Agriculture Reference
In-Depth Information
pH determine the dominance of both litter-feeders (epigeics and anecics) in nutrient
poor and/or acid soils, and of soil organic matter feeders (endogeics) in richer soils with
higher pH. In humid (5000 mm annual average rainfall) Indian monsoon forests, large
earthworm biomasses (up to 1200 kg fresh weight were found, although the soil
was young with high pH and nutrient status (Ferry, 1994). Nutrient contents are also
correlated with soil pH and local rainfall (Fragoso and Lavelle, 1992). In general, tropical
earthworms seem to be more acid-tolerant than those of temperate climates (Lavelle
et al
.,
1995). Comparison of species distributions in France (Bouché, 1972) with those at a
number of tropical sites (Lavelle
et al
., 1995) - including soils with a wide pH range -
showed that modal species diversity occurred at pH values of 6 to 7 in France and
at 5 to 6 in the humid tropics, respectively.
