and rain. Nevertheless, the growing season is coming to an end and the flux to the roots may have stopped. For these reasons autumn spraying involves the application of larger amounts of herbicides, and particularly in the Northern part of the country the results may be uncertain. Therefore, spring has proven to be the best season for weed control.

Because the amounts applied are very small (1 - 3 l/ha) and, especially in spring, the rich microbial activity in the stubble breaks down the glyphosate compound, weed control using glyphosate in connection with Real Direct Seeding is not harmful to the environment.

Things to be observed during weed control

During weed control in spring one needs to be careful that glyphosate and other herbicides are not used at the same time in the same tank mix, because then the leaves of the plants to be killed will die immediately and at the same time the flux to the roots will also stop. In summer the root weeds will revive as the glyphosate has not entered the root system.

If the soil surface will be minimally tilled after application of the slurry and manure, it pays to carry out the glyphosate control before spreading and earthing over of the slurry.
During earthing over, the couch grass roots will break and get covered, which compromises the efficiency of the weed control.

In addition to weed control using glyphosate, the couch grass may be controlled during the growing season using herbicides specifically for wheat and turnip rape stands. Thistles and sow thistles also have herbicides and application seasons of their own.

Late spring spraying also kills crop shoots from the previous growing season.

The gramm-substances are not efficient for control of thistle, sow thistle, scentless mayweed or bedstraw but it pays both to use more efficient substances and to postpone the spraying time until a period when the weeds are most sensitive.

 

FACTORS FOR SUCCESSFUL WEED CONTROL

  • Avoid forming heaps of straw during harvesting.
  • High stubble leaves the weed leaves better exposed.
  • Short straw chaff and evenly spread litter do not cover the weeds.
  • Upright plant stand and high stubble - no flattening
  • At least 2-3 leaves of the weeds must be exposed.
  • Spraying weather is warm enough so the liquid fluxes are sufficient.