Resumo -O objetivo deste trabalho foi modelar o fator k e as funções DRIS para a diagnose foliar de mangueiras cultivadas. Dez pomares comerciais, no estágio de produção, localizados no vale do Rio São Francisco, foram monitorados, mensalmente, durante dois anos, por meio da coleta de amostras foliares para determinação dos teores de N, P, K, Ca, Mg, B, Fe, Mn, Zn e Cu. Os dados foram testados quanto à normalidade e as relações entre as concentrações dos nutrientes foram usadas para calcular as normas DRIS, obtendo-se média, variância e limites máximo e mínimo de cada relação dentro da população amostrada. Os nutrientes foram classificados como macronutrientes de resposta freqüente (MAF) (N, P e K), macronutrientes de resposta rara (MAR) (Ca e Mg); micronutrientes de resposta freqüente (MIF) (B, Fe, Mn e Zn) e, micronutrientes de resposta rara (MIR) (Cu). Funções DRIS foram desenvolvidas para cada classe de nutrientes. O modelo desenvolvido expressa o balanço nutricional das plantas cultivadas ajustado a cada nutriente e reflete o comportamento biológico das plantas como resultado da variação da disponibilidade dos nutrientes.Termos para indexação: Mangifera indica, normas DRIS, diagnose foliar. Modelling of functions in calculating DRIS indicesAbstract -The objective of this work was to model DRIS functions and k factor on foliar diagnosis of mango crops. Ten commercial orchards, at yield stage, in the São Francisco River valley were monitored, monthly, during a two-year period, by means of collecting leaf samples to determine N, P, K, Ca, Mg, B, Fe, Mn, Zn and Cu concentrations. Data were tested for normality and bivariate relationships between nutrient concentrations were used to calculate DRIS norms. Mean, variance as well as minimum and maximum values were calculated for each relationship within the population. Nutrients were classified as follows: highly responsive macronutrients (HRMa) (N, P and K); rarely responsive macronutrients (RRMa) (Ca and Mg); highly responsive micronutrients (HRMi) (B, Fe, Mn and Zn), and rarely responsive micronutrients (RRMi) (Cu). DRIS functions were developed for each nutrient class. Results showed that the developed model expresses the nutritional balance adjusted for each nutrient, and reflects the expected biological behavior of plants as a result of variation in the availability of nutrients.
RESUMO -O objetivo deste trabalho foi avaliar as características químicas do solo, a concentração de nutrientes nas folhas e a produção de mangueiras cultivadas em sistema orgânico. Três compostos denominados A, B e C foram aplicados em três doses cada (0; 5 e 10 t ha -1 ), em área comercial de produção de mangueira em cultivo orgânico. O experimento foi conduzido no delineamento de blocos ao acaso, em fatorial 3 x 3 (3 compostos x 3 doses), com três repetições. Os compostos orgânicos foram elaborados com resíduos animais e vegetais, enriquecidos com torta de mamona, MB4® e termofosfato. O enriquecimento mostrou-se eficiente em aumentar a concentração de nutrientes nos compostos. Os compostos orgânicos aumentaram os teores de matéria orgânica do solo (MOS), com destaque para o composto C, que apresentou teores totais mais elevados de P, K, Ca, Mg, B, Cu, Mn e Zn. A MOS aumentou linearmente com o aumento das doses do composto. A produção e o número de frutos por planta foram maiores com os compostos B e C, que por sua vez apresentaram maiores concentrações totais de nutrientes. As doses de composto proporcionaram aumento linear na concentração foliar de N. A produção de frutos e o número de frutos por planta apresentaram aumento quadrático com as doses de composto, sem apresentar um ponto de máxima. Termos para Indexação: produção orgânica de manga, rocha moída, análise de solo, nutrição mineral, relação C:N.
Contamination of vineyard soils by the continuous use of cupric fungicides and fertilizers has been a worldwide concern. The objective of this study was to determine the total concentration of Cu, Zn, Fe, Mn, Ni and Pb from vineyard soils of a semiarid region in Brazil. Soil samples at 0-20 and 20-40 cm depth were collected in areas under 5, 6, 8, 10, 12, 15, 16 and 30 years of cultivation, and compared with native vegetation areas. Samples were digested and total metal concentrations were determined by atomic absorption spectrophotometer. In general, concentrations of Mn, Ni, Fe and Pb were similar to those values found in the reference area, being regarded as background concentrations. On the other hand, Zn and Cu were mainly derived from the widespread use of fertilizers (e.g., phosphate application) and cupric fungicides, respectively. Discriminant analysis clearly demonstrated higher metal accumulation in surface soil samples, chiefly Zn and Cu owing to Zn and Cu-containing chemicals and accumulation of organic matter. This tool was also useful to differentiate between natural and anthropogenic inputs of metals into soils. The high enrichment factor values for Cu and Zn showed that both were mainly derived from anthropogenic sources.
