Adubação com KCl revestido na cultura do milho no Cerrado

The use of coated potassium chloride can provide greater absorption of potassium resulting in the alteration of leaf contents, production components and grain yield. The objective of this study was to evaluate the effect of potassium doses using potassium chloride conventional or coated by polymer, in the corn crop under conditions of brazilian Savanna with low altitude. The experiment was conducted in Selviria, MS, Brazil, in a clayey Oxisol. The treatments consisted of four doses of K2O (0, 40, 80 and 120 kg ha(-1)), applied at sowing, and two sources: potassium chloride and potassium chloride coated by polymers. A randomized block design with eight treatments and four replications was used. The coated KCl is not efficient under the soil and climatic conditions studied, because it provided results similar to the conventional KCl for the K foliar content, crop components and grain yield of irrigated corn. The increment of K2O doses influenced positively the K and chlorophyll leaf contents, plant and spike insertion height and the number of rows and grains per spike. The maximum mean yield obtained was with 83.5 kg ha(-1) of K2O.

Root system and root and stem base organic reserves of pasture Tanzania grass fertilizer with nitrogen under grazing

The goal of this study was to evaluate the concentrations of non-structural carbohydrate (NSC) and of total nitrogen (N), as well as, to evaluate the root system in Tanzania-grass pastures fertilized with doses of urea in fall, spring and summer. The experiment was conducted at the Experimental Farm of Iguatemi, Maringa, Parana, Brazil, from March 2007 to March 2008. The experimental design was complete random blocks with subplots and four repetitions. The plots showed doses of N (50, 100 e 150 kg ha(-1) of N) plus the control (no N fertilization), and the subplots the season of the year. Root samples were taken at depths of 0-10, 10-20 and 20-40 cm. Root biomass showed a trend for mass accumulation up to a dosage of 100 kg ha(-1) for all seasons evaluated. Also, about 80% of the root system of Tanzaniagrass plants was found on the 0-10 cm layer for all dosages of N. Nitrogen fertilizer above 100 kg ha(-1) may foster fast forage plant growth reducing its NSC root storage capacity although favoring NSC and total N storage at stem base. NSC and total N concentrations were highest in fall, demonstrating that its usage is greater in spring due to the weather conditions being favorable to plant growth. In the regrowth, the largest reserve of total N was at the 0-10 cm root layer and the largest NSC reserve is at stem base.

Growth and flowering of miltonia flavescens lindl. var. stellata regel orchid under different doses of a slow release fertilizer

The Orchidaceae is one of the most numerous and diversified families in the Plant Kingdom. Miltonia flavescens Lindl. is a native orchid to the southern region of Brazil. Studies related to the nutrition and fertilization of orchids are scarce, specific and existent only for few species. The objective of this work was to evaluate the effect of different doses of a slow release fertilizer (Osmocote (R) 9/15/12 + micro) on the development of M. flavescens var. stellata Regel cultivated in pots with pine bark and coconut fiber (1:1, v:v) as the substrate. The treatments consisted of: no fertilizer application (control), application of 2.5 g, 5 g and 10 g of fertilizer per liter of substrate. The experimental design was set in randomized blocks, with five replications and three plants per plot. The experiment was carried out along 25 months and the fertilizer was applied every five months. The evaluated plant parameters were: length of the longest pseudobulb, number of pseudobulbs, diameter of pseudobulbs, number of shoots, number of leaves and flowering. There was a significant increment on all evaluated characteristics with the increase of the fertilizer dose. The highest dose provided a more profuse flowering, with a larger number of flower stems and flowers, in addition to bigger flower stems and flowers. These results show that the supply of nutrients in an appropriate amount is of a great importance for the development and flowering of M. flavescens.

Modelagem da área foliar de duas cultivares de amendoim em função das dimensões lineares dos folíolos

The purpose of this study was to determine a shape factor to estimate area of leaflets of two peanut cultivars (IAC TATU ST, IAC RUNNER 886). Correlation studies were conducted involving real leaf area (Sf) and leaf length (C), maximum leaf width (L) and the product between C and L. For each cultivar was determined a form factor (f) by means of regression analysis between the product of the length by the width and the actual area of leaves and the correlation between leaf area estimated by the correction factor and direct measurement. All evaluated models (linear, exponential or geometric) provided good estimates of leaf area (above 87%). Linear models had the best fit, passing or not through the origin. From a practical viewpoint, it is suggested to use the linear model involving the C and L product, using a linear coefficient equal to zero, with values of factor f equal to 0.7111 and 0.7266 for IAC RUNNER 886 and IAC TATU ST, respectively. The method of dimensions is feasible for the estimation of leaf area for both peanut cultivars, for showing good r(2) values (0.97), with errors below 3%, even when used with independent data.

