Manure effects on soil fertility and earthworm populations earthworm populations in organic grass/clover on sandy soils

G.J.H.M. van der Burgt, Ton Baars. 2001. Manure effects on soil fertility and earthworm populations earthworm populations in organic grass/clover on sandy soils. European Grassland Federation: Organic Grassland Farming. , Witzenhausen, Germany. July 2001.