CS vs 750a Xmas update

It’s about 6 weeks since drilling, and the field is looking good, with only a small amount of blackgrass. Excellent.

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The 750a (left) / CS (right) seam, November 13

The nice people at ProCam have set up some plant population experiments for me, and have now performed two counts. At one end of the field (slightly lighter soil) there are 10 sample locations for each drill, so the results should be statistically significant. At the other, heavier, end we have just got one sample site per drill. The first set of results were interesting, but it turns out that there had been a bit of an error, and the varying drills’ row widths had not been taken into account. In a nutshell, that’s bad news for the CS and CO8, as their plant counts had been overstated by around 45%.


The CS plots being counted, December 4th

Let’s get on to the data. Remember, all drills put seed on at the same rate, which was 225kg/ha AKA 480 seeds/m2. Here’s the lighter land bit, with 10 samples per drill:


And the heavier bit, with just the one sample:


Clearly, the 750a has managed quite a lot better rates of establishment than the other two. There has been slug activity, which probably explains the decreasing plant counts over the last month; the heavier section was pelleted, the lighter bit was not. The differing growth stages are interesting, but at this point, I don’t know what is “best”. Could it be the CS is the lowest disturbance, and less mineralised N means slower plant development? That’s not what a certain S.Townsend preaches, but I have no idea if he is right or not.


33.33cm x 33.33cm

My personal feeling is that the differences in growth stages will even out by the time summer comes around. Luckily we will be measuring the yields scientifically (and hopefully significantly), and that, as always, is what matters here.

Next update in the spring.

Day 408 – Cross Slot vs 750a

[This blog post will be of no interest to anyone sane]

I don’t think my Nuffield report mentioned hardware once. It’s pretty well incidental to the bigger picture, but that is not to say we don’t all like arguing about it anyway. Way back in March 2014 I went to visit Cross Slot in NZ, and since then have…participated…in the long and tedious debates that seem to crop up every time the drill is mentioned. The main point in summary is that the drill is incredibly expensive, and its ability to create extra yield to mitigate this is, depending on your viewpoint, unproven.

I have been trying since September 2014 to get a Cross Slot on this farm, so that I could see it with my own eyes. I had pretty well given up getting anywhere, when an opportunity arose not so long ago. There are now a handful of drills floating about this country, and one was based not far away. All it took to tempt it over here was a chequebook – it seems that demos are not possible or deemed necessary by the dealer. I had never intended to perform a trial, but it seemed like a good opportunity to try and get something done, and luckily John Deere stepped up at very short notice to send one of their machines. I had really wanted to get a Weaving GD as well, but that also proved impossible.

IMG_5774Anyway, 408 days after I first tried, a Cross Slot finally turned up at the farm. We had a few fields of wheat left to drill: mainly second wheats, but also a large field that had been peas. One second wheat field was split in half, and drilled with both our normal Horsch CO8 with narrow points, and the other half with CS. The pea field was drilled mainly with the Horsch, but one 8.8ha gap was left in the middle, which was the right size to allow two drills to put in a tonne of seed each, side-by-side. Let battle commence.

The field

At least half our farm is super easy working light/medium soil. Any drill will produce good results. The trial field is however just about our heaviest. It is classified as clay (54% clay, 30% silt, 16% sand), but is relatively easy working because there is so much calcium in there from the chalk subsoil (87.6% Ca vs 3.7% Mg). There was plenty of moisture in the soil, but still just dry enough to drill. Even so, a Horsch prototype single disc direct drill could not actually get in deeper than about 10mm when we tried a few weeks previously. As far as this farm is concerned, if a drill works here, it will probably work anywhere else.

The Cross Slot

This was a 5m drill, with 21 openers, giving a 238mm row spacing. What is really incredible is the weight in such a physically small looking drill. 12t empty is almost unbelievable, but is accomplished by filling the frame with tiny bits of steel. This gives a theoretical pressure per opener of 571kg. Massive. There was a 280hp Claas tractor on the front.


The John Deere

The elder statesman of direct drills. Well proven, but still flawed. And seemingly unloved, until this year at least, by its parents. The opening disc is much smaller than the Cross Slot, and the drill itself is much lighter, at 6.3-6.8t depending on how much ballast is added. This particular machine had none at all, which gives a theoretical pressure per opener of 175kg at a row spacing of 167mm. The standard closing wheels are often changed by owners, and here we had one side with originals, and one side with Guttlers. The tractor was a 195hp John Deere.


Doing the job

As it happened, the timing was totally perfect and both drills started off within minutes of each other. With only a tonne of seed to do each they wouldn’t be around for too long either.


Both machines were already set up for drilling wheat at around 30-40mm deep. The following are some of my thoughts from what I saw.

