Componentes produtivos do trigo afetados pela densidade de semeadura e aplicação de regulador vegetal

Improvement on yield potential of plants by crop management is the main research challenge due to the growing of food demand worldwide. The objective of this work was to study physiological and morphological traits and its relationship with yield components and yield of wheat as affected by sowing densities and plant growth regulators. The experimental design was a split-plot design with four replications. The plots were consisted by four sowing densities ( 30, 50 70 and 90 plants m(-1)) and the subplots were consisted by plant growth regulators [control, (IBA+GA+KT), Trinexapac-Ethyl e (IBA+GA+KT) + Trinexapac-Ethyl]. Dry matter accumulation, plant height, source-sink distance, gas exchange and yield were determined. Trinexapac-Ethyl application resulted in decreasing of plant height, source-sink distance and flag leaf length; however, the grain yield was not affected. The number of plants per unit area affected dry matter accumulation. Higher dry matter accumulation showed direct relationship with yield and yield components in lower plant densities.

Efeito da época e sistema de semeadura da Brachiaria brizantha em consórcio com o milho, sobre os componentes de produção e propriedades físicas do solo

The objective of this study was to evaluate the development of Brachiaria brizantha- MG-4; sown in two seasons and two seeding systems in space between two rows, and to evaluate the effect of intercropping on maize yield, as well as evaluating the physical properties of the soil after the consortium. The experiment was conducted in the agricultural year 2010, the Municipality of Quatro Pontes/PR. The experimental design was randomized blocks as a factorial 2x2, and an additional treatment that was corn cultivation single, with four replications. The treatments consisted two intercropping systems: corn intercropped with Brachiaria brizantha in the row, and corn intercropped with Brachiaria brizantha in space between two rows, and two times of sowing Brachiaria brizantha: simultaneously corn, and twenty-five days after sowing corn. The seed was planted mechanically in no-tillage system, with spacing between the lines of 0,70 m. The ears were harvested by hand and in the laboratory were evaluated: yield components and productivity. Brachiaria brizantha- MG-4 was sown and harvested manually. We evaluated the production of fresh and dry mass and yield components. For soil analyzes the soil was sampled at 0-0.10 and 0,10-0,20 m. Were determined the total porosity, macroporosity and microporosity. The results demonstrated that the production components of Brachiaria brizantha were lower when it was sown twenty-five days after sowing corn, and between sowing systems when Brachiaria brizantha was sown in line. There was no reduction in grain yield of maize intercropped with Brachiaria system independent and sowing date. The consortium of pasture with corn increased the total porosity, and reduced soil bulk density.

Manejo da adubação com sulfato de amônio no desempenho produtivo do milho cultivado após aveia e trigo

The time, dose and applied nutrients in corn have a direct effect on its productivity. Therefore, the objective was to study the application of N and S in corn as ammonium sulfate, in succession to wheat and oats and evaluate different forms of fertilizer management. The experiment was conducted in a randomized block design in Oxisol (Hapludox). The five treatments with N, at a dose of 120 kg ha(-1) were applied in 20 plots (5x4), according to the management of fertilizer: T1-N (120 kg ha(-1)) full at sowing, T2-N (120 kg ha(-1)) total coverage; T3-N (40 kg ha(-1)) at sowing and N (80 kg ha(-1)) in coverage; T4-N advance in wheat sowing and sowing oats (120 kg ha(-1)), T5-(control). The S doses were corresponding to their concentrations in the fertilizer. Only wheat received a dose of 24 kg N ha(-1) at sowing all plots and oats received 24 kg N ha(-1) at sowing only the portions related to treatment with anticipation of corn N (T4). We evaluated the biomass production of winter crops (oats and wheat), according to the fertilization at sowing, and also the influence of winter crops and management of ammonium sulfate, the corn yield. The oats produced more dry matter in relation to wheat, positively influencing the corn yield, regardless of fertilizer management. The anticipation of ammonium sulfate, the sowing of oats, was favorable to corn yield, equating to other forms of management of fertilizer. Rotation corn and oats, forms management, ammonium sulphate, at seeding, topdressing or applied in split were equally efficient in corn yields.

