THE NATURE OF THE NITROGEN COMPOUNDS IN SOIL ORGANIC MATTER EXTRACTED BY ANHYDROUS FORMIC ACID |
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| Authors: | M J JONES J W PARSONS |
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| Institution: | Department of Soil Science, University of Aberdeen |
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| Abstract: | Organic matter extracted with 9 : 1 formic acid : acetylacetone from twenty-five soils of widely varying organic content and precipitated with excess di-isopropyl ether was hydrolysed with 6N HC1. The relationships between the proportions of acid-soluble N, acid-insoluble N, amino-N, and ammonium-N thus produced, and the properties of the original soil were examined. The distribution of N in acid hydrolysates was similar to that reported in the literature for material isolated by neutral and alkaline extractants. The relatively large proportion of N released as ammonium-N from organic matter obtained from soils of high pH and low C : N ratio may derive from organically fixed ammonia. The low levels of amino-N in organic matter extracted by formic acid from soils of high clay content imply the existence of clay-amino complexes that resist extraction although formation of such complexes during extraction cannot be ruled out. |
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