Left CS, right 750a. This is fairly subjective, but I would say there is more disturbance with the 750a. HOWEVER i think this is due to there being 50% more openers per meter with the 750a, I would rate the disturbance per opener as being very similar

Left CS, right 750a. This is fairly subjective, but I would say there is more disturbance with the 750a. HOWEVER I think this is due to there being 50% more openers per meter with the 750a, I would rate the disturbance per opener as being similar

This is seed placement from the John Deere, which was nicely consistent. It seemed to be penetrating with no trouble at all, and with no ballast. I was very surprised at this after the Horsch DD could not get in at all with 25% more weight per opener. Both types of closing wheel were doing a decent job, but the Guttlers did seem a little better perhaps

This is seed placement from the John Deere, which was nicely consistent. It seemed to be penetrating with no trouble at all, with no ballast. I was very surprised at this after the Horsch DD could not get in at all with 25% more weight per opener. Both types of closing wheel were doing a decent job, but the Guttlers did seem a little better perhaps

The CS also placed the seed well, but I was slightly shocked that at one end of the field which required every gram of the 12t to get in. You can see in the video below that there was no weight at all going through the drill’s wheels whilst it was in work.

I find this very worrying given that the conditions were soft. In a dry autumn I really doubt that no-till would be possible on these heavier fields with this drill.

Here are a couple of slo-mo videos of the drills working. Obviously the CS one I took in the wheat stubble from the first field it drilled. There looks to be a lot more soil throw from the 750a, but it’s much looser in pea stubble compared to wheat, so not a fair comparison. I should have got a video of the CS in the peas but ran out of time.

The details

Here are some numbers that came up after the trials were done. I’ve added in our current drill for fun.

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And now for some financials. The purchase price for the CS is a bit of an estimate based on a few things, one of which is a quote I have for a NZ made machine which came in at £175,000 for a 6m. Running costs are averaged out from multiple owners I have spoken to for both machines. I am assuming 1,000ha of drilling per year, for 10 years. To begin with I was going to try and estimate depreciation and use that cost, but then I started thinking about the extra finance and opportunity costs involved in buying more expensive machinery, and decided it was too complicated for a simple soul like me. So I have just gone with dividing the initial cost over the full term.

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So we are looking at a difference between the 750a and CS of around £20/ha, otherwise known as about 2% wheat yield increase at current prices. [BUT very importantly, don’t forget that these are very different machines in terms of output, so to match up here would require a hugely more expensive CS setup].

What next?

I’m not sure how scientific this will get. It would be good to take plant and head counts as the year goes on. Obviously the real result, and the only one that matters here, is yield. I have some ideas on how to measure this accurately, but it will depend on some people being generous with their time and machinery. In the meantime all I can do is wait and see what the emergence looks like.


Both drills put the seed in the ground (just) and covered it with soil. I can’t see any reason at this point in time why one will give a better result than the other. I am struggling to see why for me, on this farm, at this time, there would be a benefit to spending more money to get a drill with a lower workrate that is more expensive to run. CS has a big potential benefit in that it can reduce hair pinning compared to a 750a when going in to cereal straw stubbles. For me this is not relevant as I would keep a tine drill for those jobs (cover crops and OSR mainly). CS also has incredible vertical travel on the openers (14″ IIRC), but that is about 12″ more than exists on our fields. The same goes for durability; CS has shown it can handle super rocky conditions, but then we do not have those. We farm very soft land, and some people have put tens of thousands of hectares through their 750as without much trouble (unlike this guy!).

Maybe though we will see what CS says we might, and get a 13-23% yield increase:


Day 69(ish) – Some data & final thoughts

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This is roughly speaking where I’ve travelled. It’s a little abbreviated in Brazil since that got too complicated to map easily. My time in South America is almost up, but there are a few more things to say, and random pictures to insert.

This lunch on my first visit was exceptional. Why don't we cook beef ribs?

This lunch on my first visit was exceptional. Why don’t we cook beef ribs?

I met a guy from Embrapa yesterday who is running a program near Brasilia where they are comparing conventional and Organic dairy grazing systems. It’s only been going for three years, and I haven’t seen the data (he will email it to me apparently), but they are finding hugely more efficient fertiliser use under Organic management. At the start of the trial both treatments were given the same amount of NPK fertilisers. In the conventional system these came from urea, triple super phosphate and potassium chloride. The Organic sources were animal manures and soft rock phosphate.

