Work package 2

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Analyzing the efficiency of riparian buffers to retain nutrients from diffuse sources

In work package 2 the effect of different flow conditions and types of riparian buffer strips on the retention of phosphorus from agricultural inputs are examined. The aim is to get a general understanding of the process for the interaction of various factors on the retention performance of riparian buffer strips through model tests.

We will both perform a field test as well as analyze different soil types from riparian buffer strips for their adsorption/desorption quality. For the field experiment, heavy rain events are simulated for selected riparian buffer strips to determine the phosphorus retention during rain fall of different intensities. The surface flow, sediment concentration, adsorption/desorption properties of the soil and nutrients in the water are measured. For the measurement of the adsorption/desorption quality, different soil samples are taken from riparian buffer strips and the adjacent agricultural areas and incubated in different phosphorus concentrations in the laboratory.

The following questions should be answered:

  • What´s the relationship between the physical parameters of a riparian buffer strip, the transport capacity of the surface flow and the phosphorus retention capacity?
  • Are there conditions that lead to the release of phosphorus bound to riparian buffer strips (saturation)?
  • Under which conditions the transport of phosphorus in the surface flow occurs?
  • Will the possibilities of using riparian zones change due to climate change?