From harvest to resistance

There were parts of Australia I didn’t get to see last time and so for my second trip I started in Western Australia, some 3.5 hours north of Perth with a visit to Australian scholar Bob Nixon. Bob’s farm is the epitome of what farming in Western Australia is all about. The scale has to be large (30,000 acres) due to the low yields and hence small margins on crop returns.  Using the DBS tool bar, he was slightly disappointed with their yields as things had looked well until they didn’t get quite enough rain, and then searing temperatures in the 40s in August.

However, even on what appears to be very easy soils, it was possible to see how much an improvement no-till had made to the structure as we were able to compare it to a neighbouring field which is still under conventional tillage. With no-till, he had better aggregation and the ability to hold on to moisture that little bit longer.

Left In The Picture Long Term No Till , Right Conventional Tillage Soil With Poor Structure

Left in the picture long term no till, right conventional tillage soil with poor structure

I went to visit Ty Kirby, a very progressive grower who had managed the change to CTF over a few gradual phases and moved from tine to disc, and the combine was the final piece of the jigsaw.  I got to see first-hand how they were using chaff decks to collect all the weed seed and chaff directly off the sieves and place them in the CTF wheel marks.  The idea was that this would be a hostile environment for the seed to germinate and if it did they would be able to use a shielded sprayer on the CTF wheelings.  It will be interesting to see if this works long term. At least the seed isn’t spread everywhere, but how much will germinate in these rows?

Chaff Decks Placing Trash From The Sieves , Chopper As Normal For Straw Through Main Rotor

Above: Chaff decks placing trash from the sieves, chopper as normal for straw through main rotor.

Below: Wheel marks illustrate how the chaff is placed directly in the CTF marks

Wheel Marks Illustrate How The Chaff Is Placed Directly In The CTF Marks

The system is very reliant upon the separation element of the combine removing every last seed, but ultimately, it was something Ty was more comfortable with than the chaff carts, which gather the chaff in to a bin and place in big heaps across the field, which can either be burnt or grazed for livestock.

Ty came out with a great comment, when he said “perhaps we’re getting too good at establishment” meaning that his disc system was so successful that he was achieving crop establishment on marginal ground which had moisture levels that may not always sustain a crop.

The NDF disc system he uses is one I have come across a few times now and is a very heavy duty machine. I was told that in sticky conditions the gauge wheels next to the seeding disc flex enough that they keep relatively clean. Interestingly the disc works below the depth of the seed placement coulter, giving a little bit of below seed cultivation, rather than just creating a slot.

I could see this type of machine working in the UK, but it does come with a hefty price tag and transport width is an issue. However the element I liked the sound of, apart from its ability to nearly penetrate concrete was that the manufacturer listens to customer feedback to make improvements and tweaks to the machine.

The NDF Disc Unit

Above: The NDF disc unit

I visited another NDF user further south, Trevor Syme, who has a bit more reliable rainfall and some variable soils.  There is a familiar pattern with several growers in different countries I have met that it is a gradual process of progressing from tine to disc and it has certainly become clear that tines are more forgiving in the early stages of conversion.  Trevor was able to show me a good example of this on some new ground he had taken on that had come out of pasture land, some of it he had done with the NDF and other parts with an older DBS tine system.  He explained how the soil hadn’t really stabilised at this stage and it probably needed another three years of the tine system to have more natural structure and allow the disc seeder to work better.

He was also another CTF convert and was convinced their root penetration was better. He was looking to have a modified seed boot that would band the granular fertiliser to the side of the seed row, something that appears key from what I have encountered in other countries as well.

He has an incredible piece of equipment called a soils delver, which works down to 1 metre in depth and looks very horsepower hungry.  However the idea behind it is to bring clay up from the subsurface to the top to help improve soil stability and water retention.  As is often said, a picture speaks a thousand words!

Soils Delver

I also spent a mind-blowing day at AHRI (Australian Herbicide Resistance Initiative), looking at how the resistance to herbicides in ryegrass and wild radish has increased and the factors behind it.  It was a truly brilliant day looking at resistance modelling and how it spreads and also how they are working with growers and chemical companies to beat the issue. One fascinating point was how a resistant patch can mutate and cross with resistant plants within a range four times the original patch.  But Stephen Powles and Michael Ashworth were two very passionate, determined people who were working hard to help the issue, key messages were evolution and reducing seed bank levels, sounds familiar if you have blackgrass!

As usual, too much information and not enough blog room.  Next time, I will report on my travels in Tasmania and New Zealand.



Russell McKenzie farms 750ha on predominantly heavy clay on the border between Cambridgeshire, Bedfordshire and Northamptonshire. He grows seed on contract as well as soft and feed wheat, and his usual rotation is wheat, OSR and spring beans. A Nuffield Scholar, Russ has been researching direct drilling in extreme weather in 2013 and 2014.