Estimating bioavailable reserves and potential leaching of soil P by simple chemical tests

The amounts of P extracted with acid ammonium acetate are significantly correlated with the bioavailable P reserves of Finnish soils. Together with clay percentage the simple extraction method is fairly reliable. In routine soil testing clay% can be estimated visually. Additional improvement in accuracy is possible by extraction with a strong acid. Leaching losses of P are also significantly correlated with acetate-extractable soil P, but the concentration of dissolved phosphate at a certain soil test P value varies with other soil properties and increases with decreasing pH

Phosphorus in Finnish soils in the 1900s with particular reference to the acid ammonium acetate soil test

Comprehensive research into phosphorus (P) in soils and crops began in Finland in the early 1900s. The average amount of total P in the ploughed topsoil layer of mineral soils was about two tonnes per hectare in the 1930s, before the abundant use of fertilisers. The main chemical fractions of P in mineral soils were organic matter, primary apatite and secondary complexes of the hydrous oxides of Al and Fe. Of the smaller amounts of P in light peat soils, as much as 80% was present in stable organic compounds. Field experiments showed that the native P reserves of Finnish soils are poorly available to plants, and that P fertilisers are inefficiently utilised because of the strong fixation of applied phosphate in soils. In evaluations before the late 1950s, all simple chemical tests appeared to be rather unreliable indicators of the supply of P from soils to plants, but later research has shown that the results were impaired by errors implicit in the research materials. Some soil test P values (STP)obtained from old samples stored for more than ten years evidently were too high, particularly for organic soils, and many of the soils studied were strongly acidic and therefore biologically less fertile than the chemical P tests indicated. The acid ammonium acetate method (pH 4.65) was introduced in the early 1950s and has since been used in routine soil testing in Finland, not only for P but for all macronutrients except N. In later evaluations of different methods used for estimating the requirement of P fertilisation, the acid ammonium acetate method has proven equal or superior to any other simple chemical method

Changes of yield responses and soil test values in Finnish soils in relation to cumulative phosphorus and potassium balances

Field experiments with five rates of annual P fertilisation were carried out at 24 sites in Finland 1977-1994. A summary of the yield results was calculated on the basis of the amounts of P recommended to cereals according to STP in early 1990s. The effects of repeated K fertilisation were studied at 21 sites in 1977-1994

Ethnicity and Unemployment in Finland

This research note provides the general findings from a research project analyzing the reasons behind the lower unemployment rate of the Swedish-speaking minority in Finland, compared with the Finnish-speaking majority. The main conclusion is that the unemployment gap cannot be attributed to ethnic-group differences in age, education, place of residence, or industrial structure. We believe that two latent factors are highly relevant in this context: language proficiency and social integration, although no data presently available provides information about such issues

Hierarchical causal variance decomposition for institution and provider comparisons in healthcare

Disease-specific quality indicators (QIs) are used to compare institutions and health care providers in terms processes or outcomes relevant to treatment of a particular condition. In the context of surgical cancer treatments, the performance variations can be due to hospital and/or surgeon level differences, creating a hierarchical clustering. We consider how the observed variation in care received at patient level can be decomposed into that causally explained by the hospital performance, surgeon performance within hospital, patient case-mix, and unexplained (residual) variation. For this purpose, we derive a four-way variance decomposition, with particular attention to the causal interpretation of the components. For estimation, we use inputs from a mixed-effect model with nested random hospital/surgeon-specific effects, and a multinomial logistic model for the hospital/surgeon-specific patient populations. We investigate the performance of our methods in a simulation study