Waging war on weeds: the latest research

laser weed control
Blasting a weed with a laser, leaving it smoking with a high voltage zap or watching it wither under a giant magnifying glass may well be my cathartic farm job of the future.

Waging war on weeds – whether with chemicals or tillage – is set to get a whole lot smarter, more cost-effective and kinder for the environment, thanks to new work at the University of Sydney.

I was delighted when researcher Michael Walsh agreed to give Milk Maid Marian a sneak peek at the direction of his team’s research.

MMM: Farmers traditionally use chemicals or tillage to control weeds. Why should we consider new forms of weed control?

MW: Like many other decisions on farm, cost is the driving factor behind the need to consider other forms of weed control. Herbicides and tillage are both relatively cheap to apply but there are production risks to the use of these treatments.

There is a risk of herbicide resistance that occurs every time a herbicide is applied and once resistance evolves it remains in a weed population forever and therefore the herbicide is no longer useful.

For tillage it is the risk associated with soil disturbance and the lack of selectivity. In a pasture tillage for weed control will result in the loss of grazing for that paddock.

MMM: What are the alternatives being researched at the University of Sydney?
MW: We have been evaluating targeted tillage and more recently laser weeding, but we are also keen to investigate electrical weeding and solar weeding.

Electrical weeding is simply just using electricity to “shock” weeds. A weed is touched with a positive terminal and the earth acts as the ground so the charge passes through the weed burning cells as it goes. In the UK there are commercially available hand held electrical weeders.

Solar weed control

Solar weeding is using the sun to burn weeds. It’s the magnifying glass approach where a lens (grooved plastic sheet) is used to concentrate sunlight on to a weed to burn it. These types of lenses (Fresnel lens) are used in lighthouses to focus light into a strong beam.

MMM: What are the benefits?
MW: Initially the main benefit will be the reduced reliance on herbicides.

There will be substantial savings in weed control costs associated with controlling individual weeds rather than applying a blanket weed control treatment to the whole field. These savings will depend on weed density and it is hope that with good weed identification systems we will be better able to reduce weeds to very low numbers in crop and pasture paddocks.

MMM: Other forms of automated weed control have struggled to identify weeds in pasture. How can this be overcome?
MW: The development of new camera and sensing technologies for cars and phones has created the opportunity for weed recognition and identification. This will allow us to use tillage and other physical weed control tactics to selectively target weeds in crop and pasture situations.

MMM: What needs to happen to make this technology a reality on Australian dairy farms?
MW: I guess the first thing to do is to start working on systems that are able to identify weeds in pastures. Basically it is just a matter of training a sensing system (e.g. a robot) to recognise what is a weed and what is pasture plant. This is typically achieved by building up a library of weed images as they occur in pastures over the growing season.

Thank you very much, Michael, for this glimpse of what farmers can look forward to in the war on weeds! I do hope the dairy community is quick to support such an exciting development for farmers and the planet and can begin building that library of weeds.

Feeling stressed? Come and sit in the grass with the cows

“What’s so special about that?” asked Zoe. “Nothing, and that’s why I thought we should put it on the blog.”

Apart from the twice-daily walk to and from the dairy, this is how our cows spend their time.

You won’t see footage like this anywhere else, I suspect, and certainly not on 4 Corners. There’s nothing sensational about it except perhaps that, right before your eyes, these cows are transforming grass into one of nature’s wonder foods (while wondering what the hell I’m doing sitting on their breakfast).

People and animals tell the farm’s story

This was Zoe on the Bobcat as I moved the electric tape in paddock 6 on Friday. It really was sunny enough to dig out the zinc!

Yes, two pairs of oversized sunglasses are apparently “hot” right now

I’d been away from the paddock for a week and things had got away. It’s newly sown to a high performance grass and zoomed off once the saturated soil turned to plasticene over a balmy few days. We had to get the cows in at once if there was any chance of keeping grass quality levels up over Spring.

At this time of the year, it’s really important to divide the paddock into small strips. Let them into the whole lot at once and most will be wasted as the engorged cows make nests to sleep it off. The trick is to have the cows absolutely full to pussy’s bow, but only just. It’s good for the cows, good for milk production and good for the grass.

The grass on the right has just been grazed, the grass on the left is for dinner

Grass growth will have come to a skidding halt over the last couple of glacial days though. Everything is mushy and muddy all over again. Including Patch.

Whadda you mean I can’t come inside?


 

New season has us rushing around like squirrels

It’s autumn and our dairy farm is buzzing with activity before calving starts and winter sets in.

We have sent about 50 cows off to the other side of the farm for their annual two-month holidays. Before they go, they are given long-acting antibiotic therapy and teat seal to reduce the risk of mastitis when they calve.

Dry cows go on holiday

"Yay! Holidays!"

New pastures have been sown. Those (like this one) that were too rough have been fully cultivated with discs, power harrowed and rolled. This paddock has also had lime because its pH needs to be lifted a little higher. I’ll keep a photographic log of the paddock’s progress.

