During austral summer 1978/1979 the content of dissolved oxygen, phosphates, nitrates and nitrites was determined in the waters of Admiralty Bay. Environmental conditions prevailing in Admiralty Bay are compared with the conditions in the open Antarctic waters.
The European Water Framework Directive can have enormous consequences for agricul-ture in the Netherlands. In parts of the country agriculture should be taken out of production because the nutrient loads to the surface water system are far too high. This doom scenario is of course unde-sired and a number of source-specific and effect-specific measures are necessary. The fate of nutri-ents in the soil is strongly interrelated with its hydrology. Directly, because nutrients are transported by water and the distribution of the residence time of drainage water is a good measure for the time behaviour of the nutrient loads to the surface water system. Longer residence time in the soil means more of nutrients applied by farmers but also a longer recovery period, after applying source-specific measures. In this paper three promising effect-specific hydrological measures are described buffer strips, retention strips, and controlled drainage.
Almost half (47%) of Latvian forest areas (3611 thousand ha) are considered degraded or partly improved by the hydro-technical drainage. The degradation is caused by very poor soil aeration due to waterlogged conditions. The location of waterlogged forests in Latvia is neither uniform nor occasional. Comparison of the abundance of waterlogged forests and the amount of atmospheric precipitation showed that the waterlogged forests are mainly located in areas with least precipitation. This hydrological phenomenon is connected with water discharge in drainage ditches: even during the dry summers of the years 1963, 1964, 1975, 1976 and 2002 in the drained forests with deep peat soils water flowed continuously in 1 m deep ditches and the discharge exceeded the amount of precipitation. Using the data from 182 sample plots in drained forests with the peat layer depth of 4.2 m, it was found, that coniferous forests are most productive in areas where the peat layer is most dense. One of the possible explanations for this phenomenon is that the most intensive paludification and formation of most dense peat layer are characteristic for the areas with intensive water discharge from confined aquifers. This discharge provides necessary mineral nutrients for the forest soil regardless of the peat layer thickness. The forest productivity may increase several times due to the enhancement of water movement in soil and to improved soil aeration by hydro-technical drainage. Also the flow regime of rivers connected with the drained areas changes considerably, mitigating extremely high and low flow events.
Studies of the chemical composition of surface freshwaters of the Fugleberget drainage basin, Spitsbergen, were performed in the summer of 1979. It was found that activity of birds (little auk) is the main factor differentiating the chemical properties of waters of the drainage basin. The birds faeces cause the enrichment of waters with nutrients, fertilizing the environment. There is a dependence of the concentration of determined water chemistry parameters on the distance from the bird colony.
The aim of the study was to assess the content of soluble forms of fertilizer nutrients (N, P, K) in the cultivated soil layer up to 20 cm deep from agricultural land in the river valley, and the concentration of these nutrients in the surface wa-ters of the Raszynka River.
In the years 2016–2017, the surface water samples from the Raszynka Rriver (17 points) and soil (19 points) were col-lected from agricultural areas near the Raszynka River.
The surface water samples were collected once a month during the March–October 2016–2017. The contents of nitro-gen (Ntot, NO3-N and NH4-N), phosphorus (Ptot, PO4-P), total organic carbon (TOC and K and Ca) in soils and in waters were determined in the sample solutions.
It was shown that river water was of low quality due to the high concentration of nitrogen and phosphorus and electri-cal conductivity (EC). The most polluted were the waters of the lower section of the river located in the vicinity of arable land and agricultural built-up areas. The soluble forms of nutrients content in the cultivated soil layer was varied dependingon the kind of nutrient, way of agricultural land use, and the term of soil sampling. The content of dissolved P forms in the soil was the highest in autumn on arable lands after harvesting of vegetables (GO-W: 10.24 mg Ptotꞏkg–1 in D.M.) and this component may migrate with surface runoff and increase the risk of surface water eutrophication.