Part I: Understanding Your Land
The Blackland Centre aims to describe and understand blackland, based on observation and practice on the croft at Scotvein and others in the west of Scotland. We are still at the frontiers of agricultural research – few in Britain have paid attention to small-scale, highly organic agricultural soils – so cannot say if our outcomes hold true outside the parts of North Uist where we took our measurements.
Beginning in 2010, we began to try to understand and then formulate methods for bringing our crofts back to productivity. After 5 years, we thought we had some answers; after 10 years we knew we didn’t. But everyone who manages land wants to know how to do it better, so we keep on trying to provides hints and reports on things that seem to work, or that went wrong.
First, we need to be clear what we are talking about.
Although many scientists and advisors call such soils ‘peat’ this is not sufficiently precise. (Peat is Like Snow) ‘Peat’ can be a peat bog, blanket peat, peat for burning, stuff in the garden centre and so on. For this reason, we use the word ‘blackland’ which we define as managed soils very high in organic matter (>50%), quite acidic (<pH 6), in an Atlantic climate. Although arising from peaty material, blackland has been transformed by human activity over time, and usually occurs as part of a small-scale agricultural mosaic. According to the West Highland Survey (1955), about 1/6 of all croft land in Scotland may meet this definition.
Blackland fields are usually small (less than an acre), seldom flat, and occur in a diverse pattern of arable, grassland and rough grazing. They produced hay, oats, potatoes and other crops for hundreds of years. With the arrival of large agricultural machinery and changes in support payments in the 1960s, blackland was mainly left as rough grazing for sheep; due to the Atlantic climate, it very quickly became overgrown when management ceased.
The Soil Survey of Scotland (Macaulay Institute for Soil Research1984) sampled only about once per square kilometer, and did not note differences between agricultural use and moorland.
The Land Use Capability Classfication (Macaulay/Rothamsted 1977 and subsequent) was designed to classify land for agricultural purposes, based on its ‘capability under a moderately high level of management’. The classification that would seem to best describe the black agricultural soils of the west of Scotland is Class 3: ‘Land with moderate limitations that restrict the choice of crops and/or demand careful management’ or Class 4 ‘Land with moderately severe limitations..’ However, for reasons unknown, possibly due to unfamiliarity with crofting agriculture, it is often classed as 5 or even 6 with use ‘restricted to pasture, forestry, recreation…or rough grazing’. This mis-classification has been widely accepted among advisory and planning agencies, has skewed support programmes, and has been very detrimental to crofting.
The Blackland Centre is developing a research-based description and classification system through measurements and statistical analysis to provide more precision in the study and use of our west of Scotland agricultural soils. (Classification of Blackland) We recommend describing such soils as highly organic and anthropic, or using the English term ‘earthy peats’. We are investigating similarities between blackland and the well-described moorsh soils of continental Europe which have been the subject of intensive research into the complex and permanent transformations which can take place through agriculture.
Then, we can summarise what we have learned.
The Blackland Centre also maintains a croft, makes grass silage to feed cattle, and has provided a site for field trials into traditional production methods to the SRUC/University of Edinburgh. Our work so far into regeneration of blackland systems shows that historical knowledge is essential, that large modern agricultural machinery is not suitable and that environmental impacts are minimal (compared to those arising from importation of food and fodder).
We have made up some rules to guide us:
Rule 1: Observing is essential
Many blackland areas are now derelict and overgrown. Agricultural advice in the past 50 years has mainly been concerned with boosting productivity in large-scale commercial farms on mineral soils, and has not taken much notice of traditional agriculture. It is hard to find relevant advice.
We need to learn to look carefully at our land for signs of past use, to learn to ‘read the land’. Most crofts are very varied and changeable. In a wet year, one area may be most useful, in a dry year, somewhere else may be better. Most blackland fields have been under-used since the 1960s, and a quick look today does not necessarily indicate their potential.
