Fracionamento do nitrogênio na biomassa aveia branca sob adubação nitrogenada

Abstract

The use of fertilization to increase forage mass production is an essential condition due to the fact that Brazilian soils present different mineral profiles, not always taking into account the nutritional requirements of crops. In this context, nitrogen fertilization is directly related to production, since the mineral is part of several structural molecules, as well as hormones, DNA and pigments among others. However, excessive fertilization with nitrogen can compromise not only the production but groundwater and make it impossible to use drinking water and promote animal mortality due to water contamination or high intake of this fertilizer present in the plant, when used In high amounts can become toxic to the plant and animals. For the feeding of ruminant animals, in the winter season, the species Avena spp. Is one of the most used in the southern region of Brazil, reducing the lack of food during the cold season, due to good adaptation to the cold climate and high nutritional quality. Fieldwork was carried out at the Universidade Tecnológica Federal do Paraná (UTFPR) - Campus Dois Vizinhos, Experimental Unit (UNEPE) Annual Cultures from April to September 2015. The experimental area consisted of twelve 24m² plots, divided into four blocks, with spacing between 0.5m plots, totaling an area of 312m², the experimental design was 2 x 4 x 2 factorial (two variables (ammonium and nitrate), 4 levels of N (0,60,120,240), in two post-planting systems (soybean and corn). The species Avena sativa L., URS Taura variety, submitted to the levels of 0, 60, 120 and 240 Kg N.ha- 1 , was evaluated at each cut after 21 days each, starting after standardization cut to 24 days after planting (25 cm tall plants). The white oat plants of the Taura variety were weighed and separated into stalk, leaf, dead material. After, they were dried in a forced air ventilation oven and ground separately. The samples were analyzed for ammonium and nitrate contents in the Laboratory of determination of vegetal material of USP. After all the analyzes and the results submitted to the statistical analyzes, a higher concentration of ammonia present in the stem of the white oats was obtained, due to the fact that it presents a lower photosynthetic rate, since it is a winter crop, having its period of less sunlight, using less ammonia to perform photosynthesis. Nitrate values were found to be higher in the soybean residue, the soybean plant being a leguminous, having the capacity to fix N in the soil and also has the capacity of making the organic nitrate in mineral nitrate, allowing its absorption by the plant.