African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6578

Full Length Research Paper

Effects of infiltration time on the calculated sorptivity with White method for a sandy loam soil

Wei Hu1, Quanjiu Wang2, Mingan Shao3* and Zhengshan Ju4
1Key Laboratory of Water Cycle and Related Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China. 2State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Northwest A&F University, Yangling 712100, Shaanxi, China. 3Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China. 4Land Consolidation and Rehabilitation Center, Ministry of Land and Resources, Beijing 10035, China.
Email: [email protected]

  •  Accepted: 24 August 2011
  •  Published: 19 September 2011

Abstract

Sorptivity (S) is one of the important soil hydraulic parameters, which can be estimated by disc infiltration data at the early stage with one dimensional infiltration theory. With the purpose of understanding the effects of infiltration time (IT) on the estimated S, two sizes (radius of 5 and 2.5 cm) of disc infiltrometer were used to perform disc infiltration under five pressure heads (0, -3, -6, -9, -15 cm) using a packed sandy loam soil. S values for different IT were estimated with White method. Results showed that the estimated S was in general overestimated and it increased with the increase of IT. The relative measurement error as compared with the Parlange method increased with the increase of IT, a behavior that could be well fitted by a logarithmic function. There was a tendency that the relative measurement error decreased with the decrease of pressure head, and the optimized value of IT (ITOP) in general increased exponentially with decreasing pressure head, ranging from 20 to 75 s for disc radius of 5 cm and 8 to 26 s for disc radius of 2.5 cm. The estimated S values and relative measurement errors for smaller disc were greater than those of larger disc. Attentions should be given to the suitable IT for determining by White method. Furthermore, the relatively larger disc size should be preferred under the premise of a good hydraulic contact between disc and soil surface.

 

Key words: Disc infiltrometer, Philip, sorptivity, sandy loam soil.