Grasslands of the World.pdf - Disasters and Conflicts - UNEP

V. ALEJANDRO DEREGIBUS AND MARTIN F. GARBULSKY
Other grasslands 433
Plate 11.11
Cows on grassland in the Pampas.
and sunflower as the main crops . After several years of crops, improved
pastures are sown in a four- to five-year rotation to maintain soil fertility.
When pastures are grown, the seasonal forage production alternates between
alfalfa, which grows in the warm season, and grasses and clovers that grow
in cooler weather. Oats are also a popular forage crop.
Sown pastures (Plate 11.11) are grazed by steers, yearlings or dairy cattle .
Forage legumes like Medicago sativa , Trifolium repens , T. pratense and Lotus
corniculatus and grasses such as Festuca arundinacea , Phalaris arundinacea ,
Bromus catharticus , Dactylis glomerata , Lolium perenne and L. multiflorum
or Agropyron elongatum are grown. When pastures are adequately fertilized
(principally with P), primary production may achieve 12 to 15 t DM/ha/yr or
more. This primary production allows 500 kg/ha of beef annually or 200 kg/ha
of milk fat.
Nowadays, cash crop prices and the higher profits of agriculture have led
to a decrease in cattle numbers in this area. To this can be added genetically
modified soybeans and modern no-tillage practices, that reduce the need for
pasture -cash crop rotations to maintain soil fertility.
Monte shrubland
The Monte phytogeographic province is a strip that surrounds the Calden and
Semi-arid Chaco regions up to the Atlantic coast of Chubut province, covering
50 million hectares. Its physiognomy is dominated by a tall shrub stratum with
Prosopis alpataco , P. flexuosa (Fabaceae), Larrea divaricata , L. cuneifolia and
L. nitida (Zygophyllaceae). Fodder shrubs include the genus Atriplex . Towards