Ammonia volatilization from pelletized urea with micronutrients in a controlled environment
01/Jun/2013
New technologies that enable a reduction in NH3-N volatilization losses should be developed to increase the N use efficiency of urea. The incorporation of boron and copper into urea can reduce these effects by inhibiting urease activity. The experiment was conducted in a greenhouse, testing the application of different N fertilizers (urea pellets with and without boron and copper, ammonium sulfate, urea with urease inhibitor NBPT, granulated urea and urea coated with boron and copper) to the surface of a […]
Effect of sulphur rates and incubation time on the dynamics of sulphur forms in soil
01/Jun/2013
Sulphur availability depends on the dynamics of its soil forms. An experiment was carried out to evaluate the effects of adding sulphur doses (0, 20, 50, 80, and 120 mg dm-3 of S), as calcium sulphate, and the incubation time (1, 8, 15, 30, 60, and 90 d) on the equilibrium between labile and non-labile sulphur reserves, in 10 soils. An anion exchange resin membrane was used to determine labile sulphur. A shaking period of 48 h (of water, soil […]
Soil fauna in a periodically flooded restinga salt marsh area in Marambaia, RJ
01/Jun/2013
In the litter-soil compartment, soil fauna plays an important role in nutrient availability for plants, since it regulates the microbial community involved with organic matter decomposition and fragmentation. The aim of this study was to evaluate the richness and abundance of soil fauna as well as its vertical distribution on a periodically flooded sandbank area (“restinga”) in Marambaia Island – RJ, in two season (summer -rainy and winter- dry). Litter and soil was sampled (0-5 cm), from which fauna was […]
Influence of sand fractions on water retention and availability in Caiuá and Paranavaí sandstone formations
01/Jun/2013
It has been found that the results of the land use and management techniques adopted for soils derived from Caiuá sandstone in the Northwest of Paraná are not always satisfactory in terms of crop yields. In this region, sandstone occurs in two forms: the Caiuá and Paranavaí Formations, with differences in soil particle size. We hypothesized that the water retention and availability for agricultural production is lower in the Caiuá soils, due to the higher proportion of coarse sand than […]
Soil carbon and nitrogen stocks in traditional agricultural and agroforestry systems in the semiarid region of Brazil
01/Jun/2013
In the semiarid region of Brazil, inadequate management of cropping systems and low plant biomass production can contribute to reduce soil carbon (C) and nitrogen (N) stocks; therefore, management systems that preserve C and N must be adopted. This study aimed to evaluate the changes in soil C and N stocks that were promoted by agroforestry (agrosilvopastoral and silvopastoral) and traditional agricultural systems (slash-and-burn clearing and cultivation for two and three years) and to compare these systems with the natural […]
Erodibility, soil cover and management and conservation practices in rainfed ultisol
01/Jun/2013
The soil loss prediction models have become important tools for conservation planning, being fundamental the local estimation of the parameters that influence the erosion processes. The objective of this work was to determine the soil erodibility (K factor), soil cover and management factor (C factor) and conservation practice factor (P factor) of the Universal Soil Erosion Equation (USLE), in an Ultisol. Soil losses (SL) were measured in Wischmeier standard-plots from 2006 to 2011, with the respective erosivity index (EI30). Soil […]
Root morphology and potassium uptake kinetic parameters in irrigated rice genotypes
01/Jun/2013
The efficiency of uptake of a nutrient by plants is a function of their physiological and morphological properties, which may vary between cultivars of the same species. A study was carried out to determine root morphology and kinetic parameters of potassium (K) uptake in rice genotypes. The experiment was conducted in a laboratory and the plants cultivated in pots under artificial light. Treatments were represented by 11 rice genotypes (Avaxi, BRS Atalanta, BRS Bojuru, BRS Fronteira, BRS Querência, CNA 10754, […]
Origin of sandstones from the Guará formation and their pedologic cover in Rio Grande do Sul, Brazil
01/Jun/2013
In the west and southwest regions of Rio Grande do Sul (RS) there are extensive areas with fragile soils developed from sandy sediments of the continental Mesozoic Paraná Basin. Inappropriate land use has accelerated the process of sandy desertification in these areas. In this case, the knowledge of soils is critical for the choice of appropriate management systems to regain sustainability. The objectives of this study were to understand the evolution and describe the relationships, in terms of origin, between […]
Structure quality of an oxisol submitted to compaction
01/Jun/2013
The structure change caused by soil compaction is a limiting factor to growth and development of plants. The objective of this study was to evaluate the physical parameters of an Eutrophic Oxisol in Jaboticabal, SP. Aggregate stability, hydraulic conductivity and “S” index were evaluated in a completely randomized split-plot (four levels of compaction and two depth), with four replications and an area of native forest (NF) as control. The compaction treatments consisted of C0 = 0, C1 = 2, C2= […]
Fertilization with filter cake and micronutrients in plant cane
01/Jun/2013
The response of sugarcane to application of micronutrients is still not very well known. In view of the need for this information, the aim of this study was to evaluate the application of the micronutrients Zn, Cu, Mn, Fe, B, and Mo to plant cane in three soils, with and without application of filter cake. This study consisted of three experiments performed in the State of São Paulo, Brazil, (in Igaraçu do Tiete, on an Oxisol; in Santa Maria da […]