Crescimento e produtividade de arroz irrigado por inundação sem e com calagem após manejos da palha do ano anterior

Abstract

The rice crop has great economic importance in world, being the rice at the basics food to people. About 75% of rice is cultivated in flooded irrigation system that implying higher grain yield. However, crops irrigation by flooding, when no-till is adopted, limitation may occurs in growth andyield of the culturein reason of organic acids. In addition, soil acidity can be a factor limiting rice yield, when seeding rice in dry soil. This work aimed evaluating the influence of doses flooded rice straw remaining in and with and without liming on rice growth and yield in subsequent year. Two experiments, with and without soil liming were installed, in completely randomized squeme, factorial 5 x 4 x 2, with 4 replicates. Five doses of straw (0, 5, 10 , 20 and 40 t ha-¹), four times of application (3, 2 , 1 and 0 months before sowing ) and two management systems (surface and incorporated straw). Was used flooded irrigated rice Puita Inta Cl and were determined at harvest panicle number, weight of shoot dry matter and grain yield per pot. When there was only high dose of remaining rice straw (40 t ha-¹), was greater grain yield when the straw was added three months before sowing. Soil liming not influenced flooded rice growth an yield. The productivity of rice grains increased linearly up to a dose of 40 t ha-¹ of straw on the surface and incorporated without liming, and showed quadratic effect when limestone was applied in soil with 1.6% organic matter.