Gilson Araújo de Freitas

Desenvolvimento inicial de plântulas de Theobroma grandiflorum (Willd. ex Spreng.) Schum. sob influência de sombreamento

The objective of this work was to evaluate the initial growth of sapling of Theobroma grandiflorum (cupuacu), in function of different levels of solar radiation. Fifty days, after the emergency, the saplings were submitted to three levels of shade, being: 0%, 50% and natural shade. Sapling development was carried out in randomized block design with 15 repetitions (15 saplings). The sapling height, lap diameter and the numbers of leaves being evaluated on the 60 st , 82 nd , 103 rd , 124 th , 145 days after sapling emergence. The Dry Mass of the leaves (DML), Dry Mass of the stem (DMS), Dry Mass of the root (DMR) and Dry mass of the plant (DMP), Relation shoot/root (PA/R) and relation plant height/Lap diameter, were measured at the end of the experiment, when the sapling reached the appropriate size to be planted in the field. The initial growth of Theobroma grandiflorum was corroborated with the species standard that occurs inside of the primary bushes, so its development of the parameters evaluated is better in conditions of 50% of shade. The condition of 50% of shade can be recommended for the formation of plants of Theobroma grandiflorum , which had the better performance in plant height, lap diameter, number and allocation of mass in the parts of the plant.

Produção de mudas de alface em função de diferentes combinações de substratos

O substrato utilizado na producao de mudas exerce papel primordial, no desenvolvimento inicial da planta. Neste sentido, com o presente trabalho objetivou-se avaliar a producao de mudas de alface em funcao de diferentes combinacoes de substratos. O experimento foi implantado seguindo um delineamento inteiramente casualizado, com quatro repeticoes. Os 20 tratamentos foram dispostos em esquema fatorial 4x5; sendo o primeiro fator constituido por quatro substratos (PlantHort I, PlantHort II, PlantHort III e substrato comercial Plantmax®) e o segundo constituido de cinco niveis de casca de arroz carbonizada (0; 25; 50; 75; 100%). Foi utilizada a cultivar de alface Elba (Lactuca sativa L.). As sementes foram semeadas nos diferentes substratos contidos em bandejas de poliestireno expandido, com 128 celulas, na profundidade 0,5 cm. O aumento da porcentagem de casca de arroz carbonizada nos substratos avaliados apresentou comportamentos semelhantes em todas as caracteristicas avaliadas. Os substratos PlantHort I, PlantHort II, PlantHort III considerados alternativos, independentemente da proporcao adicionada de casca de arroz carbonizada proporcionaram maiores crescimentos em relacao ao substrato comercial Plantmax®.

Adaptabilidade e estabilidade produtiva de genótipos de tomateiro em condições de temperatura elevada

The objective of this work was to evaluate the adaptability and stability of 15 tomato genotypes in the area of Gurupi, Tocantins. The experiments were carried out in two environments [greenhouse: in the summer (December to March) and in open field: winter (June to September)], with 15 experimental tomato genotypes, being: four of the type long shelf life commercial ripening mutants and pre-commercial (rin): Tyler, Rebeca, Carmem and AF 13527; nine of the type long shelf life structural commercials and pre-commercial: Lumi, Debora Max, Michelli, Tammy, AF 12525, AF 11097, AF 13363, AF 13364 and AF 13525; and two of normal fruits: Santa Clara and Drica, in randomized block design with three repetitions. The long life genotypes e Tyler, Rebeca, AF 13364, AF 13525, AF 13527 it were classified as of stability and wide adaptability and wide adaptability for yield. For the average weight of commercial fruits, the genotypes Tyler, Michelli and AF 11097 presented wide adaptability to the evaluated environments.

No-Tillage and Phosphate Fertilization Management on Soybean Culture in Brazilian Cerrado

Despite the benefits of no-till practices, soil compaction is a problem that can cause, among other things, mechanical impediment to root growth and less response to soil fertilization. The objective of this study was to evaluate the effect of subsoiling and doses of phosphate fertilization on soybean that have been cultivated over ten years under no-till systems in the Brazilian Cerrado. The experiment consisted of a randomized complete block design in a 2 × 4 factorial arrangement. Two managements in consolidated no-tillage area were considered: with and without subsoiling, along with four levels of phosphate fertilization: 0, 100, 300 and 400 kg ha -1 of P 2 O 5 . The practice of subsoiling in an area with ten years of no-till system provided an increase of 124.38 kg ha -1 in soybean productivity. Soybean plants grown under no-tillage system, with subsoil management, showed better development and pod production. The maximum phosphorus efficiency, with subsoiling, was achieved with the dose of 172 kg ha -1 of P 2 O 5 , yielding 5,693.4 kg ha -1 . In the no-tillage system, the maximum efficiency dose and crop yield were 159 kg ha -1 of P 2 O 5 and 5434.2 kg ha -1 , respectively.

Eficiência de fertilizante fosfatado na cultura da soja no cerrado baiano

Os teores de Fosforo na solucao dos solos da regiao do Cerrado sao geralmente baixos. Objetivou-se avaliar a eficiencia de doses do fertilizante comercial TOP PHOS na adubacao fosfatada para a cultura da soja no Cerrado no oeste baiano. O experimento foi conduzido em delineamento de blocos casualizados, com cinco repeticoes e tres replicatas em cada repeticao. Os cinco tratamentos avaliados foram: T1: Testemunha - 0 kg ha -1 de P 2 O 5 ; T2: 100 kg ha -1 de P 2 O 5 ; T3: 200 kg ha -1 de P 2 O 5 ; T4: 300 kg ha -1 de P 2 O 5 ; e T5: 400 kg ha -1 de P 2 O 5 . Os tratamentos foram obtidos com a aplicacao do fertilizante TOP PHOS ® nas doses de 0; 357,14;714,29; 1071,43 e 1428,57 kg ha -1 . As plantas de soja M-soy 9350 ® respondem a altas doses de P 2 O 5 aplicados em solos do Cerrado no Oeste da Bahia, aumentando sua produtividade em funcao das doses crescentes de P 2 O 5 . Para alcancar a maxima producao da soja com o uso do fertilizante Top Phos deve-se aplicar 86% a mais do fertilizante em relacao a recomendacao convencional considerando o nivel de fertilidade e caracteristicas do solo estudado.