Biomassa microbiana e degradação de serapilheira em pastos de tifton-85 manejados com índices de área foliar residual

Pós-graduação em Zootecnia - FCAV

Interação entre bactérias diazotróficas e doses de n-fertilizante na cultura da cana-de-açúcar

Pós-graduação em Agronomia (Agricultura) - FCA

Tamanho da amostra foliar para avaliação do estado nutricional e índice SPAD de capim-elefante irrigado para corte

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

Consumo foliar da traça-das-crucíferas em couve e brócolis tratados com sinigrina

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

Resposta da cultura do milho a modos de aplicação e doses de fósforo, em adubação de manutenção

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

Soil phosphorus availability and soybean response to phosphorus starter fertilizer

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

Estimativas da área da folha de figueiras 'Roxo de Valinhos' usando dimensões lineares do limbo foliar

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

Relações entre fósforo extraído por resina e respostas da cultura do alho vernalizado à adubação fosfatada em cinco solos com e sem adubação orgânica

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

Aplicação de sistemas neuro-fuzzy e espectrometria no infravermelho próximo para a identificação em tempo real do teor de nitrogênio foliar em cana-de-açúcar

Pós-graduação em Engenharia Elétrica - FEB

Características morfogenéticas, perdas de nitrogênio por volatilização, reservas orgânicas e sistema radicular do capim-Tanzânia fertilizado com doses de nitrogênio

O objetivo do trabalho foi estudar as características morfogenéticas e estruturais do capim-Tanzânia, a produção de forragem, as perdas de nitrogênio (N) por volatilização, reservas orgânicas e a avaliação do sistema radicular sob doses de nitrogênio sob pastejo. O experimento foi instalado na área Fazenda Experimental de Iguatemi da Universidade Estadual de Maringá, no período de março de 2007 a março de 2008. O delineamento experimental utilizado foi de blocos completos ao acaso, com parcelas subdivididas com quatro repetições. Nas parcelas, encontravam-se as doses de N (0, 150, 300 e 450 kg ha-1 de N) e, nas sub-parcelas, as estações do ano. As perdas de N por volatilização foram quantificadas depois da adubação N (1, 2, 3, 6, 9, 12 e 15 dias). As amostragens das raízes foram realizadas nas profundidades de 0-10, 10-20 e 20-40 cm. A aplicação do fertilizante N na pastagem foi parcelada em três aplicações. A produção de massa seca total e de lâmina foliar de forragem respondeu linearmente até 282 kg ha-1 de N na estação do verão. A adubação nitrogenada exerce efeito positivo nas taxas de alongamento e aparecimento foliar, e no número de folhas vivas em plantas de capim-Tanzânia nas estações da primavera e verão. Elevadas adubações nitrogenadas associada a intervalos menores de pastejo promovem uma maior porcentagem de lâmina foliar; no manejo de pastos de capim-Tanzânia sob lotação rotacionada com altura de 70 cm na entrada dos animais para o pastejo e saída com 30 cm de altura do resíduo. A interação entre o nível de adubação e o período depois da aplicação de uréia foi significativa para a variável volatilização acumulada de N-NH3. A aplicação da uréia acarreta perdas percentuais mais elevadas de N nos três primeiros dias após a aplicação. A perda média acumulada de N-NH3 no período para as três estações do ano... (Resumo completo, clicar acesso eletrônico abaixo)

Trocas gasosas e eficiência fotoquímica de cultivares de algodoeiro herbáceo sob aplicação de silício foliar

The objective of this study was to evaluate gas exchange and photochemical efficiency of cotton cultivars under leaf application of silicon. Therefore, the experiment was conducted in a completely randomized in a factorial 3 x 5, three cotton cultivars ('BRS Topazio', 'BRS Safira' and 'BRS Rubi'), five silicon concentrations (0, 50, 100, 150, 200 mg L-1) and four replications. Gas exchange and photochemical efficiency were determined by measuring the rate of CO2 assimilation, transpiration, stomatal conductance, internal CO2 concentration, instantaneous efficiency in water use, instantaneous carboxylation efficiency, initial fluorescence, maximum quantum efficiency of the variable and photosystem II (PSII). The data variables were subjected to analysis of variance and regression test comparison of means. There were significant differences in gas exchange and photochemical efficiency in response to concentrations of silicon. There were also significant differences among cotton cultivars evaluated. In cultivar 'BRS Top zio', the application of silicon increased CO2 assimilation rate and quantum efficiency of PSII. In 'BRS Safira' silicon reduced the rate of assimilation and internal CO2 concentration. In 'BRS Rubi' element increased the fluorescence of chlorophyll 'a' and quantum efficiency of photosystem II, and reduced the rate of assimilation and internal CO2 concentration and stomatal conductance. Silicate fertilization provided 'BRS Topazio' to express better photosynthetic rate in relation to 'BRS Safira' and 'BRS Rubi'. No damage occurred in PSII when 'BRS Top zio', 'BRS Safira' and 'BRS Rubi' cultivars received silicon as supplementary nutrition.