Atributos de solo e planta em função da aplicação cumulativa de cinza de casca de arroz no cultivo do arroz irrigado

Abstract

The rice husks have been used for grain processing agribusinesses as biomass to generate energy and drying grain. This process creates a byproduct called rice husk ash (RHA), whose fate has been the disposal on the environment and deposition in pastures or crops without any assessment of their impact on the environment. The objective of the research was to assess the cumulative effects of the incorporation of this ash, over three growing seasons in attributes of a Typic and productive and nutritional parameters of the flooded rice culture. The experiment was conducted in an experimental area belonging to Cooperativa Agroindustrial Alegrete Ltda. city of Alegrete, RS. It was used rice variety, BR-IRGA 409, in an experiment with a randomized block design, consisting of four treatments with cumulative incorporation of ash in the soil at the dosages of 4, 8, 16 and 32 t RHA ha-1 and control treatment. We evaluated the physical, chemical and microbiological parameters of soil and morfoprodutivos parameters during culture of the three production cycles (2012/2013, 2013/2014 and 2014/2015). Preliminary results indicate that the addition of the ash did not affect soil physical state assessed by the mean weight diameter of water stable aggregates, nor the proportion of macro and microaggregates. The treatments with 32 t ha- 1 RHA showed average levels of potassium in the soil higher than the other treatments. There were also observed negative impacts to soil microbiota, with even increase in microbial biomass carbon and its nutritional quality, indicating that it may be benefiting from the carbon contained in the ash. The results showed that the addition of ash did not significantly affect productivity and macro and micronutrients of plant tissues analyzed, with the exception of potassium in 32 t dosage RHA ha-1 year.