Godzinowa zmienność stężeń fosforu ogólnego na przykładzie zlewni rzeki Słupi

Abstract

The development of agriculture, especially the use of chemicals, contribute significantly to the increase in the mineral content  in the wastewater from farmland. It results in excessive fertilization of surface waters.
Due to common use of mathematical models to assess the state of surface water and forecasting changes in the environment, the representativeness of individual measurements of nutrient concentration used in model calibration become significant. Particularly important is the frequency of monitoring phosphorus, which causes the greatest problems during model simulation. To see how large the variability of phosphorus in surface waters can be, data from three cycles of field measurements, adjusted to the stage of the growing plants were gathered. The measurements were carried out on the Słupia river in Pomeranian voivodeship, in a profile located in the village of Charnowo. Cycles were carried out in November 2013, February 2014 and June 2014. The analysis showed significant changes of concentrations of phosphorus per day (up to 111%). This trend was maintained regardless
of the time of year and the stage of vegetation. It is thus important both the time of day sampling and even an hour of the measurement for the size of loads of phosphorus discharged into the sea. Also, from the point of view of the calibration of mathematical models, access to detailed information is very important and can have a direct impact on the result.