Volume 31, Number 4, 2007

This study was carried out to evaluate the effect of continuous sewage sludge applications (Sewage Treatment Station of Barueri, São Paulo State, Brazil) on the C content and stock and on the distribution of C-humic fractions of a Red Latosol (Oxisol). The experiment was installed in 1999 on an experimental field of Embrapa Environment, in Juaguariúna (SP). The data were collected after the sixth sludge application (SS) with corn cultivation. The following accumulated SS doses (dry base) were tested: 0, […]

The objective of this work was to evaluate the effects of gross irrigation depths on the nutrient concentration of Eucalyptus grandis seedlings, produced in different substrates. The experiment was carried out in Camará – Mudas Florestais, in Ibaté, São Paulo, in a factorial 5 x 4, with five daily irrigation levels (6, 8, 10, 12 and 14 mm), applied three times a day (at 10 am, 13 pm and 16 pm), on four substrates (FB- coconut fiber; CPV- pine bark […]

The objective of this study was to measure the speed of decomposition and nutrient release in situ from residues of common bean (Phaseolus vulgaris L.) crop. In field conditions, leaves of common bean cultivars senesced during the growth cycle and stems and podwalls after pod threshing were collected. These residues contained 2.3 Mg ha-1 of mass, 31 kg ha-1 of N and 2.4 kg ha-1 of P that corresponded to 63, 41 and 28 % of total mass, N and […]

Nitrogen fertilization applied as sidedressing in corn can be optimized by considering additional soil characteristics as complementary indicators of soil N availability. The objectives of this study were to evaluate the potential use, critical level and best sampling time of the soil nitrate (NO3–-N) concentration to predict soil N availability in corn, as well as to verify if the determination of the soil ammonium (NH4+-N) concentration, in addition to NO3–-N concentration, enhances the efficiency of N availability evaluation. A field […]

Ammonium sulfate (AS) and urea (U), labeled with 15N, were applied to no-till maize, 33 days before and 10 days after sowing, at a single rate of 80 kg ha-1 of N incorporated 5-7 cm deep along furrows spaced 0.8 m. Corn was sown after black oat (Avena strigosa Schieb.).The amount of immobilized N and of N-fertilizer recovered by corn plants was evaluated at the following plants stages: 4-5 leaves, 11-12 leaves, flowering, and at harvest. Treatments were applied in […]

Particle distribution in soil or sediments of coastal plains contributes to the understanding of the sedimentation processes in estuaries. It is an important attribute for applications in studies of palaeoenvironmental reconstruction, geochemical cycles and environmental pollution such as heavy metal and oil spill contamination, which are relatively common in these sites due to human impact. With the objective of characterizing the sedimentary environments according to the particle size and the process of quaternary evolution, 14 mangroves along the São Paulo […]

The integration of farming and cattle production activities in no-tillage system areas with winter cover crops can be an income supplement for summer grain farmers. However, many of them are afraid of adopting this integration system, because of possible negative effects of animal treading on soil attributes, mainly of those related to soil compaction. This study was conducted: (1) to determine the alterations in the soil physical attributes promoted by animal treading; (2) to verify if the alterations in soil […]

Among conservation tillage methods, no-till has shown to be the most effective in reducing soil losses caused by rainfall erosion, but with considerable data variation regarding water loss. Considering these aspects, this study was carried out with the objective of evaluating soil and water losses, the chemical demand of oxygen (CDO), electrical conductivity, and the pH of surface runoff, associated with interrill erosion under simulated rainfall. The field study was conducted in October 2003 in Marechal Cândido Rondon county, western […]

As a result of anthropogenic activities such as mining, metal industry and agricultural fertilizer application, metal pollution has become one of the most serious environmental problems of today. Phytoremediation denotes the use of plants and micro-biota, together or without soil amendments, to extract, sequester, and/or detoxify pollutants, has been reported to be an effective, non-destructive, inexpensive and socially accepted technique to remediate polluted soils. The objective of this work was to evaluate the efficiency of organic amendments in the reduction […]

Soil contamination by organic compounds, especially by the petroleum-derived, polycyclic aromatic hydrocarbons (PAHs), is a growing problem with serious environmental consequences. To evaluate the environmental impact of these products it is important to understand their effects on plants and the associated microbiota. The effects of PAHs on growth and mycorrhizal colonization of Brachiaria brizantha and Pueraria phaseoloides were evaluated here. Two PAHs, anthracene and creosote, were applied to a soil infested with the mycorrhizal fungus Glomus etunicatum at varied concentrations: […]