964 resultados para Agricultural geography - Brazil


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[1] Surface-based measurements of atmospheric formic acid (HCOOH), acetic acid (CH3COOH), sulfur dioxide (SO2), hydrogen chloride (HCl), and nitric acid (HNO3) were made in central São Paulo State, Brazil, between April 1999 and March 2000. Mean concentrations were 9.0 ppb (HCOOH), 1.3 ppb (CH3COOH), 4.9 ppb (SO2), 0.3 ppb (HCl), and 0.5 ppb (HNO3). Concentrations in sugar cane burning plumes were 1160-4230 ppb (HCOOH), 360-1750 ppb (CH3COOH), 10-630 ppb (SO2), 4-210 ppb (HCl), and 14-90 ppb (HNO3). Higher ambient concentrations of SO2, HCl and HNO3 were measured during the burning season (May-November). Concentrations of SO2 and HCl increased during the evening, and of HCOOH and CH3COOH were lowest in the morning, with peak levels in the afternoon. Ratios obtained between different species showed either nighttime maxima (SO2/HCOOH, SO2/CH3COOH, SO2/HNO3, CH3COOH/HNO3, SO2/HCl and HCOOH/HNO3), daytime maxima (HCOOH/HCl, CH3COOH/HCl and HNO3/HCl), or no clear trends (HCOOH/CH3COOH). Correlation analysis showed that SO2 and HCl were primary emissions from biomass burning and road transport; HCOOH, HNO3 and CH3COOH were products of photochemistry; HCOOH and CH3COOH were emitted directly during combustion as well as from biogenic sources. Biomass burning affected atmospheric acidity on a regional scale, while vehicular emissions had greater impact in urban and adjacent areas. Atmospheric ammonia levels were insufficient to neutralize atmospheric acidity, which was mainly removed by deposition to the surface.

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We report here on the application of a compact ultraviolet spectrometer to measurement of NO2 emissions from sugar cane field burns in São Paulo, Brazil, the time-resolved NO2 emission from a 10 ha plot peaked at about 240 g (NO2) s(-1), and amounted to a total yield of approximately 50 kg of N, or about 0.5 g (N) m(-2). Emission of N as NOx (i.e., NO + NO2) was estimated at 2.5 g (N) in 2, equivalent to 30% of applied fertilizer nitrogen. The corresponding annual emission of NOx nitrogen from São Paulo State sugar cane burning was >45 Gg N. In contrast to mechanized harvesting, which does not require prior burning of the crop, manual harvesting with burning acts to recycle nitrogen into surface soils and ecosystems.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Studies the effects of investment in research and extension on total agricultural production and on production of individual crops. Some distributional effects are briefly discussed. Due to the lack of data, the first part of the analysis is restricted to the State of Sao Paulo, and the second part covers the entire country.-from Author

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Agrarian reform has long been an acute issue in Brazil, where the distribution of cultivable land is extremely unequal. The Land Statute adopted by the military in 1964 constituted a genuine reform programme, which, however, was never implemented as the government chose to modernize agriculture and expand cultivated areas. This has prevented the poorest from having access to the land.-from English summary

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Includes bibliography

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Forest fragmentation occurs normally in an area around the city or with high agricultural influence, such as the Forest of Quilombo that lies in Metropolitan Campinas/SP- Brazil. This forest is one such example since it is separated from the other forest fragments in the region for several types of human action. The objective of this study is to analyze the macro and micronutrients and soil edaphic insect fauna in the forest, pasture and sugar cane and inferring the impacts caused by the Mata do Quilombo cattle farming and urban expansion in chemical aspects of soil. Samples were collected in June/11, according to the procedure of method traps pitfall traps. In addition, at each sampling point four composite samples were collected for soil fertility analysis. Samples were collected at six points: pasture, degraded forest (near pasture), preserved forest (near pasture), degraded forest (near cane sugar), preserved forest (near cane sugar), and sugar cane sugar. The samples thus prepared were analyzed Ca, P, K, Mg, pH, organic matter, H + Al, Sum of Base (SB), Base Percentage Saturation (V%), Cation Exchange Capacity (CEC) and trace elements (S, B, Cu, Fe, Mg and Zn). Generally it can be seen that the group of organisms of soil fauna presented with little biodiversity. The number of individuals also shows little species, taxonomic groups showing the highest degree of impact that the remaining forest has suffered. Regarding the analysis of fertility it can be observed that the soil of the surrounding areas of the forest is under direct influence of agriculture. © 2013 WIT Press.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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If riparian buffer zones are ineffective in preventing C-4 plant carbon from upland areas reaching the stream sediment, the composition of stream fauna can be significantly altered. The permeability of riparian forest strips in agricultural, small subtropical watersheds in south-eastern Brazil was measured in nine watersheds categorised according to the predominant land cover of the legally required 30-m buffer riparian zone. Four watersheds with well preserved riparian forest along the 30-m buffer zone were designated as FOREST watersheds; three watersheds, with a predominance of C-4 grasses from sugarcane to pasture, mixed with preserved riparian forests, were designated MIXED watersheds; and two watersheds were termed PASTURE-SUGAR because their entire 30-m buffer zone was covered by C-4 plants. Stable carbon (delta C-13) isotopes were used as tracers of upland C-4 carbon in sediments, suspended particulate organic carbon, terrestrial and aquatic invertebrates and two species of neotropical fish. Although the intact 30-m buffer zone of riparian forests did not entirely prevent the input of C-4 to the river environment and food web, there was a significant increase in C-4 carbon in those watersheds where the buffer zone was not covered by riparian forests. These findings emphasise the importance of riparian forests in mitigating disturbance in streams and support efforts to preserve such riparian corridors.

