Introduction and verification of methods used for determination of mineral nitrogen in soil
2005
Kmecl, V. (Agricultural Inst. of Slovenia, Ljubljana (Slovenia)) | Zupancic-Kralj, L. (Ljubljana Univ. (Slovenia). Chemistry and Chemical Technology Fac.)
Determination of inorganic or mineral nitrogen content (Nmin), extracted from the soil with the 0.01 M CaCl2 solution, enables improvements of fertilization recommendations with nitrogen. For this purpose we have developed analytical methods for determination of ammonium, nitrate and nitrite ions in the soil. The methods were verified; trueness, precision, limit of detection (LOD) and limit of quantification (LOQ) were determined. The trueness of measurements was proofed by successful participation of our laboratory in the international interlaboratory exchange programme WEPAL (Wageningen Evaluating Programme for Analytical Laboratories, Netherland). The precision of measurements (repeatability and reproducibility) was expresed as relative standard deviation (RSD) which was under 2% in all cases. The values of LOD and LOQ were 0,05 mg/kg and 0,18 mg/kg respectively for nitrate nitrogen and 0,09 mg/kg or 0,31 mg/kg for ammonium nitrogen.
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