The effects of addition of organic amendments on the physical properties of a degraded Ultisol were compared with those of high rates of inorganic fertilizer. The treatments were: control (C), F1 (N, P, K and Mg at 120, 30, 120 and 20 kg/ha, respectively), F2 (N, P, K and Mg at 180, 45, 180 and 30 kg/ha, respectively), RS (rice shavings at 50 Mg/ha), RS + F1 (rice shavings at 50 Mg/ha plus N, P, K and Mg at 120, 330, 120 and 20 kg/ha, respectively) and PM (poultry manure at 50 Mg/ha). All amendments were applied in 1986 and their effects monitored three months and three years later.When compared with the control, applications of rice shavings or poultry manure significantly (P=0·05) decreased bulk density and increased total and macroporosity, volumetric water retention and available water capacity, saturated hydraulic conductivity, infiltration capacity, cumulative infiltration and time to reach infiltration capacity, more than did inorganic fertilizer amendments. Their effects were more pronounced three months than three years after application. Improvements in these properties were directly related to the residual concentrations of soil organic matter left by the amendments. Organic-matter concentrations accounted for between 52 and 77% of variability in bulk density, 35 and 88% variability in water retention and available water capacity, and between 56 and 98% variability in water transmission characteristics of this Ultisol. Considering the immediate and residual effects of these treatments the order of improvements in the measured physical properties was RS>RS+F1>PM>F1⩾F2>C.
Bioresource Technology 12/1992; 42(3):167-175. DOI:10.1016/0960-8524(92)90019-T