Avalia??o de fertilizantes nitrogenados com base na ureia granulada com ?cidos h?micos e ze?lita

• Autor(a) principal: Gurgel, Gabriela Cemirames de Sousa
• Data de Publicação: 2016
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRRJ
• Texto Completo: https://tede.ufrrj.br/jspui/handle/jspui/3717
• topic: Zeolita; ?cidos h?micos; Tecnologias; Zeolite; Humic acids; Technologies; Agronomia

Urea is the main source of nitrogen (N) used in agriculture. However, it has a large amount of nitrogen loss through volatilization as ammonia (N-NH3). The main objective of this study was the evaluation of nitrogen fertilizers based on urea granules with humic acids (extracted from peat) and zeolite. After granulation in the laboratory, the fertilizers were pre-selected through the evaluation of the loss of NH3 due to volatilization compared with urea, by conducting studies in controlled conditions. After that, they were applied in the maize crop under field conditions. A greenhouse experiment was conducted in plastic trays using samples from two soils (sandy and clayey texture) with surface application of 18 fertilizers resulting from different combinations of urea, humic acid and zeolite, at the dose of 200 kg N ha-1 and quantified ammonia volatilized by the SALE method. The experimental design was entirely random, with three repetitions, and a control for each soil material, with a total of 114 experimental unities. Following, six granular fertilizers with humic and zeolite acids in the proportions of 5, 10 and 15%, singly or in combination, were applied in the maize crop, cultivar Ipanema. The doses were of 0, 50, 100 and 200 kg N ha-1. The study was conducted during a period of 30 days in a greenhouse, in pots, with measurement of ammonia volatilization for a period of 18 days. The experimental design was entirely random, and similar to previous study with a total of 114 experimental unities. At the end, it was evaluated the effect of the surface application of five nitrogen fertilizers: Urea + Humic acid (5%), Urea + Humic acid (10%), Urea + Zeolita (5%), Urea + Zeolita (10%) and Urea 5% Humic acid + 15% Zeolita, besides pure urea, in the doses of 50, 100, 150 and 200 kg N ha-1, for maize cultivated in a no-till system. The experimental design was a factorial 6 x 4 + 1 (fertilizer x doses + control), with four repetitions, totaling 100 experimental units. The nitrogen volatilization loss was quantified at the plots that received 100 kg N ha-1. The dry matter and productivity values were measured for all doses applied. The fertilizers showed difference in N losses by volatilization, with values ranging from 42.08 to 67.86% (sandy soil), and from 23.92 to 34.79% (clay soil). In the presence of the crop and for application on the sandy soil, the change of urea treatment with the addition of 10% zeolite resulted in a reduction of NH3 emissions volatilized by the superficial application of the fertilizer of 43.77% for the dosage of 100kg N ha-1. The reduction was of 16.85% for the 200 kg ha-1 dosage when applied the urea with 15% of zeolite, compared to urea control. Under field conditions, the fertilizers differed statistically for the N losses by ammonia emission, where the application of Urea + Zeolita, at the rate of 10% (m / m), reduced the losses compared to commercial urea by 17%. In general, the N accumulation in the indicator sheet was favored by the presence of humic acids on the fertilizers. Data from all experiments indicated that urea granulation with humic acid isolated from peat, regardless of the proportion used, potentiated N losses, making them superior to urea.