"Old town" Montevideo, Uruguay

“Old town” Montevideo, Uruguay

In each of the three years there has been a 20-30% yield penalty (measured by tonnes of dry matter produced per hectare) with the Organic management. However, the critical point is that every year the conventional fertiliser must be reapplied in the same amounts, whereas the Organic field is maintaining its yields with only what was put on at the beginning of the trial. How long will that go on for? Who knows, but already after three years it’s a very interesting result. Whether it could be more profitable to grow crops like this, even without an Organic premium, I couldn’t say; it’s going to depend a lot on the value of the land you’re farming. But it does make you wonder how much of the artificial fertiliser we apply is just being wasted.

Do you ever get the feeling you're missing something?

Do you ever get the feeling you’re missing something?

At a previous Embrapa meeting I was given some scientific papers to take home, and have only just had a chance to read them. One is particularly worthwhile, it’s called “Integrated crop-livestock system in Brazil: Toward a sustainable production system”. The data comes from a 16 year experiment comparing these treatments,

  • CSConventional System using disc cultivation, growing soybeans with a winter cover crop
  • NTSNo-Till System, growing a soya and maize rotation with winter cover crops
  • ICLSIntegrated Crop-Livestock System growing two years of soya & cover crop and two years of pasture
  • PPPermanent Pasture
Lack of water isn't normally a problem in Brazil (lack of power to move it can be though)

Lack of water isn’t normally a problem in Brazil (lack of power to move it can be though)

Here are some of the results that I think are notable. I’ve tried to keep it slightly readable.

  • “the ICLS system treatment yielded soybean production that was greater than or equal to that of CS and NTS. This higher efficiency of ICLS system may be related to availability of P in organic form” – this tallies with the experimental results found by Embrapa Cerrados
  • “Systems with livestock grazing had significantly greater MWD [this is a measure of how stable the physical soil structure is] compared to other systems (ICLS: 4.12mm, PP: 4.93mm, CS: 2.19mm, NTS: 3.18mm) … Ultimately, soils with greater aggregation characteristics are considered of better quality than similar soils with weaker aggregation, mainly because TOC [Total Organic Carbon] becomes physically protected in stable aggregates.” – see the famous Slake Test
  • “Concentration of TOC, TOC storage, and POC stock were increased under grazing by livestock at the following order: CS<NTS<ICLS<PP … The labile fraction of organic matter was also greater in ICLS and PP, than in NTS indicating greater energy flux in the soil system. Greater SOM lability was attributed to the presence of the forage, which adds a greater amount of organic matter to the soil than cropping alone. Moreover, there is a continuous exudation of substances from grass roots to the soil during growth which is stimulated during grazing.”Not very surprising. But it must be noted that of all the systems, it was the NTS which actually lost the most carbon overall. CS was stable, and the other two increased.
  • Total microbial activity was greater in the order you would expect, PP>ICLS>NTS>CS – I’m paraphrasing here a bit.
  • “Density and taxonomic richness of the invertebrate macrofauna [i.e. worms, beetles etc] community in soil differed among management systems. Lowest values were observed in CS, while ICLS was equivalent to that of NTS and PP and greater than that of CS … Soil macroinvertebrates perform numerous essential functions, including decomposition, nutrient cycling, SOM mineralisation, soil-structure modification, atmospheric-composition regulation, and biological control of pests and diseases.”I think it’s fairly obvious by this point what direction this paper is heading in…
  • Hold on, this is a long one: “Weed community analysis showed that areas without pasture and grazing generally accumulated more weed mass than areas that were periodically or continuously grazed. The area of soil covered by weeds was 87% greater in CS compared to the average of the other treatments. Generally, areas that were continuously or periodically grazed by livestock had fewer weeds than areas where only grain crops were grown. Livestock grazing also affected seed germination: weed seedlings from treatments that included grazing took longer to germinate and emerge from from the soil surface. Regardless of the presence or absence of tillage, crop-only systems exhibited larger areas of soil covered by weeds.” – Phew. I’ve never actually seen this information in a scientific context, and the figure they come up with (87%) is huge. Very interesting.
  • “Occurence of Rotylenchulus reniformis [a parasitic nematode pest] differed significantly among management systems, with a much larger population in CS [1500x more than the next highest]”
  • “In years with ample rainfall, soybean production was equal in the three grain-production systems. In years with poor rainfall distribution, with water deficits, ICLS and NTS exhibited smaller productivity losses compared to CS. In 2010/11, for example, CS yielded only 60% of crop production in other systems.” – No big shock here, there’s a reason all the really dry places in the world have gone to no-till. Although it’s amazing they get droughts here when it rains perhaps 1500mm in the growing season. In the tropical heat it doesn’t take long for it all to evaporate.
I'm not usually a big fan of visiting churches, but these two in Brasilia are easily the best I've ever seen

I’m not usually a big fan of visiting churches, but these two in Brasilia are easily the best I’ve ever seen

I’ve found this to be a useful paper, and to me it suggests that the oft-heard fear that having animals in a system is a drain on nutrients/soil fertility is not just unfounded, but actively wrong. Now who wants to lay some water pipe?

