Multivitamins/multiminerals in Switzerland: not as good as it seems.

BACKGROUND: Multivitamin/multimineral (MVM) supplements are commonly consumed by the general population, but little is known regarding their composition and compliance with local regulations. We assessed the composition and compliance with regulations [no indication in the label of vitamin/minerals amounting <15% of the acceptable daily intake (ADI)] of MVM available in Switzerland. METHODS: The composition of vitamin/minerals supplements was obtained from the Swiss drug compendium, the Internet, pharmacies, parapharmacies and supermarkets. MVM was defined as the presence of at least 5 vitamins and/or minerals. RESULTS: Of the 254 vitamin/mineral supplements collected, 95 (37%) were considered as MVM. The most frequent vitamins were B₆ (73.7%), C (71.6%), B₂ (69.5%) and B₁ (67.4%); the least frequent were K (17.9%), biotin (51.6%), pantothene (55.8%) and E (56.8%). Approximately half of MVMs provided >150% of the ADI for vitamins. The most frequent minerals were zinc (66.3%), calcium (55.8%), magnesium (54.7%) and copper (48.4%), and the least frequent were fluoride (3.2%), phosphorous (17.9%), chrome (22.1%) and iodine (25%). More than two thirds of MVMs provided between 50 and 150% of the ADI for minerals, and few MVMs provided >150% of the ADI. While few MVMs provided <15% of the ADI for vitamins, a considerable fraction did so for minerals (32.7% for magnesium, 26.1% for copper and 22.6% for calcium). CONCLUSION: There is a great variability regarding the composition of MVMs available in Switzerland. Several MVM do not comply with Swiss regulations, which calls for monitoring and corrective measures.

Seeds with high molybdenum concentration improved growth and nitrogen acquisition of rhizobium-inoculated and nitrogen-fertilized common bean plants

Seeds of common bean (Phaseolus vulgaris) with high molybdenum (Mo) concentration can supply Mo plant demands, but to date no studies have concomitantly evaluated the effects of Mo-enriched seeds on plants inoculated with rhizobia or treated with N fertilizer. This work evaluated the effects of seed Mo on growth and N acquisition of bean plants fertilized either by symbiotic N or mineral N, by measuring the activities of nitrogenase and nitrate reductase and the contribution of biological N2 fixation at different growth stages. Seeds enriched or not with Mo were sown with two N sources (inoculated with rhizobia or fertilized with N), in pots with 10 kg of soil. In experiment 1, an additional treatment consisted of Mo-enriched seeds with Mo applied to the soil. In experiment 2, the contribution of N2 fixation was estimated by 15N isotope dilution. Common bean plants grown from seeds with high Mo concentration flowered one day earlier. Seeds with high Mo concentration increased the leaf area, shoot mass and N accumulation, with both N sources. The absence of effects of Mo application to the soil indicated that Mo contents of Mo-enriched seeds were sufficient for plant growth. Seeds enriched with Mo increased nitrogenase activity at the vegetative stage of inoculated plants, and nitrate reductase activity at late growth stages with both N sources. The contribution of N2 fixation was 17 and 61 % in plants originating from low- or high-Mo seeds, respectively. The results demonstrate the benefits of sowing Mo-enriched seeds on growth and N nutrition of bean plants inoculated with rhizobia or fertilized with mineral N fertilizer.

Lead and zinc in the structure of organic and mineral soil components

In addition to the more reactive forms, metals can occur in the structure of minerals, and the sum of all these forms defines their total contents in different soil fractions. The isomorphic substitution of heavy metals for example alters the dimensions of the unit cell and mineral size. This study proposed a method of chemical fractionation of heavy metals, using more powerful extraction methods, to remove the organic and different mineral phases completely. Soil samples were taken from eight soil profiles (0-10, 10-20 and 20-40 cm) in a Pb mining and metallurgy area in Adrianópolis, Paraná, Brazil. The Pb and Zn concentrations were determined in the following fractions (complete phase removal in each sequential extraction): exchangeable; carbonates; organic matter; amorphous and crystalline Fe oxides; Al oxide, amorphous aluminosilicates and kaolinite; and residual fractions. The complete removal of organic matter and mineral phases in sequential extractions resulted in low participation of residual forms of Pb and Zn in the total concentrations of these metals in the soils: there was lower association of metals with primary and 2:1 minerals and refractory oxides. The powerful methods used here allow an identification of the complete metal-mineral associations, such as the occurrence of Pb and Zn in the structure of the minerals. The higher incidence of Zn than Pb in the structure of Fe oxides, due to isomorphic substitution, was attributed to a smaller difference between the ionic radius of Zn2+ and Fe3+.

