Comparação de cinco sistemas de tratamentos no desempenho vegetativo e incidência de inços na cultura do centeio (secale cereale)

Abstract

In the current agricultural scenario, there are different production systems that directly influence soil characteristics, cultivar performance and incidence of weeds. Due to the environmental impacts caused by the use of agrochemicals, the search for alternative production technologies that do not affect the ecosystem is of paramount importance. Therefore, this study aimed to compare five different treatment systems based on evaluations of rye performance and weeds incidence on the area, as well as to observe the allelopathic influence of rye and forage sorghum. The experiment was carried out in the experimental area of the Federal University of Fronteira Sul (UFFS), located in the municipality of Laranjeiras do Sul-PR. The experimental design was randomized with 6 blocks of replications and 5 treatment systems, totaling 30 experimental units. Biodynamic, organic, conventional, control and additional “testimony” or nil control (previously untilled) treatment systems were used, following a crop rotation with sudangrass (Sorghum sudanense) and rye (Secale cereale). Two rye and weed samples for destructive growth analyses were carried out, the first samplings took place in the rye tillering phase and the second in the rye flowering phase. The variables analysed were fresh weight, dry weight and dry matter percentage. The results obtained were submitted to analysis of variance, Duncan's test and Pearson's correlation test. The first sampling did not show any significant differences. In the second sampling the conventional and biodynamic treatments showed significantly better performance than the others for both rye fresh and dry weights, while not differing between them. The control and biodynamic treatments showed significantly better results than the others in terms of rye dry matter percentage, not differing between them. No significant differences were found in the second weed sampling for any of the evaluated variables. The significant inversely proportional correlation between rye and weed dry weights evidences this crop’s desirable allelopathic effect. The biodynamic treatment showed significantly better results in terms of rye development. The conventional treatment presented the worst results in the incidence of weeds. I was not possible to detect significant differences due to sudangrass cover cropping between the tilled Control plots and the no-till “absolute Testimony” or nill-control plots in terms of allelopathic or competitive weed suppression.