I seem to remember there was a cat photo in the last Australia blog too?

I seem to remember there was a cat photo in the final Australia blog too?

It’s certainly been an interesting trip, but I think I’ve run out of steam. The problem is that I’ve seen enough of the details – just look at how different the first blog posts from NZ are – and it is becoming increasingly difficult to find novel concepts. Particularly here in South America, the diversity in farming methodologies seems very limited, and largely defined by what area/climate you happen to be in. There could be two explanations for this: lack of imagination, or perhaps the farmers are more switched on to the research, and unlike back at home, they are all doing the “right” things already. It’s difficult (impossible) to tell, but I haven’t found the Gabe Brown/Coin Seis sort of guy who is trying something totally different… Well I do actually know one, the problem was that he refused to let me visit! The others are probably hiding somewhere not telling anyone about it. That’s a job for a future traveller.

It’s been great fun, but this may be the last Nuffield post. Ciao.


Day 64 – How no-till soils are different in Brazil

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Sao Paolo airport has four terminals. In the hour and a bit I spent trying to find a sim card, some reasonably priced Brazilian currency, and a bus to the Ibis hotel, I visited them all, some more than once. It’s a fun way to end the day, especially at 11pm. The next morning I had to fly out early to Brasilia, and luckily I set my alarm as the hotel forgot the wake-up call.

In the afternoon I visited the Embrapa Cerrado centre for a very quick but still useful couple of hours. Embrapa is the Brazilian government run agricultural research organisation, which is apparently very well thought of by the farmers – probably a world first?

The distinct stripes on the left hand plant are due to a Sulphur deficiency. The soil that grew the right hand plant has been treated with gypsum (calcium sulphate) and does not show the same signs

The distinct yellow stripes on the left hand plant are due to a sulphur deficiency. The soil that grew the right hand plant has been treated with gypsum (calcium sulphate) and does not show the same signs

The land here has come out of what they call Cerrado, which is a type of scrub land, but with some tall trees as well. The soil is very deep (they have found roots going down over 4m) and physically well structured. However it is naturally pretty low in fertility, with a natural SOM level of 3-3.5%, and very little in the way of nutrients. It’s also got a pH of 4, and some problems with aluminium toxicity. As a result of this, there are large responses to the standard NP&K fertilisers, and gypsum also has a large beneficial effect both on soil structure & rooting, as well as feeding the plant sulphur. If you ignore these chemical inputs, and farm with tillage, it’s possible to drop the SOM to under 0.5% within five years.

They’ve done quite a bit of work on no-till, which has produced an average yield benefit over the long term of 10%. In some years, growing soya, it has been as high as 40%. They put this difference down to the increased SOM levels under no-till; after 11 years, the tillage plots have 25% less carbon per hectare. This makes a difference with nutrient uptake efficiency in general, but they have specifically tested what happens to organic phosphorus levels – this is the type of phosphorus that is easily utilised by the plant. After 10 years of no-till the organic P is 6% higher, and after 17 years that goes up to 26%.

When this trial started, 17 years ago, it was given 240kg/ha of phosphate. Since then it has had none, and each year the crop has become worse and worse. At this point it is hardly produced any plant at all, let alone a harvestable crop. As a side effect, the organic matter is rapidly disappearing because there is so little plant residue being returned to the soil

When the trial started, 17 years ago, this plot was given 240kg/ha of phosphate. Since then it has had none, and each year the crop has become worse and worse. At this point it is hardly produced any plant at all, let alone a harvestable crop. As a side effect, the organic matter is rapidly disappearing because there is so little plant residue being returned to the soil

Like in Argentina & Uruguay, here in Brazil they are just starting to wake up to the idea of cover crops. One trial compared a standard tillage and summer fallow method (the traditional way) against using no-till and a winter cover crop. The traditional method required 25t/ha of carbon to be put onto the surface to retain 1t/ha in the soil. No-till with a millet cover crop needed 12t/ha to retain the same 1t/ha, and using mucuna (a legume you will no doubt remember from Day 61) meant that number dropped to 7t/ha. The theory here is that because the creation of SOM needs nitrogen, the process is more efficient when there is a legume in the ground. However, the millet produced over double the biomass of the mucuna, so although it is less efficient, if you want to build SOM fast, that (and probably added fertiliser) would be the way to go. It might seem fairly obvious that trying a mix of the two plants might be a good idea, but I’m not sure South America is ready for that concept just yet.