Newly sown paddock April 1st

Here it is, one day after sowing on April 1

We’ve invested in new stone and gravel for sections of the cow tracks and gateways.

New gravel

La la lush new gateway gravel!

And, last but not least, a new pair of boots.

New rubber boots

How long 'til the pink turns khaki?

By the way, how do you know when your boots are too tight (especially when they were too loose the day before)?
“When you can’t do what you used to do with your boots.”
“What’s that, Zoe?”
“Put your big toe on top of the toe next to it.”
Obviously!

Parched pastures and potassium

Red clover

Gorgeous feed like this can be more water use efficient with potassium

Despite the last few days of searing heat, we still have some nice pasture on hand. It won’t last forever but I am hoping that we can make the spring pastures stretch longer into summer with some judicious fertiliser choices.

I’ve bitten the bullet this year and invested in soil testing for each and every paddock on the farm. It’s shown that our fertiliser regime is working but we still have a way to go in some cases. The main issues we must address are potassium and pH.

Potassium (K) allows plants to use water more efficiently, making them more resilient to both waterlogging and drought. Some of our paddocks only have half the potassium levels they should, especially the rises that dry off first, so I’m hoping that regular applications of potash will allow us to make much better use of those paddocks.

Unfortunately, potassium is readily leached from the soil, so even my extra doses (70kg of MOP behind the cows throughout autumn/winter/spring) simply maintained rather than make a significant improvement in K levels last year.

For a neat technical explanation of the role of potassium in agriculture, see this: Potassium in Agriculture.

As the grass grows golden everything changes again

Feed bails

The new feed ration ready for tonight's diners


I shouldn’t admit this but I use the lawn as a bit of a guide to pasture growth rates. Our lawn is far from manicured and includes just about every grass species known to man. Of course, it’s not grazed either, so it’s really easy to see how it is performing. And, this week, we raised the mower’s cutter deck in an attempt to preserve its greenness.

That’s not to say I don’t watch the paddocks like a hawk. Out on the farm, we’ve been battling to prevent the grass from bolting to head, raising seed heads atop stalky stems that fill the cows with fibre rather than goodness. The seed heads also signal senescence – a type of hibernation for grass – dramatically reducing growth rates.

It means that rather than being able to graze a paddock, say, every 21 days, we must rest it for up to 60 days when summer really kicks in. To manage this, we strip graze the paddocks so the cows get a much smaller yet still fresh portion each day. With less grass on offer, we must make up the daily ration with supplementary feed. I have some gorgeous vetch hay waiting in the shed and there’s all that silage we baled just a few weeks ago.

My first step though is to lift the amount of grain we’re feeding to balance out the increasing fibre in the grass. Just a 1kg boost – easy enough to turn up the dial but, oh, what a performance it turned out to be!

The feed system is governed by a timer rather than a checkweigher, so we have to guess how much extra time to dial up, scoop samples into buckets, weigh and review if necessary but the scale’s batteries were flat. Determined to get it right though, I dumped a 1 litre juice bottle on top of a bucket of the current ration and, with Clarkie’s help, set up a rudimentary scale with a scrap metal rod suspended from a roof truss with hay band. It wasn’t glamorous but it worked a treat!

All I want for Christmas now is a yard hydrant wash system, an underpass and a pasture meter like Graeme’s.

Cows are discerning diners

Dairy cows are every bit as discerning about their food as a MasterChef judge. They don’t like grass that’s too long, a species that’s unfamiliar and, less surprisingly, anything that’s got mud, manure or urine on it.

They don’t like longer grass because it gets fibrous. Our girls are thoroughly spoilt and only lush and juicy will do – so much so, they’d rather make a bed of it than eat stalky pasture.

This means that if you don’t have the grass eaten down far enough, it will get stalkier and stalkier as time goes by and the cows continue to refuse it.

According to the gurus, we should aim for a residual of four to six centimetres after the cows have left the paddock. If there’s only enough grass for half a grazing, you’re left with the dilemma of leaving it too long and seeing quality spiral or running out of feed. The textbook answer is to skip the paddock and “top” it with a mower but we don’t have enough people to do those types of jobs.

My alternatives are to save it for silage (topping’s automatically thrown in) or graze it and move them at lunchtime. And here they are:

Moving the cows

Mmmm...dessert!

Most of our farm’s internal fences are single-strand electric, which lends them perfectly to this type of manoeuvre. It took the cows five minutes or so to realise what I’d done but you can see how enthusiastic they were about their “second course” once the first pioneering diner ventured into cow nirvana.

New technology sparks a revolution on farm

I will never look at cow poo the same way again. A revolutionary technology arrived at the farm this week that is a huge win for the environment and for the farm.

Slurry Kat

New effluent technology

While most of the manure produced by our cows (and they dump a massive 40 litres each every day!) goes straight back onto the paddock, we do have to wash away the stuff that drops on the dairy yard while they’re waiting to be milked.

