M. van Meirvenne, P. de Groote, M. Kertész, T. Tóth and G. Hofman. 1996. 
Multivariate geostatical inventory of sodicity hazard in the Hungarian Puszta. 
in: Monitoring soils in the environment with remote sensing and GIS.
(Proceedings of the ISSS International Symposium Working Group RS and DM)
Ouagadougou, from 6 to 10 Feb. 1995. p293-305., ORSTOM éditions PARIS, 
pp.293-305. ISBN: 2-7099-1331-3.

The Hortobágy National Park, located in the east of Hungary, contains the last 
remnants of the typical Puszta ecosystem of the Great Hungarian Plain. It is 
characterized by a semi-natural vegetation growing on sodic soils. In order to 
preserve the original vegetation, the Park authorities wish to have better 
information about the salinization of the area and its relationship with 
vegetation. The basis of the soil and vegetation sampling was a panchromatic 
SPOT image. This image was subdivided by a quadtree subdivision resulting in 256 
quadtree leaves of which the centres have been visited in the field. Sampling 
included characterisation of the vegetation type and soil samples at 3 depths 
(0-10, 10-20 and 20-30 cm). The soil samples were analyzed for water saturation, 
pH, electric conductivity and sodium content measured on a saturated soil paste. 
Univariate, multivariate (principal component analysis) and regionalized 
multivariate (Factorial Kriging Analysis, FKA) techniques were used to analyse 
the relationship between soil variables, or scores on the first principal axis, 
and vegetation types. FKA was found to perform best and was used to map a 
"sodicity index".