[Show abstract][Hide abstract] ABSTRACT: O sistema de semeadura direta constitui uma importante técnica para a manutenção e
recuperação da capacidade produtiva de solos manejados convencionalmente e de áreas
degradadas. O objetivo do trabalho foi avaliar a produção de soja e milho sobre a
palhada de cinco plantas de cobertura e vegetação espontânea. Os experimentos foram
instalados em Votuporanga, SP e Selvíria, MS, em março de 2008, após o preparo
convencional do solo. O delineamento experimental utilizado foi o de blocos
casualizados com quatro repetições, utilizando as seguintes plantas de cobertura em
diferentes gastos de sementes por hectare que constituíram os tratamentos:
Sorghum bicolor: 6; 7 e 8 kg ha-1, Pennisetum
americanum: 10; 15 e 20 kg ha-1, Sorghum
sudanense: 12; 15 e 18 kg ha-1, híbrido de S.
bicolor com S. sudanense: 8; 9 e 10 kg ha-1,
Urochloa ruziziensis: 8; 12 e 16 kg ha-1. Também se
utilizou um tratamento controle com vegetação espontânea. Após o manejo das
coberturas, no primeiro ano de estudo foi semeada a soja e no segundo ano semeou-se o
milho, ambos em sistema de semeadura direta. Avaliou-se a matéria seca acumulada
pelas diferentes coberturas, e as características agronômicas da soja e do milho.
Concluiu-se que as diferentes coberturas mostraram-se como boas opções de plantas de
cobertura antecessoras à cultura da soja em Votuporanga, SP e a cultura do milho em
Selvíria, MS, e que os diferentes gastos de sementes utilizados para cada planta de
cobertura propiciaram diferenças em relação às características agronômicas das
culturas da soja e do milho.
Revista Ciencia Agronomica 01/2015; 46(1):89-98. DOI:10.1590/S1806-66902015000100011 · 0.62 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A busca por novas tecnologias que visem a diminuir os custos de produção de sementes é de fundamental importância. O presente estudo objetivou avaliar a viabilidade econômica da produção de sementes de soja enriquecidas com molibdênio. Foram utilizadas a cultivar BRS Valiosa RR e quatro doses de molibdênio (0 g ha-1, 200 g ha-1, 400 g ha-1 e 800 g ha-1), em duas aplicações via foliar: metade no estádio R3 e metade em R5-4. Foram estimados o custo operacional total, receita bruta, lucro operacional, índice de lucratividade, produtividade de equilíbrio e preço de equilíbrio. Concluiu-se que a aplicação foliar de molibdênio é uma forma economicamente viável de produção de sementes de soja enriquecidas com esse micronutriente.
[Show abstract][Hide abstract] ABSTRACT: The no-tillage system is an important technique for maintaining and restoring the productive capacity of conventionally managed soils and degraded areas. The aim of this study was to evaluate the production of soy and maize grown on the straw of five cover crops and on spontaneous vegetation. The experiments were carried out in Votuporanga, in the state of Sao Paulo and in Selviria, in Mato Grosso do Sul, Brazil, in March 2008, after conventional soil preparation. The experimental design was of randomised blocks with four replications, using the following cover crops in different amounts of seed per hectare, to make up the treatments: Sorghum bicolor - 6, 7 and 8 kg ha(-1); Pennisetum americanum - 10, 15 and 20 kg ha(-1); Sorghum sudanense - 12, 15 and 18 kg ha(-1); S. bicolor and S. sudanense hybrid - 8, 9 and 10 kg ha(-1); and Urochloa ruziziensis - 8, 12 and 16 kg ha(-1). A control treatment with spontaneous vegetation was also used. After management of the cover crops, soy was planted in the first year of the study, and maize sown in the second, both under a no-tillage system. The dry matter accumulated by the different cover crops, and the agronomic characteristics of the soy and maize were all evaluated. It was concluded that the different cover plants proved to be good options for preceding the soy crop in Votuporanga, SP and the maize in Selviria, MS, and that the different amounts of seed used for each cover crop resulted in differences in relation to the agronomic characteristics of the crops of soy and maize.