Eucalyptus trees with an understory of Brachiaria, a widely used type of C4 grazing grass

That was the first half an hour outside, the second was spent looking at an interesting agroforestry scheme. Some of the land has been very badly degraded by over-grazing and poor pasture management, to the point where it is hardly productive any more. One of the solutions Embrapa is looking at is to use crops, grass and trees to turn it around. Also, since us Europeans chopped all our trees down long enough ago that it doesn’t count, we’ve told the Brazilians they can’t do the same to the Amazon. Now they need to find other ways to make their flat pack furniture, and this might be a solution.

Eucalyptus are planted in rows, and for the first two years they can grow three crops per year between the trees: first comes soya, and then maize, both of which can go from planting to harvest in 100 days. A cover crop is planted into the standing maize, so it is ready for grazing immediately after harvest. The same thing happens the second year, except the cover crop then becomes a permanent pasture, as in the photo above. Cattle will graze this for 10-15 years, by which time the trees are tall enough to cut. Eucalyptus has two characteristics which make it ideal for this application. It is very fast growing (in this climate it can average 6m per year), and it will also regrow after the wood has been harvested. Man-sized-cut-and-come-again. Now that the shade has been temporarily removed it’s possible to get in another year or two of cash crops before the trees are too big, and it turns back in to grazing. So the cycle continues…

On a different subject, if you’re looking for something cheery to watch, don’t go and see I Am a Girl, although it is a good documentary. If you do see it, and still feel a bit too upbeat, maybe try Once Were Warriors.

Day 62 – Pasture rotations & SOM

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Today was another INIA day, but at their HQ, with a researcher called Andres Quincke. Here they have been running a trial which is now in its 52nd year, they are looking at the effect of rotations on SOM levels. There are three continuous cropping treatments. Two use the same rotation: maize – barley/sorghum – wheat/sunflower – maize. The difference is that one has been run in a conventional system, and the other without using any fertiliser at all. The third continuous cropping rotation contains soya, sunflower & wheat, with cover crops every other year. This is new though, so there are (I hate saying that) no data yet.

SOM levels in different treatments. Green is 50% pasture, red is 66%, white is  33%. Black is continuous cropping, and white is continuous with no fertiliser

SOC (multiply by 1.7 to get approximate SOM) levels in different treatments. Green is 50% pasture, red is 66%, white is 33%. Black is continuous cropping, and white is continuous with no fertiliser

The remaining treatments use the same cash crops (maize, sorghum, sunflower, wheat, barley) but have differing amounts of pasture – 33%, 50% and 66%. The results are clear and interesting, but perhaps not entirely surprising. Any rotation with pasture will have significantly more SOM than continuous cropping. As you can see from the graph above, the 50 and 66% rotations are getting on for double the SOM compared to continuous cropping, and the trend is still upwards.

These are soil profiles taken from the trial. On the left is a core from the continuous cropping/no fertiliser field, and in the middle is one from the 50% pasture rotation. Although both soils naturally crack vertically, only the pasture rotations showed organic matter going deep in to the profile. It may be fluke that the samples were taken in these places, but it was consistent across all five cores they had on display. On the right is a close up of the higher organic matter soil from about a meter deep

These are soil profiles taken from the trial. On the left is a core from the continuous cropping/no fertiliser field, and in the middle is one from the 50% pasture rotation. Although both soils naturally crack vertically, only the pasture rotations showed organic matter going deep in to the profile (it is very clear, but the lighting was not very good for photographing). It may be fluke that the samples were taken in these places, but it was consistent across all five cores they had on display. On the right is a close up of the higher organic matter soil from about a meter deep. It was also found that soils which had pastures on them were less compacted at depth than those which did not

We’re often told that adding artificial nitrogen fertiliser destroys organic matter, and I’m sure that’s true. In a lab. But in the field it is clear in this experiment that the opposite happens. That’s because with the fertiliser there is hugely more crop residue going back into the soil. That benefits not only the SOM levels, but also massively increases resistance to soil erosion. The photo below was taken in one of the plots with no fertiliser: this happens every year, and does not happen in any of the other treatments. “We have shown now that this rotation does not work, perhaps it is time to change it to something new” says Andres. This has further repercussions too – if tillage creates crops with more biomass, it’s feasible that these systems will produce more organic matter than no-till ones. Something to think about.

Soil erosion in a bad rotation

Soil erosion in a bad rotation

The other striking thing came from a trial within the trial. They decided to look at whether the pasture phases (which all contain legumes) meant there was more available nitrogen for the following cash crops. To test this they have made small plots within the main ones, and have treated a maize crop with zero, half, normal and double nitrogen rates (0, 60, 120 and 240kg/ha). In the continuous cropping plot (with fertiliser), the difference was huge, and the plants with no fertiliser were very yellow and sick looking. In contrast, in the 50% pasture rotation, there was no visible difference between any of themThis was pretty amazing really, but of course you’ve got to wait until harvest to see what has really happened. This is definitely our situation at home; we are addicted to nitrogen.

