Abstract

Wathib S S Alnuaymy, Ali M S Alalusi

Compacted and Undisturbed soil samples were collected, from a field in the west of Baghdad. soil samples were wetted according to the capillary property. sawdust extract was injected into soil cylinders in form of a solution to get soil moisture to limits of field capacity, and with three treatments, control and equivalent of 5% of organic matter into the soil as once at first wetting and drying cycle, and third treatment was an application same amount on seven cycles. Distribution size of the aerobically dried soil aggregates, dry sieve for the second half of the sample, using a set of sieves 9.5, 4, 2, 1, 0.5, and 0.25 mm. Bulk and soil bulk density was estimated, the clay flocculation index CFI, and the soil penetration; results can be summarized as follows: Soil aggregates greater than 9.5 were not affected by the application of extract only in aggregates with a size of 4-9.5 mm, while the wetting and drying cycles significantly affected the percent of large soil aggregates (greater than 9.5 mm and those with a size of 4-9.5 mm), at the same time, the interaction effect of in these two volumetric ranges was more significant than the effect of fraction factors; A decrease in the bulk density and soil penetration is indicated by the application of sawdust extract compared to the control treatment; on the other hand, values of two indicators decreased in most of the seventh wetting and drying cycles. Samples treated with the full amount appear under an electron microscope with greater and more granularity and smooth edges compared to the division of quantity on wetting and drying cycles, which in turn appear better.