Sunday, 13 July 2014

The Battle on Blackgrass

Has there ever been so many conversations about one grassweed .... so here are some strategies that could be considered in the forthcoming season. These are only suggestions please check with your own advisors and agronomists.
There's no doubt many other options, but here is a starter for ten !!

  1. Stale seedbeds and delayed drilling.... tricky on heavy soil in a wet year.
  2. Competitive prostrate wheat varieties with increased/variable seed rates. Double drilling corners and parts of poor headland seed beds.
  3. Introduction of temporary grass for 3 years.
  4. Widen rotation, there is no doubt that poor crops in 2012, especially oil seed rape let blackgrass thrive. Gross margins on spring crops may now not look so bad.
  5. Cover crops followed by spring crops. Probably the most talked about change that many growers are considering. Not only the restructuring, erosion and nutrient benefits but a chance to germinate blackgrass and control with glyphosate in the spring. Need to carefully consider the issues of vetch and brassicas as a cover crop in a rotation that includes osr and beans. Look at varieties that may offer resistance to clubroot. May be less successful if blackgrass infestation is bad. This option may also fit in with Greening Ecological Focus Areas's (EFA).
    Multiple benefits of cover crops.
  6. Winter beans replacing spring beans. This is a difficult decision, spring beans human consumption premiums may have to be sacrificed to sow winter beans. Better crop cover and the ability to use propyzamide may help with blackgrass control.
    Winter beans offer good crop cover.
  7. Using fallow to reduce blackgrass seed numbers. This may or may not be allowable under new Greening EFA's. Should be ok this autumn whilst waiting for rules to be implemented on Jan 1st 2015.
  8. Rogueing............small numbers turn into big numbers!!
  9. 'In crop' glyphosate, probably too late for this season and always difficult to decide on when and how much of the field to take out.
    Difficult decisions.. to spray 'in crop' or not.
  10. 'In crop' selective chemical control, pedimethalin, flufenicet, (in winter wheat) propyzamide, (wosr and wbeans). The temptation with propyzanide can be to spray to early, when sprayer travelling conditions are good but warm temperatures reduce effectiveness of active ingredient.  Clethodim(wosr and sugar beet) has reportedly caused damage to some osr crops but has been effective on blackgrass in some situations. A robust strategy on tank mixes and sequences is essential.