THE EFFECT ON EARTHWORM ABUNDANCE AND SELECTED SOIL PROPERTIES AFTER 14 YEARS OF SOLID CATTLE MANURE AND NPKMG FERTILIZER APPLICATION

Long-term manure application could increase soil earthworm abundance i n cultivated soils. The objective of this study was to evaluate the ef fect of 14 yr (1977-1991) of manure and NPKMg fertilizer on earthworm populations, soil structural stability, N mineralization (NO3) and bio logical activity (CO2) on a Le Bras clay loam (Humic Gleysol) situated at St Lambert, Quebec. The field experiment, in a split plot design, consisted of two manure rates (0 Mg, 20 Mg ha(-1)) as principal treatm ents with secondary treatments receiving mineral Fertilizer (NPKMg) an d a control. These treatments were carried out over a 4-yr crop rotati on of silage corn, (Zea mays L.), wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and canola (Brassica campestris is L.). Soil and earthworm sampling was done in fall 1991 under corn. Compared to mine ral fertilizer treatment, long-term application of manure increased ea rthworm populations. However, the interaction between the treatments o f mineral fertilizer and of manure was nor significant. Of the earthwo rms extracted by formalin and hand sorting, Aporrectodea genus was dom inant in soil, representing 98-100% of the population. Several Allolob ophora chlorotica and Lumbricus juveniles from the genus Lumbricus wer e found only in manured plots. Soil water stable aggregates and biolog ical activity (CO2) were both increased by manure application. Mineral fertilizer application had no significant effect. A strong correlatio n was obtained only between earthworm abundance and biological activit y (CO2) The results indicate that 14 yr application of solid cattle ma nure improved soil earthworm populations and diversity, biological act ivity (CO2) and structural stability compared to fertilizer treatments and the control.