Peat in horticulture: a synthesis

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Peat in horticulture a synthesis

• Hans Joosten
• Greifswald University
• International Mire Conservation Group

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Horticulture

• Population growth, increased urbanisation
• High quality mass products
• Increasingly intensive higher yields per m2
• ? High quality substrates that guarantee such
  yields

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Substrates

• Properties are essential
• Reliability, adjustability, availibility
• ? Sphagnum peat has become the number one
  substrate

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(No Transcript)
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peat
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Sphagnum peat is 'nothing'

• From merely rain
• and dew of heaven
• has it grown
• it is not fed from Earth (Dau 1823)
• The 'nothing' enables storage of water and air
• The 'nothing' enables easy adjustment of adequate
  pH and nutrient conditions
• ? 'Nothing' is everything!

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'Nothing' grows

• Peat grows in living peatlands (mires)
• Peat grows very slowly
• How to replace 'nothing?

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Peat extraction destroys mires
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Augstumal (Litauen, C.A. Weber 1902 )
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Augstumal (Litauen) 2002
1 km
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Wise Use

• International Peat Society (IPS)
• International Mire Conservation Group (IMCG)
• Global Guidelines for Wise Use of peatlands
• Joosten, H. Clarke, D. (2002) Wise use of
  mires and peatland Background and principles
  including a framework for decision-making. 304 S.

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IPS/IMCG Wise Use book

• Includes detailled questionaries to judge the
  wisdom of peat extraction for horticulture
• But also states
• it is not possible to reduce all complexities to
  simple principles or single measures
• Wise Use is not simple or simplistic and cannot
  be reduced to formulae

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Wise Use definition

• those uses of mires and peatlands for which
  reasonable people now and in the future will not
  attribute blame
• No blame for decisions taken after due reflection

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IPS/IMCG Wise Use

• The wisdom of a decision is judged on how it
  balances
• The benefits and disadvantages
• The (direct and indirect) effects on
• all (present and future) people.

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IPS/IMCG basis criterion I

• Utilisation of peat is in principle allowed,
• When the use is not substitutable and vital for
  human survival OR
• As long as the good/service is abundantly
  available.
• In the latter case the side effects have to be
  taken into account.

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IPS/IMCG basiscriterion I

• With respect to peat
• Peat is not vital
• Is peat abundant?

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Availability

• West- and central Europe are almost empty
• No good overview how much Sphagnum peat is still
  available

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From Joosten 2003

• Mires left
• lt 10
• 10-50
• gt 50
• of original area
• Total left
• 48
• (33 excl. Russia)

Europe is the continent with the largest losses
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Availability

• Most of the million km2 of peatlands on Earth do
  not contain slightly humified Sphagnum peat
• That peat is only won in a narrow zone (north
  temperate/ south boreal zone)
• Estimates are too optimistic
• Better inventories necessary

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The mire zones of Eurasia and Africa
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IPS/IMCG basiscriterion II

• With respect to side effects, peat use is in
  principle allowed when
• No negative side effects occur OR
• The affected goods/services remain abundant or
  are easily (and completely) substitutable OR
• The intervention is easily reversible.

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IPS/IMCG basiscriterion II

• With respect to side effects, peat use is in
  principle allowed when
• No negative side effects occur OR
• The affected goods/services remain abundant or
  are easily (and completely) substitutable OR
• The intervention is easily reversible.

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Side-effects

• The question is whether the affected
  goods/services remain abundant or are easily
  substitutable
• Then IPS/IMCG basiscriterion II
• In all other cases a complete cost-benefit-analys
  is is necessary.

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Irreversibly affected

• Carbon store of the peat
• Palaeo-ecological archive value
• Cultural archive value
• Long-term natural phenomena (macro- and
  microrelief/-pattern, rare species)
• Option-function (future)
• Individual human appraisal

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Reversibly affected

• CO2 sequestration
• Regulation of hydrology and chemistry
• Plants, animals, landscape
• Their indication values
• Recreation, esthetics, spirituality

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While covering only 3 of the Worlds land area,
peatlands contain 550 Gt of carbon in their peat.
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Finland
This is equivalent to 75 of all C in the air,
equal to all terrestrial biomass, and 2 times the
carbon stock in the total forest biomass of the
world.
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Sichuan, China
This makes peatlands the top long-term carbon
stock in the terrestrial biosphere.
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Globally, degraded peatlands emit 3 Gtons CO2 a-1
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0.6 of the land surface is responsible for 10
of the total global anthropogenic CO2 emissions
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Annual peat losses
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Is peat renewable?

• Popular question
• Relation to finiteness of the resource
• Relation to effect of peat combustion on climate

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Is peat renewable?

• Ancient question
• Asked since man has been using peat
• First comprehensive discussion in the first book
  on peat by Schoockius (1658, Groningen)

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Is peat renewable?
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Is peat renewable?
1658
Chapter 14 Whether excavated sod material can
over time be restored?
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Is peat renewable?

