A calibration to estimate primary production of subhumid rangelands from remotely sensed data.

PARUELO J. M.; OESTERHELD, M; DI BELLA, C.M.; ARZADUM, M.; LAFONTAINE, J; CAHUEPE, M

APPLIED VEGETATION SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2000 vol. 3 p. 189 - 195

1402-2001

Above-ground Net Primary Production (ANPP) isthe main determinant of forage availability and hence ofstocking density. A tool to track the seasonal and interannualchanges in ANPP at the paddock level will be very importantfor livestock management. We studied the relationship betweenfield ANPP data and the Normalized Difference VegetationIndex (NDVI) for rangelands of the Flooding Pampa ofArgentina using spectral data provided by sensors on board oftwo satellites: NOAA/AVHRR and Landsat TM. The relationshipbetween NDVI and ANPP was linear both for dataderived from NOAA/AVHRR and Landsat TM. Changes inANPP accounted for a large proportion of the temporal andspatial variation of NDVI: 71% of NOAA/AVHRR data and74% of Landsat TM data. By inverting these models, ANPPmay be inferred from NDVI data at a seasonal and paddockscale. NOAA/AVHRR data captured better the seasonal variationin ANPP and were less sensitive to local variations thanLandsat TM data. In contrast, Landsat TM data were moresensitive to inter-site differences in primary production, exceptfor the winter months. Thus, combining information fromthese two sources offers a good alternative for monitoringrangeland production at high temporal and spatial resolution.