Produção do capim marandu em função de fontes de nitrogênio

Abstract

The objective was to evaluate the effect of the application of three nitrogen sources on the yield of Urochloa brizantha cv. Marandu in successive cuts, as maintenance fertilization. The experiment was carried out at Fazenda Frutins located in the municipality of Araguaína, in an already established pasture, during the period from March to September 2021. A randomized block design was used, with four treatments and four replications. The treatments consisted of three nitrogen sources (Ammonium Sulfate, Urea and Fortgreen) and a control (control). The total dose of nitrogen was 150 kg/ha of N, with Fortgreen applied in a single dose at the beginning of the experiment as a source of slow release of nitrogen, and the other sources were split after the cuts were carried out at a dose of 50 kg/ ha of N. The variables evaluated were: production of total dry mass of forage (kg/ha), production of dry mass of leaf blade (kg/ha), production of dry mass of stem (kg/ha), percentage of blade leaf (%) and forage canopy height (cm). Nitrogen sources provided a significant increase in forage dry mass production in successive cuts. The efficiency of Fortgreen as a source of slow release of nitrogen occurs for a period of two successive cycles of forage plant regrowth, there is no significant difference for the variables dry mass of forage, dry mass of stem and population density of tillers between the sources of nitrogen in the first two cuts, in the third cut that represents the transition period, the urea and ammonium sulfate sources provided higher values in all the variables studied, in relation to the fortgreen and the control treatment.