A major limitation for using sewage sludge in agriculture is the risk of soil contamination with heavy metals and their possible transference to humans via food chain. The objective of this study was to evaluate the soil content of Cd, Cr, Pb, and Zn by two digestion methods (HNO3 + H2O2 + HCl and HClO4 + HF) in maize plants grown on a Typic Eutrorthox soil treated with sewage sludge for nine consecutive years, and the effects on dry matter […]

A large proportion of soybean fields in Brazil are currently cultivated in the Cerrado region, where the area planted with this crop is growing considerably every year. Soybean cultivation in acid soils is also increasing worldwide. Since the levels of toxic aluminum (Al) in these acid soils is usually high it is important to understand how cations can reduce Al rhizotoxicity in soybean. In the present study we evaluated the ameliorative effect of nine divalent cations (Ca, Mg, Mn, Sr, […]

Successive applications of cupric fungicides to grapevine can increase total copper concentration in the soil and modify its desorption in the soil profile. This study was carried out in 2006 in the soil chemistry and fertility laboratory of the Universidade Federal de Santa Maria to evaluate copper forms and desorption dynamics in Udorthent and Haplumbrept soils (in the layers 0-20 and 20-40 cm) under grapevine for 40 years and under successive applications of cupric fungicides. The soils were collected in […]

Land application represents an efficient alternative for disposal of biosolids. However, depending on the origin (urban and/or domestic) and the treatment system, biosolids may contain high amounts of heavy metals, which can gradually build up in the soil. Soil chemical amendments in contaminated areas can reduce the bioavailability and mobility of heavy metals and, consequently, minimize the risks of their adverse effects on the environment. The objective of this study was to evaluate the effects of four chemical amendments [calcium […]

A greenhouse experiment was carried out to evaluate: (a) the soil Cd and Zn availability to maize plants with and without liming, using the DTPA, EDTA, Mehlich-1, and Mehlich-3 extractants; (b) The effect of Cd and Zn doses on plant growth and metal accumulation in maize; and (c) toxicity symptoms and anatomical changes in leaves and roots exposed to Cd and zinc. Maize was grown for 30 days in soil contaminated with either Cd (0, 1, 3, 5, 10, 20 […]

The objectives of the present study were to evaluate the effects of arbuscular mycorrhiza, the plant P nutritional status and increasing levels of P in nutrient solution on Zn toxicity to Trema micrantha (L.) Blum. In a first experiment trema seedlings were grown in a substrate with increasing P rates [0, 100, 200 and 400 mg dm-3 as Ca(H2PO4)2], besides a mycorrhizal treatment inoculated with Glomus etunicatum (Ge). After 60 days of growth, the plants were transferred to pots with Clark’s nutrient solution […]

The final disposal of sewage sludge has become a cause of environmental concern. Because of its high content of both organic matter and plant nutrients, sewage sludge has been used as fertilizer. However, it is important to know the fractions and bioavailability of heavy metals in sludge-amended soils. In the case of zinc, one of the most abundant metals in sewage sludge, knowledge on forms and plant availability are important to predict its behavior in soils. The present experiment was […]

The presence of heavy metals can restrict the use of sewage sludge as a source for plant nutrients since they may contaminate soil, aquifers and plants. Urban sewage sludge from the Treatment Station of Ilha do Governador (ETIG), Rio de Janeiro, Brazil, was enriched with 1.667 mg kg-1 Cd and 8.000 mg kg-1 Zn. After 20 days of incubation under a constant humidity of 50% (g g-1), doses of 0, 20, 40 and 80 t ha-1 were applied to two soil samples (red-yellow Latosol (LV) and red-yellow Argisol […]

The effects of lime rates on the growth of Eucalyptus camaldulensis in soil mixtures with increasing proportions of Zn and Cd contamination were evaluated. The experiment was carried out under greenhouse conditions and the metal contamination levels were obtained by mixing 0, 25, 50, and 100% of a contaminated soil with a non-contaminated one used as diluter. Lime rates were 0, 10, 20, 40, and 80 t ha-1 and the experiment was conducted in pots containing 1.5 kg of soil with treatments arranged […]

Sewage sludge from wastewater treatments contains organic matter and plant nutrients that may play an important role in agricultural production and maintenance of soil fertility. The present study aimed to evaluate the effect of increasing sewage sludge rates on soil chemical properties, heavy metal concentration in soils and plants, and the growth of maize and bean plants cultivated in pots under greenhouse conditions. Two soil types with different clay contents were used for application of six sewage sludge rates (equivalent […]