Top: continuous cropping. Bottom: 50% pasture rotation. In both photos, the plants on the left had 60kg/ha of N, on the right they had none

Top: continuous cropping. Bottom: 50% pasture rotation. In both photos, the plants on the left had 60kg/ha of N, on the right they had none. The colours in the two photos are slightly different as I was facing north in one and south in the other, so the light was not the same

So far so good, but I have two main problems with this trial. The first is with the pasture phases. They have no animals involved. This is an issue because they actually have to bale and remove the residues sometimes, which will obviously reduce, at least slightly, the potential to cycle carbon back in to the soil. Another problem is that grazing can possibly (so says Kris Nichols) actually have an extra beneficial effect on soil fertility, which goes beyond the simple addition of what comes out of the back end of a cow. So although the trials show a significant benefit from pasture, perhaps the effect would be even greater with grazing added in as well?

And there is the elephant in the room…money. They have measured SOC, which goes up. Hooray – but how many farmers, outside the hard core fanatics, are willing to farm just for this? Yields also go up, when taken in isolation. I.e. in the same year, a crop of maize/sorghum etc will yield more in a pasture rotation than in a continuous cropping one. However, they have not modelled overall profitability. Of course this is very hard to do, just choosing what numbers to put in for the value of the crops and beef has a massive effect. But what farmer is going to be convinced to change their system when the researcher cannot tell them if they will make more money?

Day 53 – UWA Trials & Microbes

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Early start today, 5am, although it was a lie in compared to yesterday. You can fly in Australia without showing any sort of ID at all, which feels unusual. I thought it was a mistake the first time it happened.

I had to be in Perth early to meet Dr Ken Flower, from the University of Western Australia. They have been running a trial comparing different crop rotations under no-till systems, which is currently in its 9th year. The four treatments they have used are,

  1. Maximum carbon – continuous cereals, including wheat, barley & oats
  2. Maximum diversity – cereals, OSR/Canola/Legume & occasional cover crops
  3. Controls – Permanent pasture & continuous wheat
  4. Maximum profit/standard district practice – cereals & legumes

All of the treatments are also split into high and low residue sections. In the high residue all the straw is kept, whereas in the low it is wind rowed and burnt. They have been measuring profit levels, weed burdens, soil biology, soil carbon, and I’m sure plenty of other bits and bobs too. Here’s a summary of some of the interesting things they have found, both in the trial and generally in the region.

  • Despite having more fungal problems, and possibly more insect damage, the continuous wheat treatment is actually the most profitable. It also seems to be requiring less nitrogen each year, possibly as soil-borne N fixing bacteria becomes more prevalent.
  • As of yet, there is no difference in SOM between any of the treatments. Ken thinks that one may start to show up in the longer term, but the effect is subtle if it exists at all.
  • There is also no difference in SOM between burning the residues and keeping them. This backs up some results from NZ on the same subject, and is contrary to the general belief of people involved in Conservation Agriculture etc.
  • In some circumstances mouldboard ploughing has doubled farmers’ yields. The mechanism for this is a reduction in the non-wetting properties of their soils, and it also makes lime applications more effective.
  • In other situations, mouldboard ploughing can be catastrophic, as it allows massive wind erosion in a very short time.
  • Grazing stubbles with sheep has no effect on following crop yields, and does not really reduce the amount of carbon returned to the soil.
  • Grazing a growing wheat crop normally impacts its final yield, and also has the potential to cause significant weed problems. This is the opposite to what Hugh Dove told me, but several other farmers I have seen since have agreed that weeds can be stimulated by the grazing.
Mustering Merinos

Mustering Merinos

After leaving Perth I headed down to Arthur River and met up with John Pascoe, who farms 2,000ha of pretty unfriendly rock-strewn land. I wouldn’t like to drive a combine around there, I’d pick up a boulder for sure. He runs 5,000 ewes on a mixture of permanent pasture and in rotation with his crops.

John’s big thing is microbes, both for the crops and in the future the livestock too. He buys a blend of bacteria (not sure yet exactly what’s in it, need to find that out) and then uses it as a seed dressing. There have been some interesting results in his on-farm trials: When treated with the bacteria, the fertiliser need is massively reduced, to the point where sometimes there is no response to added N (and it yields the same as normally treated seed with full fertiliser rates). Interestingly, when a normal, fungicide dressed, seed is planted and not fertilised, it has a much lower yield. This would suggest that the fungicide dressings are impeding some sort of microbial interactions in the growing plant – presumably mycorrhizae. Sounds like an interesting idea to try out in the UK.

