Navegando por Autor "Guelfi, Douglas Ramos"

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Ammonia volatilization from blends with stabilized and controlled-released urea in the coffee system
(Editora UFLA, 2016-09) Chagas, Wantuir Filipe Teixeira; Guelfi, Douglas Ramos; Caputo, André Luiz Carvalho; Souza, Taylor Lima de; Andrade, André Baldansi; Faquin, Valdemar
Application of stabilized and controlled-release urea blends can reduce the losses of N-NH3 as compared to conventional urea. The aim of this study was to quantify ammonia volatilization from conventional nitrogen fertilizers and blends of urea + (urea + NBPT) + controlled release urea applied in drip irrigated coffee system. The experiment was conducted under field conditions in in a Red Latosol located in Lavras-MG, Brazil. The randomized complete block design with six treatments: Urea = 450 kg ha -1 yr -1 N (100% of the recommended dose) divided in three splittings equal to 150 kg ha -1 N with an interval of 50 days; ammonium nitrate = 450 kg ha -1 yr -1 N (100% of the recommended dose) in three splittings equal to 150 kg ha -1 N with an interval of 50 days; Polyblen Extend ® -100%= 450 kg ha -1 yr -1 (100% of the recommended dose) applied in two splittings, 315 kg ha -1 N in the 1o split and 135 kg ha -1 N in the 2o split; Polyblen Extend ® -70% = 315 kg ha -1 yr -1 N (70% of the recommended dose) in two splittings, 220.5 kg ha -1 N in the 1o split and 94.5 kg ha -1 N in the 2o split; Polyblen Montanha ® -100% = 450 kg ha -1 yr -1 (100% of the recommended dose) in an unique application in the 1o split and Polyblen Montanha ® -70% = 315 kg ha -1 yr -1 N (70% of the recommended dose) at an unique application in the 1o split, with three repetitions. Total accumulated N-NH3 losses followed the decreasing order: Urea (83.2 kg ha -1 N) > Polyblen Extend ® - 100% (60.3 kg ha -1 N) > Polyblen Montanha ® - 100% (46.8 kg ha -1 N) > Polyblen Extend ® - 70% (35.1 kg ha -1 N) > Polyblen Montanha ® - 70% (24.2 kg ha -1 N) > nitrate ammonium (2.0 kg ha -1 N ). The use of Polyblen Montanha ® decreases two splittings compared to conventional sources such as urea and ammonium nitrate, by applying only 70% of the recommended dose without affecting yield and coffee crop nutrition.
Eficiência agronômica do superfosfato triplo revestido por polímeros no crescimento inicial do cafeeiro
(Editora UFLA, 2016-07) Chagas, Wantuir Filipe Teixeira; Guelfi, Douglas Ramos; Caputo, André Luiz de Carvalho; Dominghetti, Anderson William; Faquin, Valdemar; Lopes, Raphael Machado; Chagas, Rafael Mattioli Rezende
Grande parte do P aplicado ao solo, na forma de fertilizantes, é fixado com óxidos de ferro e alumínio, tornando- se indisponíveis às plantas. Uma opção para contornar esse problema é agregar compostos aos fertilizantes, fosfatos convencionais para reduzir a intensidade das reações de precipitação e adsorção. Para quantificar a eficiência agronômica e avaliar características de crescimento e nutricionais como altura, massa seca de plantas, área foliar, teor e acúmulo de P nas folhas do cafeeiro, conduziu-se o experimento, em casa de vegetação da Universidade Federal de Lavras, em vasos preenchidos com 14 kg de solo e duas mudas de café cultivar Acaiá IAC 474-19. Utilizou-se o delineamento em blocos ao acaso, esquema fatorial 2x5, sendo os tratamentos constituídos por duas fontes de P (Superfosfato triplo revestido por polímeros e Superfosfato triplo convencional) e cinco doses de P 2 O 5 (0; 5; 10; 15; 20 g vaso -1 ), com quatro repetições. Ao final do experimento, concluiu-se que a adubação fosfatada influenciou as características avaliadas, onde a aplicação de fósforo promoveu aumento no crescimento inicial do cafeeiro. O revestimento do fertilizante fosfatado com polímeros aumentou a altura, a massa seca, o acúmulo de fósforo nas folhas do cafeeiro e a eficiência agronômica, em relação ao SFT convencional.
Monoammonium phosphate coated with polymers and magnesium for coffee plants
(Editora UFLA, 2018-05) Guelfi, Douglas Ramos; Chagas, Wantuir Filipe Teixeira; Lacerda, Jordana Reis; Chagas, Rafael Mattioli Rezende; Souza, Taylor Lima de; Andrade, André Baldansi
The coating of phosphate fertilizer granules with polymers and magnesium (Mg) is a technology that can improve phosphorus (P) use efficiency and mitigate problems of low Mg supply in coffee crops. The objective of this work was to evaluate the growth and nutrition characteristics of coffee seedlings and the agronomic efficiency (AE) of monoammonium phosphate (MAP) coated with anionic polymers and Mg in comparison with other phosphate fertilizer technologies. The experiment was carried out in a greenhouse in 20 L pots. Two five-month-old coffee seedlings were transplanted into each pot. The experimental design was completely randomized with three replicates. The following treatments, applied at a dose corresponding to 20 g pot -1 of P 2 O 5 , were carried out: MAP; MAP coated with anionic polymers (Policote Phós ® ); MAP coated with anionic polymers+Mg (Policote Phós_Mg ® ); Top-Phós ® ; and Agrocote ® . A control (without P) was prepared. Plant height; leaf area; dry mass of leaves, stems, and roots; total dry mass; shoot/root ratio; specific leaf weight; P and Mg content in plants and their availability in the soil after cultivation and efficiency indicesof the phosphate fertilization treatment were evaluated. The recovery of applied P and the agronomic efficiency of phosphate fertilizers was found to increase in the following order: MAP = Top-Phós ® = Agrocote ®
Nitrogen loss by volatilization of nitrogen fertilizers applied to coffee orchard
(Editora UFLA, 2016-03) Dominghetti, Anderson William; Guelfi, Douglas Ramos; Guimarães, Rubens José; Caputo, André Luiz Carvalho; Spehar, Carlos Roberto; Faquin, Valdemar
Ammonia volatilization (N-NH3) is one of the main pathways of Nitrogen loss reducing nitrogen use efficiency in coffee orchard. This work aimed at quantifying ammonia volatilization (N-NH3) losses from N-sources to be used in coffee plantations fertilization in Brazil. The experiment was conducted in the field on a dystrophic red latosol (Ferralsol in FAO’s classification) at the Coffee Research Sector, University of Lavras, MG, Brazil. The experimental design was of complete randomized blocks with three repetitions of the following treatments: conventional urea, ammonium nitrate and urea + 0.15% Cu and 0.4% B, urea + anionic polymers, urea + elementary sulfur (S 0) + polymers, and urea + plastic resin. These N sources were split into three doses of 150 kg ha -1 and band applied. The N-NH3 losses by volatilization and variations of pH (H2O) were measured, before and after N application. The N-sources contributed to reduce the soil pH, measured after the third nitrogen fertilization. The N-NH3 losses by volatilization (average from three applications) was as follows: urea + anionic polymers (35.8%) > conventional urea (31.2%) = urea + S 0 + polymers (31.0%) > urea + 0.15% Cu + 0.4 % B (25.6%) > urea + plastic resin (8.6%) = ammonium nitrate (1.0%).