ORGANIC MATERIALS, MINERAL FERTILIZER AND LIMING EFFECTS ON YIELD OF FLOODED RICE

The management system adopted in flooded rice fields in the North regi on of the State of Rio de Janeiro, Brazil, has caused a progressive re duction in the organic layer of gley soils. The present work investiga tes the effects of fertilizer and lime on this system. The experiment was carried out in a greehouse, using soil samples of two horizons (A and Cg) of a low humic gley soil from the valley of the Sao Joao River , RJ. The effects of addition of cow manure, rice straw, NPK and lime, singly or in combination, on rice yield, were investigated. Results i ndicated highly significant differences between soil horizons, showing better responses under superficial horizon (A) as compared to the sub superficial horizon (Cg). Mineral fertilization increased dry matter p roduction of rice tops and grains on both soil horizons, while cattle manure increased these parametres only on the superficial one. Rice st raw application also raised dry matter production of rice tops, but de creased grain yeld on superficial horizon, while on subsuperficial one it reduced dry matter production of the tops and did not induce grain formation.