engleski

Modeling water and isoproturon dynamics in a heterogeneous soil profile receiving different urban waste compost

Compost amendments and tillage practices can modify soil structure and create heterogeneities at the local scale, which can have a significant effect on water and solute transport. Two composts, a municipal solid waste compost (MSW) and a co-compost of green wastes and sewage sludge (SGW) have been evaluated in a long term field experiment. In each plot, wick lysimeters, TDR probes and tensiometers were installed at various depths. A modeling study using HYDRUS-2D was carried out to evaluate how the presence of heterogeneities due to different compost application and soil tillage affects water flow and isoproturon dynamics in soil. Cumulative amount of outflow on six years showed the largest value for the control (CONT) plot (1403 mm) compared to the SGW (1047 mm) and MSW (1000 mm) plots. After calibration on year 2008, the model was able to describe the entire 2004-2010 cumulative outflow with high accuracy for all three plots (model efficiency E = 0.99). Isoproturon concentration had similar behavior in the two composted plots, while the CONT plot had the largest values of isoproturon cumulated loss. Isoproturon fate was correctly described after optimization of the degradation rate in solid phase. Preferential flow events were observed in the CONT and MSW plots. Water and isoproturon fluxes were associated mostly with noncompacted soil zones and interfurrows while compacted clods were bypassed because of their low hydraulic conductivity.

Soil heterogeneity; Compost amendments; Water flow; Isoproturon; Modeling

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