Seeding of weeds an issue
Prevent barnyard grass growth
.WELL, here is a good photo isn’t it?
Barnyard grass seed by the cupful after a 2017-18 grain sorghum crop. Very dry still two months after harvest and in this lighter red soil.
First cropping thought most of us have is to build up the subsoil moisture levels so you at least have a chance of a successful crop next season.
Next thoughts are on weed control.
I know it sounds obvious but annual weeds like barnyard grass must set seed if the species wants to continue. So stopping seed set is one of the big six major principles from the WeedSmart handbook.
So how to do this in your country in your farming system? Many of your plans and actions may be different to neighbours down the road.
On this reddish sloping block, the last reasonable thing you want to do is cultivate the country. Sure you could bury that plethora of barnyard grass seed down to 4-6cm to reduce immediate germination numbers, however I would judge this soil type would be fairly light and subject to wind or water erosion.
This cultivation process would also initiate an undesirable stubble breakdown, with the added consideration that many of your more deeply buried weed seed numbers would remain viable for longer.
Now, we all know barnyard grass can be prostrate or have an upright architecture or plant structure. So the Harvest Weed Seed Control methods that I bang on about using the header front are not always going to be successful for gathering up to 30,000 physiological mature weed seeds per plant into it.
I suspect if your summerplanted crops had good crop competition by well-placed plant numbers and accurate row spacing, then all the weeds would assume a taller stature. Not always easy to achieve this erect weed seed target.
I have mentioned HWSC and fallow cultivation methods for ensuring a reduction in your burgeoning barnyard grass problem. Neither may be very appealing or successful, however remember our main aim is to stop seed set.
For years we have been using knockdown or residual herbicides and now we are trying to take the pressure of increasing herbicide resistance levels and the few modes of action we do have.
So your future challenges are to prevent weed seed set or destroy growing weeds by various practices. What those practices are we all may have to weigh in with ideas for our farming futures.
It is no sense just assuming you are going to be able to continue for years to apply robust rates of glyphosate and then double knock with Gramoxone for fallows. We are still getting herbicide resistance affecting these jobs and it will get worse.
It is no sense assuming your residual herbicides like atrazine and metolachlor will complete the whole job for years to come. We need to consider other more cultural means like our southern and western Australians did for their winter weeds, which are some of the most resistant in the world.
This is our challenge for the future.