01724naa a2200373 a 450000100080000000500110000800800410001910000160006024500910007626000090016752008240017665000110100065000120101165000090102365000130103265000090104565000130105465000130106765000090108065300130108965300130110265300110111565300110112665300090113765300110114665300150115765300160117265300210118870000180120970000230122770000170125070000180126777300650128517840392017-04-04       1991    bl ---       0--  u    #d1 aEDEN, M. J.  aEffect of forest clearance and burning on soil properties in northern Roraima, Brazil.  c1991  aClearance of evergreen seasonal forest for cattle pasture is examined in an area of northern Roraima. Coloniao (Panicum maximum Jacq.) and kikuyu grass (Brachiaria humidicola (Rendle) Scweik) are commonly established on cleared forest land. Current rates of clearance are rather low as also is grazing intensity (1-2 animals ha-1), but soil physical and chemical changes are occurring. Thus, topsoil bulk density increase over time in new pasture. Also, available nutrients decline from the enhaced levels that prevail after initial clearance and burning. In particular, available P is low in the acid soils and, as elsewhere in Amonia, probably limiting to pasture growth. For local ranchers, the best source of nutrients is the standing forest, so every incentive exist to continue forest destruction for new pasture.  aBrazil  aburning  asoil  aFloresta  aFogo  aPastagem  aQueimada  aSolo  aClareira  aClearing  aEfeito  aEffect  aFire  aForest  aProperties  aPropriedade  aRoraima (Brazil)1 aFURLEY, P. A.1 aMcGREGOR, D. F. M.1 aMILLIKEN, W.1 aRATTER, J. A.  tForest Ecology and Managementgv.38, n.3/4, p.283-290, 1991.