Velayuthan M., Raghu Mohan N.G., Bourgeon Gérard, Harindranath C.S., Shivaprasad C.R., Salvador Sylvain.
1998. Estimations précises et cartographie du carbone organique des sols au niveau d'un district de l'Inde du Sud.
In : Congrès mondial des sciences du sol = World congress of soil science = Congreso mundial de la ciencia del suelo. AISS; AFES
Titre anglais : Detailed estimations and mapping of soil organic carbon at district level in South India
Résumé : Loss of soil organic matter (SOM), which usually follows deforestation with or without soil erosion, is both a source of atmospheric CO2, as well as a major cause in the reduction of the agronomic potential of lands. Accurate estimations of SOM content and variations are therefore of great interest and, in order to obtain them, it is imperative to take land use and land cover parameters into consideration in the estimation models as will be demonstrated here. 1 - For a large area (the study area, + or - 200 000 km2 ) regrouping the major soil-crop-climate complexes of South India : ¿ the existing information about soils and about the different soil forming factors (climate, geology, vegetation), land use and erosion was gathered; ¿ regression equations between the carbon content (C) and the different factors, codified as per the legends of maps, were calculated using the general linear procedure of Systat software. 2 - For a district (Shimoga district, + or - 10 500 km 2 ) within the study area : soil map and different maps representing the factors explaining the carbon content were digitized; a general overlay was done through GIS; regression equations established for the whole study area were used to calculate the carbon content for each polygon; ¿ small polygons were eliminated and the remaining polygons were grouped, taking into account the precision of the carbon estimation, to produce the carbon map. The results obtained show great variability in the organic carbon content due to the different land uses. Thus, in the upper horizon of clayey Ultisols from the western part of the district, the content drops from 6.1% under evergreen forest cover (climax formation) to 2.0% under perennial plantations, 1.5% under irrigated crops and only 1.1% under rainfed crops. Estimations can be made following the same procedure, but using the climax formations map instead of present land use map. This will visualise the changes resulting from cultivation.
Classification Agris : P01 - Conservation de la nature et ressources foncières
P35 - Fertilité du sol
Auteurs et affiliations
- Velayuthan M.
- Raghu Mohan N.G.
- Bourgeon Gérard, CIRAD-AMIS-AGRONOMIE (FRA)
- Harindranath C.S.
- Shivaprasad C.R.
- Salvador Sylvain
Source : Cirad - Agritrop (https://agritrop.cirad.fr/391456/)
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