Zapata, F. (ed.)Roy, R. (ed.)2016-04-192016-04-192004FAO Fertilizer and Plant Nutrition Bulletin 1392-5-105030-90532-0488http://hdl.handle.net/10919/65499Metadata only recordThis publication deals with the direct application of phosphate rock (PR) sources to agriculture. Phosphorus (P) is an essential plant nutrient and its deficiency restricts crop yields severely. Tropical and subtropical soils are predominantly acidic, and often extremely P deficient with high P-sorption (fixation) capacities. Therefore, substantial P inputs are required for optimum plant growth and adequate food and fibre production.text/plainen-USAll rights reserved. Copyright FAO 2004Soil nutrientsSoil degradationSoil managementSubtropicsTropical zonesSoil fertilitySustainable agricultureRock phosphateP deficient soilsInorganic fertilizerAcid soilsEcosystem Farm/Enterprise ScaleAbstract