Articles
DETERMINATION OF MICRO NUTRIENTS IN SUBSTRATES BY WATER EXTRACTION AND INTERPRETATION OF THE ANALYTICAL DATA
Article number
819_8
Pages
87 – 98
Language
English
Abstract
In 1974 the 1:1½ volume extract was published (Sonneveld et al., 1974) as a water extraction method for the determination of available nutrient elements and of the salinity status of peaty substrates.
The analytical data of this extract were related to the data of the substrate solution extracted from the substrates with a moisture condition of -3.2 kPa.
The method has been widely used and offers a suitable basis for fertilization of peaty substrates.
In the years after publication, the composition and application of substrates has undergone much change and the irrigation methods have also been thoroughly adjusted.
The latter was responsible for increased water contents in the substrate during crop growth.
Therefore, another study was carried out in which the analytical data of the 1:1½ volume extract was compared with the analytical data of the substrate solution, where the substrate solution was defined at the moisture condition of -1.0 kPa.
There was a good agreement between the results of both studies.
However, the regression coefficients for the relationships between the data of the extracts differ, as expected, because of the higher moisture contents on which the substrate solution was defined.
In addition to the data of major elements published, in the second study, micro nutrients were determined in the extracts, but not published.
Therefore in this paper the relationships between the concentrations of micro nutrient as determined in the 1:1½ extract and in the substrate solution are given.
The relationships presented support the interpretation of analytical data of micro nutrients by means of water extraction.
The analytical data of this extract were related to the data of the substrate solution extracted from the substrates with a moisture condition of -3.2 kPa.
The method has been widely used and offers a suitable basis for fertilization of peaty substrates.
In the years after publication, the composition and application of substrates has undergone much change and the irrigation methods have also been thoroughly adjusted.
The latter was responsible for increased water contents in the substrate during crop growth.
Therefore, another study was carried out in which the analytical data of the 1:1½ volume extract was compared with the analytical data of the substrate solution, where the substrate solution was defined at the moisture condition of -1.0 kPa.
There was a good agreement between the results of both studies.
However, the regression coefficients for the relationships between the data of the extracts differ, as expected, because of the higher moisture contents on which the substrate solution was defined.
In addition to the data of major elements published, in the second study, micro nutrients were determined in the extracts, but not published.
Therefore in this paper the relationships between the concentrations of micro nutrient as determined in the 1:1½ extract and in the substrate solution are given.
The relationships presented support the interpretation of analytical data of micro nutrients by means of water extraction.
Publication
Authors
C. Sonneveld, W. Voogt
Keywords
analytical error, complex formation, dilution effects, substrate solution
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