Regynaldo Arruda Sampaio

Bio: Regynaldo Arruda Sampaio is an academic researcher from Universidade Federal de Minas Gerais. The author has contributed to research in topics: Sludge & Soil fertility. The author has an hindex of 15, co-authored 128 publications receiving 1001 citations. Previous affiliations of Regynaldo Arruda Sampaio include AmeriCorps VISTA & Federal University of Roraima.

Precipitação pluviométrica mensal provável em Boa Vista, Estado de Roraima, Brasil

Abstract: O objetivo deste trabalho foi de estimar a precipitacao mensal provavel para o municipio de Boa Vista, RR (2o 49'17" N; 60o 39'45" W e 90 m). Foram utilizados dados de precipitacao pluviometrica mensal de 48 anos da serie historica compreendida entre os anos de 1923 a 1997. A estimativa da precipitacao mensal provavel, em niveis de 10, 20, 25, 30, 50, 60, 70, 75, 80 e 90% de probabilidade, foi obtida utilizando-se as funcoes de distribuicao normal e gama mista. Verificou-se um bom ajuste dos valores mensais de precipitacao pluviometrica principalmente a distribuicao gama mista, exceto para os meses secos de janeiro e fevereiro. Ficou caracterizada estacao chuvosa, compreendida entre os meses de abril e setembro, e seca, entre os meses de outubro e marco.

Fruit size, mineral composition and quality of trickle-irrigated tomatoes as affected by potassium rates

Abstract: Para determinar o efeito da fertirrigacao com K sobre o tamanho, a composicao mineral e a qualidade dos frutos do tomateiro, foi conduzido um experimento com aplicacao de seis doses de K, na forma de KCl, correspondendo a 0, 48,4, 118,6, 188,8, 259,0 e 399,4 kg ha-1, com quatro repeticoes, distribuidas no delineamento experimental em blocos casualizados. Foram observadas respostas quadraticas das producoes das classes de frutos graudo 2 (diâmetro > 60 mm), graudo 1 (56 a 60 mm) e graudo (52 a 56 mm) em relacao as doses de K aplicadas na adubacao. As producoes maximas de frutos de cada classe foram obtidas com as doses de K de 116, 190 e 233 kg ha-1, respectivamente. O conteudo de materia seca e os teores de P, S e Mg dos frutos nao foram influenciados pelas doses de K, mas os teores de nitrato e de potassio aumentaram com o aumento das doses. Os teores de vitamina C, solidos soluveis, licopeno e b-caroteno nao foram influenciados pelas doses de K; porem, os incrementos nas doses reduziram o pH e aumentaram o conteudo de acidos nos frutos.

Fibra de coco e resíduo de algodão para substrato de mudas de tomateiro

Abstract: O efeito da mistura de fibra de coco (FC) e residuo compostado de algodao (RA) foi avaliado na formacao de substrato para producao de mudas de tomateiro Kada Gigante. O experimento foi conduzido em casa de vegetacao no ICA da UFMG em Montes Claros-MG. Utilizou-se o delineamento experimental em blocos ao acaso, com quatro repeticoes. Os tratamentos avaliados foram: T1) Substrato comercial Hortimix®; T2) 100% massa seca de residuo algodao proveniente da compostagem do residuo da industria textil (RA); T3) 20% FC+80% RA; T4) 40% FC+60% RA; T5) 60% FC+40% RA; T6) 80% FC+20% RA; T7) 100% FC+% RA. Foram avaliados o diâmetro do caule, a altura da planta, o indice de velocidade de emergencia, a porcentagem de germinacao, a massa fresca da parte aerea e a massa fresca da raiz, a massa seca da aerea seca e a massa da materia seca da raiz. Observou-se que o aumento da proporcao de fibra de coco verde em relacao ao residuo compostado de algodao proporcionou maior emergencia, e indice de velocidade de emergencia, entretanto, o diâmetro do caule, a altura da planta, a massa fresca e seca da parte aerea e do sistema radicular diminuiram com o aumento dessa proporcao. O residuo de algodao proveniente da compostagem do residuo da industria textil, constitui-se em um material util na producao de substratos comerciais.

