Calcium problems in Latin America

Abstract
A general discription of soil characteristics of Latin America is given with emphasis being put on the oxisols of the subtropical and tropical regions; the relationships among pH and degree of Al and Ca saturation is presented; special mention of the cerrado soils of Brazil is made. Calcium requirements of main crops are tabulated. A review is made of known cases of Ca deficiency under field or green house conditions with an attempt to differentiate between Ca responses and other effects of liming and/or fertilization on observed crop responses. Losses by leaching, erosion, and crop removal of Ca are estimated; a rough balance sheet of inputs and outputs is presented. Trends in fertilizer use and technology in Latin America are discussed with regard to the Ca economy of the region; the role of liming is assessed.