Robson Giacomeli

Propriedades físicas do solo e produtividade de arroz irrigado em diferentes sistemas de manejo

The State of Rio Grande do Sul is the greatest producer of flooded rice of Brazil, concentrated mostly along the western border. The objective was to evaluate soil physical properties and flooded rice yield in no-till and conventional tillage systems and rice straw levels in no-till system. The study consisted of four experiments (E), laid out in experimental design was completely randomized blocks, with four experiments (E) and 10 repetitions in experiment 1, 2 and 3 and 6 in experiment 4. The management system in E1 consisted of no-till (E1PD) and conventional tillage with two harrowings (layer 0.0-0.07) m after levelling (E1C), on soil where rice had been gown for one year followed by seven years of fallow, with rye grass sowing in the winter and grazing all year long; E2: no-till (E2PD) and conventional tillage (E2C), after native grassland; E3: no-till (E3PD) and conventional tillage (E3C) after no-tillage rice for two years on a native grassland area; E4: four rice straw levels had been used before rice sowing. The yield of flooded rice did not differ between no-till and conventional tillage. The residual dry mass of rice before sowing did not influence the flooded rice yield.

Escarificação do solo e sulcadores em semeadora para cultivo de milho em Planossolos

The objective this work was to evaluate deep tillage and different furrow opener seeders for growing corn in Planosols. Two experiments were carried out in the field, in two different locations: Santa Maria and Formigueiro, in the state of Rio Grande do Sul, Brazil. A randomized complete block experimental design was used, with four replicates, and treatments of deep tillage (DP) and no‑till, using different seed‑furrow openers: shank (SH); shank plus furrow accommodation mechanism (SHA); double disk (DD); and notched disk (ND). In Santa Maria, the raised-bed treatment using shank was added (RBS). The following parameters were evaluated: soil bulk density, porosity, and macroporosity; soil penetration resistance (RP); root system distribution; and grain yield. In Formigueiro, the DP, SH, and SHA treatments resulted in lower bulk density and higher soil macroporosity in the 0.05–0.10 and 0,10–0.20-m soil depths. The RP was lower in the DP treatment and in the furrow of the SH treatment until 0.15 m, where roots developed better. Corn grain yield in Planosols is greater when sowing is carried out using raised bed, deep tillage, or no‑till using shank in the seeder.