AU - Azizi Agh-ghale, B. TI - Effects of Three Kinds of Organic Matter on Maximum Dry Bulk Density and Critical Moisture Content during Soil Compaction PT - JOURNAL ARTICLE TA - JCPP JN - JCPP VO - 5 VI - 3 IP - 3 4099 - http://jcpp.iut.ac.ir/article-1-64-en.html 4100 - http://jcpp.iut.ac.ir/article-1-64-en.pdf SO - JCPP 3 ABĀ  - The effects of three kinds of organic matter on the physical characteristics of two soil series (Coarse Loamy, Mesic, Typic, Xerofluvents and Fine Mixed, Calcixerollic, Xerochrepts) were studied along with the measurement of maximum dry bulk density (MDBD) and the corresponding critical moisture content (CMC). Soil samples were taken from a depth of 0-20 cm and the percentage of organic matter and soil texture were determined. Three kinds of organic matters (peat, farmyard manure and filter press apple) were mixed with the soils at four levels (0, 4, 8 and 12% by mass), and were compacted using 10, 20 and 30 proctor hammer blows. The compaction tests on soils were carried out at different moisture contents. The present experiment, using factorial design, was randomly conducted in three replications. The results of this study showed that while the mean MDBD declined significantly (P CP - IRAN IN - LG - eng PB - JCPP PG - 49 PT - Research YR - 2001