Impacts of limestone and nitrogen top dressing application on the potassium content in the soil profile and marandu-grass leaf concentration

Objetivou-se avaliar os efeitos de nitrogênio (0, 100, 200, 300 e 400 kg/ha.ano), com ou sem aplicação de calcário dolomítico em cobertura, sobre o teor de potássio (K) do solo nas profundidades de 0 a 5; 5 a 10; e 10 a 20 cm e a concentração de potássio na planta. O experimento foi realizado em Latossolo Vermelho distroférrico de relevo suavemente ondulado, disposto em esquema fatorial 5 × 2, em blocos casualizados, com quatro repetições. A adubação nitrogenada promoveu aumento linear na concentração de potássio na planta e no teor desse mineral na camada de 0 a 5 cm do solo. Ocorreu efeito de inibição competitiva entre a absorção de potássio e cálcio e entre potássio e magnésio. Embora uma fração significativa de potássio retorne à camada superficial do solo pelo resíduo de forragem, em decorrência da maior produção de massa, o aumento da concentração de potássio na planta nas mais altas doses de nitrogênio comprova a importância do suprimento de potássio para a planta, por intensificar a massa de forragem.

Variação sazonal da concentração de nutrientes em folhas de bananeiras, no Vale do Ribeira-SP

The Vale do Ribeira, SP, main agricultural activity is the banana crop, which accounts for most of this fruit production in the State of São Paulo. The nutritional balance of the plant is one of the most important factors for the banana plant can complete the cycle and achieve high productivity. Aiming to evaluate the seasonal variation of leaf nutrient concentration in banana plants in Vale do Ribeira-SP, we used the results of 252 chemical analyses of plant tissue, collected from August 2009 to September 2010, in the 18 representative properties for the region, ten cultivated with subgroup Cavendish banana plant and eight of subgroup Prata banana plant. The largest variation between the macronutrient occurred for K and S, and among the micronutrients, especially for Fe and B. In some dates of evaluation, there was a higher leaf concentration of P, K, Ca and Zn, in subgroup Cavendish banana plants, while the subgroup Prata banana plants showed higher leaf concentration, especially of Mn, B and N. Climatic conditions, especially rain, influenced the leaf nutrient content, especially for K, N, S, B and Fe.

Fontes e doses de nitrogênio para o feijoeiro em sucessão a gramíneas no sistema plantio direto

O nitrogênio é um nutriente essencial ao feijoeiro. Contudo, ainda há dúvidas sobre qual fonte e dose utilizar para o fornecimento desse nutriente em cobertura à cultura, no sistema plantio direto. O objetivo deste trabalho foi avaliar a influência de fontes e doses de N, aplicadas em cobertura, na nutrição e produtividade do feijoeiro (Phaseolus vulgaris L.) cultivado no sistema plantio direto, em um Nitossolo Vermelho. O delineamento experimental foi o de blocos ao acaso com quatro repetições, num esquema fatorial 2x4, constituído por duas fontes de N (nitrocálcio e uréia) e quatro doses de N (0, 30, 60 e 120 kg ha-1) em cobertura. A aplicação de doses elevadas de N, na forma de nitrocálcio, promoveu maior absorção de nitrato, K, Ca e Mg pelo feijoeiro em plantio direto, em comparação com a aplicação de uréia. A adubação nitrogenada em cobertura, utilizando como fonte o nitrocálcio ou a uréia, proporcionou aumento no teor de N nas folhas, na massa de matéria seca da parte aérea, no número de vagens por planta e na produtividade do feijoeiro no sistema plantio direto, em sucessão a aveia-preta, até a dose estimada de 95 kg ha-1 de uréia.

Correlação entre leituras de clorofila e níveis de nitrogênio aplicados em feijoeiro

Foram realizados dois ensaios, sendo um em solução nutritiva e outro em solo, utilizando seis níveis de nitrogênio (28, 56, 84, 112, 140 e 168 mg/L de N) a fim de ajustar as leituras diretas, feitas nas folhas de feijoeiro, com um clorofilômetro (Minolta SPAD-501), aos níveis crescentes de nitrogênio e ao seu teor nas folhas. Avaliaram-se os parâmetros: área foliar; massas dos materiais verde e seco; teor de clorofila; produção de grãos e teores de N, Ca, Mg e S. Todos esses dados, mais as leituras do aparelho, foram correlacionados entre si e com os níveis de N aplicados. As correlações positivas entre as leituras e os níveis de N fornecidos (R = 0,86) e entre as leituras e os teores de N nas folhas (R = 0,75) indicam que há perspectivas favoráveis quanto ao uso desse equipamento para detectar deficiências de nitrogênio em feijoeiro.

