Individual study: Earthworms are more abundant under no-tillage, but less abundant with reduced fertilizer input, on spring barley plots in eastern Scotland
Gerard B.M. & Hay R.K.M. (1979) The effect on earthworms of ploughing, tined cultivation, direct drilling and nitrogen in a barley monoculture system. Journal of Agricultural Science, 93, 147-155
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Reduce fertilizer, pesticide or herbicide use generally
A replicated trial on an experimental farm in eastern Scotland (Gerard & Hay 1979) found fewer earthworms (Lumbricidae) at lower nitrogen application rates. There were 78 earthworms/m2 and 0.42 tonnes earthworm/ha in plots with no nitrogen, compared to 106 earthworms/m2 and 0.53 tonnes/ha in plots with 100 kg N/ha. The highest nitrogen treatment (150 kg N/ha) had fewer earthworms but higher biomass because there were more large-bodied species like Lumbricus terrestris (93 earthworms/m2, 0.59 tonnes/ha). Earthworm biomass decreased with decreasing nitrogen application at a rate of 0.06 t/ha for every 50 kg N/ha. Only one of the eight species recorded, Allolobophora rosea, was more abundant in plots with lower fertilizer inputs (9 earthworms/m2 at 0 kg N/ha, compared to 3.7 earthworms/m2 at the highest rate of 150 kg/ha). The experiment was replicated eight times. Spring barley crops were managed from 1967 until 1973 with either 0, 50, 100 or 150 kg N/ha added annually.
A replicated trial on an experimental farm in eastern Scotland (Gerard & Hay 1979) found that the average number and biomass of earthworms (Lumbricidae) was significantly higher in untilled soil (137 earthworms/m2 and 0.9 tonnes earthworm/ha) than in cultivated treatments (67-93 earthworms/m2 and 0.3-0.4 tonnes/ha). The experiment was replicated eight times. Spring barley crops were managed from 1967 until 1973 with either deep ploughing (30-35 cm), normal ploughing (15-20 cm), tined cultivation (12-30 cm deep) or no ploughing (untilled, direct drilled). Between 1969 and 1973, the average number of adult and large juvenile earthworms on two replicates increased from 37 earthworms/m2 to 114 worms/m2 under direct drilling, but did not change significantly under the three cultivation treatments (21 to 80 earthworms/m2).