The Blackland Centre has developed simple methods of evaluating the potential of a disused blackland area. The Blackland Index has 5 easy tests plus one soil analysis which must be sent to a lab or SAC.
Rule 1 a: Do not skip your soil tests.
Rule 1 b. Do not apply fertiliser without a soil test (unless you aim to waste money).
Some form of winter shelter for stock will produce manure/bedding to compost and return to the fields as fertiliser. Science shows that composted manure provides not only nutrients but encourages many beneficial soil processes.
Rule 2: Understand and restore drainage
Common agricultural problems in Scotland are drought and frost. The West has neither. We normally do not have a ‘soil moisture deficit’, but rather a surplus. Therefore we need to focus on getting rid of the water so as to allow more air into the soil system. It is air that starts all kinds of beneficial reactions in the soil, both chemical and microbial. (Actually, our rainfall is not particularly high – an average of 950mm/yr between 2008-2015 – but due to the climate, evaporation from the soil and transpiration from plants is quite slow.)
Most managed fields were carefully sited to take advantage of natural drainage (on a gentle slope for example), or open drains were put in to intercept or remove water. The lazybed system also improves drainage for the growing area.
So, find and clear drains as much as possible. Do not hope that you can improve your land without doing this. Spend a lot of time trying to understand water management – good drainage systems arose from centuries of experience.
Another way of removing water from the land is by removing excess vegetation.
Rule 3: Mow and remove litter
If a field is seriously overgrown, there can be a cold wet blanket of vegetation (usually moss, dead grass and other vegetation) lying on the surface which holds moisture and prevents the ground from drying and warming in the spring.
To our great joy, we discovered that if you mow (in the right places, see Blackland Index), you will get grass! Believe it. There are plenty of useful grasses (bents, fescues, cocksfoot, yorkshire fog, even sometimes a little rye) struggling with the blanket. When it is removed, they will grow, and you will have grass.
Mowing can be done with tractor and mower, a ‘topper’ pulled by a quad or even a large riding mower. In a seriously overgrown/mossy field you should probably rake off the debris. (Field 3a at Scotvein had about 300mm of moss, but we knew from aerial photos that it once had been useful.) An alternative for the first season is to wait for a good burning day and burn the field before mowing – ash is more convenient than litter! and returns nutrients to the ground.
But in light of recent experience, we also warn against heavy interference with the sward – you invite weeds from rush to ragwort.
Rule 4: Consider pH
After water management, soil pH is the most important thing: it affects how nutrients become available to plants. As a result of your soil test, you will probably find that the pH is at most 5. They say that optimum pH on blackland is 5.3 – 5.5 (SAC 2016), unlike mineral soils where >6 is recommended. We believe that the best way to raise pH is through application of shell sand: Uist shell sand can be more than 40% lime equivalent. We prefer sand to agricultural lime as it is less likely to wash away, needs to be done only every 5 years or so, and improves soil structure. Lime is quicker acting but you are trying to tune a system, not shock it. (see below, Getting It Wrong)
Rule 5: Suit the crop to the land, don’t try to change the land for the crop.
It seems that many desirable and nutritious grasses and other plants will actually grow well on blackland outside of their theoretical ranges. Some likely grasses are mentioned above in Rule 3; even some clovers can establish around pH 5. Useful herbs such as plantain and chicory will do fine. We have made grass silage out of local grasses without fertiliser (except for sand and muck) that tests at a level sufficient to maintain healthy livestock.
Don’t be seduced by the claims of the seed catalogues which disparage ‘weed grasses’ (i.e. the ones that grow here) and promote new mixes with names like Tornado or Typhoon. Most modern grasses are bred for drought- and frost-resistance and to respond to high levels of synthetic fertilisers. The older ones were tougher and more resilient, more suited to a system aiming for equilibrium rather than high-input rotations. We are experimenting to see which if any modern grasses will establish and perform here, but so far have found nothing suitable, unfortunately.