Perfilhamento do trigo afetado pela densidade de semeadura e aplicação de reguladores vegetais

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Doses, fontes e épocas de aplicação de nitrogênio em arroz de terras altas cultivado em sistema de semeadura direta

The crop demand by nitrogen varies from one crop to other as well as the amount and application time, and this nutrient can be lost by leaching, volatilization and erosion. The objective of this study was to evaluate doses, sources and times of nitrogen application in rice of high lands cropped in no till system. The work was conducted in Selviria, State of Mato Grosso do Sul, Brazil, in a soil originally under Cerrado vegetation. A randomized blocks design, with the treatments disposed in a factorial scheme 5x3x2 was used. The treatments were constituted by five nitrogen doses (0, 50, 100, 150 and 200 kg ha(-1)), three nitrogen sources (urea; ammonium sulfonitrate plus nitrification inhitor and ammonium sulfate) and two application times (at sowing or at flower bud differentiation), with four repetitions. The sources of nitrogen, as well as the application times had similar effects for most of evaluations. The N doses influenced linearly or with quadratic adjustment the plant height, N leaf content and grains yield, in the two growing seasons. The chlorophyll content and the number of ears m(-2) were affected only, in the first year. The highest yield in the growing season of 2007/08 was obtained with the dose of 149 kg ha(-1) of N. In 2008/09 growing season the increase of N doses provided increment in the grains rice yield, until the maximum dose evaluated (200 kg ha(-1) of N).

ASIAN SOYBEAN RUST INTEGRATED MANAGEMENT POTENTIAL: DISEASE SEVERITY, PLANT DEVELOPMENT AND YIELD COMPONENTS, CULTIVAR MG/BR-46 (CONQUISTA)

Soybean rust caused by Phakopsora pachyrhizi Sydow & P. Sydow is one of the major diseases of the soybean crop. The aim of this study was to evaluate the effects of sowing dates, plant populations and reduced doses of fungicides on soybean rust severity and its effects on plant development and yield, cultivar MG/BR46 (Conquista). Field experiments were conducted in the 2009/2010 and 2010/2011 harvests, under natural rust infestation of soybean rust. As from the appearance of the first disease symptoms, also began the fungicide spraying and the disease severity assessments. To understand the nature and extent of the effects of different treatments, a multivariate analysis of factors was applied. For the majority of the agronomic characters and factors, one-third to two-thirds of their variability can be explained by changes in plant populations or by differences in the fungicide treatments, and the remainder, was explained by sowing date variations. The fungicide treatments and sowing dates are determinants in disease severity and its interference on crop productivity. The characters of plant growth are more dependent on plant population variations. Treatments with azoxystrobina + ciproconazol promoted smaller disease severities, reflecting in productivity increase. The plant populations can be reduced up to 160.000 plants ha(-1) without losses in the disease control and the soybean yield. In general, the earliest sowings provided increase in the plant development, although the rust control was less efficient.

MINERAL NITROGEN SUBSTITUTION BY CHICKEN LITTER IN SUCCESSION OAT/CORN

The constant search for sustainability of production systems have driven research to find alternatives to the problems arising from the intensified use such systems. In this context the present work aimed study the effects of substitution of mineral nitrogen by chicken litter in oat and corn crop in succession and the chemical characteristics of soil. The study was conducted during the period May 2009 to March 2010 in area of Oxisol. The design was of randomized block with four replications. The six treatments were obtained by a combination of different amounts of chicken litter (0, 1500, 3000, 4500, 6000 and 7500 kg ha(-1)) applied 30 days before the sowing of oats combined with the mineral nitrogen applied in coverage in corn (311.1, 257.8, 202.2, 148.9, 95.6, 42.2 kg ha(-1) of urea), for the total supply of 140 kg ha(-1) of nitrogen (N). The application of poultry litter in oat promotes increased the production of dry matter, and content and accumulation of N. The mineral nitrogen substitution by chicken litter increases the yield of corn crop. The use of poultry litter alters the chemical properties of soil, increasing the levels of organic matter, exchangeable Al and acidity potential. However lowers the pH, K, Ca, Mg, sum of bases and base saturation.

INTERCROPPING OF BRAQUIARIA WITH SOYBEAN

The objective of this work was to study the intercropping of Brachiaria brizantha. Marandu with soybeans. The experiment has been planted in a 3 year prevailing area with no-tillage, in eutrophic Oxisol at Maripa - PR. The experimental design was a randomized block with five replications. For the forage study, four treatments were performed which consisted of seeding times brachiaria [early ( seven days before planting soybeans) joint (same day of soybean planting) and after (at stages V-3 and R-1 culture)] intercropping with soybean. To study the yield and crude protein and oil levels of the grain were adopted six treatments, which consisted of sowing dates of capim Marandu [early (seven days before planting soybeans), joint (same day of soybean planting) after (V-3, R-1 and R-5 soybean) and in single culture (single)]. The forager higher productivity of dry matter occurs with early sowing, however, the greatest reduction in soybean yield also occurs in this case. The sowing of Brachiaria until R-5 soy has no influence on the nutritional value of the forage. The intercropped of soybean with Brachiaria brizantha. Marandu has no impact on the leaf Nitrogen content, oil content and enzyme activity of soybean peroxidase. The highest yield of soybeans occurs when it is grown single or Brachiaria is sown in stage R-5. The crude protein content of soybean grain is reduced when brachiaria seeding is early or together with soybeans compared to single culture.

