Propriedades físicas e infiltração de água de um Latossolo Vermelho Amarelo (Oxisol) do noroeste do estado de São Paulo, Brasil, sob três condições de uso e manejo

This study presents the results obtained in a field experiment carried out at Glicério, Northwest of São Paulo state, Brazil, whose objective was to analyze changes of selected soil physical properties and water infiltration rates on a Yellow-Red Latosol, under three different management conditions. The experimental design was arranged as completely randomized split-block with twelve treatments, which corresponded to four depths (0-0.05 m; 0.05-0.10 m; 0.10-0.20 m and 0.20-0.40 m) and three conditions of soil use and management with four replications. The soil surface conditions were: conventional tillage (one disking with moulboard plus two levelling passes with harrow), nine months before starting filed experiences; recent conventional tillage (also one disking with moulboard plus two levelling passes with harrow) and native forest. The conventional tillage areas were cropped for about fifteen years with annual cultures. The considered soil general physical properties were: macroporosity, microporosity, total porosity, bulk density, soil moisture and penetration resistance and, in addition; soil water infiltration rates were also recorded. According to our results, differences on general soil physical properties and infiltration rates appeared when both tilled sub-treatments and native forest were compared. Both, plots recently prepared by conventional tillage and those prepared by tillage but left nine months in rest, presented a statistically significant decrease of constant (final) water infiltration rates of 92.72% and 91.91% when compared with native forest plots.

Concentração de flúor nas águas de abastecimento público de municípios da região noroeste do estado de São Paulo, Brasil

It may be difficult for small and medium cities to obtain information about the fluoride content of public water, because of the lack of equipments and technicians. This study aimed to analyze the fluoride levels of the water supplied by the public treatment stations of 40 cities situated in the northwest region of São Paulo State, during a period of 6 months, to verify if fluoridation occurs in a continuous manner and if the fluoride levels are within the recommended. Maps of the water distribution system were obtained from the water treatment companies and utilized to randomize the addresses of the collection sites, so that they included all regions with treated water sources. One water sample by month was collected and analyzed in duplicate using an ion-specific-electrode. Samples with 0.6 to 0.8 mgF/L were considered acceptable. In the 38 cities that regularly provided the samples in the 6 months of the study, water from 144 collection sites was collected and a total of 864 samples were analyzed, of which 61.81 percent were classified as unacceptable. It was observed that 33 cities performed fluoridation but in 78.79 percent of these cities there were variations in the fluoride level among the sites and in the same site during the period of study. One can conclude that most of these cities do not control the fluoride levels in the public water, since fluoridation occurs in a discontinuous manner and in most of the situations not within the recommended concentrations.

Inflação e desenvolvimento econômico na América Latina: o caso do Brasil

Curso Intensivo de Treinamento em Problemas de Desenvolvimento Econômico

Desenvolvimento no Brasil: relembrando um velho tema

Incluye Bibliografía

O Brasil na primeira década do século XXI: perspectivas do desenvolvimento com estabilidade

Incluye Bibliografía