Spectroscopic quantification of soil phosphorus forms by 31p-nmr after nine years of organic or mineral fertilization

Long-standing applications of mineral fertilizers or types of organic wastes such as manure can cause phosphorus (P) accumulation and changes in the accumulated P forms in the soil. The objective of this research was to evaluate the forms of P accumulated in soils treated with mineral fertilizer or different types of manure in a long-term experiment. Soil was sampled from the 0-5 cm layer of plots fertilized with five different nutrient sources for nine years: 1) control without fertilizer; 2) mineral fertilizer at recommended rates for local conditions; 3) 5 t ha-1 year-1 of moist poultry litter; 4) 60 m³ ha-1 year-1 of liquid cattle manure and 5) 40 m³ ha-1 year-1 of liquid swine manure. The 31P-NMR spectra of soil extracts detected the following P compounds: orthophosphate, pyrophosphate, inositol phosphate, glycerophosphate, and DNA. The use of organic or mineral fertilizer over nine years did not change the soil P forms but influenced their concentration. Fertilization with mineral or organic fertilizers stimulated P accumulation in inorganic forms. Highest inositol phosphate levels were observed after fertilization with any kind of manure and highest organic P concentration in glycerophosphate form in after mineral or no fertilization.

Effect of fertilization at sowing on nutrition and yield of crambe in second season

The interest in crambe (Crambe abyssinica ) cultivation in Brazil is on the rise, whereas information on the nutrient requirements for this crop is scarce. The objective of this work was to evaluate the effect of nitrogen-phosphorus-potassium (N-P2O5-K2O formula 8:28:16) fertilization (0, 150, and 300 kg ha-1) on crambe shoot biomass production, grain and oil yields, and nutrient extraction and exportation in the second growing season after soybean. The experiment with a Haplorthox (Dystroferric Red Latosol) was carried out for two years in Botucatu, São Paulo State, Brazil. A randomized complete block design with eight replications was used. Fertilization with NPK at sowing increased the shoot biomass production, grain yield, grain oil content, as well as nutrient extraction and exportation at harvest. In the fertilized treatments, the average amounts of nutrients extracted per hectare were 91 kg K, 71 kg N, 52 kg Ca, 9.4 kg P, 9.4 kg Mg, 7.9 kg S, 2,348 g Fe, 289 g Zn, 135 g Mn, and 18.2 g Cu; while the average values of nutrient exportation per hectare were 54 kg N, 20 kg K, 12.3 kg Ca, 10 kg P, 6.6 kg S, 3.2 kg Mg, 365 g Zn, 60 g Fe, 50 g Mn, and 7.3 g Cu, with NPK fertilizer application.

Extractants to assess zinc phytoavailability in mineral fertilizer and industrial by-products

Efficient analytical methods for the quantification of plant-available Zn contained in mineral fertilizers and industrial by-products are fundamental for the control and marketing of these inputs. In this sense, there are some doubts on the part of the scientific community as well as of the fertilizer production sector, whether the extractor requested by the government (Normative Instruction No. 28, called 2nd extractor), which is citric acid 2 % (2 % CA) (Brasil, 2007b), is effective in predicting the plant availability of Zn via mineral fertilizers and about the agronomic significance of the required minimal solubility of 60 % compared to the total content (HCl) (Brasil, 2007a). The purpose of this study was to evaluate the alternative extractors DTPA, EDTA, neutral ammonium citrate (NAC), buffer solution pH 6.0, 10 % HCl, 10 % sulfuric acid, 1 % acetic acid, water, and hot water to quantify the contents of Zn available for maize and compare them with indices of agronomic efficiency of fertilizers and industrial by-products when applied to dystrophic Clayey Red Latosol and Dystrophic Alic Red Yellow Latosol with medium texture. The rate of Zn applied to the soil was 5 mg kg-1, using the sources zinc sulfate, commercial granular zinc, ash and galvanic sludge, ash and two brass slags. Most Zn was extracted from the sources by DTPA, 10 % HCl, NAC, 1% acetic acid, and 10 % sulfuric acid. Recovery by the extractors 2 % CA, EDTA, water, and hot water was low. The agronomic efficiency index was found to be high when using galvanic sludge (238 %) and commercial granular zinc (142 %) and lower with brass slag I and II (67 and 27 %, respectively). The sources galvanizing ash and brass ash showed solubility lower than 60 % in 2 % CA, despite agronomic efficiency indices of 78 and 125 %, respectively. The low agronomic efficiency index of industrial by-products such as brass slag I and galvanizing ash can be compensated by higher doses, provided there is no restriction, as well as for all other sources, in terms of contaminant levels of arsenic, cadmium, chromium, lead, and mercury as required by law (Normative Instruction No 27/2006). The implementation of 2nd extractor 2 % CA and the requirement of minimum solubility for industrial by-products could restrict the use of alternative sources as potential Zn sources for plants.

