Spraying out your old crop before regrassing or planting a new crop is standard operating procedure for most farmers. Using a glyphosate-based product, like Roundup Ultramax or Stinger 510, reduces cultivation passes, prepares the paddock for direct drilling or minimal tillage, lowers the turf clods on the seedbed surface, eliminates pasture regrowth, and helps control future pests, too. One thing glyphosate does not do is effectively target broadleaf weed species, but there are things you can do to spike the competition.
Spiking for control
Adding other herbicides, known as ‘spike’ or companion herbicides, to your glyphosate at spray-out speeds up the ‘brown down’ of broadleaf weeds and previous crops, and helps control the broadleaf weeds.
Every product has their individual strengths and weaknesses across the weed spectrum, so carefully consider which product is best for your system and weed profile. Identifying the weeds present informs which product is best suited to be used use as a spike.
Residual concerns
Glyphosate does not have any residual effects on future crops when used in isolation. However, some spike herbicides do, with some lasting up to two years depending on the products and following crop. Care must be taken when choosing the appropriate broadleaf spike to ensure future crops are unaffected.
Working together
Adding an adjuvant helps improve performance especially with glyphosate, as is choosing the right companion product. Not all spike products are complimentary to the glyphosate mode of action. For instance, the addition of a broadleaf weed spike may target the broadleaf but reduce the glyphosate’s effectiveness against other weeds. Taking a paddock walk to make a pre-spray assessment of the weed species present helps you choose the right products for the job. Perhaps that means foregoing a spike altogether and increasing the rate of the glyphosate or choosing a different spike to one you have used before, one unique to your paddock’s needs.
Advice you can count on
With their agrichemical knowledge and weed identification skills, your PGG Wrightson Technical Field Representative (TFR) is a valuable resource. By working together, your TFR can tailor advice on the products, rates, and timings specific to your operation and make spray-out work for you.
