Lixiviação de nitrato e volatização de amônia em um Latossolo cultivado com café sob diferentes fontes de nitrogênio

• Autor(a) principal: Souza, José Adinan
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5495
• topic: Soluto no solo; Nitrogênio; Cafeicultura; Solute in the soil; Nitrogen; Cafeicultura; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO

Among many products that exist to reduce the loss of nitrogen fertilizer we give importance to the use of urea inhibitor (NBPT). There are many studies in the literature history that confirms the efficiency of this inhibitor, mainly for the harvest of corn, sugarcane and rice. However, studies that verify the risk of contamination of the water table that occurs because of the loss by leaching NO3- are rare. Mainly for the people that harvest coffee grounds under elevated doses of N. Therefore this study was developed, whose objective was to evaluate the loss of NO3- leaching and the volatilization of NO3-. The experiment was made in a commercial upland coffee field. They adopted a block division at random, in a division of (3x2) + 1, with 4 repetitions being three nitrogen doses: 200, 400, 600 kg ha-1, two kinds of urea: normal and with the urea inhibitor, a additional treatment with no nitrogen doses. To obtain the flow of the solution in the ground it was installed three tension measurement in each layer 0,90; 1,00; 1,10 m fixed to the mercury manometer. Yet it was installed, in each layer a solution extractor from the earth like 1m deep to determine the concentration of NO3- in the soil solution. To quantify the loss of NH3 by volatilization were installed NH3 collectors, like semi-open. It was registered a total of 1172mm precipitation during the experiment, from all these 620 mm were percolated, that corresponds a 52,90 %. It wasn t observed any statistic difference between the treatments, for an internal drainage. The related numbers of losses by volatilization of ammonia didn t suffer any influence of the dose, in average the urea with NBPT was showed losses of 3,51 % and the normal urea showed 11,21 %. As a result it can be concluded that the urea with NBPT was statistically more effective to reduce the losses by volatilization. When we take into consideration the losses by leaching, it can be observed that this one suffers strong influence by climate factors like the precipitation, mainly in the time distribution of the rains. The results allow us to conclude that the losses by leaching suffered influence of the fertilizer dose used. It was shown that the treated urea with the inhibitor of urea brings the high risk of contamination of the water table with NO3-; we can conclude that the use of treated urea with urea inhibitor is a good alternative to reduce the losses by volatilization, but the use of that above 200 kg ha-1 can represent reasonable risk of contamination of the water table with NO3-; compared to the proportioned risk by the use of normal urea. Furthermore, it shows meaningful losses of fertilizers. Yet we can conclude that the use of elevated doses of N didn t add amounts of productivity, nor it led to the content increase of nutrients in the leaves of the plants.