Léon Parent , Alain Viau, François Anctil

Nitrogen and phosphorus fractions as indicators of organic soil quality

Parent L., Viau A., Anctil F. Nitrogen and phosphorus fractions as indicators of organic soil quality.

Tiivistelmä

The state of the environment is currently evaluated by indicators of air and water quality. Sustainable land use requires an assessement of soil quality. Soil quality indicators should relate soil processes to management practices. The supply of N and P contributes to crop productivity, but can degrade air and water quality. In this paper, we will present organic soil N and P attributes that can make up soil functions. Nitrate was the only detected mineral N form in organic soil materials with pH (0.01M CaCl2 ) exceeding 4.4. Lowest C/N ratio of cultivated sapric soil materials was 15, showing high nitrate-supplying capability. Total P concentration was between 760 and 1960 mg P kg–1 both in organic and inorganic forms when pH (0.01M CaCl2 ) increased above 4.7, the recommended minimum pH value for cultivated organic soils. Lowest C/P ratio as organic forms was 340 for sapric materials containing less than 22% ash, indicating organic P sequestration capability (C/P > 300). However, the low N/P ratio of 23 (i.e. 340/15) also indicated capability for organic P availability to plants. Since N and P are related to organic matter transformations, the C/N/P/S multiratios of selected organic matter fractions, analyzed as compositional data (computation procedure presented), need further consideration as integrated N and P attributes in combination with pH and climatic indexes, in order to adapt N and P diagnosis and recommendation models to specific organic soil agroecological zones.

Avainsanat
pH; Soil quality indicators; nitrification; phosphorus fractionation; C/N/P/ S ratio

Vastaanotettu 31.10.2017 Julkaistu 1.1.2000

Katselukerrat 1404

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