AVALIAÇÃO DA DESORDEM NUTRICIONAL DE PLANTAS DE AMENDOIM CULTIVADAS EM SOLUÇÃO NUTRITIVA SUPRIMIDAS DE MACRONUTRIENTES

Com o objetivo de avaliar o efeito da omissão de macronutrientes no crescimento e no estado nutricional do amendoim (Arachis hypogaea L.), bem como descrever sintomas visuais de deficiência nutricional, foi desenvolvido um experimento em solução nutritiva na FCAV/UNESP. O delineamento experimental foi o inteiramente casualizado, com sete tratamentos, que corresponderam à solução completa e à omissão individual de N, P, K, Ca, Mg e S, com três repetições. As plantas de amendoim cv. Runner IAC 886 foram cultivadas em solução nutritiva de Hoagland & Arnon em vasos contendo 5 dm³. Foram avaliados a altura das plantas, o diâmetro do caule, o número de folhas, o índice SPAD, a massa seca da parte aérea, das raízes e planta inteira, os teores e o acúmulo dos macronutrientes na parte aérea e raízes e a descrição das desordens nutricionais. A omissão de K, Ca, N, P e Mg foram as que mais limitaram o crescimento vegetativo do amendoim, reduzindo consideravelmente a altura, o diâmetro do caule, o número de folhas, assim como a produção da massa seca do amendoim. Foram observados sintomas de deficiência nutricional de cada elemento. Os teores de nutrientes observados nas plantas de amendoim do tratamento completo e da omissão, na parte aérea, foram, respectivamente: N = 19,0 - 12,2; P = 4,7 - 1,1; K = 27,9 - 4,7; Ca = 10,4 - 1,6; Mg = 6,2 - 0,96; S = 1,2 - 0,7 g kg-1

Biochars in soils : towards the required level of scientific understanding

Key priorities in biochar research for future guidance of sustainable policy development have been identified by expert assessment within the COST Action TD1107. The current level of scientific understanding (LOSU) regarding the consequences of biochar application to soil were explored. Five broad thematic areas of biochar research were addressed: soil biodiversity and ecotoxicology, soil organic matter and greenhouse gas (GHG) emissions, soil physical properties, nutrient cycles and crop production, and soil remediation. The highest future research priorities regarding biochar's effects in soils were: functional redundancy within soil microbial communities, bioavailability of biochar's contaminants to soil biota, soil organic matter stability, GHG emissions, soil formation, soil hydrology, nutrient cycling due to microbial priming as well as altered rhizosphere ecology, and soil pH buffering capacity. Methodological and other constraints to achieve the required LOSU are discussed and options for efficient progress of biochar research and sustainable application to soil are presented.Peer reviewe

The effects of fresh versus aged biochar on the leaching of metals from multi-element contaminated soils

Biochar has been proposed as an effective soil amendment for the management of metal(loid)s [1] via a number of mechanisms: directly sorbed on its surface, by the occlusion of soil particles and, in particular, by modifying soil chemistry such as pH or dissolved organic carbon (DOC). An increase of soil pH induced by biochar has been shown to reduce metal solubility, while a release of labile compounds from biochar has resulted in soil metal leaching [2-4]. Different results may therefore be expected depending on the use of "fresh" or "aged" biochar, subject to weathering which can modify the surface and chemical properties of the biochar. Column leaching experiments were conducted in August 2014 by Frédéric Rees and Dr. Luke Beesley with the help of Aline Peregrina Puga at the James Hutton Institute of Aberdeen (UK), with the support of COST Action TD1107. One agricultural soil contaminated by repeated sewage sludge amendments was tested together with one biochar, used as purchased or aged by exposure to natural rainfall. Instead of amending soils with biochar in a single column, a new protocol was tested (Fig. 1), using one column for each material, linked in a loop system so that the retention of metals from soils by the biochar and the modifications of the biochar on the eluent fed back directly to the contaminated soils could be elucidated. Samples of the leaching solution were regularly collected after the soil column and the biochar column, which enabled the chemical evolution of the soil-biochar systems towards equilibrium to be monitored. Chemical equilibration between soils and biochar was fast, as seen by the identical final pH at the different sampling points of the system. Fresh and aged biochar retained metals released from the agricultural soil and decreased further metal release by increasing soil pH. Fresh biochar became however saturated with Zn at the end of the experiment, while aged biochar did not, indicating that aged biochar had a greater sorption capacity for metals. In conclusion, this work indicated that the simple ageing of biochar before its use as a sorbent amendment can increase its metal retention capabilities

