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Leaching of nutrients was studied at a tile drain outlet and in two pairs of groundwater pipes in an arable field in central Sweden in order to identify trends and impacts of the climate. In the study period (1973–2005), crop production was dominated by spring barley, winter wheat, rape and, in later years, potatoes. Winter crops were cultivated 60% of the time. Leaching of total nitrogen (TotN) and total phosphorus (TotP) to drain water was low, on average 10 kg ha−1 year−1 for TotN and 0.07 kg ha−1 year−1 for TotP based on measurements. Nitrogen fertilisation increased slightly from 121 to 142 kg ha−1 year−1 during the period in a balanced way in line with increasing crop yields of cereals, from 5.8 to 6.6 tonnes year−1. For the entire study period, the temperature was estimated to increase significantly by a total of +2 °C for the growing season (April–September). Precipitation (+16 mm) and humidity (+11%) were also estimated to have increased significantly, mainly in June. Simulations with a ...

Leaching of nutrients and major ions from a tile-drained arable field was evaluated over a 25-year period (1980–2005). The soil, classified as a Gleyic Cambisol, received moderate applications of fertilizers. During later years the soil was more frequently under ley, and since 2002, an area of ravine (29% of the total field) has been managed as a permanent fallow with annual cutting without removing the grass material. A decrease in the concentration of nitrate nitrogen (NO3−N) in the drainwater was estimated in 1980–2005, based on non-parametric tests on concentrations flow-normalized with a robust fitting curve procedure. The average concentration of soluble reactive phosphorus after pre-filtration (RPf) of 0.030 mg l−l corresponded to a calculated degree of phosphorus saturation (DPS) of 6% in acid extract of ammonium lactate from the topsoil. Between 1995 and 2005, concentrations of suspended solids (SS), RP and total organic carbon (TOC) decreased significantly in the drainage water from the...

Soil tests with extractions are commonly used for risk assessments of phosphorus (P) leaching. Procedures for routine analysis of crop-available soil P by extraction with acid ammonium lactate (P-AL) have been used for nearly 50 years in Sweden, Norway and several East European countries. Aluminium and iron (Al-AL and Fe-AL) were determined in the same extract for 40 well known clayey, loamy or sandy soils from the Swedish long-term studies. Average outcome was 16.8 and 6.0% for the two elements related to extraction with chelating ammonium oxalate (Al-AO and Fe-AO) and concentrations had a correlation coefficient of 0.947 and 0.891, respectively, when the two extraction agents were compared. On average, P-AL determination using inductive coupled plasma (ICP) resulted in 19% higher soil P concentrations compared to analysis using a colorimetric method based on non-calcareous and calcareous soils from the southern counties in the Swedish soil survey, represented mainly by sandy loam soils. Degree ...