RESIDUAL EFFECT OF Calci ?? RIVER ON THE PRODUCTION OF RICE CROP IN SOILS OF RIVER VI ?? RZEA pari ??

Abstract

Lowland soils of the state of Pará, generally have good production capacity. However, we do not know the effect of liming on rice in rotational cultivation. In this sense, there was an experiment aiming to evaluate the residual effect of liming on the production of rice after cowpea cultivation. The work was conducted in a greenhouse at the Institute of Agricultural Sciences (ICA) of the Federal Rural University of Amazonia (UFRA) in Bethlehem, PA. Gleissolos samples collected in three floodplains of the Pará River, in the 0 to 20 cm depth were used. The sites were: lowland UFRA, Bethlehem; floodplain near the Loop Road / Moju and floodplain Vigia. The experimental design was completely randomized with three soil samples and five doses of limestone, on a 3x5 factorial design, with four replications. The soil samples were subjected to doses of limestone in amounts equivalent to 0; 0.4; 0.8; 1.2 and 1.6 times
the need for liming (NC) soil, determined based on the potential acidity to pH 7.0 (H + Al) and NC (t ha-1) = H + Al (cmol c dm-3). Seeds of rice cultivar BRS Jaburu were used. In smaller doses the residual effect of liming promoted increased dry mass of shoots of cultivated soils of UFRA Handle Road and plants. The maximum tillering was estimated at doses of 0.83 and 0.85 times the need for liming, soil of UFRA and Strap Road respectively. The residual effect of liming caused reduction in grain production of rice grown in soils of floodplains. Soil Strap Road had the highest potential for rice production, regardless of setting.