In this paper are reported the results of experiments conducted during several years at three different sites of the State of São Paulo: Campinas, on terra roxa misturada soil; Ribeirão Prêto, on terra roxa legítima soil, and Engenheiro Hermilo, on glacial soil. In the Campinas experiment, beside other treatments, manure at the rate of 12.8 metric tons per hectare was compared with a mixture containing 30-90-70 kilograms per hectare of N, P2O5 and K2O respectively as sulfate of ammonia, bone meal (occasionally, superphosphate), and potash chloride, (and also with plots which received half the doses of minerals in addition to half the quantity of manure. The materials used and the rates of application per hectare in Ribeirão Prêto and Engenheiro Hermilo were: 10 metric tons of manure; 80 kilograms of P2O5 in the form of bone meal, and 50 kilograms of K2O as coffee bean ash. The asli supplied also 20 kilograms of P2O5. Each of these materials was used alone or in the possible combinations. At the three locations the manure and minerals were applied annually, before every corn crop. The results obtained in the Campinas experiment with each of the fertilizer treatments were excellent. With small differences, their effect increased in the order: minerals alone, manure alone, 1/2 manure + 1/2 minerals. At Ribeirão Prêto corn gave no response to phosphorus, whereas either manure or coffee bean ash increased considerably the yield. The combination manure-ash was not better than manure alone, showing that the potash content of the later was sufficient for the maximum yield under the conditions of the experiment. Here, manure acted principally as a potash fertilizer. At Engenheiro Hermilo potash did not affect the yield, but bone meal, as well as manure, brought out substantial increases. T increase due to the combination manure-bone meal corresponded to the addition of the increases caused by each material. Under the conditions of this experiment, on soil fairly supplied with organic matter and potash manure acted practically as a mere phosphorus fertilizer.