ABSTRACT. This study presents an evaluation of the viability of using protected urea under different irrigation depths to reduce nitrogen losses caused by the volatilization of ammonia (NH3) under the conditions of the Southwestern Amazon. The study was carried out at the Experimental Station of Embrapa Rondônia, in the municipality of Porto Velho, Rondônia State, Brazil. The experiment was conducted in a Red-Yellow Latosol and arranged in a 5 x 6 factorial design consisting of a combination of five treatments (N sources) with six irrigation depths. The sources of N were as follows: 1) urea (45.5% N); 2) urea (44.3% N) + 0.15% copper and 0.4% boron; 3) urea (45% N) + NBPT; 4) urea (43% N) + sulfur (1%); and 5) control (without N). The irrigation depths were 0, 5, 10, 15, 20, and 25 mm. The results showed that, regardless of the use of urease inhibitors, an irrigation depth of 10 mm is suitable for incorporating urea into the soil and stabilizing N losses from NH3 volatilization. NBPT is the most efficient inhibitor under nonirrigated conditions. All N sources promote increases in the concentrations of nitric and ammonia nitrogen in the soil. In the first 15 days after fertilizer application, the highest concentrations of ammonium were in the 0 - 10 cm and 10 - 20 cm soil layers, and NBPT showed the highest ammonium content compared to that of the other sources in the 0 - 10 cm layer. The nitric nitrogen content in the soil was slightly influenced by the irrigation depth in the first 15 days after fertilizer application. However, the ammonia nitrogen content decreased exponentially with the increase in irrigation depth due to the movement of ammonia in the soil.

Resumo: O objetivo deste trabalho foi avaliar inibidores de urease quanto à redução de perdas por volatilização de amônia proveniente da ureia, em solos da Amazônia. O experimento foi realizado em um Latossolo Amarelo de textura muito argilosa, em um Latossolo Vermelho de textura argilosa, e em um Plintossolo Argilúvico de textura franco-siltosa. Cada experimento foi realizado em arranjo de parcelas subdivididas no tempo, com uso de ureia convencional, ureia+benzimidazol, ureia+benzoiltioureia, ureia+N-(n-butil) triamida trifosfato, e um controle sem fertilizante. A amônia volatilizada foi coletada 48, 96, 144, 192, 240, 288, 336 e 384 horas após aplicação dos fertilizantes. Os picos de volatilização de amônia atingiram o máximo às 144 horas nos tratamentos com ureia convencional, ureia + benzimidazol e ureia + benzoiltioureia. Picos de volatilização entre 192 e 288 horas ocorreram no tratamento ureia + N-(n-butil) triamida trifosfato. Em Latossolo Amarelo, os compostos benzimidazol e o benzoiltioureia promoveram redução de 22 e 10%, respectivamente, das perdas de amônia, em solos sem inibidores de urease. No entanto, nenhum desses agentes reduziu significativamente a volatilização da amônia à taxa determinada para ureia convencional, em Latossolo Vermelho e em Plintossolo Argilúvico. N-(n-butil) triamida trifosfato é o inibidor de urease mais eficiente para os solos do sudoeste da Amazônia.

Abstract: The objective of this work was to evaluate urease inhibitors for the reduction of ammonia volatilization in Amazonian soils. The work was carried out on a clayey yellow Oxisol, a clayey red Oxisol, and on a light silty Ultisol. Each experiment was conducted in split plots, using standard urea, urea + a benzimidazole-type urease inhibitor (BZI1), urea + a benzoylthiourea-type urease inhibitor (RTB68), urea + N-(n-butyl) triamide thiophosphate (NBPT), or a fertilizer-free control. Volatilized ammonia was collected at 48, 96, 144, 192, 240, 288, 336, and 384 hours after fertilization. Ammonia volatilization reached a maximum at 144 hours in the urea, urea + benzimidazole, and urea + benzoylthiourea treatments. A peak level was reached at 192 and 288 hours in the urea + N-(n-butyl) triamide thiophosphate treatment. In yellow Oxisols, benzimidazole and benzoylthiourea reduced the ammonia losses by 22 and 10%, respectively, in soils without urease inhibitors. However, neither of these agents significantly reduced ammonia volatilization at the rate determined for standard urea in red Oxisols or Ultisols. N-(n-butyl) triamide thiophosphate is the most efficient urease inhibitor for the soils of southwestern Amazonia.

Com a crescente demanda de madeira serrada nos últimos anos, o estudo da cadeia produtiva do segmento é de fundamental importância para a melhor gestão desse setor. Dessa forma, o objetivo deste trabalho foi caracterizar os resíduos gerados pelo processamento ou beneficiamento dos produtos madeireiros comercializados no município de Eunápolis-BA. Os dados foram obtidos por meio de entrevistas, com aplicação de formulários aos responsáveis em todas as serrarias do município. Os aspectos observados foram quanto à utilização de seus resíduos, bem como a sua destinação final. Observou-se resíduos nas serrarias do município de Eunápolis em torno de 165 m³ mensais, sendo 55% destes destinados para fins energéticos. Neste estudo, foi notada a necessidade de abordagens mais detalhadas sobre o aproveitamento e a maior agregação de valor para os resíduos gerados pelas serrarias.

With the growing demand for lumber in recent years, the study of the production chain of this segment is of fundamental importance for the better management of the sector. Therefore, the objective of this study was to characterize the wood waste generated from the processing of timber products sold in Eunapolis, State of Bahia. Data were obtained by means of interviews with questionnaires applied to those responsible for all logging activitiesin the municipality.The use of woodwasteand its final destination were the main features observed. The waste accumulation of themills in Eunapolis is around 165 cubic meters per month, 55% of whichintended for energy purposes. This study uncovered the need for more detailed information on the utilization and higher added value of the waste generated by sawmills.