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

Screen Shot 2015-03-05 at 22.23.18

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.

IMG_4717

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 48 – Biodynamic cherries

Screen Shot 2014-11-15 at 12.42.39People often wonder why bother with Nuffield, you could just do it yourself. True, in the main part; but there are benefits. Like when you call up a stranger at lunch time on a Saturday and they agree to give you four hours of their time at zero notice.

Kym Green asked if my project was going into left-field, and warned that he may be what I referred to as “Wacky”. Well, I can confirm now that he probably does fit into that category…

Kym is a cherry and apple grower, and I fluked an excellent time to visit. The cherry season started just yesterday, which meant there were tonnes (literally) of perfectly ripe fruit just waiting to be eaten by me – yum.

It isn’t just birds (see caption below) that are dangerous to the ripe fruit, too much rain at the wrong time can cause them to split, and become ruined right at the very last second. Some varieties will apparently burst, leaving just the stone hanging by the stem.

When the cherries are almost ripe they are netted to stop bird attacks

When the cherries are almost ripe they are netted to stop bird attacks

Kym does not fit neatly into any sort of production pigeon hole. For the most part he tries to farm with Biodynamics, but he is not [too] averse to using conventional pesticides if they are needed. For example, there are certain fungal diseases which can only be treated chemically, and he also uses Roundup to terminate the cover under his trees. Insecticide use has gone from 8 applications a year to 1.

As good as they look

As good as they look

You may have heard of Biodynamics, but probably don’t know what it involves. Well one thing is for sure – it won’t be to everyone’s taste. If you visit the Biodynamic Agriculture Australia website one of the first things you will see is information on what stage the moon is currently at, which gives a little flavour of the gist. It stems from the work of Austrian polymath Rudolf Steiner, who died in 1925, who developed a system of holistic fertility management that draws pretty deeply from the more spiritualistic side of the coin.

Kym uses conventional soil tests to measure the level of nutrients in the soil, and then applies the Biodynamic principles to the results. In this system, there is a precedence of which substances are most important. The order is

  1. Sulphur
  2. Boron
  3. Silica
  4. Calcium
  5. Carbon
  6. Nitrogen
  7. Magnesium
  8. Potassium
  9. Phosphorus

The idea is that it is most important to fix the sulphur levels first, then the boron, etc etc. There are a whole range of treatments [sorry, but some of these are a little silly, “Yarrow flowers placed in the stags bladder, hung in the sun during the summer and buried in rich soil during the next winter”] that can be used to get the soils balanced, but Kym will also use more conventional fertilisers like ammonium sulphate if necessary. He has found though that he can use much smaller quantities of manure, compost tea, and other, errrmm, potions, to get the same or better fertility than applying hundreds of kilos of urea. He’s not the first person to claim increased nutrient efficiency from biologically active systems, and I think there is definitely something in it.

This is composted cow manure. But not just any composted cow manure, it has been aged in a cow's horn, and is known in Biodynamic circles as "Preparation 500"

This is composted cow manure. But not just any composted cow manure, it has been aged in a cow’s horn, and is known in Biodynamic circles as Preparation 500

Another tool he uses (and Cam McKellar too) is the Field Broadcaster. I’ve got to say, I’m pretty skeptical about this one. It’s basically a pipe into which you place soil from your farm, and various homeopathic preparations, and it then broadcasts out an energy which can either help your crops, or get pests to go and bother your neighbour instead. It is important to also include a map of your farm in the broadcaster, so it knows where to aim. Plenty of people report that these things work, but personally I believe it’s time for my favourite Wikipedia page, Confirmation Bias. However, it’s not hurting anyone, so if you like it, then go for it.

Time for a new word, to me at least. Radionics. If you Google it, the second result is the “Skeptics Dictionary”, and the Wikipedia page tells us that it is “commonly considered a pseudoscience”, which it also says of Biodynamics, incidentally. Kym uses his manually operated, and powered, Radionics machine to get information about the general condition of his soil, and what he can do to improve it. It can also be used to decide on pest control strategies.

The Radionics machine, and all the related paraphernalia

The Radionics machine, and all the related paraphernalia

It is a little box that looks a bit like an old fashioned radio, with knobs and dials. It has receptacles into which you can put whatever you want to measure, such as a bag of soil from a particular field. Certain parameters are then entered on the dials, and questions can literally be asked to the machine, like “would urea improve this soil” or “what rate of seaweed extract do I need here”. Tactile feedback gives the answer. It’s not very easy to explain!

I don’t believe it works. At least not as it is supposed to; I think it is a thinking man’s Ouija board. Now this could have been due to him just demonstrating it quickly, but the impression I got was that Kym knew the answers he wanted from it already. I don’t consider this a bad thing, it’s a tool for making decisions, and a confidence booster. That is not a bad thing in my eyes.

Obviously the answers you get out are only going to reflect how good a farmer you are, and anecdotally Kym seems to be on the ball, I’ve only got his word for it though! If you scrape away the hocus-pocus, the underlying system he’s using is not really that different to what I have already been looking at – improving soils biologically and chemically to maximise their efficiency. Kym talks the talk, and claims some pretty impressive results in a range of areas. If he’s correct, does it matter how he got there?