Compensation of agriculture impact on water quality.
Wagner - Lotkowska, Iwona1, Zalewski, Maciej2, 1 Department of Applied Ecology, University of Lodz, Lodz, Poland2 International center for Ecology, Polish Academy of science, Lodz, Poland
ABSTRACT- Unsustainable agriculture alters the hydrological cycle and modifies nutrient pathways in landscapes. The consequent effect of opening of biogeochemical cycles seriously impact quality of water bodies by altering extend and timing of their external supply with nutrients and agricultural originated contaminants. Eutrophication of impoundments located in agricultural catchments, which results from the above processes needs a system approach to reverse degradation of water quality and related ecosystem services. The presented approach proposes 2-step compensation of these negative effects. The first step reconcile number of management practices in cultivated areas, directed toward control of diffused pollution export and stabilisation of water balance in the landscape (e.g., Ryszkowski & Kedziora, 1996). The second step considers river valleys and land-water interface, instream processes and hydrodynamic processes in reservoirs as areas of high carrying capacity potential to be used for mitigation of the agriculture impact on waters. According to the Ecohydrology concept (Zalewski, 2000) a 2-way regulation should be applied in the sequence of the above enumerated habitats. Shaping biota structure can be applied towards optimising the system retentiveness against nutrients and pollutants, stabilising ecological resilience and resistance of the system against stressing factors, and mitigation river hydrological extremes. The vice versa regulation uses control of hydrological processes in floodplains in order to optimise sedimentation and primary productivity of valley vegetation in order to enhance the purification processes (Wagner & Zalewski, 2000). The paper presents example of long term studies on the Pilica River floodplain toward protection of a lowland Sulejow Reservoir against Eutrophication.
Key words: agricultural landscape, water cycling, eutrophication, compensation
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