A significant limitation in using sorption coefficients (K(d)) to predict solute transport through natural soils is the spatial variability of soil properties over large field areas. Spatial variability in K(d) for imazethapyr was determined on representative samples from a 31.4-ha field, covering a pH range from 4.9 to 7.6 and an organic carbon (OC) range from 1.45 to 5.80 g kg-1. K(d) varied from 0.18 to 3.78 across the field, with an average value of 1.56. The analysis of K(d) variability showed two distinct patterns in spatial distribution: areas in which pH > 6.25 and K(d) < 1.5, where K(d) variation is based primarily on pH, and areas in which pH < 6.25 and K(d) > 1.5, where other soil properties, i.e., OC content, have a significant influence on K(d) variation. Based on soil pH distribution, an easily measured property, the field was divided into two potential management areas. This separation allowed identification of portions of the field where herbicide sorption would be minimal, with a relatively higher potential for leaching (i.e., areas with K(d) < 1.5), and provided a rationale for site-specific imazethapyr application.
|Original language||English (US)|
|Number of pages||6|
|State||Published - Mar 1 1999|
- Spatial variability