Inoculação de Azospirillum brasilense em sementes de capim Sudão para corte e pastejo

Abstract

The objective of this work was to evaluate the response of Sudan grass (Sorghum sudanense) to the use of Azospirillum brasilense inoculant in the seeds. The experiment was conducted in the municipality of São Jorge D ́Oeste, PR, using different doses of inoculant (0,50, 100 and 200 ml / ha) containing Azospirillum brasilense strain Ab-V5 and Ab-V6. Phosphorus and potassium based fertilization and nitrogen fertilization with 50 kg / ha cover were performed in the first and second cut / grazing totaling 100 kg / ha. Seeding density was 25 kg / ha of pure and viable seeds, being carried out by means of seeding at haul. A randomized block design with 4 treatments and 4 replications per treatment was used, totaling 16 experimental plots with 6 m2. When the plants reached 50 cm in height, 3 squares of 0.25 m² each (50x50 cm) were randomly launched, and where they fell, the number of plants and tillers were counted and subsequently cut at 20 cm from the ground. to evaluate green and dry mass yield, leaf / stem ratio, inflorescence, senescent material and weeds. The results were subjected to analysis of variance and the cutoff averages were compared by Tukey's 5% significance test and the inoculant dose averages were tested by the 5% significance regression test. Inoculation with Azospirillum brasilense bacteria did not affect yield, accumulation rate, leaf and stem ratio, leaf / stem ratio, inflorescence ratio, senescent leaves, weeds, plants per square meter, tillers per square meter and tillers/plants ratio. Variations in the variables were observed only throughout the growing season. It was concluded that the Azospirillum brasilense inoculant does not alter the mass production and the components of the Sudan grass production, besides the Sudan grass presenting high dry matter production and maintaining the leaf /stem ratio throughout its vegetative cycle.