Optical crop sensor for variable-rate nitrogen fertilization in corn: i - plant nutrition and dry matter production

Variable-rate nitrogen fertilization (VRF) based on optical spectrometry sensors of crops is a technological innovation capable of improving the nutrient use efficiency (NUE) and mitigate environmental impacts. However, studies addressing fertilization based on crop sensors are still scarce in Brazilian agriculture. This study aims to evaluate the efficiency of an optical crop sensor to assess the nutritional status of corn and compare VRF with the standard strategy of traditional single-rate N fertilization (TSF) used by farmers. With this purpose, three experiments were conducted at different locations in Southern Brazil, in the growing seasons 2008/09 and 2010/11. The following crop properties were evaluated: above-ground dry matter production, nitrogen (N) content, N uptake, relative chlorophyll content (SPAD) reading, and a vegetation index measured by the optical sensor N-Sensor® ALS. The plants were evaluated in the stages V4, V6, V8, V10, V12 and at corn flowering. The experiments had a completely randomized design at three different sites that were analyzed separately. The vegetation index was directly related to above-ground dry matter production (R² = 0.91; p<0.0001), total N uptake (R² = 0.87; p<0.0001) and SPAD reading (R² = 0.63; p<0.0001) and inversely related to plant N content (R² = 0.53; p<0.0001). The efficiency of VRF for plant nutrition was influenced by the specific climatic conditions of each site. Therefore, the efficiency of the VRF strategy was similar to that of the standard farmer fertilizer strategy at sites 1 and 2. However, at site 3 where the climatic conditions were favorable for corn growth, the use of optical sensors to determine VRF resulted in a 12 % increase in N plant uptake in relation to the standard fertilization, indicating the potential of this technology to improve NUE.

Coberturas vegetais, manejo do solo, doses de nitrogênio e seus efeitos na nutrição mineral e nos atributos agronômicos do milho

Pesquisas são desenvolvidas buscando identificar a melhor dose de N para o milho nos mais diferenciados sistemas de manejo do solo. O objetivo deste trabalho foi avaliar a influência de coberturas vegetais, os sistemas de manejo do solo e as doses de N em cobertura sobre a produção de matéria seca, nutrição mineral, quebramento e altura de planta e inserção de espiga do milho. Os experimentos foram conduzidos no município de Selvíria, MS, durante os anos agrícolas 2009/2010 e 2010/2011, em Latossolo Vermelho distrófico típico argiloso (20º 20' S e 51º 24' W, com altitude de 340 m). Foram estabelecidos 36 tratamentos com quatro repetições, em blocos casualizados, resultantes da combinação entre coberturas vegetais (milheto, Crotalaria juncea e milheto + Crotalaria juncea), manejo do solo (preparo com escarificador + grade "leve", grade "pesada" + grade "leve" e sistema plantio direto) e doses de N em cobertura (0, 60, 90 e 120 kg ha-1 - utilizando-se ureia como fonte). O híbrido de milho utilizado foi o DKB 350 YG® e o N, aplicado no estádio V5 (quinta folha expandida). O cultivo de crotalária e de milheto + crotalária, como antecessoras, resultou em maior massa de matéria seca da parte aérea, teor de P foliar e quantidade de N, P e K acumulada. O sistema plantio direto proporcionou maior população inicial e final de plantas e matéria seca de parte aérea e menor altura de planta e de espiga. A aplicação de 120 kg ha-1 de N em cobertura proporcionou maior teor de P foliar, teores de N e de P na planta inteira, matéria seca de parte aérea, quantidade de N, P e K acumulada, altura de planta e de inserção de espiga do milho.