Produção de bulbos e incidência de pseudoperfilhamento na cultura do alho vernalizado em função de adubações potássicas e nitrogenadas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The role of matrix effects on the quantification of abscisic acid and its metabolites in the leaves of Bauhinia variegata L. using liquid chromatography combined with tandem mass spectrometry

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

Nutrição e produtividade da nogueira-macadâmia em função de doses de nitrogênio

The objective of this work was to evaluate the influence of nitrogen doses on mineral nutrition and yield of macadamia nut (Macadamia integrifolia). The experiment was carried out during three agricultural years, in Jaboticabal, SP, Brazil. The experimental design was a complete block with four replicates. Five doses of N (0, 50, 100, 150, and 200 kg ha-1 per year), applied as urea, were evaluated. The increase in N doses increased the nutrient concentration in the leaves and the yield of nuts and almonds. Ca, Mg, and S contents decreased and the ones of Fe and Mg increased linearly with N fertilization. Nut and almond yields were positively correlated with leaf N concentration, and the range from 14 to 18 g kg-1 allowed the highest yields. The dose of 150 kg ha-1 of N per year provides higher nut yields, without reducing the recovery rate of almonds.

Estado nutricional de mudas de baru (Dipteryx alata) em área de recuperação e remanescentes de cerrado

The Dipteryx alata is a tree specie with possibility of use in human and animal nutrition, and in the pharmaceutical industry. For reclamation of degraded areas, the revegetation has been an alternative, however, requires fertilizer addition. The objectives of this study were to evaluate the nutritional status and growth of Dipteryx alata seedlings, introduced in degraded soil under recovery process, with residues (organic and agroindustrial), compared to collected seedlings in preserved Cerrado, and evaluate the residues impact on soil chemical properties. In this work the degraded soil received the incorporation of residues, organic - RO (macrophytes) and agroindustrial - RA (ash derived from burning bagasse from sugarcane), with the following doses: 0, 16 and 32 t ha- 1 and 0, 15, 30 and 45 t ha-1 respectively. Within three months of incorporation of residues into the degraded soil, the D. alata seedlings were introduced in the experimental area, and 12 months later were evaluated for height, stem diameter, chlorophyll content and leaf contents of N, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn. For purposes of comparison, the foliar concentration of those elements was determined in Dipteryx alata seedlings collected in preserved Cerrado area. Concomitant with the collect of leaves, at Cerrado and experimental area, soil was collected (0.0 - 0.20m deep) for evaluation of chemical parameters (P, OM, pH, K, Ca, Mg, H + Al, Al, Cu, Fe, Mn and Zn). Comparing the seedlings collected in the Cerrado with the seedlings from experimental area it is observed that the leaf concentration of N, P, K and Mg was higher in seedlings from preserved Cerrado in relation to those introduced in the experimental area. Fe, Mn and Zn, have lower foliar concentration in plants collected in the Cerrado, in the case of Mn the worst results occur in the absence of macrophytes indicating the importance of organic residue. The foliar concentration of Ca, S and Cu was similar in...

Avaliação do estado nutricional de mudas de Gonçalo Alves (Astronium Fraxinifolium)

The planting of seedlings, the establishment and maintenance of the natural regeneration process, or the combination thereof, are methods used in the recovery of degraded or disturbed environments, however, often require the addition of soil conditioners. This study aimed to evaluate the influence of conditioners, introduced in degraded soil on growth and nutritional status of Astronium fraxinifolium seedlings. To conduct the experimentation were used as degraded soil conditioner, ash from sugarcane bagasse (CZ) and macrophytes (MC), at the doses of 0, 15, 30 and 45 t ha-1 and 0, 16 and 32 t ha-1 respectively, which combined produced 12 treatments, with three replications, and for field installation, was used the experimental randomized block design. Astronium fraxinifolium (Gonçalo Alves) seedlings, native tree species in cerrado, were introduced in the experimental area and, after 12 months, were evaluated for leaf concentration of nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, copper, iron, manganese and zinc (N, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn, respectively). Seedlings and adult plants of A. fraxinifolium were collected in preserved cerrado reserve were also analyzed for nutrients foliar concentration to perform a comparative analysis. The leaves collection in the preserved cerrado and experimental area, was accompanied by soil sampling (0.0 - 0,20 m deep), which was analyzed for phosphorus, OM (organic matter), pH, K, Ca, Mg, Al+H (potential acidity), Al (aluminum), Cu, Fe, Mn and Zn. The results show that the applied residues contributed to raise the foliar concentration of Cu and Fe. The foliar concentration of nutrients was higher in A. fraxinifolium seedlings from preserved cerrado, except for B, which was similar between areas, besides Cu and Fe with higher levels in the seedlings from experimental area. The combined addition of residues (MC and CZ), led to increase the plants height and diameter. This...

