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Peat in horticulture: a synthesis

Horticulture . Population growth, increased urbanisationHigh quality mass productsIncreasingly intensive: higher yields per m2? High quality substrates that guarantee such yields. Substrates. Properties are essentialReliability, adjustability, availibility? Sphagnum peat has become the number

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Peat in horticulture: a synthesis

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    1. Peat in horticulture: a synthesis Hans Joosten Greifswald University International Mire Conservation Group

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

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

    6. 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!

    7. 'Nothing' grows Peat grows in living peatlands (mires) Peat grows very slowly How to replace 'nothing‘?

    11. 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.

    12. 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”…

    13. 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

    14. 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.

    15. 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.

    16. IPS/IMCG basiscriterion I: With respect to peat: Peat is not vital Is peat abundant?

    17. Availability West- and central Europe are almost ‘empty’ No good overview how much Sphagnum peat is still available

    18. Mires left < 10% 10-50% > 50% of original area Total left : 48 % (33 % excl. Russia)

    19. 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

    21. 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.

    22. 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.

    23. 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-analysis is necessary.“

    24. 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

    25. Reversibly affected CO2 – sequestration Regulation of hydrology and chemistry Plants, animals, landscape Their indication values Recreation, esthetics, spirituality…

    31. Annual peat losses

    32. Is peat renewable? Popular question: Relation to finiteness of the resource Relation to effect of peat combustion on climate

    33. 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)

    34. Is peat “renewable”?

    35. Is peat “renewable”?

    36. 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): "Skĺnska resa" 1749

    37. 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

    38. 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)

    39. 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

    40. ‘Green’ peat extraction? ? There is no ‘green’ peat extraction Peat extraction is unsustainable, destructive, environmentally damaging, ugly…

    41. 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.

    42. 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.

    43. 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.

    44. 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.

    45. 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.

    46. 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

    47. 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

    50. Visions of Leo Lesquereux 1844

    51. “Qu’elles soient rejetées par un grand nombre de propriétaires dont l’unique vouloir est le profit du moment, je le comprends. Mais il se trouvera peut-ętre quelque homme de coeur, ami de son pays, qui emploiera une parcelle de sa fortune ŕ 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.

    52. “Puissent les résultats obtenus emmener enfin mes concitoyens ŕ cette conviction, qui se fortifie toujours plus en moi, c’est 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 ŕ l’avenir, non point enfin un sol inutile et qu’il faut se hâter de détruire, mais un de ces bienfaits de la sage nature que l’homme doit reconnaître et étudier; un de ces trésor dont il peut profiter pour luimęme, mais dont il doit compte ŕ 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.”

    53. www.imcg.net

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