Biochar from different residues on soil properties and common bean production

Abstract: The production of biochar from organic residues promises to be an interesting strategy for the management of organic waste. To assess the effect of biochar on soil properties and the production and nutrition of common bean (Phaseolus vulgaris L.), three simultaneous experiments were conducted in a greenhouse with different biochar from organic residues (rice husk, sawdust, and sorghum silage) used as filtration material for swine biofertilizer. In each experiment the treatments consisted of five different biochar concentrations (0, 25, 50, 75 and 100 L m−3), arranged in a completely randomized design, with four repetitions. In the experiments, the use of biochar increased soil pH, cation exchange capacity, nutrient availability in the soil, and nutrient accumulation in grains. The biochar concentrations corresponding to the maximum production of grain dry matter of bean plants were 100, 68, and 71 L m−3 for biochar from rice husk filter (BRHF), biochar from sawdust filter (BSF), and biochar from sorghum silage filter (BSSF), respectively.

Produção de mudas de tomateiro em substratos contendo fibra de coco e pó de rocha

Abstract: Com o objetivo de avaliar proporcoes dos residuos fibra de coco (FC) e po de rocha de granito (RG) como substratos na producao de mudas de tomateiro, cultivar Kada Gigante, realizou-se um experimento em casa de vegetacao na UFMG-ICA. Foi utilizado o delineamento experimental em blocos ao acaso, com quatro repeticoes. Os tratamentos foram constituidos por uma testemunha e seis proporcoes de fibra de coco (FC) e po de rocha de granito (RG): T1 - Substrato comercial Hortimix®; T2 - 0% FC + 100% RG; T3 - 20% FC + 80% RG; T4 - 40% FC + 60% RG; T5 - 60% FC + 40% RG; T6 - 80% FC + 20% RG; T7 - 100% FC + 0% RG. O cultivo foi feito em bandeja de poliestireno expandido com celulas de 3,5 x 3,5 x 5,0 cm. Foram avaliados o diâmetro do coleto, a altura da planta, o indice de velocidade de emergencia, a percentagem de emergencia e a massa fresca e seca da parte aerea e da raiz. Em praticamente todas as caracteristicas avaliadas o substrato comercial foi superior aos substratos contendo fibra de coco e po de rocha. Considerando-se apenas os substratos contendo fibra de coco e po de rocha, as mudas com melhores caracteristicas foram obtidas com a mistura de aproximadamente 70% em volume de fibra de coco.

Revista Brasileira de Ciência do Solo

Abstract: Resumen en: The aim of this study was a survey of the estimated costs of soil erosion, an issue of fundamental importance in view of the current worldwide discussion...

Matéria orgânica do solo.

Abstract: Compartimentos da materia orgânica do solo; Fatores que regulam a dinâmica de materia orgânica no solo; A modifica¢ao do ambiente solo;Manipulacao da quantidade e qualidade dos aportes orgânicos; Manipulacao da fauna do solo (agentes de decomposicao) via preparo, cobertura morta ou uso de pesticidas; Modelagem da dinâmica da materia orgânica do solo.

