Effect of manure on organic carbon content and fractal dimensions of aggregates

Effects of farmyard manure treatments on some soil structural parameters such as, aggregate stability (AS), geometric mean weight (GMWD) and mean weight (MWD) diameters, fragmentation (D) and mass (D m ) fractal dimensions, bulk density (BD) and organic C (OC) contents of aggregates were determined in a clay soil. Application of 67 Mg ha -1 farmyard manure to Vertic Haplustoll soil decreased AS 12.14% compared with the control. Manure treatment increased the proportion of microaggregates in the fractions 1.00 mm in size. While OC contents of aggregates increased between 22.8% and 123.4%, BD values decreased between 0.8% and 16.6% with the manure treatment. Fragmentation (D) and mass (D m ) fractal dimensions were increased with decreasing numbers of macroaggregates of the clay soil. GMWD (1.16 mm) and MWD (1.86 mm) obtained in the manure treatment were lower than that in the control treatment (1.20 mm and 1.95 mm, respectively). Although OC content of the aggregates increased with the manure treatment, the number of macroaggregates of clay soil decreased with decreasing AS..