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The Dutch way….

The Dutch way…. ….The humus form as a display of ecosystem processes. Bas van Delft Rein de Waal Rolf Kemmers. Contents. Dutch humus profile research Who, where Ecological soil classification (ecosystem approach) Examples of humus profile development series

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The Dutch way….

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  1. The Dutch way…. ….The humus form as a display of ecosystem processes Bas van Delft Rein de Waal Rolf Kemmers

  2. Contents • Dutch humus profile research • Who, where • Ecological soil classification (ecosystem approach) • Examples of humus profile development series • primary succession in coastal dunes • acidification in grassland • Dutch humus form classification

  3. Dutch humus profile research • University of Amsterdam (Sevink, Emmer, Smit) • Fundamental (chemical properties - soil forming processes) • Alterra (De Waal, Kemmers, Van Delft) • Applied research • Related to ecosystem processes • Both forest and non-forest ecosystems • Both terrestrial and semi-terrestrial systems • Humus form classification as a tool for ecosystem description and monitoring

  4. Ecological soil classification • Dutch soil classification • based on long term soil forming processes (centuries) • designed for agricultural applications • not appropriate to recognise changes in the ecosystem • Ecological soil classification • designed to describe relevant site factors (moisture, nutrients, acidity) • based on Ecosystem theory of Jenny (1941) • humus profile reflects ecosystem properties Humus form classification important part of ecological soil classification

  5. Ecological soil classification (approach) VEGETATION Operational Site factors DEPENDENT FACTORS cm 0 o 20 SOIL HUMUS- Decomposition processes 40 PARENT MATERIAL Phys.-chem. processes HYDROLOGY Hydrological processes INDEPENDENT FACTORS Geo(morpho)logical processes TOPOGRAPHY Meteorological processes CLIMATE Physiological: Availability (N, P) Aeration Moisture deficit Toxicity Conditional Site factors Physical/chemical: Stocks (N, P) ANC Moisture capacity

  6. FrameworkEcologicalSoilClassificationTwolevels Veg. Dynamic Humus form =f (pH, moist,...) 2. Dependent factors Humus form Parent material 8 Physiographic Units (Soil map) Topography (=Hydrology) 1. Indep. factors Persistent Humus form as an indicator of actual site conditions !!

  7. Humus profile development series: Primary succession in coastal dunes Initially calcareous sand loam content < 5 % fast decalcification

  8. Humus profile development series: Primary succession in coastal dunes (initial stage) pH(KCl) 0-5cm 4,5 - 6,5 3,5 - 4,5 3,5-4,0 3.0-3,5 2,5 - 3,0 10 cm L F H 0 cm Ah/AC AE 10 cm AB or B 20 cm Initially calcareous sand fast decomposition humus form: calcareous sandmull vegetation: Berberidion vulgaris humusform changes by decalcification decalcification (free CaCO3) C 30 cm 40 cm

  9. Humus profile development series: Primary succession in coastal dunes pH(KCl) 0-5cm 4,5 - 6,5 3,5 - 4,5 3,5-4,0 3.0-3,5 2,5 - 3,0 10 cm L F H 0 cm Ah/AC AE 10 cm AB or B 20 cm decalcification (free CaCO3) C 30 cm 40 cm humus form changes by decalcification: • eluviation of lime • no acid buffer in sand • fast acidification of topsoil • slow decomposition • accumulation of organic matter Chronosequence

  10. Humus profile development series: Primary succession in coastal dunes (final stage) pH(KCl) 0-5cm 4,5 - 6,5 3,5 - 4,5 3,5-4,0 3.0-3,5 2,5 - 3,0 10 cm L F H 0 cm Ah/AC AE 10 cm AB or B 20 cm decalcification (free CaCO3) C 30 cm 40 cm humus form changes by decalcification: • humus form: Forest-xeromormoder • vegetation: Quercion roboris

  11. Humus profile development series: Primary succession in coastal dunes pH(KCl) 0-5cm 4,5 - 6,5 3,5 - 4,5 3,5-4,0 3.0-3,5 2,5 - 3,0 10 cm L F H 0 cm Ah/AC AE 10 cm AB or B 20 cm decalcification (free CaCO3) C 30 cm 40 cm 1 soil unit 5 humus forms! Calcareous sandmull Acid sandmull Ecto- sandmull Dune- sandmullmoder Forest- mormoder