ABSTRACT-In perennial crops, fertilizers are applied to restore the amount of nutrient removed from the plant by harvesting. Nevertheless, the immobilized nutrient inside the whole plant should be considered. Based on it, the nutrient concentrations in the guava leaf and fruit and the nutrient contents removed by fruits and post-harvest pruning were evaluated in an irrigated orchard, in Petrolina, State of Pernambuco, Brazil. The greatest contents removed by fruits were N and K among the macronutrients, while Fe, Zn and Mn presented higher levels among the micronutrients. More than 60% of the total content of N, P, K, Mg, Fe, and B removed by pruning were immobilized in the leaf and non-marketable fruit. Index terms: Psidium guajava, mineral nutrition, foliar analysis, fruit analysis. LEVANTAMENTO DOS NÍVEIS DE NUTRIENTES
Resumo -O objetivo deste trabalho foi estudar a translocação e a redistribuição de S pelo transporte acrópeto e basípeto em plantas de milho e de soja. Plantas das duas espécies foram cultivadas em solução nutritiva contendo 35 S em casa de vegetação. O 35 S aplicado em uma única raiz foi prontamente absorvido e translocado para a parte aérea, assim como para as demais raízes cultivadas na ausência de enxofre. O radioisótopo aplicado em uma única folha foi transportado tanto na direção acrópeta quanto na basípeta. Entretanto, o milho e a soja mostraram comportamentos diferentes na absorção e na redistribuição do enxofre. O milho, apesar de ter apresentado maior absorção radicular, reteve grande parte desse elemento na raiz, enquanto a soja absorveu consideravelmente menos, porém apresentou maior eficiência de translocação. Nas plantas de soja, as folhas superiores, principalmente as mais novas, mostraram ser os principais drenos fisiológicos do enxofre.Termos de indexação: Zea mays, Glycine max, transporte de nutrientes, raiz, absorção. Translocation and redistribution of sulphur in corn and soybean plantsAbstract -The objective of this work was to study the S translocation and redistribution by acropetal and basipetal transport in corn and soybean plants. Plants of both species were cultivated in nutritive solution containing labeled 35 S, in a greenhouse. The 35 S applied to only one root was absorbed quickly and transported to the shoot, as well as to the other roots cultivated in non-labeled solution. The 35 S applied to only one leaf was transported both to acropetal and basipetal direction. However, corn and soybean showed different behaviors in S absorption and redistribution. In spite of having larger root absorption, corn retained great part of that S in the root, while soybean absorbed considerably less, but presented greater translocation efficiency. The upper leaves, mainly the youngest, showed to be the main physiologic sinks for S in soybean plants.
RESUMO -Com o objetivo de se obter maior tamanho de baga, peso médio de cacho e produtividade, os cachos da variedade Superior Seedless foram pulverizados com ácido giberélico (1 + 20 mg.L -1 ), bioestimulante Crop Set nas doses de 0,1 e 0,2% e com ou sem anelamento no caule. Esses tratamentos foram aplicados de forma isolada ou combinados entre si. O trabalho foi conduzido durante o período 2001-2002 (dois ciclos de produção), no Campo Experimental de Bebedouro da Embrapa Semi-Árido em Petrolina-PE. O delineamento experimental foi em blocos ao acaso, com 12 tratamentos e três repetições, sendo duas plantas por parcela. Não foram observadas diferenças significativas entre os tratamentos nos dois ciclos de produção. Entretanto, quando o ácido giberélico foi associado ao Crop Set 0,1% e anelamento, observou-se uma tendência de aumento no peso de cachos, bem como no peso e tamanho de bagas na safra de 2001. Os cachos tratados com ácido giberélico apresentaram engaços mais grossos e pesados, embora não se observem diferenças significativas entre os tratamentos. Algumas plantas submetidas ao anelamento apresentaram problemas de cicatrização, o que provocou a morte das mesmas, recomendando-se evitar a realização desta prática nas condições em que se realizou este trabalho. Termos para indexação: uvas sem sementes, bioestimulante, ácido giberélico, Crop Set GIRDLING AND GROWTH REGULATORS: EFFECTS ON THE BIOMETRIC MEASUREMENTS AND QUALITY OF BUNCHES OF VINE 'SUPERIOR SEDLESS'ABSTRACT -Aiming to increase the berry size, weight of bunches and yield, the bunches of the cv. Superior Seedless was powdered with gibberelic acid (1 + 20 mg.L -1 ), bio-stimulant Crop Set in the dosis of 0.1 and 0.2%. In adition was used the treatment known as girdling. Those treatments were applied in an isolated way or combined to each other. The work was carried out during 2001-2002 (two harvest seasons), in the Experimental Station of Bebedouro, Semi-arid Embrapa in Petrolina, Pernambuco State. The experimental design were in randomized blocks with 12 treatments and three replications. The differences among the treatments were not statistical significant in the two evaluated seasons. However, when the gibberelic acid was associated with Crop Set 0.1% and girdling, it was observed a tendency to increase the weight of bunches, as well as, the weight and berry size in the 2001 season. The bunches treated with gibberelic acid presented stronger rachis, although significant differences are not observed among the treatments. Some plants submited to the girdling presented problems with cicatrization, that caused death of them, recomending to avoid this practice in the conditions of this work.