Deficiências de macronutrientes em plantas de soja cv. BRSMG 68 (Vencedora) cultivada em solução nutritiva

Soybean is a crop of great importance for Brazil, and knowledge of their nutritional status allowsproduction and high quality products. Thus, the present work aimed to evaluate the culture of thesoybean cv. BRSMG 68 (Vencedora), submitted to macronutrients omission on the development,nutritional status and the visual symptomatology of nutrient deficiency. The design used wascompletely randomized, with seven treatments that corresponded to the complete (macro andmicronutrients) solution and the individual omission of N, P, K, Ca, Mg and S. The treatments wereapplied two weeks after the emergency of the soybean. The nutrient solution was constantlyoxygenated and replaced weekly, and the pH monitored daily remained around 5. After six weeksof application of the treatments, the height of the plants, number of leaves, stem diameter wasevaluated, matter dry accumulated in the roots, it leaves aerial and the nutritional state and thecharacterization of the visual symptoms. The macronutrient deficiency promoted a decreasein production of root and shoot dry mass of soybean cultivar BRSMG 68 (Vencedora) in nutrientsolution, for the full treatment. The most limiting nutrient for dry matter production of soybeancompared to complete treatment were N, S and K, with decreases of 90, 76 and 73%, respectively.Individual omissions resulted in morphological changes, which were translated by characteristicvisual symptoms of nutritional deficiency of the respective nutrient.A soja é uma cultura de grande importância para o Brasil, e o conhecimento de seu estadonutricional adequado possibilita produções elevadas e produtos de qualidade. Deste modo, opresente trabalho objetivou avaliar plantas de soja cv. BRSMG 68 (Vencedora), submetidas àomissão de macronutrientes no desenvolvimento, estado nutricional e a sintomatologia visual dedeficiência. O delineamento experimental foi inteiramente casualizado, com sete tratamentos quecorresponderam à solução nutritiva de Hoagland completa (macro e micronutrientes) e a omissãoindividual de N, P, K, Ca, Mg e S. Os tratamentos foram aplicados duas semanas após a emergênciada soja. A solução nutritiva foi oxigenada constantemente e substituída semanalmente, tendo opH monitorado diariamente mantendo-se ao redor de 5. Após seis semanas da aplicação dostratamentos, avaliou-se a altura das plantas, o número de folhas, o diâmetro de caule, a matériaseca acumulada nas raízes, parte aérea e o estado nutricional e a caracterização dos sintomasvisuais. A deficiência de macronutrientes promoveu decréscimo da produção de matéria secade raiz e da parte aérea da soja cultivar BRSMG 68 (Vencedora) em solução nutritiva, em relaçãoao tratamento completo. Os nutrientes mais limitantes a produção de matéria seca das plantasde soja comparado ao tratamento completo foram N, S e K, com decréscimos de 90, 76 e 73%,respectivamente. As omissões individuais resultaram em alterações morfológicas, que foramtraduzidas por sintomas visuais característicos da deficiência nutricional do respectivo nutriente

Dacronutrient deficiencies in soybean cv. BRSMG 68 (Vencedora) cultivated in nutritive solution

Aoybean is a crop of great importance for Brazil, and knowledge of their nutritional status allowsproduction and high quality products. Thus, the present work aimed to evaluate the culture of thesoybean cv. BRSMG 68 (Vencedora), submitted to macronutrients omission on the development,nutritional status and the visual symptomatology of nutrient deficiency. The design used wascompletely randomized, with seven treatments that corresponded to the complete (macro andmicronutrients) solution and the individual omission of N, P, K, Ca, Mg and S. The treatments wereapplied two weeks after the emergency of the soybean. The nutrient solution was constantlyoxygenated and replaced weekly, and the pH monitored daily remained around 5. After six weeksof application of the treatments, the height of the plants, number of leaves, stem diameter wasevaluated, matter dry accumulated in the roots, it leaves aerial and the nutritional state and thecharacterization of the visual symptoms. The macronutrient deficiency promoted a decreasein production of root and shoot dry mass of soybean cultivar BRSMG 68 (Vencedora) in nutrientsolution, for the full treatment. The most limiting nutrient for dry matter production of soybeancompared to complete treatment were N, S and K, with decreases of 90, 76 and 73%, respectively.Individual omissions resulted in morphological changes, which were translated by characteristicvisual symptoms of nutritional deficiency of the respective nutrient

