Godofredo Cesar Vitti

Concentração de metais pesados em grãos de plantas cultivadas em solo com diferentes níveis de contaminação

The aim of this work was to evaluate the absorption and capacity of translocation of heavy metals from the soil to rice and soybean grains. Experiment was carried out in a greenhouse using a dystrophic Typic Hapludox soil from the district of Paulinia, SP. Soil samples were collected in seven different points and were organized according to the distance from a factory, source of pollution. The experimental design used was the completely randomized, with four replications. The roots, aerial leaves and grains were submitted to humid digestion. The concentrations of heavy metals were determined by ICP-OES. Cadmium and copper concentrations in the grains were at normal levels for both cultures, however manganese and zinc concentrations were in excess, according to the levels of soil contamination, possibly being able to reach top trophic levels. The roots limited the translocation of cadmium, copper, iron and lead to the aerial parts of both cultures. Although the translocation of lead was also limited by the roots, it was present in high concentrations in soy grains and, well as manganese and zinc, it can reach the food chain.

Heavy metal toxicity in rice and soybean plants cultivated in contaminated soil

Os metais pesados podem-se acumular no solo, causando fitotoxicidade em plantas, apresentando alguns sintomas especificos. Por esta razao, este estudo avaliou os sintomas especificos, em plantas de arroz e de soja, causados por excesso de metais pesados no solo. As plantas de arroz e de soja foram cultivadas em vasos, contendo solos com diferentes quantidades de metais pesados. O delineamento experimental foi inteiramente casualizado, com quatro repeticoes, utilizando-se duas culturas e sete amostras de solos com diferentes niveis de contaminacao. As plantas de arroz e de soja exibiram diferentes respostas as elevadas concentracoes desses metais no solo. Por exemplo, altas concentracoes de Zn disponivel no solo causaram fitotoxicidade no arroz e na soja, principalmente cloroses e inibicao do crescimento das plantas. As plantas de arroz acumularam maiores teores de Cu, Mn, Pb e Zn e foram mais sensiveis as concentracoes elevadas desses elementos no solo, absorvendo-os mais facilmente do que as plantas de soja. Alem disso, altas concentracoes de Zn no solo reduziram a concentracao de Fe na parte aerea das plantas de soja e de arroz para niveis considerados deficientes.

Assimilação foliar de enxofre elementar pela soja

The objective of this work was to evaluate the elementary sulfur (S0) assimilation applied on soybean leaves, and its efficiency compared to the fertilization done in the soil, according to the dose and nature of the nutrient source. The S0 applied to leaves, independently of the dose and source, was assimilated by the plant, what resulted in increase of total protein content in the leaf. All S sources applied to leaves increased the grain yield, similarly to the application to the soil. The same productivity was observed with the use of 20xa0kgxa0ha-1 of S0 in the soil or 6xa0kgxa0ha-1 applied to leaves. The elementary S application efficiency on leaves, based on the content of total soluble protein, was superior to application efficiency on soil.

Desempenho produtivo de soja e milho submetidos à aplicação foliar de magnésio

The objective of this work was to evaluate the effect of magnesium foliar spray on yield performance of soybean (Glycine max) and corn (Zea mays) cultivated in soil with adequate levels of base saturation and magnesium content in Brazil. The field trials were conducted on a Typic Hapludox cultivated with soybean and corn in the 2013/2014 and 2014/2015 crop seasons, respectively. Treatments consisted of Mg rates (50, 100, 250, 500, 1,000 and 1,500 g ha-1 and a control without Mg) applied during the V4, R1, and R5.1 (soybean) or V4 and R2 (corn) phenological growth stages as magnesium sulfate heptahydrate (MgSO4∙7H2O). The SPAD index, leaf Mg content, grain yield, and 100-grain weight were evaluated. The Mg foliar spray increased the SPAD index in soybean and the leaf Mg content in corn. The Mg rates of 540 and 890 g ha-1 increased in 325 and 737 kg ha-1 the yield performance of soybean and corn, respectively, regardless of the phenological growth stages. The Mg application during the reproductive stages increased in 2% the 100-grain weight for both crops. Foliar spraying of Mg improves the yield performance in soybean and corn crops.