Day 46 – Grazing wheat & OSR

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In March we came to Canberra for a few days with all the 2014 scholars from around the world for a conference, and today was a bit of a flashback. Not only did I accidentally stay in the same hotel, but I also visited a sheep farmer call John Hyles, just as we had back then. John farms 5000ha at Booroomba, just south of Canberra, and has a small flock of Merino sheep (currently 18,000), and also 1,000 Angus cattle. Because this must not keep him busy enough, he also runs a quarry business selling sand, gravel, river pebbles, top soil and land fill. He’s also interested in property development, and arable farming. Many pies to be fingered. At the moment they are shearing, at a rate of about 1,700 animals per day. It’s an impressive setup. I’ll use a few photos to decorate this post, which is really about who I saw before I drove out to John’s.

CSIRO is Australia’s national research organisation, and it does a lot of work with agriculture. Hugh Dove is a scientist who has spent 15 years looking in to the grazing of wheat and OSR (Oilseed Rape, or Canola as they call it here). This is of particular interest to me, as we have a wheat grazing trial at home this year. Grazing OSR is something I have thought about a little bit, especially as I reckon it may be a tool to use in our fight against the flea beetle. Having spoken with Hugh for a couple of hours, the principals are largely similar between the two crops.

Firstly, it is important to get the plant sown as soon as possible. They have actually done trials (and some farmers use the technique for real) where OSR is planted so early, and then grazed multiple times, that by harvest is has been in the ground for 15 months. That’s pretty extreme, and apparently it can allow root diseases to become problematic. There are other potential problems with very early drilling, such as aphids that cause BYDV (Barley Yellow Dwarf Virus), and fungal diseases. But if these can be avoided, earlier drilling means more biomass to be grazed. It should also mean better root growth, which could potentially be useful later in the season.


The second rule is that it is not so important when the grazing starts, but timing when to remove the animals is critical. At the very latest they must be gone by the time stem extension starts, which in the UK on wheat is probably the end of March. However, the more time the plant is given to recover the more chance it has of not losing any yield potential. Amazingly, it is possible to graze almost all of the leaf area off and still not affect yield; they have measured increased photosynthetic activity to compensate for this loss of leaf area.

One of the big benefits of this system is in weed control. Particularly when grass weeds like ryegrass are a problem, they are finding that the sheep will eat it all up, and the grazed areas are cleaner than the un-grazed. The ultimate selective herbicide! Apparently the effect is so pronounced that for some farmers it is the main reason they are grazing the crops.

The next point needs a little bit of a science lesson, which I will try not to get wrong. Back in the day, when wheat was first being bred into what we use today, the strain that became bread-making wheat (as opposed to noodle-making, or Durum) picked up a gene called Kna1. Without going in to details (because I don’t know them and the internet here is too slow to look it up), this gene means that the plant uses potassium (K) instead of sodium (Na). This is a useful adaptation to have, because it gives a greater ability to grow in saline soils; however it also means that there is almost no sodium at all in the leaves. This only becomes a problem when wheat is fed to ruminants, because they require a certain level of sodium to allow the uptake of magnesium. So, if they don’t get enough sodium, they will develop hypomagnesemia, or grass staggers as we call it. The solution is to supplement the animals with a mix of salt and magnesium oxide. This will increase growth rates by around 40%, for very little cost. No brainer.

Interestingly, when grazing oats, which do not have the Kna1 gene, there is no response to supplementing, and when grazing OSR, it is actually detrimental – for as yet unknown reasons.IMG_4008

And what about yield? CSIRO work has show all possibilities, from increases to decreases. Overall their results have shown a negative impact, of -8%, but with a very large standard deviation (25%). So basically they are not quite sure. The whole idea will live or die on this point, it will not be economical with any significant reduction.

I think it’s a really exciting prospect, which could potentially open up a new system of farming. Integrating cover crops, OSR and wheat grazing effectively could provide effectively free forage for 4-6 months of the year. [That’s free to us, not to the grazier, in case our sheep man is reading this] Tie in companion cropping, and the selective four-legged herbicide, and it looks even better.

One last thing: I finally found a good place to use the slo mo video that my phone does. I think this is quite fun.

Day 45 – More Pasture Cropping

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Reality check.

