# The Nutrient Action Programme Regulations (Northern Ireland) 2019, Paragraph 9


Soil analysis for Olsen extractable phosphorus: The measure of phosphorus which is available for crop growth shall be given by the amount extracted from soil at 20 ± 1 °C with a sodium bicarbonate solution of pH 8.5. Details of the analytical procedure are given in The Analysis of Agricultural Materials, Third Edition, pp183-185, Ministry of Agriculture, Fisheries and Food reference Book 427, 1986. Olsen extractable phosphorus results are expressed as milligrammes phosphorus per litre (mg P/l) of soil, rounded to the nearest whole number.

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Source: https://www.legislation.gov.uk/nisr/2019/81/schedule/5/paragraph/9 (the official version)
Page: https://openlegislation.uk/nutrient-action-programme-regulations-northern-ireland-2019/schedule-5/paragraph-9
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.