EFFECT OF COMPACTION AND ORGANIC MATTER ON SOME SOIL PHYSICAL PROPERTIES AT DIFFERENT DEPTHS

A field experiment was conducted in the field of the Department of Field Crops - College of Agriculture located behind the University of Babylon 32022'51.892" N 44023'46.00" E, which is 10 km from the center of Babylon province.The soil of the field was of clay, silty texture, and it was classified according to the modern American classification (2010 soil survy staff) within the rank torrifluvent typic. The aim of the study was to know the effect of compaction and organic matter on some physical properties of the soil under different depths. Bulk density, total porosity and stability of aggregates. A factorial experiment was carried out using a randomized complete block design (RCBD) according to the split-split-plot system, with three replicate. As the main factor was the organic fertilizer (compost) M, with three levels, namely the first level without adding M0, the second level adding 2% by weight M1, and the third level adding 4% by weight M2, and the secondary work represents compaction L and three levels,The first level is without passing L0, the second level is repeating the passage twice on the same track L1, and the third level is repeating the passage four times on the same track L2. The sub-secondary factor represents depth D with two levels, the first level D1 (0-15 cm) and the second level D2 (15-30 cm( Stacking levels were conducted by a 1990 Fiat agricultural tractor with two-wheel drive at the rear, with a total weight of 2046 kg. The results of the study showed that increasing the level of sedimentation led to a significant increase in the bulk density, and a significant decrease in the total porosity and stability of soil aggregates. Where the highest value of the bulk density was found to be 1.437 µg.m-3 at the L2 stacking level and the lowest to 1.316 µg.m-3 for control treatment. Also, the lowest value of the total porosity was found to be 47.61% at the L2 stacking level and the highest value to 53.96% for control treatment.Also, the lowest value of 43.65% was found for the stability of the clusters at the L2 stacking level, and the highest value of 51.88% was found for control treatment. The results of the study also showed that when increasing the level of organic matter addition, it led to a significant decrease in the bulk density values under the influence of the M2 level, and a significant increase in the values of total porosity and stability of the aggregates. It was found that the highest average bulk density was 1.421 Mg.m-3 in control treatment and the lowest average was 1.352 Mg.m-3 at the level of adding 4% organic matter. While it was found that the highest percentage of total porosity was 54.476% at the level of adding 4% organic matter, and the lowest percentage was 45.954% in control treatment. The highest value of the stability of the aggregates was 54.11% in the treatment with 4% organic material added, and the lowest value was 40.82% in control treatment.The results of the study also showed that increasing the depth level led to an increase in the bulk density value, as well as a decrease in the stability of the aggregates and the total porosity of the soil. Where the highest value of bulk density was found to be 1.416 µg.m-3 at depth D2, and the lowest value for aggregate stability was 42.71%, and for total porosity 49.624% at depth D2. The results of the study showed when increasing the level of compaction with the stability of other factors led to a significant increase in the values of bulk density and a significant decrease in the total porosity and the stability of clusters, as the results of the study showed when increasing the level of organic matter led to a significant decrease in the values of bulk density and a significant increase in the values of total porosity and stability of soil aggregates. It appears from the results that with increasing the level of organic matter and the level of compaction, the soil response to compaction decreases. As it was noticed that the highest value was 1.51 µg.m-3 for the bulk density at the level of compaction L2 and depth D2 without the addition of organic matter, it decreased to 1.26 µg.m-3 at the level of compaction L0 and depth D1 and the level of addition of organic matter M2.The highest value of total porosity of 58.20% was observed in the M2L0D1 treatment and the lowest value of 41.30 under the influence of the M0L2D treatment. When comparing between the treatment M2L2D2 (50.30%) and the treatment M0L0D2 (48.85%), the effective role of the organic matter appears in reducing the negative compaction in the total porosity.It was also found that the highest value of the soil agglomeration constant was (65.27%) in the treatment M2L0D1 and the lowest value (34.71%) under the influence of the treatment M0L2D2. When comparing between the treatment M2L2D2 (43.78%) and the treatment M0L0D2 (40.18%), the effective role of organic matter appears in reducing the negative compaction in the stability of soil aggregates.This result shows the role of organic matter in improving soil properties, as it reduced the effect of depth and compaction on the interaction of soil properties under study.