University of Tehran Press Iranian Journal of Soil and Water Research 2008-479X 48 4 2017 11 22 Effect rock fragment Content on Some physical quality indices of a silt loam Soil Effect rock fragment Content on Some physical quality indices of a silt loam Soil 789 797 64152 10.22059/ijswr.2017.215985.667538 FA Hosein Asgarzadeh University of Urmia 0000-0002-5535-0150 Farrokh Asadzadeh University of Urmia Parvin Khaleghi University of Urmia Journal Article 2016 09 28 This study was conducted to investigate the role of rock fragment content on water retention and soil penetration resistance curves as well as determining the correlation of soil physical quality indices with therock fragment content of the soil.A silt loam soil, containing 5% w/w 2 to 5 mm in diameter rock fragments, was used for this study. Experiment was carried out based on completely randomized design atsix treatmentsand three replications. The treatments including six levels of 5, 10, 15, 20, 25, and 30% w/w 2 to 5 mm in diameter gravel. Large drainable soil bins (40 cm × 50 cm with 50 cm depth) were used in this study. The bins were put outside (under natural conditions) after sowing of wheat (Triticum aestivumL.) and received enough amounts of water using irrigation and rainfall.There were significant differences (p<0.05) between the soil water content values in important matric suctions. The highest (i.e., 0.322 cm3 cm-3) and the lowest (i.e., 0.269 cm3 cm-3) means of water content at matric suction 100 hPa were obtained for the 10 and 30 percentage of the rock fragment content, respectively.Increase in rock fragment content of the soil significantly reduced the water content that the critical penetration resistance(2 MPa) happened. There was significant relationship between the water content of 2 MPa and rock fragment content of the soil. Increasing of the rock fragment from the normal value (5%) to 30% was causedthatthe bulk density and the infiltration time increase more than 11 and 254, respectively. This study was conducted to investigate the role of rock fragment content on water retention and soil penetration resistance curves as well as determining the correlation of soil physical quality indices with therock fragment content of the soil.A silt loam soil, containing 5% w/w 2 to 5 mm in diameter rock fragments, was used for this study. Experiment was carried out based on completely randomized design atsix treatmentsand three replications. The treatments including six levels of 5, 10, 15, 20, 25, and 30% w/w 2 to 5 mm in diameter gravel. Large drainable soil bins (40 cm × 50 cm with 50 cm depth) were used in this study. The bins were put outside (under natural conditions) after sowing of wheat (Triticum aestivumL.) and received enough amounts of water using irrigation and rainfall.There were significant differences (p<0.05) between the soil water content values in important matric suctions. The highest (i.e., 0.322 cm3 cm-3) and the lowest (i.e., 0.269 cm3 cm-3) means of water content at matric suction 100 hPa were obtained for the 10 and 30 percentage of the rock fragment content, respectively.Increase in rock fragment content of the soil significantly reduced the water content that the critical penetration resistance(2 MPa) happened. There was significant relationship between the water content of 2 MPa and rock fragment content of the soil. Increasing of the rock fragment from the normal value (5%) to 30% was causedthatthe bulk density and the infiltration time increase more than 11 and 254, respectively. https://ijswr.ut.ac.ir/article_64152_92914b863caab3084c5cf0cb02e72b11.pdf