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The time required to regrowth a forest in degraded areas depends on how the forest is removed and on the type of land use following removal. Natural regeneration was studied in abandoned old fields after intensive agricultural land use in areas originally covered by Brazilian Atlantic Forests of the Anchieta Island, Brazil in order to understand how plant communities reassemble following human disturbances as well as to determine suitable strategies of forest restoration. The fields were classified into three vegetation types according to the dominant plant species in: 1) Miconia albicans (Sw.) Triana (Melastomataceae) fields, 2) Dicranopteris flexuosa (Schrader) Underw. (Gleicheniaceae) thickets, and 3) Gleichenella pectinata (Willd.) Ching. (Gleicheniaceae) thickets. Both composition and structure of natural regeneration were compared among the three dominant vegetation types by establishing randomly three plots of 1 x 3 m in five sites of the island. A gradient in composition and abundance of species in natural regeneration could be observed along vegetation types from Dicranopteris fern thickets to Miconia fields. The gradient did not accurately follow the pattern of spatial distribution of the three dominant vegetation types in the island regarding their proximity of the remnant forests. A complex association of biotic and abiotic factors seems to be affecting the seedling recruitment and establishment in the study plots. The lowest plant regeneration found in Dicranopteris and Gleichenella thickets suggests that the ferns inhibit the recruitment of woody and herbaceous species. Otherwise, we could not distinguish different patterns of tree regeneration among the three vegetation types. Our results showed that forest recovery following severe anthropogenic disturbances is not direct, predictable or even achievable on its own. Appropriated actions and methods such as fern removal, planting ground covers, and enrichment planting with tree species were suggested in order to restore the natural forest regeneration process in the abandoned old fields.

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The time required to regrowth a forest in degraded areas depends on how the forest is removed and on the type of land use following removal. Natural regeneration was studied in abandoned old fields after intensive agricultural land use in areas originally covered by Brazilian Atlantic Forests of the Anchieta Island, Brazil in order to understand how plant communities reassemble following human disturbances as well as to determine suitable strategies of forest restoration. The fields were classified into three vegetation types according to the dominant plant species in: 1) Miconia albicans (Sw.) Triana (Melastomataceae) fields, 2) Dicranopteris flexuosa (Schrader) Underw. (Gleicheniaceae) thickets, and 3) Gleichenella pectinata (Willd.) Ching. (Gleicheniaceae) thickets. Both composition and structure of natural regeneration were compared among the three dominant vegetation types by establishing randomly three plots of 1 x 3 m in five sites of the island. A gradient in composition and abundance of species in natural regeneration could be observed along vegetation types from Dicranopteris fern thickets to Miconia fields. The gradient did not accurately follow the pattern of spatial distribution of the three dominant vegetation types in the island regarding their proximity of the remnant forests. A complex association of biotic and abiotic factors seems to be affecting the seedling recruitment and establishment in the study plots. The lowest plant regeneration found in Dicranopteris and Gleichenella thickets suggests that the ferns inhibit the recruitment of woody and herbaceous species. Otherwise, we could not distinguish different patterns of tree regeneration among the three vegetation types. Our results showed that forest recovery following severe anthropogenic disturbances is not direct, predictable or even achievable on its own. Appropriated actions and methods such as fern removal, planting ground covers, and enrichment planting with tree species were suggested in order to restore the natural forest regeneration process in the abandoned old fields.

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"One of a series of reports on agricultural, pastoral, and forest industries in the American Republics."