Fig 1.
Photos of (A) the general aspect of the field, (B) the buffer strip, (C) Blue and rhodamine application on plot C, and (D) gullies near plot B and interception of particles in the buffer strip grass after the most intense rain during the studied period (Photos: Soil Physics and Hydrodynamic Group, Université Laval).
Table 1.
Soil properties of different horizons near (8 m) the buffer strip.
Fig 2.
Schematic representation of the experimental set up and installation of the lysimeter plates (not scaled).
The plots were not protected after tracer application, and the farm maintained its normal production routine. It is important to keep in mind, however, that the tracers were applied after fall soil tillage and the plots were sampled later that fall.
Table 2.
Background efficiency and linear sorption coefficient (Kd) of two tracers (FD&C Blue 1 and rhodamine WT) in different horizons near (8,) the buffer strip.
Fig 3.
Precipitation and creek flow during 2011 and 2012.
Table 3.
Descriptive statistics of creek height and flow during the studied period of 2012 to 2012 downstream from the lysimeter plates.
Table 4.
Descriptive statistics of tracer concentration (FD&C Blue 1 and rhodamine WT) in the creek, lysimeter plates, drain, and buffer strip soil over the 2-year period (fall 2010 to fall 2011 and fall 2011 to fall 2012).
Fig 4.
Blue and rhodamine concentration in the creek in 2011 and 2012.
Fig 5.
Maximal Blue and rhodamine concentrations in the lysimeter plates during both years (no samples were taken from November to beginning of May).
Fig 6.
Sampling scheme and distribution of Blue and rhodamine in two series of measurements in the buffer strip soil in November 2011.
The absence of Blue circles at spots corresponding to the sampling scheme indicates no Blue detection. Circle size indicates tracer concentration.
Fig 7.
Sampling scheme and distribution of Blue and rhodamine in two series of measurements in the buffer strip soil in May 2012.
The absence of Blue circles at spots corresponding to the sampling scheme indicates no Blue detection. Circle size indicates tracer concentration.
Table 5.
Estimation of the shortest time required for water and tracers to reach the B horizon in the middle of the buffer strip from the closest application plots (Plots A and B) assuming constant saturated conditions and movement exclusively in the matrix by hydrodynamic dispersion.