A simplified method for the extraction and analysis of available nitrogen, phosphorus, and potassium in soils

Abstract

Sodium bicarbonate (NaHCO₃) and calcium chloride (CaCl₂) are proposed as simultaneous extractants of available nitrate‐nitrogen (NO₃ ^‐‐N), phosphorus (P), potassium (K) in soils. Flow Injection methods were used for the determination of NO₃ ^‐ and P, and atomic emission spectroscopy for K. Parameters, such as reproducibility, precision, and recovery of the different extraction processes were studied. The usefulness of the proposed extractants was tested by applying them to different samples from the Spanish Soil Collection. The results obtained were compared with those provided after using the extractants recommended by the official methods. Sodium bicarbonate turned out to be suitable for the simultaneous extraction of NO₃ ^‐, P, and K in alkaline soils, whereas CaCl₂ was only advisable for NO₃ ^‐.

Notes

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