Manejo do solo, palha residual e produtividade de arroz irrigado por inundação

The objective of this study was evaluate the effect of management systems and straw in flooded irrigated rice yield. The experimental design was a completely randomized with three experiments and, 10 replications in experiment 1 and 2 and, 6 replications in experiment 3. The experiments were: E1 – no-till system (E1PD) and conventional system with two harrowings at 0.0–0.07 m layer and leveling with remaplam (E1PC), after three years of sowing rice, after fallow of rice tillage, with sowing of rye grass in winter and grazing; E2 – no-till system (E2PD) and conventional system after native field (E2PC); E3 – no-till without straw on soil surface (E30P), current straw on soil surface of 3,726 kg ha-1 (E31P), two times current straw of 7,452 kg ha-1 (E32P) and three times current straw of 11,178 kg ha-1 (E33P). In soil, were evaluated the average geometric diameter of aggregates, soil bulk density, soil porosity, macro and microporosity, in 0.0-0.05 and 0.05-0.10 m layer. In harvest were evaluated the panicles number in 0,25 m2 area, number of filled, empty an total grains in 10 panicles, mass of one thousand seeds and rice grains yield in 2 m2. The conventional system presented greater macroporosity and total porosity, compared with no-till system, however, does not result in differences in production components and rice grains yield. Soil tillage in no-till, with rice straw on soil surface up to 11,178 kg ha-1, before sowing, not reduces flooded irrigated rice grains yield.