The Abundance of Earthworms in Agricultural Land Under Citrus

Abundance and distribution of earthworms were studied in the Mitidja plain at five stations under citrus. Earthworm abundance showed distinct seasonal patterns, with winter maxima and summer minima. Eleven species belonging to seven genera and three families have been identified. Allolobophora rosea (Savigny 1826) and Nicodrilus caliginosus (Savigny 1826) s.l. are the dominant species. The lowest density is represented in Hadjout, whilst the highest at Mefath, Boufarik and Reghaia, successively. Temperature and precipitation affected the distribution of species and possibly with the texture and the structure of the soil. The earthworm fauna of cultivated areas appears to be qualitatively and quantitatively different from that of the forests of Algeria.