02163naa a2200205 a 450000100080000000500110000800800410001910000240006024500680008426000090015252016140016165000220177565000130179765300200181065300240183065300210185465300160187565300200189177300460191117864652013-08-21       1976    bl ---       0--  u    #d1 aSANTHIRASEGARAM, K.  aRecent advances in pasture development in the Peruvian tropics.  c1976  aA pasture improvement programme currently in progress at Pucallpa in the Peruvian tropics has been described. Traditional the rain forest is burned and Hyperrhenia rufa is sown on the ultisols which are acidic, high in aluminium and deficient in nitrogen and phosphorus. Such grass pastures stabilize with the invasion of less productive species at a  carrying capacity of less that 0.5 cows per hectare, accompanied by long calving intervals and low growth rates. Pasture productivity was improved by the inclusion of legumes adapted to the high acidity and to the high aluminium content of the soils. Dry matter yields and protein content increased. Phosphorus deficiency was corrected by the application of 100 kg/ha of simple superphosphate every six months. The resultant grass-legume pasture doubled bothstocking rate and growth rate, and gave more than a fourfold increase in livestock gain per hectare compared with the traditional pastures. Liveweight gains averaged 638 kg per hectare per year, and compared favourably with gains from similar  pastures in other parts of the tropics. Preliminary economic estimates, based on 80 percent efficiency in farm management, suggested an 18 percent return on investment from the grass-legume pastures compared with negative returns from the traditional pastures. Further improvements in productivity and profitability are possible through the selection of better grasses and legumes, greater attention to the efficiency of nitrogen fixation by the legumes, and the development of improved grazing and stock management systems with in the whole farm economy.  aFloresta Tropical  aPastagem  aDesenvolvimento  aPasture development  aPeruvian tropics  aRain forest  aTropico peruano  tWorld Animal Reviewgv.17, p.34-39, 1976.