Application of a simulation model (VARLEACH) for calculation of herbicide distribution in the soil under field conditions. Part 1. Influence of spatial variability of soil properties
1992
Bunte, D. (Biologische Bundesanstalt fuer Land- und Forstwirtschaft, Braunschweig (Germany). Inst. fuer Unkrautforschung) | Pestemer, W. | Gottesbueren, B.
The application of the simulation model VARLEACH (Variable Leaching) to estimate the degradation and leaching behaviour of herbicides with regard to spatial variability of soil properties is exemplified by using simazine. Grid sampling of two different field sites (sandy soil, site 1, loamy soil, site 2) to estimate the spatial variability of soil properties showed considerable horizontal variability of organic carbon content and distribution coefficients (K((d)) values) of simazine at site 1, whereas site 2 was more homogenous (coefficients of variance for organic carbon content and K((d)) value over 70 % and below 35 %, respectively). A close relationship was found between organic carbon content and K((d)) values of simazine for site 1 (r = 0.914) which was less marked at site 2 because of higher clay contents and its change in sorption behaviour (r = 0.581). By using VARLEACH for the simulation of degradation and leaching of simazine considering the spatial variability 12 to 45 % and 13 to 22 % of the total residues could be predicted 120 days after application for site 1 and 2, respectively
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