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Agriculture is the leading source of non-point sources of water pollution, especially in terms of the runoff process. Agricultural management promotes extensive water contamination, soil erosion and sedimentation in streams and reservoirs. The water reservoir Švihov on the Želivka river supplies drinking water to more than 1.5 million people. The catchment area of the water supply reservoir is intensively used for agriculture, more than 55% of the catchment area is arable land. Nutrients such as phosphorus and nitrates in the upper water-ways of tributaries are a huge problem. The aim of the research is to evaluate concentration trends and losses of nutrients (nitrates and phosphorus) at the chosen tributaries to the Švihov reservoir during 2018–2021. From the data on monthly concentrations and monthly discharges the monthly and annual losses of nitrates and phosphorus on each profile were calculated. The effect of discharges and concentrations on the magnitude of losses was investigated by correlation analysis. The influence of the forebay Trnávka dam on the magnitude of nutrient losses was also evaluated. The results show the importance of discharge magnitude on nutrient losses. The Trnávka forebay dam significantly reduces the transport of phosphorus from the Trnava catchment to the Švihov reservoir. In the catchment area of the reservoir it is recommended to implement nature-friendly and technical measures for water retention and accumulation in the landscape in order to reduce nutrient transport. [ABSTRACT FROM AUTHOR]

The aim of our research is to confirm or refute the hypothesis, which says that agriculture is the main source of surface water pollution. Nowadays, when more than 82 % of the Czech population is connected to public sewerage system, it is assumed, that the wastewater has not a significant impact on the quality of surface water, as there are waste water treatment plants and similar facilities for cleaning the sewage. Thanks to a detailed field survey and regular sampling followed by laboratory analysis of water from selected streams in southern Moravia and the Highlands it was found although municipalities are connected to the public sewerage system, which brings the sewage water into the treatment plants, deteriorating the quality of the water flow right through the village. The results of laboratory analyses of water from the monitored flows show the process of self-purification, they are seeing a significant decrease in the concentration of certain substances by water flow through the selected sections of land use. On the other hand, in urban areas or flow through the arable land the water is enriched by pollutants, this is on many places evidenced by developing of undesirable algae. [ABSTRACT FROM AUTHOR]

When growing wide-row crops on sloped lands, there is significant surface runoff. In relation to the runoff process, potatoes are classified as a risk crop. This study aimed to grow potatoes in the Bohemian-Moravian Highlands, where the protection zone of the water supply reservoir of Švihov is also located. At selected experimental areas, water samples were taken after precipitation events when surface runoff and water erosion occurred. These samples were analysed (nitrates, total P, and selected pesticides used for potato growing) in an accredited laboratory. We located three different variants of nitrogen fertilisation in each experimental area. Precipitation and the amount of water from surface runoff after each higher precipitation event were also measured in the experimental areas. By knowing the acreage of each experimental area, the volume of surface runoff water and the concentration of nitrates, phosphorus, and pesticides, it was possible to calculate the balance of these substances. We also calculated the percentage of surface runoff. The results imply that a new potato cultivator in the technology of stone windrowing should be designed for weed control as part of a weed control system with reduced herbicide application requirements. Innovative agrotechnical processes reducing pollution of water sources by phosphorus and nitrates should also be enhanced. These are based on a precise application of mineral fertiliser into the root area of plants within the period of an intensive intake of nutrients. [ABSTRACT FROM AUTHOR]