Angus Maurice is a friend of Colin Seis, and spent over 5 years training people how to implement Pasture Grazing on their own farms. He also taught “No Kill” farming, which is similar to Pasture Cropping, but more extreme. It uses no chemicals at all, and also stipulates the cash crop must be drilled with a disc opener machine, so that there is minimum disturbance.IMG_3991The problem is, he now doesn’t really believe that it works. You can’t say he hasn’t tried, after 7 years of continuous Pasture Cropping and a field that he has left in the system now to see what happens in the even longer term. What Angus finds is that crop yields are just too badly effected – he reckons on average they will produce only 50% of a conventional system. This is obviously a huge drop, and the slight increase in grazing income, plus the reduction is crop growing costs, does not get anywhere near to making up the difference.

As I mentioned, there is one field that has been left in Pasture Cropping, and this year it is growing spelt. It had been attacked by insects earlier in the season and had some pretty big bare patches; however Angus did not believe that was due to the cropping system. But there was no denying that this field looked significantly worse than his conventionally cropped land. It was uneven, and looked at least 3 weeks behind. he is anticipating it will yield half as much as the other fields. It must be said that one difference here is that the fields were drilled with a cash crop every year, rather than once every 4-7 years as at Colin’s farm. Angus says he has tried all different techniques – high inputs, low inputs, but nothing makes it work. He puts this down to competition from the “dormant” grasses for moisture and nutrients.

Angus no longer works as a Pasture Cropping educator.

Angus grows spelt, which yields around 40% less than wheat, but sells for twice the price. It also gives good grazing for his sheep in the winter

Spelt yields around 40% less than wheat, but sells for twice the price. It also gives good grazing for sheep in the winter

My second visit of the day was to the NSW Department of Primary Industries to meet one of their soil scientists, Warwick Badgery (great name!). He too is not a great believer in Pasture Cropping, and has done quite a lot of research into it. I should also mention that both Warwick and Angus do not know of anyone else who has managed to make Pasture Cropping work as well as it does with Colin Seis. Warwick puts this down to the unusual soil Colin has, which is very drought prone, and also very low in nutrients.

[It was plain to see when I visited Colin that the ground was made up almost entirely of granite, not dissimilar to some wine growing regions I have seen. The results of his soil tests did also show very low levels of total P, of around 850kg/ha.]

Warwick does not rubbish the idea of Pasture Cropping completely, he thinks it is a good technique to be able to use opportunistically when conditions are favourable and a cash crop looks like it may be profitable. This whole situation really shows up the fine line between the “it won’t work on my farm” conservative mentality, and the reality that conditions are different on each piece of land. It’s a tricky one.

Warwick has done a lot of work into farmland carbon sequestration rates, and how to maximise them. Apparently in Australia 70% of the nitrogen used by cash crops comes from SOM (Soil Organic Matter) mineralisation. This means that the organic matter is effectively burnt; the carbon leaves as CO2, and the nitrogen (and other nutrients) are left behind to be used by the crop. Obviously this is not sustainable in the long term unless there are recovery periods being used – which is where mixed farming comes in to play. A lot of farms over here incorporate grazing pastures into their cropping land, and this is how they can get away with it.

In Australian conditions, the absolute maximum amount of carbon that can be sequestered is 1t/ha/yr, which works out as roughly 0.3% of SOM. To get this figure a field must be a perennial pasture, and it must have high levels of inputs (nitrogen and phosphorus particularly). Interestingly, he claims that although it is possible to capture carbon without the inputs, it will remain in an unstable form that is easily lost again. On a similar note, I’m told that there are indeed bacteria that will fix phosphorus from the soil, but they only work when the levels are so low already that it would not be possible to grow a profitable crop.

Grazing system trials in Orange NSW

Grazing system trials in Orange NSW

One of the trials that is just finishing now is comparing different grazing methods, and different stocking densities. There are treatments ranging from low intensity set stocking, through to high intensity, long rest systems. The longest rests are around 120 days, which Warwick used to check the claims that this would allow better nutrients cycling and availability. He thinks they are wrong; 120 days appears to be too long for this climate, which is much more temperate than that at any of the other farms I have been to in the last few days.

One of the trials had severe over grazing last year, it was set stocked at a high animal density. The big surprise is that for some reason this year it has come back with incredible productivity, much higher than most of the other treatments. It looks as if either better nutrient cycling (through the sheep numbers), or a plant response to being grazed so heavily, has kicked them into overdrive. Not so surprisingly, the results are showing that with longer rests and higher stocking rates, feed quality and animal performance goes down. This is mitigated though by more efficient plant growth, so more animals can be farmed on a given area. Swings and roundabouts? But more animals and more plant matter must also mean more carbon going into the soil?

There’s no point living in an echo chamber and only speaking to people who agree with everything you already think. I think today was an good one, and although I didn’t hear what I “wanted” to, it has to be better to get the full picture. Even if it does make things more complicated. Excellent.