IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Silvopastoral systems: Estimation of understory winter grass productivity by remote sensing.
Autor/es:
69. GRANIERI L., CORNAGLIA P., GOLLUSCIO R.A. Y OESTERHELD M
Lugar:
Hohhot, China
Reunión:
Congreso; XXI International Grassland Congress- VIII International Rangeland Congress.; 2008
Institución organizadora:
Internacional Rangeland Society
Resumen:
Introduction
Silvopastoral systems combine
forest production with pastoral use of the understory. Most rangelands of the Flooding Pampas are dominated by C4
species (Perelman et al. 2001), which determines a low quantity and quality of
forage supply during winter, a critical period for livestock production
(Paruelo et al. 2001). Clavijo et al. (2005) found a larger proportion of C3
species, with significant winter production, in the herbaceous layers of sites
afforested with poplars than in the open grassland. This indicate that planting
deciduous trees may constitute an alternative to revert the dominance of warm
season grasses and therefore increase
winter productivity. Remote sensing allows for the estimation of biomass, plant
cover and productivity of grasslands (Oesterheld et al. 1998; Purevdorj at al.
1998; Paruelo et al. 2001). The objective of this work was to identify and
interpret by remote sensing changes in the herbaceous winter productivity
associated to the establishment of deciduous trees.
Materials
and Methods
We obtained NDVI (as a
surrogate of primary production) from satellite images, and then we confronted
it with the field information obtained on the same grasslands. NDVI was
compared in 9 Poplar afforestations (F) with their respective paired plots with
original grassland (G). The plots were
located at Castelli, province of Buenos Aires, Argentina (36º05`S;
57º48`W). Multispectral images of Landsat 5 TM satellite (Path: 224-Row: 085),
of 30 meters of spatial resolution, during the winter period were used.
Satellite data were accompanied with basal cover and other parameters
previously obtained in the field (Clavijo et al. 2005). Data were analyzed
using ANOVA model with repeated measures.
Results
and Discussion
The NDVI from F and G stands
were not significantly different (P=0.97). However, F stands had larger NDVI
per unit of basal cover of C3 than G stands (P<0.07, Figure 1).
These results would explain the increase of relative abundance of C3
grasses below trees due to microenvironmental conditions that enhance its
growth (Clavijo et al. 2005).