Abstract

BECERRA, MIGUEL ALEJANDRO; HANG, SUSANA  and  DIAZ-ZORITA, MARTÍN. ANÁLISIS GEOESPACIAL DEL ÍNDICE DE ADSORCIÓN (Kd) DE ATRAZINA CALCULADO SEGÚN CARTAS DE SUELOS Y MUESTREO EN GRILLA. Cienc. suelo [online]. 2015, vol.33, n.2. ISSN 1850-2067.

Soil surveys provide information, sometimes under-used, about distribution and variability of soil characteristics at a regional scale. Pedotransfer functions generate information on new soil attributes. The purpose of this study was to characterize the spatial variability of the atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) retention index, Kd, calculated from two data sources: soil surveys (estimated Kd) and a recent regional soil sampling (Kd_m); and to assess different methods to estimate Kd at the regional scale from soil surveys data. To obtain the estimated Kd, five methods were assessed: one using the data of the predominant soil series of the cartographic unit, another using the weighted arithmetic mean of the data of the soil series within the cartographic unit, and the remaining three from different interpolation methods. Two hydrological units with contrasting soil characteristics were studied: Morteros (SHM) and Río Quinto (SHRQ). Kd_m corresponding to SHM oscillated from low to high with an average of 2.03 ± 0.87 L kg^-1 while Kd_m values of the SHRQ were mostly low, with an average of 0.79 ± 0.71 L kg^-1. Linear regression analysis between Kd_m and the estimated Kds fitted better with the interpolated Kds than with the soil surveys Kds. Lower estimation errors (< 1 L kg^-1) corresponded with the Kd_m range between 0.06 and 2.84 L kg^-1. Higher estimation errors (> 1 L kg^-1) were less common for the interpolations than for cartographic unit maps, representing 20.6% and 34.1% of the cases, respectively. This study showed that the information from soil surveys was consistent with the data obtained from a recent sampling.

Keywords : Spatial variability, interpolation criteria, GIS, environmental risk.

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