  12. Humus profile development series: Acidification in brookvalley grasslands (optimal conditions) ‘Optimal’ conditions • Acid-buffer supplied by seepage water (pH  5.5) • Active soil fauna (earthworms) • Strong bioturbation • Fast nutrient cycling • Humus form: Mull • Vegetation: Cirsio-Molinietum

  13. Acid buffering systems lime ion-exchange aluminum Ca-saturation = 60% pH-H2O = 6

  14. Humus profile development series: Acidification in brookvalley grasslands (threats) ‘Optimal’ conditions • Acid-buffer supplied by seepage water (pH  5.5) • Active soil fauna (earthworms) • Strong bioturbation • Fast nutrient cycling • Humus form: Mull • Vegetation: Cirsio-Molinietum • Threatened by dropping groundwater table • brookvalleys drained for agricultural use • seepage flow decreased • acid buffer depleted

  15. Acid buffering systems: Shifting humus profiles lime ion-exchange aluminum Ca-saturation = 60% pH-H2O = 6

  16. Humus profile development series: Acidification in brookvalley grasslands (sub-optimal conditions) ‘Sub-Optimal’ conditions • Acid-buffer depleted (pH decreased) • Soil fauna activity decreased • Accumulation of organic matter • Slow nutrient cycling Humus form: Moder Vegetation: Caricion nigrae

  17. Acid buffering systems: Shifting humus profiles lime ion-exchange aluminum Ca-saturation = 20% pH-H2O = 4.5 Ca-saturation = 60% pH-H2O = 6

  18. Dutch humus form classification • Classes and criteria must be ‘ecologically relevant’ • reflect environmental changes • reflect natural succession • Connection to existing systems • Applicable in field situation • Both forest and non-forest ecosystems • Both terrestrial and semi-terrestrial systems

  19. Dutch humus form classification First level: Order (N=5) accumulation Mull Mullmoder Moder Mormoder Mor

  20. Dutch humus form classification Semi-Terrestrial Mull Terrestrial Mull Semi-Terrestrial Mullmoder Terrestrial Mullmoder Semi-Terrestrial Moder Terrestrial Moder Terrestrial Mormoder Semi-Terrestrial Mor Terrestrial Mor Second level: Suborder (N=9) Mull Mullmoder Moder Mormoder Mor

  21. Dutch humus form classification Vague mull Limestone mull Hydromull Plaggenmull S Mull Sandmull T Wormmull S Hydromullmoder Mullmoder T Xeromullmoder S Peatmoder Moder Hydromoder T Xeromoder Mormoder T Xeromormoder S Sphagnomor Mor Mesimor T Xeromormoder Third level: Group (N=15) Divided into 90 subgroups

  22. Position of the examples: Dunes, initial stage Vague mull Limestone mull Hydromull Plaggenmull S Mull Sandmull T Wormmull S Hydromullmoder Mullmoder T Xeromullmoder S Peatmoder Moder Hydromoder T Xeromoder Mormoder T Xeromormoder S Sphagnomor Mor Mesimor T Xeromormoder Third level: Group (N=15) Calcareous sandmull terrestrial mull calcareous sand loam < 20%

  23. Position of the examples : Dunes, final stage Vague mull Limestone mull Hydromull Plaggenmull S Mull Sandmull T Wormmull S Hydromullmoder Mullmoder T Xeromullmoder S Peatmoder Moder Hydromoder T Xeromoder Mormoder T Xeromormoder S Sphagnomor Mor Mesimor T Xeromormoder Third level: Group (N=15) Forest-xeromormoder terrestrial mormoder Hh < 2 cm F+H > 5 cm

  24. Position of the examples : Grassland, first stage Vague mull Limestone mull Hydromull Plaggenmull S Mull Sandmull T Wormmull S Hydromullmoder Mullmoder T Xeromullmoder S Peatmoder Moder Hydromoder T Xeromoder Mormoder T Xeromormoder S Sphagnomor Mor Mesimor T Xeromormoder Third level: Group (N=15) Brook-hydromull semi-terrestrial mull non-calcareous sand loam > 20%

  25. Position of the examples : Grassland, final stage Vague mull Limestone mull Hydromull Plaggenmull S Mull Sandmull T Wormmull S Hydromullmoder Mullmoder T Xeromullmoder S Peatmoder Moder Hydromoder T Xeromoder Mormoder T Xeromormoder S Sphagnomor Mor Mesimor T Xeromormoder Third level: Group (N=15) Rhizo-hydromoder semi-terrestrial moder non-calcareous sand M > 2 cm and Ah < M

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