Omissão de macronutrientes no crescimento e no estado nutricional da chicória cultivada em solução nutritiva

Com o objetivo de avaliar o efeito da omissão de macronutrientes no desenvolvimento e no estado nutricional da chicória, um experimento foi desenvolvido em casa de vegetação na FCAV/UNESP, Câmpus de  Jaboticabal.  O  delineamento  experimental  foi  inteiramente  casualizado,  com  sete  tratamentos,  que corresponderam à solução nutritiva completa (macro e micronutrientes) e à omissão  individual de N, P, K, Ca, Mg e S, com três repetições. Cada unidade experimental constou de um vaso plástico de 8 L, com duas plantas. Foram avaliadas a altura das plantas, a área foliar, o número de folhas, a matéria seca da parte aérea e da raiz, os teores e acúmulo dos macronutrientes da parte aérea e raiz. A deficiência dos macronutrientes causou  prejuízos  ao  crescimento  das  plantas,  redução  nos  teores  e  acúmulo  dos  nutrientes  e, consequentemente, sintomas visuais típicos da deficiência de cada nutriente

Chemical composition of corn and sorghum grains cultivated in Oxisol with different application methods and doses of zinc

In general, tropical soils present low concentrations of zinc (Zn), and the deficiency of Zn is recognized as a world nutritional problem for cereal production and human beings. Therefore, the main goal of this study was to assess the effects of different methods of Zn application on the quality of corn and sorghum grains grown in Oxisol. Two experiments were set up in the experimental area of UNESP (campus of Jaboticabal, Brazil). The following nine treatments were applied: three doses of Zn by banded application (seed furrows), three doses of Zn by incorporation into soil (0-20 cm depth), foliar application, seed application, and control (no Zn applied). The treatments were arranged in randomized blocks with four replicates. The contents of Zn, carbohydrates and proteins were determined for corn and sorghum grains. Regardless of the method, Zn application promoted higher contents of this micronutrient in corn and sorghum grains. The banded application method of Zn in soil promoted greater contents of total carbohydrates, starch and protein in both cultures. The incorporation of Zn into the soil method provided higher contents of soluble carbohydrates in both corn and sorghum grains.Los suelos tropicales, en general, tienen una baja concentración de zinc (Zn), y la deficiencia de este micronutriente es reconocida como un problema nutricional mundial para la producción de cereales y para los seres humanos. Así, el objetivo de este estudio fue evaluar los efectos de diferentes métodos de aplicación de Zn sobre la calidad del grano de maíz y sorgo. Para esto, se realizaron dos experimentos en el área experimental de FCAV/UNESP, Jaboticabal, Brasil. Se aplicaron nueve tratamientos: tres dosis de Zn aplicadas en forma localizada en los surcos de las semillas, tres dosis de Zn aplicadas en forma incorporada al suelo (0-20 cm de profundidad), una dosis aplicada en forma foliar, y el tratamiento control (sin aplicación de Zn); dispuestos en un diseño de bloques completos al azar con cuatro repeticiones. Las variables medidas fueron: contenido de Zn, proteínas y carbohidratos en los granos de maíz y sorgo. La adición de Zn, independientemente del modo, promovió mayores niveles de este micronutriente en los granos de maíz y sorgo. El modo de aplicación de Zn en el suelo de una forma localizada mostró mayores niveles de carbohidratos, almidón y proteína en las semillas de ambos cultivos. La aplicación de Zn en el suelo de modo incorporado resultó en altos niveles de carbohidratos solubles en los granos de maíz y sorgo