Resposta do arroz à saturação por bases como critério de recomendação de calagem em Latossolo Amarelo no estado do Amazonas

Abstract

Tropical Latosols, such as those in the Amazon region, are mostly acidic, have low base saturation, and high levels of exchangeable aluminum. Under these conditions, the rational and economical use of soil acidity correctives becomes fundamental for an adequate liming recommendation in rice cultivation. The objectives of this work were: a) To evaluate the effect of increasing doses of base saturation (V%) on the dry matter yield of the aerial part of rice in a Yellow Latosol in the State of Amazonas; b) To determine the ideal percentage of base saturation (V%) on the dry matter yield of the aerial part of rice in a Yellow Latosol in the State of Amazonas. The experiment was conducted in a greenhouse at FCA/UFAM. Pots were used, and the rice crop (cultivar BRS Esmeralda) was used as a test plant. The soil in the experiment was a Yellow Latosol, characterized physically and chemically to determine particle size distribution, pH, Al, H + Al, Ca, Mg, P, K, and organic matter. The experimental design was completely randomized with six (6) treatments, corresponding to six percentages of Base Saturation: 0; 20; 40; 60; 80 and 100%, with four repetitions, totaling 24 experimental units (pots). The plant variable evaluated was the shoot dry matter yield (SDM). The data were subjected to analysis of variance (ANOVA) and the comparison of treatment means by Tukey's test (p< 0.05). The effect of the base saturation percentages (V%) was adjusted by means of polynomial regression, to obtain a linear response of SDM yield as a function of increasing base saturation percentages. This research work allowed us to draw the following conclusions: There was a decreasing effect of SDM yield as a function of increasing V% doses, indicating the good development of the rice crop in the treatment without lime; which suggests that rice (cultivar BRS Esmeralda) is tolerant to soil acidity. The ideal base saturation percentage (V%) on the dry matter yield of the aerial part of rice cultivation in a Yellow Latosol in the State of Amazonas would be around 40%.