Titre :
|
The spatial variability of soil nitrates in arable and pasture landscapes : Implications for the development of geographical information system models of nitrate leaching
|
Auteurs :
|
S. Wade ;
I. Foster ;
S. Baban
|
Type de document :
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article/chapitre/communication
|
Année de publication :
|
1996
|
Format :
|
p. 95-101
|
Langues:
|
= Anglais
|
Catégories :
|
AGRONOMIE
|
Mots-clés:
|
SOL
;
NITRATE
;
VARIABILITE SPATIALE
;
MODELE
;
SYSTEME D'INFORMATION GEOGRAPHIQUE
;
PATURAGE
;
LESSIVAGE DU SOL
|
Résumé :
|
In response to the European Community Nitrate Directive (91/676) a catchment scale Geographical Information System (GIS) model of nitrate leaching has been developed to map nitrate vulnerability and predict average weekly fluxes of nitrate from agricultural land units to surface water. This paper presents a pilot study which investigated the spatial variability of soil nitrates in order to : (1) define an appropriate pixel size for modelling N leaching; (2) quantify the within-unit variability of soil nitrate concentrations for pasture and arable fields; and (3) assist in the design of an efficient sampling strategy for estimating mean nitrate concentrations. Soil samples, taken from two 800 m transects in early September 1994, were analysed for water soluble nitrate. The arable soils had a mean nitrate-nitrogen concentration of 0.693 mu g/g (S.E. 0.054 mu g/g) and the pasture soils had a higher mean nitrate-nitrogen concentration of 0.86 mu g/g (S.E. 0.085 mu g/g). Spatial variability was investigated using variograms.
|
Source :
|
Soil use and management, vol.12
|