Revista Ciencia Agronomica 01/2015; 46(1):89-98. · 0.62 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study aimed to evaluate soil cover and the suppressive effect on weeds by different cover crops at different seed densities. The experiments were set up in Votuporanga, state of Sao Paulo, Brazil and in Selviria, state of Mato Grosso do Sul, Brazil, in March 2008, after conventional tillage. The experimental design was a randomized complete block with four replications, using the following cover crops at different seed densities per hectare: Sorghum bicolor: 6, 7 and 8 kg ha(-1), Pennisetum americanum, 10, 15 and 20 kg ha(-1), Sorghum sudanense, 12, 15 and 18 kg ha(-1), hybrid of Sorghum bicolor with Sorghum sudanense: 8, 9 and 10 kg ha(-1), Urochloa ruziziensis: 8, 12 and 16 kg ha(-1). A control treatment with spontaneous vegetation was used. Soybean was sown after the management of cover crops. Dry matter and weed density were evaluated at cutting/harvesting of cover crops. In Votuporanga, another assessment of weed plants was made at 35 days after soybean had been sown. The ground cover provided by cover crops was assessed at the time of desiccation and flowering of soybeans. It was concluded that U. ruziziensis and S. sudanense reduced weed infestations by more than 90% and kept ground cover above 80% by the time of flowering of soybean.
[Show abstract][Hide abstract] ABSTRACT: The foliar application of micro- and macronutrients is often practiced by farmers to improve yield and seed physiological potential. For calcium and molybdenum, positive results have been observed, even in soils with high nutrient content. The purpose of this study was to assess the effects of foliar applications of calcium and molybdenum on yield and seed physiological potential in common bean plants. A randomized block design was implemented, with the treatments fixed in a factorial scheme: two molybdenum rates (with or without) and four calcium rates, with four replications. The calcium rates applied on the leaves were 0, 150, 300 and 600 g·ha-1 for the first year of the investigation (2005) and 0, 300, 600 and 900 g·ha-1 for the second year (2006). In both years, the molybdenum rates applied on the leaves were 0 g·ha-1 (without) and 75 g·ha-1 (with). The results showed that the foliar calcium application, with or without molybdenum, did not improve yield. Foliar application of calcium alone improved seed physiological potential in common bean plants when applied at the full bloom stage.
[Show abstract][Hide abstract] ABSTRACT: This study evaluates the effects of different nitrogen (N) rates (0, 50, 100, 150, and 200 kg ha−1) and sources (ammonium sulfate, urea, and ammonium sulfonitrate with a nitrification inhibitor, Entec®) applied either as a single application during sowing (next to the planting rows) or as side dressing (stage 3.2 on Zadok scale), on production components and grain yield of irrigated wheat grown under no-till in a low-elevation Brazilian cerrado and Dark Red Dystrophic Latosol with clayey-texture. It was adopted a randomized block design (5 × 3 × 2) in factorial scheme with four replications. The N sources provided similar grain yields and chlorophyll contents. Increased nitrogen rates increased grain yield up to the 120 kg N ha−1, regardless of application time and N source. Nitrogen fertilization as side dressing can be recommended based on leaf chlorophyll readings. Early application of all nitrogen fertilizers at sowing time was viable.
[Show abstract][Hide abstract] ABSTRACT: Este trabalho foi realizado com o objetivo de avaliar a cobertura do solo e o efeito supressivo sobre plantas daninhas utilizando plantas de cobertura, em diferentes densidades de semeadura. Os experimentos foram instalados em Votuporanga-SP e Selvíria-MS, em março de 2008, após o preparo convencional do solo. O delineamento experimental utilizado foi o de blocos casualizados com quatro repetições, onde as plantas de cobertura com diferentes densidades de semeadura constituíram os tratamentos: Sorghum bicolor : 6, 7 e 8 kg ha-1; Pennisetum americanum: 10, 15 e 20 kg ha-1; Sorghum sudanense: 12, 15 e 18 kg ha-1; híbrido de S. bicolor com S. sudanense: 8, 9 e 10 kg ha-1; Urochloa ruziziensis: 8, 12 e 16 kg ha-1; e um tratamento controle com vegetação espontânea. Após o manejo das coberturas, foi semeada a soja. Avaliou-se a biomassa seca e densidade das plantas daninhas no momento do corte/colheita das plantas de cobertura. Em Votuporanga, também foi feita uma avaliação das plantas daninhas aos 35 dias após a semeadura da soja. A cobertura do solo proporcionada pelas coberturas foi avaliada no momento da dessecação e no florescimento da cultura da soja. Concluiu-se que U. ruziziensis e S. sudanense reduziram a infestação das plantas daninhas em mais de 90% e mantiveram a cobertura do solo superior a 80% até o florescimento da cultura da soja.