Reserva mineral de potássio em Latossolo cultivado com Pinus taeda L.

No Brasil, aproximadamente 1,87 milhões de hectares são plantados com as espécies de Pinus, normalmente em solos pobres quimicamente. Os objetivos deste trabalho foram estudar a mineralogia das frações areia, silte e argila e estimar a reserva mineral de K por diferentes métodos de extrações químicas em solo naturalmente pobre nesse nutriente e cultivado com Pinus taeda L., no Segundo Planalto Paranaense. Foram selecionadas cinco árvores com maior diâmetro (árvores dominantes), em uma área de 500 m², para abertura de uma trincheira (1,6 m) na projeção da copa de cada árvore. Todos os perfis foram classificados como Latossolo Vermelho-Amarelo distrófico típico e apresentaram similaridade na morfologia e na sequência dos horizontes, cujas profundidades médias foram: O = 0,04 m, A1 = 0-0,09 m, A2 = 0,09-0,24 m, BA = 0,24-0,43 m, B1 = 0,43-0,66 m e B2 = 0,66-1,60+ m. As amostras coletadas em cada horizonte foram submetidas a análises físicas (granulometria) e químicas (pH, carbono orgânico, acidez potencial, Al3+ e bases trocáveis, P disponível, K total e não trocável), e as frações areia, silte e argila foram estudadas por difratometria de raios-X (DRX). As frações areia e silte dos solos apresentaram mineralogia bastante uniforme, com predomínio absoluto de quartzo e apenas ocorrência de discretas reflexões de mica por DRX. A fração argila também apresentou limitada ocorrência de minerais micáceos. Os tratamentos sequenciais para remoção de óxidos de Fe, gibbsita e caulinita foram eficientes para concentração de mica na fração argila, o que facilitou a identificação de biotita e muscovita por DRX. Os baixos teores de K não trocável obtidos com diferentes concentrações de HNO3 fervente (máximo de 91 mg kg-1) e de K total extraído com HF concentrado (máximo de 202,7 mg kg-1) foram consistentes com a pobreza das frações do solo em minerais primários, fontes desse nutriente. As correlações positivas e significativas entre os teores não trocáveis de K no solo e os teores e conteúdos do nutriente nas árvores indicaram a importância de formas de reservas do nutriente na nutrição da espécie em solos altamente intemperizados e pobres em K trocável.

Paragênese mineral de solos desenvolvidos de diferentes litologias na região sul de Minas Gerais

Estudos sistemáticos sobre os fatores de formação do solo são relativamente escassos no Brasil, em razão da dificuldade de amostrar vários níveis de um fator, mantendo os demais constantes. A região de Lavras, MG, possui grande diversidade geológica em uma área pequena, o que possibilita avaliar o controle exercido por diferentes litologias na mineralogia e nas demais características do solo. Foram selecionados oito solos embasados sobre quartzito, mica-xisto, gabro, itabirito, serpentinito, metacalcário, gnaisse e filito, em condições semelhantes de vegetação (floresta tropical semidecidual), relevo (terço médio de encosta) e clima. Após a descrição dos perfis, coletaram-se amostras dos horizontes e das rochas, e realizaram-se análises físicas e químicas de rotina, composição química total e mineralogia da rocha, da areia e da argila do solo. Todos os solos são pobres em bases trocáveis (exceto o Argissolo sobre itabirito), e notou-se grande variação na composição granulométrica, mineralógica e química. Os teores de Al2O3, SiO2 e Fe2O3 presentes nas rochas não evidenciaram correlação com os respectivos teores nos solos derivados, enquanto o teor de Fe2O3 foi fortemente correlacionado à densidade de partículas e suscetibilidade magnética. Apesar de evidências de material parcialmente alóctone em alguns casos, pôde-se notar forte influência da litologia subjacente na paragênese mineralógica. Os solos foram genericamente agrupados em: cauliníticos com minerais 2:1 (Argissolos sobre mica-xisto e itabirito; e Cambissolo sobre quartzito), cauliníticos (Argissolos sobre gnaisse e filito) e oxídicos (Latossolos sobre metacalcário e gabro; e Plintossolo sobre serpentinito). Os processos de monossialitização e alitização predominam na região, sendo respectivamente associados a rochas com valores intermediários e baixos em sílica, enquanto a presença de minerais 2:1 é acessória à caulinita e parece depender da presença de mica e altos teores de sílica na rocha de origem.