EFFECT OF ADDITION OF NANO SAWDUST TO SOIL ON STABILITY AND SUSTAINABILITY OF SOIL AGGREGATES

A laboratory experiment was conducted in the laboratories of the College of Agriculture, University of Anbar, to study the effect of wetting and drying cycles (DW) and sawdust extract. Soil samples were taken from one of the fields of the College of Agriculture and were distributed in size greater than 9.5, 4, 2, 1, 0.5, 0.25 and less than 0.25. mm, containers with a diameter and height of 100 mm were filled with 800g of soil with the same size distribution as the main soil sample. Injecting sawdust extract equivalent (SDE) to 5% of the organic matter in the soil with three types of addition. Then the containers were exposed to 5 DW and incubation at a temperature of 22 degrees C. MWD, rho b, f and some other characteristics were estimated. The results showed that nano-crushed (NCSDE) increased MWD upon rapid wetting significantly compared to the extract as a solution (SSSDE) and without application (WOSDE) in DW1, MWD values started low when SSDE was added and then increased significantly by 179, 180.5 and 146.3% from DW3 to DW5, respectively. As for slow wetting, the effect of SSDE supplementation was higher than that of NCSDE and WOSDE supplementation. And at all DW cycles, it was noted from the SEM images and in the DW1 cycle that the WOESDE type of addition shows sharp-angled soil aggregates and small aggregates appear cumulatively. In DW3 and when WOSDE is added in a spherical shape but at acute angles, clusters of acute lamellar shape accumulate on top of it, while NCSDE shows its large spherical aggregates with smooth edges and the aggregates of the SSDE type appear lamellar with large and small aggregates with sharp edges, in DW5 the soil aggregates of the WOESD type appear spherical and of large size, while the addition of NCSDE shows their aggregates in not large sizes. And the addition of SSDE shows its clusters in relatively large sizes, often spherical, with lumpy clusters and smooth edges.