|Prieksat, Mark - DANIEL B STEPHENS & ASSOC|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 31, 1997
Publication Date: N/A
Technical Abstract: Placing fertilizers in agricultural fields to minimize leaching losses requires knowledge of the influence of plant roots on water flow paths. Thirty-two undisturbed soil columns were obtained from four positions in a corn field after harvest, but before fall tillage. The four positions were; center of a trafficked interrow (TRK), center of an untrafficked interrow (UNT), between corn plants in the row (BPIR), and directly over corn plants in the row (OPIR). Saturated hydraulic conductivity (Ksat), chloride breakthrough, and drainable porosity (DP) were measured after surface residues were removed. Corn plants were then grown in 16 of the columns. After the corn plants had reached the nine-leaf stage, measurements were repeated on all 32 soil columns. Saturated hydraulic conductivity and DP increased and chloride breakthrough occurred more rapidly in columns taken from TRK, UNT, and BPIR field positions after corn had been grown in them. Increased Ksat and DP were attributed to changes in porosity or pore continuity. No significant changes in Ksat, DP, or chloride breakthrough were noted in columns that did not have corn grown in them, except those columns from the OPIR position. Saturated hydraulic conductivity and DP increased in columns from the OPIR position both with and without plants. The magnitude of the increase was the same for columns from the OPIR position with or without corn plants. This study seems to indicate that corn roots create pathways for rapid water movement through soil and that the decay of the roots is not necessary for this to occur. Additionally, corn roots had no effect on water movement in undisturbed soil volumes that previously had corn plants growing in them.