EFFETS DE L'APPORT PROLONGE DE FUMIER DE BOVINS SUR QUELQUES PROPRIETES PHYSIQUES ET BIOLOGIQUES D'UN LOAM LIMONEUX NEUBOIS SOUS CULTURE DE MAÏS

This study was undertaken to quantify the effects on long-term application of solid cattle manure on physical and biological properties of a Neubois silty loam. Rates of 0, 20, 40, 60, 80 and 100 Mg ha−1 manure were applied every 2 yr to the soil cropped to corn. Significant improvements, proportional to application rates, of water-stable aggregation, bulk density, and water content of the soil were measured. These physical properties were highly correlated with the soil microflora (0.83 ≤ r ≤ 0.98). A positive interaction exists between physical and biological properties of soils following long-term manure application. Key words: Solid cattle manure, aggregation, bulk density, biological activity </jats:p

ÉTUDE COMPARATIVE DE L'AGRÉGATION ET DE LA MATIÈRE ORGANIQUE ASSOCIÉE AUX FRACTIONS GRANULOMÉTRIQUES DE SEPT SOLS SOUS CULTURE DE MAÏS OU EN PRAIRIE

Water-stable aggregation and organic matter associated with particle-size fractions were compared for seven pairs of soils that were either under meadow or continuous corn cropping for more than 5 yr. Soils that have remained under meadow contained 25 and 29% more carbon and nitrogen than those under continuous corn. Carbon contents of the sand- and silt-size fractions were also 61 and 15% higher, respectively, under meadow than under continuous corn. The cropping system had no significant effect on the carbon and nitrogen contents of the clay-size fractions. The amount of water-stable aggregates (&gt; 1 mm) was on average 34% higher in soils under meadow than in soils under corn cropping. Significant correlations were found between water-stable aggregates and total C (r = 0.77) and C in sand-size fraction (r = 0.79). The results also indicate that the beneficial effect of meadow over continuous corn on soil aggregation increases as soil clay content increases. Key words: Aggregation, organic matter, particle-size fractions, corn, meadow </jats:p