Here’s my final Nuffield report. Just need to do the presentation in November and I’m free.
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.
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.
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.
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,
- CS – Conventional System using disc cultivation, growing soybeans with a winter cover crop
- NTS – No-Till System, growing a soya and maize rotation with winter cover crops
- ICLS – Integrated Crop-Livestock System growing two years of soya & cover crop and two years of pasture
- PP – Permanent Pasture
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’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?
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.
Who doesn’t want to fly two sides of a triangle to get to the right place? It’s even better when there’s a nice drive in the dark, rain and traffic at the other end. Still, we only nearly died once. This morning all the clouds had gone and it was a short drive to Fazenda Boa Vista. Lucio Damalla is one of the pioneers of no-till around here, he started doing it 39 years ago and is now heavily involved in all of their industry associations. In the afternoon I visited the local Embrapa centre, and met a couple of guys who are working on livestock integration.
Both visits had the same message, which was that having grass and animals in a rotation is going to be better for your soils, and give higher crop yields. The Embrapa guys had done the most work on systems which are 50% pasture (2 years pasture, 2 years crop). I don’t think there is much doubt that this is going to be a more efficient way of farming, the question really then just comes down to economics: can the livestock phase make enough money to be economically viable? I don’t think it can in the UK, not in the good arable areas anyway.
Lucio is more of a crop farmer than a cowboy. He does not breed any cattle, he just buys them in at certain times of year to do some grazing. There are no permanent pastures here, he just uses the Santa Fe system, as discussed on Day 65. Quick refresher – that’s when Brachiaria is planted at the same time as maize in the second crop slot. After harvest, the grass is ready to go, and can be grazed during the winter.
This idea is pretty similar in principle to how we use cover crops, so it’s interesting to see it in action. The benefits are the same as in the 50% pasture system, but just not as pronounced. Lucio has increased SOM from 2-3% in the 10 years that he’s been doing it, which compares to levels of around 4% in the trial rotations with permanent pastures. They both see significant yield increases in following cash crops, due to both the increased SOM, and also the changed physical soil properties. The grass roots open up the soil profile, allowing the cash crop roots to go down further, whilst also improving water infiltration. Although the rainfall here is ~2,000mm, they still suffer from small droughts in the summer, and it’s in these periods that the crops after grass show their real advantage.
I’ve long had the debate in my mind and with other people about whether it’s best to graze cover crops or not. It seems obvious that by grazing you’re going to lose some carbon (meat & methane), but is it a significant amount? The researchers at Embrapa are certain that it’s better to graze. They say you will get a measurably better crop afterwards (I think most would acknowledge this anyway), but also that it’s better for the long term soil fertility as well. The theory is that soil biology is stimulated by what comes out of the animal (both ends), and they also share Kris Nichols’ opinion that the physical act of grazing a plant causes some (as yet unquantified) beneficial soil effect, maybe by releasing a burst of root exudates. So far so good, that’s basically what I believe. I was really hoping though that thy would have some data on this particular situation, but it seems to be more of a hunch.
As an aside, one of the Embrapa guys, Julio Cesar, had the usual researchers’ habit of answering questions with “it depends”. I teased him a bit about it, and said he was fully qualified to come and work as a scientist in the UK because he wouldn’t give a straight answer or opinion. But it then occurred to me afterwards that when he did say what he thought (grazing cover crops is better), I said I needed to see the data. Maybe they just can’t win?
Don’t hold your breath, this is a short post. I’ve never seen Coffee plants before, so this is a very brief description of how they work.
Fazenda Malunga is the biggest producer of Organic lettuce in the whole of Brazil. There are 200m people here, but I don’t think many of them are into Organics just yet. Still, the farm is a big operation, with about 120ha of land in total, 45ha of which is the main, original, block. As well as growing lettuce, which accounts for around half of their production, they also have tomatoes, beetroot, cucumber, coriander, okra, bell peppers, radish (plus some more, I didn’t take notes, oops).
Because it is an organic farm, they need to get nitrogen from somewhere. [I don’t get this about the Organic movement: it’s fine to mine phosphorus from the soil – rock phosphate – but mining nitrogen from the air – urea – is forbidden.] Some of this comes from leguminous green manures that are grown as every second or third crop, and the rest is comes as compost from the farm’s 70 cow milking herd.
So although I don’t agree with some of the principles of Organics, [or for that matter think it represents what the customer believes the are getting], we should still be able to learn from how they farm. The over-riding philosophy here is that a healthy plant will fight off disease by itself, with less need for artificial inputs. I’ve written before that farmers are often reactive rather than proactive, and this is made much easier by the way a lot of problems can be solved, in the short-term at least, by opening a bottle. This type of farming is the complete opposite.
The main plant nutrition comes from the green manures, home made compost and bought in peat, all of which act on the soil. In addition, they use a lot of foliar sprays, and fertigation (mixing small amounts of fertiliser with irrigation water) to add trace elements. The foliar potions are Bokashi recipes, ranging from straight mineral blends to some which have molasses added to stimulate microbial life. One particular additive, called Compost Aid, is used when they have lost the bacteria off the plant leaves (I don’t know what might cause this). It gives a quick boost to get the bugs back colonising the leaf surface, which doesn’t allow space for too many bad ones to come in and cause problems.
One of the most interesting things they were doing was living in a sealed plastic barrel, which was full of a damp sandy mixture, smelling a bit like fermenting beer. It was made by taking some of the native soils from out in the bushland, and adding extra carbohydrates as a food source. The top is then sealed and it sits around for a couple of months stewing, before being put into big tea bags and bubbled around in a water tank to extract the goodies. Now it’s ready to be sprayed on to the plants.
I like the idea of this – the native microbes are obviously going to be the best adapted to the local conditions. I’m not so sure about sealing the lid and making the whole thing anaerobic, as that’s not a condition generally associated with healthy plants. At least not the type that we want to grow. The other problem might be that they seem to be thinking almost exclusively about bacteria, and not much about fungi. That could easily be a case of local conditions being different to ours, but if you believe Elaine Ingham, most of our soils are severely lacking in fungal biomass.
After a quick carbo-loading session (rice, cassava, beans, pasta & potato on the same plate) it was off to a different farm for the afternoon. It is run by a father and son team of Japanese Brazilians, and until three years ago they were a crop-only operation. But then compaction and soil borne disease problems started to appear, and they thought it would be a good idea to experiment with some cattle and rotational pastures. But this is Brazil, and a small trial means 100ha of irrigated Mombasa grass, and 1,200 head of cattle. It’s too soon to draw any conclusions from what’s happening here, but it’s safe to say that grass grows a bit faster here than at home:
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 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%.
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.
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.