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Brochure, flyer, fact-sheetStandard operating procedure for saturated soil paste extract 2021
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Salt-affected soils severely limit crop growth, reduce yield, and cause plant stress and soil structure degradation. Therefore, soil salinity/alkalinity interpretation is essential to develop and apply sustainable agricultural practice and suitable irrigation techniques in semiarid and arid environments. Salinity is a soil condition characterized by a high concentration of soluble salts, generally defined as one in which the electrical conductivity (EC) of saturate soil paste extract (ECe) in the root zone exceeds 4 dS m-1 at 25 oC (Richards, 1954). Sodic soils are those with a percentage of exchangeable sodium (ESP) greater than 15. Because of the considerable experimental errors involved in ESP determination, emphasis has been placed on using the sodium adsorption ratio (SAR) of the equilibrium soil solution instead of the ESP for classification purposes. The electrical conductivity of saturation soil extracts may vary, but usually remains below 4 dS m-1 at 25 °C. The pH of saturated soil paste in sodic soils is 8.2 or higher, and in extreme cases may exceed 10.5. However, many crops exhibit a yield reduction at a lower ECe because soil salinity/alkalinity affects a number of morphological, physiological and biochemical processes and water and nutrient or toxic elements uptake (FAO, 2018; Filipovic et al, 2018). The main aim of this SOP is to prepare a saturated soil paste to measure electrical conductivity (ECe) and soluble salts of a soil from a saturated paste extract. -
Brochure, flyer, fact-sheetStandard operating procedure for soil total nitrogen - Dumas dry combustion method 2021
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No results found.This Standard Operating Procedure (SOP) describes, in general terms, the quantification of TN content in soil samples by an elemental analyzer. The procedure measures both organic nitrogen and inorganic nitrogen together. A typical limit of detection is 0,1 g kg-1 N, and a typical limit of quantification is 0,3 g kg-1 N, however this varies depending on the manufacturer and detector settings. -
BookletStandard operating procedure for soil available phosphorus - Bray I and Bray II method 2021
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No results found.P-Bray 1 and P-Bray 2 methods are normally limited to acid soils with water pH values less than 6.8. The P-Bray 1 Method removes a fraction of the “adsorbed” phosphorus (Al-P, Fe-P, Mn-P and Ca-P but less efficient) while the P-Bray 2 Method is best suited to acid soils where rock phosphate has been the primary P fertilizer source and/or the major portion of P exists in the soil in various forms of calcium phosphate. Bray extractants should not be used on alkaline soils because the acid tends to be neutralized and/or excessive calcium phosphates may be extracted, giving a false high test for available P.
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