Uma das maneiras de aumentar a eficiência dos fertilizantes nitrogenados, visando, por exemplo, à redução de perdas de amônia por volatilização, é o revestimento desses com polímeros. Objetivou-se avaliar o efeito da aplicação de ureia revestida com polímeros no controle da volatilização de amônia e a sua influência nos componentes da produção na cultura do milho. O experimento foi instalado na safra 2009/10 no município de Uberlândia, MG, em um Latossolo Vermelho-Amarelo (LVA) distrófico textura argilosa. Os tratamentos consistiram na aplicação, em cobertura no milho, de ureia revestida com polímeros e ureia convencional nas doses de 45; 67,5; e 90 kg ha-1 de N, mais um tratamento-controle (sem N), dispostos em blocos casualizados. A aplicação de N influenciou positivamente o teor do nutriente nas folhas e nos grãos, a leitura SPAD e a produtividade de grãos, porém a ureia revestida não alterou as taxas de volatilização de amônia, a leitura SPAD e o teor de N nas folhas e grãos, assim como a produtividade de grãos em relação à aplicação do fertilizante convencional.

A form of increasing the efficiency of N fertilizer is by coating urea with polymers to reduce ammonia volatilization. The aim of this study was to evaluate the effect of polymer-coated urea on the control of ammonia volatilization, yield and nutritional characteristics of maize. The experiment was carried out during one maize growing cycle in 2009/10 on a Geric Ferralsol, inUberlândia, MG, Brazil. Nitrogen fertilizers were applied as topdressing on the soil surface in the following urea treatments: polymer-coated urea at rates of 45, 67.5 and 90 kg ha-1 N and one control treatment (no N), in randomized blocks with four replications. Nitrogen application had a favorable effect on N concentrations in leaves and grains, Soil Plant Analysis Development (SPAD) chlorophyll meter readings and on grain yield, where as coated urea had no effect on the volatilization rates, SPAD readings and N leaf and grain concentration, nor on grain yield in comparison to conventional fertilization.

The way of applying zinc can influence the zinc uptake and productivity of crops, especially cereals that have high demand for this nutrient. The aim of this study is to evaluate methods of Zn application on soil, nutritional status and productivity of maize. For this, an experiment was undertaken at FCAV/UNESP, Jaboticabal-SP, in Oxisol clay (DTPA on Zn: 0.5 mg dm-3) with maize (hybrid Simple Impact), from December through May 2009. Nine treatments with three doses of Zn in soil banded application (in furrows) and three doses of Zn by incorporation in soil (0-20 cm depth), foliar application, seed application and control (no Zn). The treatments were arranged in a randomized block design with four replications. Regardless of the method, Zn application promoted higher contents of this micronutrient in soil and higher accumulation in the shoots as well as increasing Zn in the maize grain. However, it did not affect the nutritional status and yield of the maize. The Zn application in the soil resulted in a greater Zn uptake by plants and maize yield, compared to Zn application in the plant by seed or foliar.

La manera de aplicar zinc puede influir en la absorción de zinc y productividad de los cultivos, especialmente los cereales que tienen alta demanda de este nutriente. El objetivo de este estudio es evaluar los métodos de aplicación de Zn en el suelo, el estado nutricional y el rendimiento de maíz. Para ello, se realizó un experimento en FCAV/UNESP, Jaboticabal en Oxisol arcilloso (Zn-DTPA: 0,5 mg dm-3), el maíz (híbrido de impacto simple) de diciembre a mayo de 2009. Se aplicaron nueve tratamientos con tres dosis de Zn en forma localizada (en las crestas) y tres dosis de Zn mediante la incorporación en el suelo (0-20 cm), foliar, las semillas y el control de la aplicación (sin Zn). Los tratamientos se dispusieron en un diseño de bloques al azar con cuatro repeticiones. Independientemente del método, la aplicación de Zn promovió mayores niveles de zinc mayor acumulación en el suelo y en el aire, así como aumento de Zn en el grano. Sin embargo, no afectó el estado nutricional y el rendimiento de maíz. La aplicación de Zn resultó en un incremento de la absorción de zinc por las plantas y el rendimiento de maíz en comparación con la aplicación de Zn a la semilla de la planta o forma de hoja.

In general, tropical soils present low concentrations of zinc (Zn), and the deficiency of Zn is recognized as a world nutritional problem for cereal production and human beings. Therefore, the main goal of this study was to assess the effects of different methods of Zn application on the quality of corn and sorghum grains grown in Oxisol. Two experiments were set up in the experimental area of UNESP (campus of Jaboticabal, Brazil). The following nine treatments were applied: three doses of Zn by banded application (seed furrows), three doses of Zn by incorporation into soil (0-20 cm depth), foliar application, seed application, and control (no Zn applied). The treatments were arranged in randomized blocks with four replicates. The contents of Zn, carbohydrates and proteins were determined for corn and sorghum grains. Regardless of the method, Zn application promoted higher contents of this micronutrient in corn and sorghum grains. The banded application method of Zn in soil promoted greater contents of total carbohydrates, starch and protein in both cultures. The incorporation of Zn into the soil method provided higher contents of soluble carbohydrates in both corn and sorghum grains.

