[Original humus forms in a semi-deciduous tropical forest in Guadeloupe].
Humus profiles underneath the canopy of dominant tree species in two secondary semi-evergreen forest sites in Grande-Terre (Guadeloupe) were analysed with a micromorphological method. In the vertisol of a tree plantation, the humus formed was rather similar under all tree species being an eumull and essentially due to the activity of the endoanecic earthworm Polypheretima elongata. In a natural secondary forest located on a steep slope and associated with a rendzina soil (without endoanecic earthworms), the humus forms were described at lower, mid- and upper slope. In this forest, two particular humus forms were observed. At the middle slope, underneath the canopy of Pisonia subcordata L. that produces nitrogen-rich litter, a calcareous amphimull, characterised by an OH horizon made of millipede faecal pellets, was formed. In the upper slope, underneath the canopy of Bursera simaruba (L.) Sarg. that produces a litter rich in resins and aromatic compounds that are poorly consumed by soil animals, a dysmull with a thick root mat (OFRh horizon) developed. Other humus forms were intermediate. The formation of these humus forms is discussed.
Loranger
G
G
Laboratoire d'écologie des sols tropicaux, IRD Bondy, 32, avenue Henri-Varagnat, 93143 Bondy, France. gilorang@mtu.edu
D000818:Animals; D019430:Guadeloupe; D009835:Oligochaeta / Q000378:metabolism; D012987:Soil / Q000032:analysis*; D014197:Trees; D014329:Tropical Climate
D012987:Soil
Formes d'humus originales dans une forêt tropicale semi-décidue de la Guadeloupe.