ABSTRACT:Viticulture is an activity of great social and economic importance in the lower-middle region of the São Francisco River valley in northeastern Brazil. In this region, the fertility of soils under vineyards is generally poor. To assess the effects of organic and nitrogen fertilization on chemical properties and nitrate concentrations in an Argissolo Vermelho-Amarelo (Typic Plinthustalf), a field experiment was carried out in Petrolina, Pernambuco, on Syrah grapevines. Treatments consisted of two rates of organic fertilizer (0 and 30 m 3 ha -1) and five N rates (0, 10, 20, 40, and 80 kg ha), in a randomized block design arranged in split plots, with five replications. The organic fertilizer levels represented the main plots and the N levels, the subplots. The source of N was urea and the source of organic fertilizer was goat manure. Irrigation was applied through a drip system and N by fertigation. At the end of the third growing season, soil chemical properties were determined and nitrate concentration in the soil solution (extracted by porous cups) was determined. Organic fertilization increased organic matter, pH, EC, P, K, Ca, Mg, Mn, sum of bases, base saturation, and CEC, but decreased exchangeable Cu concentration in the soil by complexation of Cu in the organic matter. Organic fertilization raised the nitrate concentration in the 0.20-0.40 m soil layer, making it leachable. Nitrate concentration in the soil increased as N rates increased, up to more than 300 mg kg -1 in soil and nearly 800 mg L -1 in the soil solution, becoming prone to leaching losses.
-Yield and physical and chemical characteristics of 'Paluma' guava fruit were evaluated as a function of the harvest at different maturity stages, under influence of nitrogen and potassium fertilization, in Petrolina, State of Pernambuco, Brazil. Fertilizer rates were 67 kg N + 33 kg K 2 O, 133 kg N + 67 kg K 2 O, 200 kg N + 100 kg K 2 O and 267 kg N + 133 kg K 2 O per hectare. Fruits were evaluated at maturity stages 2, 3, 4 and 5, established according to peel color. Higher doses of N and K induced higher yields. Nevertheless, fertilization with 200 kg of N + 100 kg of K per hectare improved fruit quality, delaying ascorbic acid breakdown and conserving pulp firmness. Main changes took place at maturity stages 4 and 5, when the fruit should present ideal conditions for consumption, namely the increase on soluble solids and soluble sugars content. Index terms: Psidium guajava L., nutrition, maturity stages, fruit quality. EFEITOS DOS NÍVEIS DE NITROGÊNIO E POTÁSSIO NA PRODUTIVIDADE E NA MATURAÇÃO DOS FRUTOS DE GOIABEIRA IRRIGADA NO VALE DO SÃO FRANCISCORESUMO -O presente trabalho avaliou a produtividade e as características físicas e químicas dos frutos de goiabeira 'Paluma' em diferentes estádios de maturação, sob a influência de adubações nitrogenada e potássica, em Petrolina-PE. As plantas foram submetidas à aplicação de 67 kg N + 33 kg K 2 O, 133 kg N + 67 kg K 2 O, 200 kg N + 100 kg K 2 O and 267 kg N + 133 kg K 2 O por hectare, sendo os frutos avaliados nos estádios de maturação 2; 3; 4 e 5, caracterizados conforme a cor da casca. As maiores doses de N e K resultaram em maiores produtividades, mas as aplicações de 200 kg de N + 100 kg de K por hectare favoreceram a qualidade do fruto, resultando em menor degradação de ácido ascórbico e preservação da firmeza da polpa. As principais mudanças que ocorreram entre os estádios 4 e 5, quando o fruto apresentaria condições ideais para consumo, foram relativas ao acúmulo de sólidos solúveis e de açúcares solúveis. Termos para indexação: Psidium guajava L., nutrição, estádios de maturação, qualidade do fruto.
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