SILICON IN ROW AND NITROGEN IN TOPDRESSING FERTILIZATION ON RICE UNDER DRY LAND AND SPRINKLER IRRIGATION CONDITIONS

The objective of this work was to evaluate the effects of silicon application adjusted with nitrogen fertilization via top-dressing on grain productivity, the silicon contents of the soil, in the plant tissue and nitrogen contents in dry and irrigated conditions. The experimental outlining was from designed blocks with subdivided parcels and four repetitions. The treatments consisted of culture system (dry and irrigated) and the under parcels by the combination of silicon (0 and 100 kg ha(-1)), in magnesium and calcium silicate form (with 23% of SiO2), and four doses of N (urea) via top-dressing (0, 30, 60 and 90 kg ha(-1)). Silicon application at sowing furrow was a viable technique because it provided significant increase in the content of this element in the root growth of rice. The application of silicon in the sowing furrow did not change the content of the element nor the nitrogen nutrition in rice plants. The nitrogen application reduced the silicon content and increased nitrogen nutrition in rice plants. Silicon application at sowing furrow provided no increase in rice grain yield. When there was no water limitation to nitrogen fertilization enhanced linearly on rice grain yield, whereas under water stress the effect of nitrogen fertilization was limited.

GERMINATION OF EUCALYPTUS SEEDS UNDER WATER AND SALT STRESS

The knowledge of the physiology of Eucalyptus spp. germination may contribute significantly to the development of management and choice of suitability of the deployment areas. The aim was to evaluate the effects of water and salt stress on seed germination of Eucalyptus camaldulensis, E. citriodora, E. grandis, E. robusta and E. urophylla. The seeding was done with four replicates of 0.05 g of seeds in paper moistened with solutions at potentials of 0.0, -0.2, -0.4, and -0.8 MPa, induced with polyethylene glycol (PEG 6000) and NaCl. The germination test was in 25 degrees C in the presence of light. Were evaluated the first test score seven days after sowing, and weekly germination (normal seedlings) until 28 days. Were also calculated the germination speed index. Water stress causes a greater reduction in the rate of germination and accumulated germination of E. camaldulensis and E. citriodora seeds than salt stress, and the seeds of E. robusta are more adapted to germinate under salt stress moderate, between -0.2 and -0.4 MPa. Regardless of the substance used to induce stress, the threshold for germination was -0.8 MPa. The E. camaldulensis is the most sensitive specie to water stress and E. urophylla most sensitive to salt stress.

Período anterior à interferência de corda-de-viola em cana-planta

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Velocidade de semeadura e profundidade da haste em sistema plantio direto de milho e soja

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Produtividade e sólidos solúveis da melancia irrigada em função de doses de nitrogênio

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Uso de composto de poda de árvore e lodo de esgoto como substratos na formação de mudas de sangra d'água (Croton urucurana Baill.) irrigadas com três lâminas de água

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Germinação de sementes e desenvolvimento inicial de Erythrina mulungu (Mart. ex. Benth)

The aim of this study was to determine the best pre-germination treatments for seeds and the best size container for seedlings growing of coral tree Erythrina mulungu (Mart. ex. Benth). Among the treatments applied to seeds, scarification with sulfuric acid during 10 minutes and cutting stylus in the region opposite to hilum resulted, respectively, in highest values of germination percentage (82.8% and 82.1%) and rates of germination speed (1.15 and 1.71). The biometric variables indicated no effect of container size on leaf area and dry mass plants. At 63 days after sowing, although with Dickson quality score statistically similar (mean 0.26), only plants grown in small and large bags reached the diameter collect close to 5 mm, minimum recommended for field planting. According to the results, for initial development of coral tree, it is recommended pre-seed treatment with sulfuric acid commercial, sowing in plastic bags of 17 x 20 cm, and wait 63 days before planting in the field.