INVESTIGADORES
GUNDEL Pedro Emilio
artículos
Título:
Forage production in natural and afforested grasslands of the Pampas: Ecological complementarity and management opportunities.
Autor/es:
NORDENSTAHL, M.; GUNDEL, P.E.; CLAVIJO, M.P. & E.G. JOBBÁGY.
Revista:
AGROFORESTRY SYSTEMS
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2011 vol. 83 p. 201 - 211
ISSN:
0167-4366
Resumen:
In managed
rangelands periods of low primary productivity determine troughs of forage availability,
constraining animal production yearround. Although alternative tools to
increase forage availability during critical seasons exists, most of them are
unaffordable and short-lived in marginal areas. We explore the potential
benefits of deciduous tree plantations favoring winter forage productivity by
comparing aboveground net primary productivity (ANPP) patterns in herbaceous
understory to tree plantations and natural grasslands in the Pampas (Argentina).
These temperate subhumid grasslands are characterized by the coexistence of
winter species, mainly C3 grasses of the native genera Stipa, Piptochaetium,
and Bromus and the exotic genera Lolium and Festuca) and summer species (mainly
C4 grasses of the native genera Paspalum, Bothriochloa, and Stenotaphrum) that
replace each other throughout the seasons, with domination of the latter. We
hypothesize that the natural decoupling of growing seasons between winter deciduous
trees and winter grasses could provide the basis for the sustainable promotion
of winter forage. We measured ANPP on two 23-year-old Populus deltoides
plantations and their understory and compared them with adjacent open
grasslands. Afforested stands had 5575% higher annual ANPP than their
non-afforested neighbors, with trees contributing *70% to total ANPP.
Herbaceous canopies beneath plantations achieved about half of the ANPP
observed in nonafforested situations with a contrasting seasonal distribution
associated with shifts from C4 to C3 grass dominance. Winter ANPP, the most
critical source of forage in these grazing systems, was similar or higher in
the herbaceous understory of tree plantations to that on their non-afforested
counterparts, suggesting that mixed systems involving deciduous trees and
understory pastures are a valid and viable option in the region.