Rather than allow it to pollute our waterways, we collect it in an effluent pond to be applied on the paddocks as fertiliser. Sounds ideal but, unfortunately, there’s been a deal of guesswork in knowing exactly what’s in it and what rate to spread.

The only way until now was to agitate the pond (at significant expense) and send a sample off to a lab before agitating it all over again and getting it out with a slurry tanker that literally splashes it all over the pasture like Vegemite on toast.

The local and forward-thinking Bowden’s Agricultural Contracting owner, Wayne Bowden, has just bought a Slurry Kat that monitors the nitrogen content of the effluent as it’s pumped out and lets me choose just how much is applied per hectare.

In practice, that means instead of saying: “Aaah, about a quarter inch thick, please”, I can say “60 units of N per hectare, please”. Wayne can even tell me how much phosphorous is going on.

Why do I care? It means less likelihood of leaching excessive nutrients and we don’t use too much or too little bought-in fertiliser.

How the Slurry Kat works
The Slurry Kat system involves three tractors:

  1. An agitator that ensures the heavy slurry at the bottom of the pond isn’t left behind
  2. A pump stationed at the pond to push the effluent out to the paddock at up to 160,000 litres per hour via a 5″ hose.
  3. The spreader tractor, which uses lots of hoses to dribble the effluent along the ground in lines.
Agitating the effluent pond

Agitating the effluent pond

Effluent agitator and pump

The front tractor pumps the effluent up the umbilical hose

Slurry Kat spreading effluent

Slurry Kat spreading effluent

How it helps us manage our effluent for a better environment and greater productivity
Aside from the extra information and control the system brings us, the benefits are:

  • Safety. Because there’s no need to reverse a tanker up to the effluent pond dozens of times, there’s less chance of someone falling in.
  • Lower greenhouse gas emissions. Manure dribbled onto the ground rather than splashed onto a plate and sprayed means less volatilisation of its nitrogen.
  • We can affordably apply effluent to paddocks 1.5 km from the effluent pond rather than limiting ourselves to those close-by.
  • Less odour. I couldn’t smell it from the road.
  • Lower access requirements – less damage to tracks and paddocks near gateways
  • Quicker return to pasture because there’s no thick slurry to wash off leaves.

Slurry Kat lines after 24 hours

Slurry Kat lines of effluent after 24 hours on the paddock


I love it (and, no, I didn’t get paid to say any of this)!

Feeding the cows who feed us

Gone are the days when dairy cows just ate grass. These days, there are people who get really geeky about feeding cows. Starch, protein, fat, fibre (only the right type, mind you) and energy levels can be perfected for optimal health and milk production.

This can really only be achieved when cows are fed a total mixed ration (TMR) and is more tricky when cows like ours are largely pasture-fed. Still, we can do better, so I was delighted when local DPI extension officer David Shambrook visited today to talk about what we’re feeding.

At the moment, the cows each eat just over 7kg of a rolled wheat, triticale, canola oil, limestone and salts mix during milking. The herd is also allocated about 2.9 hectares of fresh grass per day and fed two bales of top quality vetch hay (10.3 megajoules of energy and 22.8% crude protein for the benefit of farmer readers).

David had a look at the pasture they’ve left in the paddock, the pasture they’ll go to next, the milk production stats, the cows’ body condition score, whether they are chewing their cuds, their manure and rumen fill (indicated by how much a triangle of flesh bulges out). All these signs point to whether the cows are being well fed.

I have a gut feel (forgive the pun) for all of this but am determined to learn more about dairy cow nutrition. The combination of intellectual and physical challenges is one of the things I love most about dairy farming.

Cocksfoot a tender winner in a tough paddock

Uplands Cocksfoot with red clover pasture

Uplands Cocksfoot with red clover pasture

Most dairy pastures in this part of Victoria are ryegrass, whether annual, Italian or perennial. Not the one Zoe’s posing in! It’s a new variety of cocksfoot called Uplands. Planted with nitrogen-fixing clover, this so-called Spanish cocksfoot has turned the farm’s worst-performing paddocks into one of its most productive.

This north-west facing paddock has an acidic sandy-loam over clay soil type and used to be routinely skipped in grazing rotations. A crop of rape and millet failed miserably, producing a massive forest of fat hen. We ploughed that in and called it a “green manure crop” to save a little dignity, then sowed the Uplands cocksfoot and red clover.

I had been warned it would be slow to establish but began to wonder when it looked like being overwhelmed by capeweed in the first six months. In late Spring, however, this paddock took off and has not looked back! The cocksfoot is fine-leaved, very persistent and resistant to cockchafer grubs.

The cows seem to like it too, even showing a preference for the cocksfoot over the clover.

PS: Astute farmers will see it’s got a bit out of hand. I should have grazed it earlier but access was too wet until now.