engleski

Experimental and mathematical modeling of water regime and nitrate dynamics on zero tension plate lysimeters in soil influenced by high groundwater table

Unlike laboratory experiments, which are mostly performed under controlled conditions, lysimeter experiments generally simulate actual field conditions. This paper focuses on an efficiency of the zero tension plate lysimeters, which were implanted in silty-clay soils influenced by a high groundwater table. Measurements and following numerical simulations using the HYDRUS-2D model were performed separately for each of 4 years (2007–2010) to assess water flow and nitrate fluxes (applied as NPK or UREA fertilizer). Low efficiency of lysimeters during the vegetation period was mostly caused by high plant water demand and possible water diversion to the sides when the groundwater table was low. The HYDRUS-2D model was able in some degree to reproduce observed water and nitrate outflows. The water outflow through the lysimeter occurred when the groundwater table was high and greater rainfall events occurred. Water and solute diverged from the plate towards the dryer surrounding soil when groundwater table was low. Pressure head, water velocity and nitrate concentration distributions simulated around the lysimeter plate illustrated that the lysimeter plate had a significant impact on the water regime and nitrate behavior within the soil profile. The lysimeter plate also acted as a barrier for water flow and solute transport also.

zero tension plate lysimeter; agriculture;  modeling;  HYDRUS

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