[Show abstract][Hide abstract] ABSTRACT: Common bean is an important crop in Brazil primarily because of its nutritional characteristics. Some agronomic practices, such as weed management, are fundamental to cultivation, as a means of obtaining a high crop yield. However, some studies have shown that weed management may alter the function of the cultivar cycle. Thus, this study aimed at determining the optimal phenological stage in early-maturing common bean cultivars to perform the weed control without providing reductions in yield and seed quality. The experimental design was randomized blocks with 20 treatments and four replications, in a 2×2×5 (cultivars × types of weed control × periods of weed control) factorial scheme. The periods of weed control for both cultivars (Carioca Precoce and IPR-Colibri) consisted of full cycle weeded (control), weed control at the V4-3 stage (first three nodes on the main stem with trifoliate leaves), at the R5 stage (beginning of bloom) and at the R8 stage (appearance of pods) and full cycle unweeded (no weed control). The types of weed control used were chemical (fluazifop-p-butyl + fomesafen) and mechanical (hoe). The Carioca Precoce cultivar demonstrated higher agronomic performance and yield than the IPR-Colibri cultivar, although the IPR-Colibri seeds had a higher vigor. The type of weed control (chemical or mechanical) did not affect the agronomic characteristics, yield and seed physiological potential of the cultivars. The ideal period for weed control in early-maturing common bean cultivars to obtain a higher yield and seed physiological potential was observed at the V4-3 phenological stage.
[Show abstract][Hide abstract] ABSTRACT: Chemical composition of seed displays, in general, the same compounds found in other parts of the plant, and the environment where they grow plants, fertilizer and many other factors are able to change this constitution, increasing or decreasing the amount of certain components. The study aimed to determine the effect of application by seed doses of calcium and molybdenum on protein content of peanut seeds cv.IAC 886. The experimental design was randomized blocks in a factorial design with four replicates per treatment, which are constituted by the combination of molybdenum doses (0, 50, 100 and 150 g ha(-1)) and calcium by seeds (0, 1000, 2000 and 3000 mg L-1). The peanut harvest was done manually. Seeds were removed from the pod manually and individually for each treatment and were taken to the Laboratorio de Genetica de Populacoes e Silvicultura, do Departamento de Fitotecnia, Tecnologia de Alimentos e Socio-Economia, da Faculdade de Engenharia de Ilha Solteira da Universidade Estadual Paulista, where we determined the protein (albumin-Alb, prolamin-PRO, glutelin-GLU and globulin-GLO, mg g(-1). Regardless of the doses used the albumin protein fraction showed the highest in the peanut seeds. The addition of molybdenum resulted in increased seed prolamin content in the peanut seeds. The combination of calcium and molybdenum applied to seeds resulted in increased levels of albumin, globulin and glutelin in the peanut seeds.
[Show abstract][Hide abstract] ABSTRACT: The lodging of some rice cultivars, at harvest time, can cause significant losses in grain yield. The use of plant regulators is one of the alternatives to reduce lodging, however, information on that subject are still scarce. This study aimed to evaluate the use of ethyl-trinexapac doses (0 g ha-1, 50 g ha-1, 100 g ha-1, 150 g ha-1, and 200 g ha-1), at the floral differentiation stage, in rice cultivars with different types of plants (Caiapó - traditional; BRS Primavera and BRS Soberana - intermediate; and IAC 202 - modern), in order to evaluate grain development and yield. The experiment was carried out in Selvíria, Mato Grosso do Sul State, Brazil, during the 2007/2008 growing season. It was observed that the application of 50 g ha-1, 100 g ha-1, and 150 g ha-1 of ethyl-trinexapac, during the floral differentiation stage of the Caiapó, BRS Soberana, and BRS Primavera cultivars, respectively, decreased plants height and eliminated lodging; it was not necessary to use growth regulator for the IAC 202 cultivar, due to its lack of lodging; the application of 50 g ha-1 and 150 g ha-1 of ethyl-trinexapac, during the floral differentiation stage, improved grain yield for the Caiapó and BRS Primavera cultivars, respectively, and the 100 g ha-1 dose interfered little in the BRS Soberana cultivar.
[Show abstract][Hide abstract] ABSTRACT: The use of high vigor seed constitutes basic and fundamental. Given the increasing development os the seeds industry and the improvement of vigor tests used to differentiate subtle variations in the quality of seeds of vegetable crops, is needed. The objective was to study variations in conducting the accelerated aging test, to verify their sensitivity for identifying different vigor levels of arugula seed. Were used the cultivars Cultivada and Gigante, using five lots of seeds for each. The seeds were subjected to the determination of water content, germination, first germination, emergence of seedlings and variations in the accelerated aging test, without salt solution ( traditional procedure) and with salt solution in 48, 72 and 96 hours; at 38 degrees C, 41 degrees C and 45 degrees C. The accelerated aging test in traditional procedure is not efficient to evaluation the vigor of arugula seeds. The accelerated aging test with saline solution using the combination 41 degrees C for 72 hours, was sensitive to evaluated of the physiological potential of arugula seeds.