Organic materials, mineral fertilizer and liming effects on yield of flooded rice

Abstract

The management system adopted in flooded rice fields in the North region of the State of Rio de Janeiro, Brazil, has caused a progressive reduction in the organic layer of gley soils. The pre- sent work investigates 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 São João River, RJ. The effects of addition of cow manure, rice straw, NPK and lime, singly or in combination, on rice yield, were investigated. Results indicated highly significant differences between soil horizons, showing better responses under superficial horizon (A) as compared to the subsuperficial horizon (Cg). Mineral fertilization increased dry matter production of rice tops and grains on both soil horizons, while cattle manure increased these parametres only on the superficial one. Rice straw application also raised dry matter production of rice tops, but decreased grain yeld on superficial horizon, while on subsuperficial one it reduced dry matter production of the tops and did not induce grain formation.