Pb-210-derived chronology in sediment cores evidencing the anthropogenic occupation history at Corumbata River basin, Brazil

Activity profiles of excess Pb-210 combined with chemical data determined in two sediment cores from Corumbatai River basin, São Paulo State, Brazil, provided new insights into the reconstruction of historical inputs of anthropogenic constituents, contributing to improving management strategies of the hydrological resources in the basin since most of the municipalities extensively utilize the waters of Corumbatai River and tributaries for drinking purposes, among other uses. Excellent significant relationships between loss on ignition (LOI) and organic matter were found for sediments of both analyzed profiles. Silica was found to be inversely related to organic matter at both analyzed profiles: its decrease accompanied an increase in the specific surface of the sediments. This relationship was confirmed by a great number of inverse significant correlations among silica and oxides Na2O, K2O, CaO, MgO, Al2O3, P2O5, Fe2O3, MnO, and TiO2. It was possible to identify the role of organic matter on adsorption of several oxides/elements in the core sediments profiles. Apparent sediment mass accumulation rates corresponding to 224 and 802 mg cm(-2) year(-1) were obtained, and are compatible with field evidence, indicating a higher value associated with sand mining activities interfering with the natural/normal sedimentation process, due to modifications of the channel drainage.

Crescimento radicular e aéreo de cultivares de arroz de terras altas em função da calagem

This work aimed to evaluate root growth, shoot development and nutrient absorption efficiency by rice cultivars Caiapo and Maravilha as affected by lime application. The experiment was carried out in a greenhouse, with treatments set up by Caiapo and Maravilha cultivars in combination with the base saturation (V%) of 10%, 40% and 70%. The experiment was in a randomized complete block design, with four replications. The number of tillers, root length, root dry matter, leaves and stems, leaf content and macronutrients absorption efficiency were evaluated. Comparing cultivars, Maravilha cultivar presented higher root dry weight, root length, number of stems, dry matter of stems and shoot than Caiapo cultivar, as well as accumulated more nutrients in the shoots. on the other hand, nutrient contents were higher in the cultivar Caiapo compared to Maravilha. Maravilha cultivar shows greater root and shoot growth while Caiapo shows higher nutrient absorption efficiency from the soil. The base saturation of 40% is the most effective for both cultivars.

Condutividade elétrica da solução nutritiva e acúmulo de macro e micronutrientes no cultivo de crisântemo

The study of growth and uptake of nutrients is important to determine the times of increased demand in order to schedule the fertigation. The present research was developed with the objective of evaluating the effects of different levels of electrical conductivity on growth and accumulation of nutrients in chrysanthemum plants under greenhouse conditions. The electrical conductivity levels on the applied solution were 1.42, 1.65, 1.89, 2.13 and 2.36 dS m-1 (bud vegetative stage); 1.71, 1.97, 2.28, 2.57 and 2.85 dS m-1 (bud stage). The dry mass of the aerial portion of the plant and the contents of macronutrients and micronutrients were determined every 14 days. The nutrient accumulation in chrysanthemum plant showed similar trend as compared to dry matter accumulation. The nutrients presented the following order of absorption: K>N>Ca>Mg>P>S (1425, 892, 184, 150, 110 and 59 mg plant-1) and Fe>Zn>B>Mn>Cu (2254, 2219, 1725, 1287, 210 μg plant-1). The content of most nutrients increased with increase in electrical conductivity of the solution, without salt effect up to EC of 2.85 dS m-1.

Crescimento e acúmulo de nutrientes da cultura do quiabeiro

With the objective to quantify the okra crop's growth and macro and micronutrients accumulation during its life-cycle obtaining equations that best represent it, an experiment was carried out at Jaboticabal city, SP, Brazil, from January 14th to May 14th, 2009. The cv. Santa Cruz 47 was directly sowed into open soil furrows, in a spacing of 1 x 0,2 m. During the life-cycle were realized random samples of plants at 15 days intervals. The means were adjusted to polynomial regression equations set of non-linear parameters. After 50 days from sowing there has been a large increase of dry matter in plant' parts. At the final harvest, 120 days after sowing, the leaves, stems and fruits accounted for 21, 71 and 8%, respectively, from the total plant dry matter. The decreasing sequence of nutrient accumulation was K, Ca, N, Mg, P, Fe, B, Mn, Zn and Cu equivalent to 6,002.8; 4,733.8; 2,930.8; 1,196.3; 473.7; 436.2; 49.8; 10.4; 7.1; 7.1 e 1.5 mg plant-1. The quantity accumulated of culture were 146.5; 23.7; 300.1; 236.7; 59.8 e 21.8 kg ha-1 of N, P, K, Ca, Mg and S, respectively, and 520.0; 76.0; 2,491.0; 355.0 e 355.0 de B, Cu, Fe, Mn and Zn, respectively.

Acúmulo e exportação de nutrientes em cenoura 'Forto'

In order to quantify the growth, accumulation and exportation of macronutrients by carrot 'Forto', and obtain equations that best represent them, it was conducted an experiment in the São Gotardo (MG), from May to September 2004. Samples were taken at 40, 50, 60, 70, 80, 90, 100, 110 and 120 days after sowing (DAS) to determine dry matter and accumulation of macronutrients in leaves and roots. At 40 DAS, five days after thinning, the plants had 0.18 g and 0.04 g in dry leaves (LDM) and of roots (RDM), respectively. From then, until 88 DAS, the partitioning of photoassimilates and accumulation of matter in the shoots were more pronounced. The RDM was low until 80 DAS, which corresponded to two thirds of the crop cycle, from when the amount of material allocated in this part of the plant had strong growth, surpassing, at 88 DAS, the amount of LDM. The nutrient accumulation was small in the first 60 DAS, coinciding with the period of lower dry matter accumulation. The order of decreasing macronutrient accumulation by the crop were: K > N > Ca > P > S > Mg, in the amounts of 906.7, 438, 155.46, 87.4, 58 and 37.63 mg plant-1, respectively. The root participated with 60.5% of the accumulation of N, 86.1% of P, 58% of K, 25.5% of Ca, 55.6% of Mg and 65.5% of S. Considering a population of 590,000 plants per hectare, the total quantity of nutrients by the crop of carrots was 258.3, 51.6, 534.8, 91.7, 22.2 and 34.2 kg N ha-1, P, K, Ca, Mg and S, respectively.

Disponibilidade de fósforo em função da aplicação de calcário e silicatos em solos oxídicos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Alterações dos atributos químicos do solo e resposta da soja à cobertura vegetal e à calagem superficial na implantação do sistema de semeadura direta

Pós-graduação em Agronomia (Agricultura) - FCA

Eficiência agronômica de fertilizantes organominerais sólidos e fluidos em relação à disponibilidade de fósforo

Pós-graduação em Agronomia (Agricultura) - FCA

Uso do extrato pirolenhoso: Efeito no solo e nas plantas de tomate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Acúmulo de matéria seca e macronutrientes por cultivares de sorgo sacarino

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

Marcha de absorção de macronutrientes e de micronutrientes em mudas de goiabeira Paluma e Século XXI

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Crescimento e acúmulo de macronutrientes em cenoura Forto‟

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

Fontes de fósforo e saturação por bases no solo no cultivo de alho vernalizado livre de vírus

Pós-graduação em Agronomia (Horticultura) - FCA

Crescimento e acúmulo de nutrientes em quiabeiro ‘Santa Cruz 47'

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Marcha de absorção de nutrientes em dois híbridos de mamona de porte baixo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)