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Field method for separating the contribution of surface‐connected preferential flow pathways from flow through the soil matrix
Author(s) -
Sanders Emily C.,
Abou Najm Majdi R.,
Mohtar Rabi H.,
Kladivko Eileen,
Schulze Darrell
Publication year - 2012
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2011wr011103
Subject(s) - macropore , ponding , loam , soil science , infiltration (hvac) , water content , moisture , environmental science , materials science , soil water , geotechnical engineering , geology , chemistry , composite material , drainage , mesoporous material , ecology , biochemistry , biology , catalysis
Liquid latex was used as a method to seal visible surface‐connected preferential flow pathways (PFPs) in the field in an effort to block large surface‐connected preferential flow and force water to move through the soil matrix. The proposed approach allows for the quantification of the contribution of large surface‐connected cracks and biological pores to infiltration at various soil moisture states. Experiments were conducted in a silty clay loam soil in a field under a no‐till corn‐soybean rotation planted to corn. Surface intake rates under ponding were measured using a simplified falling head technique under two scenarios: (1) natural soil conditions with unaltered PFPs and (2) similar soil conditions with latex‐sealed large macropores at the surface. Results indicated that the contribution of flow from large surface‐connected macropores to overall surface intake rates varied from approximately 34% to 99% depending on the initial moisture content and macroporosity present. However, evidence of preferential flow continued to appear in latex‐sealed plots, suggesting significant contributions to preferential flow from smaller structural macropores, particularly in two out of four tests where no significant differences were observed between control and latex‐sealed plots.