EFFECT OF TILLAGE REDUCTION AND FERTILIZER ON SOIL MACRO- AND MICROAGGREGATION

Abstract

This study was undertaken to determine the effect of tillage and fertilizer on soil structure in fields under corn production in Quebec. Three types of tillage (moldboard, chisel and zero-till) and two types of fertilizer (manure and inorganic fertilizer) were applied yearly for 6 yr on a clay and a sandy loam soil. Macroaggregation was obtained after dry and wet sieving and microaggregation after sonification. Soil geometric mean diameter and aggregate stability were increased after manure applications and still further by zero-till. The amount of aggregates in each size fraction was affected differently by the fertilizer and tillage treatments. The fraction of organic matter binding the < 250-μm units into > 250-μm units played a greater role in soil aggregation than total soil organic matter content. Key words: Aggregation, manure, organic matter, soil pH, reduced tillage