A Simplified Method

Abstract: A simplified method for the determination of the rate of synthesis of albumin after the i. v. injection of 14C-carbonate is described. A number of experiments to check the accuracy of the 14CO2 measurements is reported. Good agreement is obtained between the specific activity of urinary urea, measured by means of our method and by the manometric method. Recoveries of 101.9 and 101.1% respectively are found for 14C-urea added to plasma or urine. Endogenously formed 14C-urea shows a maximal specific activity 2—3 h after the i. v. injection of 14C-carbonate. Thereafter the specific activity of 14C-urea gradually decreases. Enzymic conversion with arginase and urease and analysis with an amino-acid analyser give the same values for the arginine content of an albumin hydrolysate. Good agreement between the rates ot synthesis and catabolism of albumin, determined respectively with 14C-carbonate and 131I-albumin, was obtained in individual patients. In a group of 6 patients an average rate of synthesis of 10.6 mg/kg · h and an average catabolic rate of 9.5 mg/kg · h were measured. The difference between this simplified method and the manometric technique lies in a direct measurement of the concentration of urea and arginine in the method described here in contrast to the conversion of urea and arginine to CO 2 in the manometric method. Advantages of the simplified method for the determination of the rate of synthesis of albumin are discussed. Es wird eine einfache Methode zur Bestimmung der Synthesegeschwindigkeit von Albumin nach i. v. Injektion von 14C-Carbonat beschrieben. Dazu wurden verschiedene Untersuchungen zur Prufung der Genauigkeit der 14CO2-Messungen durchgefuhrt. Wir fanden eine gute Ubereinstimmung zwischen unserer und der manometrischen Methode bei der Bestimmung der spezifischen Aktivitat des UrinharnstofFs. Es wurden Wiederfindungswerte von 101,9 und 101,1% erzielt, falls 14C-Harnstoff entweder Plasma oder Urin zugefugt wurde. Endogen gebildeter 14C-HarnstofF zeigte 2—3 h nach der i. v. Injektion von 14C-Carbonat eine maximale spezifische Aktivitat. Danach nahm die spezifische Aktivitat des 14C-HarnstofFs langsam ab. Sowohl die enzymatische Umwandlung durch Arginase und Urease als auch die Analyse mittels Aminosaure-Analysator ergaben gleiche Werte fur den Arginingehalt eines Albuminhydrolysats. Bei den einzelnen Patienten wurde eine gute Ubereinstimmung zwischen der Synthese- und Abbaurate von Albumin, bestimmt durch die Untersuchung mittels 14C-Carbonat bzw. 131J-Albumin,

The Lavrados of Roraima: Biodiversity and Conservation of Brazil's Amazonian Savannas

Abstract: The savannas (lavrados) of Roraima are located in the far northern portion of the Brazilian Amazon and are part of the “Savannas of Guyana” ecoregion of the Amazonian Biome. They cover an area of approximately 43,358 km 2 , or 70% of the total area of savannas that straddle the borders of Brazil, Guyana and Venezuela. This ecoregion contains diverse types of phytophysionomies forming a mosaic of non-forest (open areas) and forest ecosystems associated with different soil types, altitudinal gradients and climates. This diversification of ecosystems generates a great heterogeneity of habitats and is reflected in the diversity of plants and animals. The few existing studies of biological diversity are almost all concentrated along the main highways and therefore fail to indicate the true magnitude of the biodiversity of Roraima’s savannas. In spite of Brazilian authorities having classified these ecosystems as having extremely high priority for conservation, no protected areas exist in the savannas of Roraima. However, 57.3% are protected in the form of Indigenous Lands. Large rural properties and settlements occupy 19.4% of the total area. The number of settlements in these savannas can be expected to increase significantly in the coming years due to legal impediments to creation of settlements in forest areas in Amazonia and due to the expansion of soy production, irrigated rice and commercial tree plantations in the state. It is estimated that 23.3% of the savanna area in Roraima is still available for creation of conservation areas.

Distribuição das chuvas no município de Tangará da Serra, médio norte do Estado de Mato Grosso, Brasil

Abstract: It is of great importance to know the rain distribution in the region of Tangara da Serra (latitude 14°37’55”S, longitude 57°28’05”W and altitude 488 m), as it is an agricultural region, which makes such information essential for an adequate planning, maximization of agricultural potential and optimization of hydric resources. Thus, this work was aimed at evaluating the annual, monthly and ten-day pluviometric variability, and also quantifying the number of dry and rainy days and different levels of rain probability for the region. Pluviometric data provided by ‘Agencia Nacional de Aguas’ (ANA) were used to analyze a period of 38 years (from January 1970 to December 2007). Precipitation behavior in Tangara da Serra has annual and monthly variations, constituting two well defined seasons – a dry one from May to September, and a rainy one from October to April. Annual variability during the analyzed period corresponds to the maximum value of 2,861, minimum of 1,404 and average of 1,830 mm, respectively. The incomplete gamma function adequately expresses precipitation probability in Tangara da Serra. Precipitation averages range from 40 to 50% probability for rainy months and from 30 to 40% for dry ones. According to the results, this type of research might help the elaboration and development of irrigation projects in this region.