Pulsing With Low Concentration Gibberellin Plus Benzyladenine or Commercial Floral Preservatives Affect Postharvest Longevity, Quality, and Leaf Chlorosis of Cut Lilies and Gladioli

Effects of pulsing with different concentrations of gibberellin plus benzyladenine (GA(4+7) + BA), a proprietary mixture of GA(4+7) plus BA in a commercial floral preservative (GA(4+7) + BA + preservative), or a propriety mixture of sugar plus acidifier developed for bulbous flowers (floral bulb preservative) were studied on postharvest performance and quality of cut lily (Lilium hybrids) and gladiolus ( Gladiolus hybrids) flowers. Pulsing of cut stems of lily with GA(4+7) + BA at 5 or 2 mL.L-1 GA(4+7) + BA + preservative for 20 hours at 3 +/- 1 degrees C extended the vase life and controlled leaf chlorosis of 'Cobra'oriental lily and 'Cappuccino'and Pot Corn'asiatic lily. Cut 'Orange Art'asiatic lily performed best when pulsed with GA(4+7) + BA at 10 mg.L-1. For cut gladiolus, pulsing with GA(4+7) + BA at 10 mg.L-1 extended the vase life of 'Alice', 'Mammoth', and 'Passion', while 'Scarlet'had the longest vase life when pulsed with 5 mg.L-1 GA(4+7) + BA. GA(4+7) + BA + preservative also extended the vase life and controlled leaf chlorosis, but the floral bulb preservative had no effect on vase life extension or preventing leaf chlorosis of lilies. Gladiolus cultivars had no or minor leaf chlorosis during vase period. Overall, overnight pulsing with GA(4+7) + BA + or GA(4+7) + BA + preservative extended the vase life and prevented leaf chlorosis

Synthetic amides toxic to the leaf-cutting ant Atta sexdens rubropilosa L. and its symbiotic fungus

1 Nine synthetic amides similar to natural N-piperidine-3-(4,5-methylenedioxyphenyl)-2-(E)-propenainide and N-pyrrolidine-3-(4,5-methylenedyoxiphenyl)2-(E)-propenamide were synthesized and identified by their spectroscopic data.2 the toxicity of these synthetic amides to the Atta sexdens rubropilosa workers and the antifungal activity against Leticoagaricus gongylophorus, the symbiotic fungus of the leaf-cutting ants, were determined.3 Workers ants that were fed daily on an artificial diet to which these compounds were added had a higher mortality rate than the controls for N-pyrrolidine-3(3',4'-methylenedioxyphenyl)-2-(E)-propenamide and N-benzyl-3-(3',4'-methylenedioxyphenyl)-2-(E)-propenamide at a concentration of 100 mu g/mL.4 the completely inhibition (100%) of the fungal growth was observed with N-piperldine-3-(3',4'-methylenedioxyphenyl)-2-(E)-propenamide and N,N-diethyl-3-(3',4'-methylenedioxyphenyl)-2-(E)-propenamide at concentrations of 50 and 100 mu g/mL and N-pirrolidine-3-(3',4'-methylenedioxyphenyl)-2-(E)-propenamide at a concentration of 100 mu g/mL.5 the possibility of controlling these insects in the future using synthetic piperamides that can simultaneously target both organisms is discussed.

Activity of sesame leaf extracts to the leaf-cutting ant Atta sexdens rubropilosa (Hymenoptera : Formicidae)

Crude extracts of new and old sesame leaves (Sesamum indicum, Linaeus) obtained by a sequential process of extraction were tested through contact experiments to investigate their toxicity to Atta sexdens rubropilosa (Forel) workers. Methanol extract of old leaves was toxic to leaf-cutting ants at the lower tested concentration (20mg.ml(-1)). This extract was fractioned and their fractions were tested showing a toxic effect of the methanol fraction. The methanol fraction was fractioned again and the sub fraction responsible for worker's toxicity is composed of some sugars.

Preliminary studies on the effects of d-limonene to workers of the leaf-cutting ant Atta sexdens rubropilosa and its implications for control

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of Silicon and Drought Stress on Tuber Yield and Leaf Biochemical Characteristics in Potato

Silicon has beneficial effects on many crops, mainly under biotic and abiotic stresses. Silicon can affect biochemical, physiological, and photosynthetic processes and, consequently, alleviates drought stress. However, the effects of Si on potato (Solanum tuberosum L.) plants under drought stress are still unknown. The objective of this study was to evaluate the effect of Si supply on some biochemical characteristics and yield of potato tubers, either exposed or not exposed to drought stress. The experiment was conducted in pots containing 50 dm(3) of a Typic Acrortox soil (33% clay, 4% silt, and 63% sand). The treatments consisted of the absence or presence of Si application (0 and 284.4 mg dm(-3)), through soil amelioration with dolomitic lime and Ca and Mg silicate, and in the absence or presence of water deficit (-0.020 MPa and -0.050 MPa soil water potential, respectively), with eight replications. Silicon application and water deficit resulted in the greatest Si concentration in potato leaves. Proline concentrations increased under lower water availability and higher Si availability in the soil, which indicates that Si may be associated with plant osmotic adjustment. Water deficit and Si application decreased total sugars and soluble proteins concentrations in the leaves. Silicon application reduced stalk lodging and increased mean tuber weight and, consequently, tuber yield, especially in the absence of water stress.

Changes in leaf proline and fruit production induced by potassium stress in eggplant

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)