Evaluation of Kostiakov, Horton and Philip's Infiltration Equations as Affected by Tillage and Rotation Systems in a Clay-Loam Soil of Northwest Iran.
Mohammad A. Hajabbasi, Isfahan University of Technology, College of Agriculture, Isfahan, Iran
Infiltration rate is a function of water absorption rate by soil particles and pore size distribution. Thus, factors like soil texture, topography, and organic matter can affect the amount and rate of infiltration. Lack of proper infiltration rate could cause runoff, loss of water and thus soil erosion. The aim of this study was to evaluate three rotations (wheat-wheat, cowpea-wheat, and fallow-wheat) and tillage (conventional, reduced and no-till) systems on the amount and rate of infiltration in a rainfed soil (fine mixed mesic Typic xerochrepts) in Maragheh Research Station (northwest Iran). The empirical infiltration models of Kostiakov and Horton and the analytical model of Philip were evaluated. Soil physical properties including bulk density, organic matter content, aggregate stability, soil moisture content, and penetration resistance were also measured. The application of no-till system resulted in an increase in soil organic matter but had no effect on aggregate mean weight diameter, thus no effects on infiltration. Applying no-till and reduced tillage systems caused an increase in soil moisture content, which is the reason of higher infiltration rate in these systems. The Horton's equation is the most recommended model for the region, to estimate and evaluate the infiltration rate. Key words: infiltration, tillage, crop rotation, rainfed agriculture, drylands, Maragheh Iran.