This seems a good time to quote the American farmer and writer Wendell Berry:
“It is too simple to say that the ‘marginal’ farms of New England were abandoned because they were no longer productive or desirable as living places. They were given up for one very practical reason: they did not lend themselves readily to exploitation by fossil fuel technology… Industrial agriculture sticks itself deeper and deeper into a curious paradox: the larger its technology grows in order to ‘feed the world’, the more potentially productive ‘marginal’ land it either ruins or causes to be abandoned”. (1979).
Rule 6: Suit the stock to the land, and manage your grazing.
Small blackland fields with moderate grasses never supported large modern breeds. Hardy traditional breeds such as Highlanders, Dexters, Blackface, Hebrideans are adapted to this land and this climate. Unfortunately, some of the old breeds such as Luing or Aberdeen Angus have been bred to be larger and more profitable when sold as supermarket beef. Hopefully, as the local food movement grows, we can develop more opportunities to market small, delicious animals.
Some form of rotational grazing is essential. If hungry animals are left on a field for season after season, they will overgraze the delicious grasses, and ignore the unpalatable plants which will flourish. The field will get worse.
There are many theories about best practice in grazing/cutting management, but at a minimum, a holding needs to be divided into smaller areas so that stock can be moved around.
After several years of making silage and managing our grass with mixed success, we recently discovered the French researcher Andre Voisin (whose work gave rise to modern methods of ‘managed grazing’ or ‘mob grazing’ as practiced on dairy farms). Working on his own farm in the 1950s, he dedicated himself to understanding the physiology of grass. How does it respond to cutting and grazing? As he asks, “What does the cow think?” According to Voisin, by taking into account the time that grass requires to regenerate after grazing/cutting, and the varying of this period depending on season and weather, proper management can nearly double grass yields. (Probably less so on our marginal land, but any improvement is welcome).
The Scottish guru of grassland is David Younie (SAC ret.); his book “Grassland Management for Organic Farmers” (Crowood Press, 2012) is thorough, fascinating and useful, although clearly written as advice for mainland Scottish soils, not blackland.
How do we balance the practicality of stock management with the need of the grass to regenerate? Can we afford to do this? can we afford not to do this?
Conclusion: there are no quick fixes in agriculture.
It takes time to make a change, to undo decades of underuse, to learn about your land, to persuade different vegetation to take hold. At a minimum, it will take several years before you think you know what you are doing. Plan, be patient and keep working at it. We have all been trained to expect ‘solutions’ to ‘problems’ – got a weed? poison it! Want tomatoes? apply ‘tomato food’! There are no quick answers, only processes. It will take a while. The answer to almost any agricultural question is “Ten years”.
We must also realise that the west of Scotland is one of the most marginal areas in Europe for agriculture, so anything we can do is a triumph. The old guys did it, why not us?
Part 2: Getting it Wrong
The old guys had a lot more experience – indeed centuries – that’s why, so we offer:
A CAUTIONARY TALE: the sad story of field 1a
Sometimes, doing what you are ‘supposed to do’ can have the opposite effect, and upset the balance of a functioning natural system. This was the case with field 1a at Kenary – a half-acre blackland field used for oats and hay during the mid-20th century, and then left fallow for 50 years. Reinstating management in 2010 – aiming at productive permanent grassland – led to surprising changes in soil chemistry, species distribution and productivity. A lot of interesting questions arose.
Teaching ourselves about equipment and basic management of grass, we made good ‘haylage’ out of local grasses^ (bents, Yorkshire Fog, fescues, crested dogstail, sweet vernal and cocksfoot with some wild white clover and plantain) in 2014. It tested at the very respectable DM 35% DVal 65 Protein 12.4 ME10.1 Then we decided to tamper with success: we got interested in ‘improvement’ and ‘better grasses’.
^ These are the ones sneered at by seed merchants as ‘weed grasses’.
pH Responses 2010-16
– The soil in field 1a tested at pH 4.6 in 2010, and seemingly raised itself to pH 5.3 in 2012 after flail mowing to remove excess vegetation and let the surface dry out. ‘They say’ that it takes huge amounts of lime* to alter pH and that pH 6 is ideal for grasses, so we figured there was a way to go.