• To burn a peat moss does twenty times as much
  damage, as a forest can twenty times grow up
  before a new and equally good peat moss matures.
• It may seem to be a good invention to use the
  mires for fuel and thus spare the wood but a
  forest can grow several times in a seculum,
  whereas a mire is not filled with peat in several
  secula.
• Carl von Linné (1707-1778) "Skånska resa" 1749

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Is peat renewable?

• 17th 19th century Peat renewability important
  for long term energy security
• Since 1850 economic interest disappeared because
  of the emergence of coal and oil
• Since 1960 peatland restoration again interesting
  from a conservation point of view

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Biomass fossil peat

• Peat extraction mobilises carbon from a long-term
  store where it would otherwise remain
  indefinetely
• This is the fundamental difference between
  biomass (wood, straw) and fossil carbon
  resources (peat, coal)

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Biomass fossil peat

• In case of biomass, organic material is oxidised
  that soon would have oxidised (by decomposition)
  anyhow
• In case of utilisation humans use the energy, in
  case of decomposition microbes/fungi
• In both cases the same amount of CO2 ends up in
  the atmosphere
• In case of peat material is oxidised that
  otherwise would have remained unaltered
  indefinitely
• As opposed to biomass, peat whether 10, 1000 or
  10 000 years old would without human use not
  end up in the atmosphere as CO2

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Green peat extraction?

• ? There is no green peat extraction
• Peat extraction is unsustainable, destructive,
  environmentally damaging, ugly

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Wise Use of peat?

• But peat extraction takes place with an aim that
  can be good.
• Whether the balance is wise ist, depends how
  good the aim of peat extraction is and how
  bad the alternatives are.

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Wise Use of peat?

• It always concerns a balancing between the loss
  of peat, peatland and their values on the one
  side, and societal advantages on the other side.
• If a small evil helps to prevent a big evil or to
  achieve a big good, the smaller evil might be
  allowed.

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Wise Use of peat?

• Such judgement can only take place in the
  framework of a complete life-cycle-analysis, from
  extraction up to disposal.
• It means that use of peat for a specific purpose
  can be wise, but for another purpose not.

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• For the wise use of non-renewable resources some
  simple rules can apply (Hartwick 1977)
• A non-renewable resource should not be squandered
  on low-grade applications
• The profits from non-renewable resources should
  be invested in the development of renewable
  substitutes.

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Future

• The industry has to focus stronger on preparing
  growing media from renewable resources, including
  wastes and cultivated plant material.
• Only then she can address the societal demands
  for
• sustainable development,
• conservation of biodiversity, and
• decrease in Carbon-emissions.

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Future

• The Stone Age has not ended because of lack of
  stone.
• And so it will also be with peat
• Reidar Petterson IPS-President 1992 -1996

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Conclusions

• Peat extraction for growing media must be
  concentrated on already degraded peatlands (50
  million ha!)
• Don squander high quality peat for low-quality
  applications (amateur gardening)
• Sustainability requires the substitution of
  fossil resources by renewable resources
• Restoration can combine conservation and
  exploitation

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Nov 2004
Mai 2004
Aug 2005
Peatmoss cultivation to replace peat in
horticulture
Aug 2006
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Cultivation of peatmoss (Sphagnum) for
horticultural substrates (alternative for peat).
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Visions of Leo Lesquereux 1844
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• Quelles soient rejetées par un grand nombre de
  propriétaires dont lunique vouloir est le profit
  du moment, je le comprends. Mais il se trouvera
  peut-être quelque homme de coeur, ami de son
  pays, qui emploiera une parcelle de sa fortune à
  des expériences que le riche seul peut faire.
• that these (ideas) are rejected by a large
  number of (peatland) proprietors whose only wish
  is short-term profit, I can understand. But maybe
  some man of honour, a friend of his country, can
  be found, who will devote a parcel of his fortune
  to experiments, as only the rich can do.

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• Puissent les résultats obtenus emmener enfin mes
  concitoyens à cette conviction, qui se fortifie
  toujours plus en moi, cest que les marais
  tourbeux sont, non point un bien mort, mais une
  fortune active, non point une chose profitable
  pour le présent seul, mais nécessaire à lavenir,
  non point enfin un sol inutile et quil faut se
  hâter de détruire, mais un de ces bienfaits de la
  sage nature que lhomme doit reconnaître et
  étudier un de ces trésor dont il peut profiter
  pour luimême, mais dont il doit compte à ses
  descendants.
• May the results obtained bring my fellow
  citizens to the conviction, that increasingly
  becomes stronger in me that the peat mires are
  not dead goods but an active fortune, not
  profitable only for the present, but necessary
  for the future, finally not a useless soil that
  we must rapidly destroy, but one of the benefits
  of the wise nature that man has to acknowledge
  and study one of these treasures of which he may
  benefit for himself, but for which he has to
  render account to his descendants.

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