Los suelos tropicales, en general, tienen una baja concentración de zinc (Zn), y la deficiencia de este micronutriente es reconocida como un problema nutricional mundial para la producción de cereales y para los seres humanos. Así, el objetivo de este estudio fue evaluar los efectos de diferentes métodos de aplicación de Zn sobre la calidad del grano de maíz y sorgo. Para esto, se realizaron dos experimentos en el área experimental de FCAV/UNESP, Jaboticabal, Brasil. Se aplicaron nueve tratamientos: tres dosis de Zn aplicadas en forma localizada en los surcos de las semillas, tres dosis de Zn aplicadas en forma incorporada al suelo (0-20 cm de profundidad), una dosis aplicada en forma foliar, y el tratamiento control (sin aplicación de Zn); dispuestos en un diseño de bloques completos al azar con cuatro repeticiones. Las variables medidas fueron: contenido de Zn, proteínas y carbohidratos en los granos de maíz y sorgo. La adición de Zn, independientemente del modo, promovió mayores niveles de este micronutriente en los granos de maíz y sorgo. El modo de aplicación de Zn en el suelo de una forma localizada mostró mayores niveles de carbohidratos, almidón y proteína en las semillas de ambos cultivos. La aplicación de Zn en el suelo de modo incorporado resultó en altos niveles de carbohidratos solubles en los granos de maíz y sorgo.

To evaluate the growth and pattern of nutrient absorption (N, P, K, Ca, Mg and S amongst others) in three berry cultivars (treatments), four plants by treatment in different phonological stages were harvested. The experiment was arranged in randomized design of factorial 3x5 with three replicates. There cultivars were used FM Shima-Miura, IZ 56/4 and Miura and above ground biomass was harvested in five occasions 45, 60, 75, 90 and 115 days after plantation. It was observed that the accumulation of nutrients presented different pattern and cv. IZ 56/4 was superior compared with PM Shima-Miura for N, P, K, Ca, Mg and S and N, P, K and S for Miura. For example, the accumulation of N expressed on mg plant"¹ per berry plant cultivar PM Shima-miura, IZ 56/4 and Miura was respectively 4,21; 8,14 and 5,56, for K 2,71; 5,22 and 2,64 and for Ca 2,47; 4,52 and 3,59.

Com objetivo de avahar o crescimento e a marcha de absorção de nutrientes (N, P, K, Ca, Mg e S) em três cultivares de amoreira (tratamentos), colheu-se quatro plantas por tratamento, em diferentes estadios fenológicos. O delineamento experimental utilizado foi inteiramente casualizado, em esquema fatorial 3x5 em 3 repeticSes. As cultivares usadas foram 'FM Shima-Miura', TZ 56/4' e 'Miura' e estabelecido cinco épocas de colheita da biomassa 45; 60; 75; 90 e 115 dias após a cepa. Observou-se que o acumulo de nutrientes apresentou comportamento diferente e a cv. IZ 56/4 foi superior comparado com às cv. PM Shima-Miura para N, P, K, Ca, Mg e S e Miura para N, P, K e S. Por exemplo, o acumulo de N em mg por planta-1 planta de amoreira das cultivares PM Shima-miura, IZ 56/4 e Miura foi respectivamente 4,21; 8,14 e 5,56. Para o K 2,71; 5,22 e 2,64. Para o Ca 2,47; 4,52 e 3,59.

The effect of the application of three doses N, P and K on substrates on the nutritional status of root stock of 'Citrumelo' lemon (Citrus paradisi x Poncirus trifoliata) was evaluated. The experiment followed a fully randomized factorial design (3x3) (three nutrients x three doses plus a control) with three replicates. The treatments consisted of Dl = half standard dose, D2 = one standard dose and D3 = twice standard dose, in addition to the control that did not received fertilization at all. At four months after the emergence of the root stock of lemon 'Citrumelo' the plants tissue (leaves) were determined for nutrients analysis to obtain its accumulation. The results showed that plants of lemon 'Citrumelo' 'Swingle' are responsive to the application of N, P and K. The application of nitrogen showed a linear accumulation pattern of N and K, while the applications of phosphorus and potassium provided a quadratic response.

Estudou-se o efeito da aplicação de três doses N, P e K em substratos sobre o estado nutritional de porta-enxertos de limoeiro 'Citrumelo' (Citrus paradisi x Poncirus trifoliata). O experimento obedeceu ao delineamento estatístico inteiramente casualizados em esquema fatorial 3x3 + 1 (três nutrientes x três doses + urna testemunha) com 3 repetições. Os tratamentos foram constituidos por: T)x = metade da dose padrão; D2 = a dose padrão; e, D3 = duas vezes a dose padrão, além da testemunha (sem adubação). Aos quatro meses após a emergência dos porta-enxertos do limoeiro 'Citrumelo' as plantas foram submetidas a determinação do teor e acumulo dos nutrientes. A análise dos resultados revelou que plantas de limoeiro 'Citrumelo' 'Swingle' são responsivas a aplicação de N, P e K. A aplicação de nitrogênio afetou de forma linear o acumulo de N e K; já as aplicações de fósforo e potássio proporcionaram efeito quadrático no acumulo de P e K, respectivamente.