– In 2013 and 14, we put on not-very-much sand* maybe equivalent to 3T/ha.
– By 2015, we had some composted muck to apply.
– A soil test in 2016 averaged pH 6.4 (P 7.62 K 120) and up to pH7.5 at the surface 100 mm layer. What was going on?
* We use shell sand here as it is locally available, tests >40% lime-equivalent, and improves the structure of organic soils such as blackland.
Grasses & silage
After a crop of big-bulk, poor-quality silage in 2013, we improved the haylage energy predictions in 2014 to the good results above simply by cutting early in the season (before/ at heading) and late in the day to allow sugars to rise; we got 46 small bales in 2 cuts. 2015 was a very poor crop (18 bales), due partly to goose damage and a wetter year with some rush appearing. Trying to figure out what was going on, we observed that the Yorkshire Fog had practically disappeared. The grasses had naturally sorted themselves into prefer-drier (fescues, cocksfoot) and prefer-wetter (Fog) and Fog-based sward had become very patchy and open in the damper half of the field. ‘Advice’ is very strong that grasses prefer pH c.6, so we naturally assumed this would be true for Fog as well. Guess not – the most likely cause of Fog disappearance (after growing on its own for decades) would seem to be pH shooting up to 6.4 and more.
‘Advice’ says that to successfully top-sow, you need to graze hard, then scarify. We tried this in early in 2015. What they don’t say is that opening a blackland sward in any way can encourage rush germination and the invasion of creeping buttercup. So we got those too. ‘Advice’ also forgets to mention that in order for seed to take you need P easily accessible to little roots and ours was low, a common problem on old blackland. So seed establishment = 0%.
In an effort to find older, more tolerant grass varieties that don’t need high nutrient input and are not designed for frost and drought tolerance (neither of which have we got), we read too many seed catalogues and tried to find research institutes interested in the problem (nada). So to satisfy our curiosity, we grew out 16 modern grass and clover varieties in a small test plot (5e), including 4 PRG, 2 meadow fescue, 2 tall fescue, 2 cocksfoot, a local ‘blend’, and 5 white clovers of various sizes. To be honest, the trials were casual and the results were inconclusive – nothing did as well as the grasses here already!
Lessons, conclusion and speculation
It took several exhausting frustrating years to learn the hard way that ‘advice’ can be very wrong: ground-truthing says so!
Our main conclusion is that we should have left well enough alone, and not been influenced by ‘advice’ and seed merchants. In one of the most marginal areas in Europe for agriculture, we now aim to work with what we have and make the best of it – apparently from the silage tests, that’s not bad at all.
We speculate that blackland soils may be poorly buffered / very reactive:
not-very-much liming resulted in a big pH swing. ‘Advice’ also assumes that liming material is being ploughed in, rather than simply spread on existing grassland.
We are surprised that tough old Fog is apparently intolerant of higher pH. We aim to use the best-performing of our grass trials to fill in bald spots in the sward.
This was a perfect storm of trying everything you’re supposed to do – and inadvertently setting strong negative processes in motion. Blackland seems to have not-so-much in common with ‘peat’ but perhaps quite a bit in common with the moorsh soils of eastern Europe where the chemistry and transformations of highly organic soils have been intensively studied for decades. We aim to follow this up.
Poor field 1a will be left alone for a few years apart from goose-scaring, Dexter grazing, and annual soil tests to see what happens and if it can get its mojo back.
All the above is based on careful measurement but not replicated field trials on blackland >60% OM in the Atlantic climate of the Hebrides – which is not really very wet (av. 945 mm rainfall p.a.) but has very slow evapo-transpiration.
N.B. As used above, ‘Advice’ refers to information imparted by Scottish Research Institutes and Advisory Services – very little of it useful, having been developed on the mineral soils of commercial agriculture.