Navegando por Assunto "Cultura de soja"

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Acesso aberto (Open Access)
Balanço de água em área de cultivo de soja no Leste da Amazônia
(Universidade Federal do Pará, 2007) BISPO, Carlos José Capela; RIBEIRO, Aristides; http://lattes.cnpq.br/8652338930029697; ROCHA, Edson José Paulino da; http://lattes.cnpq.br/2313369423727020
The expansion of the agricultural frontier, driven mainly by soy cultivation (Glycine max (L) Merrill), covers a large regional extent and is highly important to understanding the changing face of Amazonia. A field observation experiment was established to study water balance components of the soy agriculture ecosystem and analyze the impact of the water balance associated with forest conversion. The experiment also evaluated the crop’s need for water according to its development phase. For the water balance study, the BRS Candeia cultivar was used along with its respective phenological phases. The experiment measured soil water storage, precipitation, plant cover water interception, superficial drainage of soil water, evapotranspiration (Etc), and water content retained by the soy plant. Water infiltration in the soil was also measured. Interception and superficial drainage were 45,9% and 1% of the precipitation, respectively. The greatest evapotranspiration occurred during the flowering phase (R1-R2) with a gradual decline in values until crop harvest and a cycle average of 3,80mm.day-1, which was very similar to that found in forest. The period between the vegetative phase (V) and fruiting (R3-R4) was when the plant presents the greatest percentage of water, declining gradually during the grain-forming phase (R5). Overall, no water deficiency occured in the mean soil water balance. Precipitation was greater than the amount necessary to compensate for evapotranspiration and supply adequate water storage, creating a surplus of water in the soil.
Acesso aberto (Open Access)
Características agrometeorológicas da cultura de soja (Glycine max (L.) Merrill) variedade Candeias em Paragominas – PA
(Universidade Federal do Pará, 2008-01-31) SANTOS, Ana Patrícia Ramos Araújo dos; RIBEIRO, João Batista Miranda; http://lattes.cnpq.br/1874829087396349
The local authority of Paragominas belongs to the South-east Mesorregião from Pará (03 ° 00 ' 00 ” S and 47 ° 21 ' 30 " W) where there is the whole area already altered for deforestation and pastures only waiting for being incorporated to the productive agricultural process. The culture of the soy has significant importance for the national economy, being one of the principal agricultural produce of export and generation of emblems, pertaining to the family of the leguminous plants, is adapted in a spacious belt of climates, being able to be cultivated in all the types of ground. The objective of this study is to value the conditions agrometeorológicas during the vegetative cycle of the soy at Paragominas - PA. In this area there was built a meteorological automatic tower of 4 meters of height, being the farm white Ox located to 03°02 ´ 15 " S and 47°17 ´ 56 " W and when a station was installed with measures to each (5) five minutes of the next variables: temperature of the air (Tar), specific moisture of the air (q), temperature of the ground (Tsolo), moisture of the ground (Usolo), speed of the wind (W), direction of the wind (D), solar radiation incident (Sin), solar radiation reflected (Sout), balance of radiation (Rn) and flow of heat in the ground (G) and Haste. Microclimatic variations have quite straight effects in the development of the plant. The collections when the beginning of June of 2006 was carried out between February show that the days 84, 98 and 126 were the days of bigger haste and the days 70 and 154 and 161 there was no rain. In accordance with the development of the planting we notice that in the February the beginning of April on the very specific moisture of the air maintained elevated 21,0 g/Kg. The journey of the temperature the maxim of the air was maintained between 23,5 ºC and 32,5 ºC accompanying the development of the culture. The middle temperature of the ground in three measures (5, 10 and 20 cm), noticed to itself that the temperatures are between 25 ºC to 35 ºC. In the beginning of the planting the speed of the wind was about 3 m/s decreasing, and in the end of the cultivation 2,5 was m/s. In the period of blooming the speed was maintained stable what contributes to the dispersal of pollen and seeds. The wind comes from all the directions, meantime, the wind is predominant of northeast. When the ground is still completely naked, the albedo is lifted up, since the radiation that enters in the system is same that it goes out. When the albedo begins to develop the planting it has a tendency to lessen, since the quantity of solar radiation that reaches the system part is reflected and other one absorbed by the surface. The middle moisture of the ground in three measures (10, 20 and 30 cm), where we notice that the moisture is between 0,2 m⁄m to 0,45 m⁄m. The flow of heat in the ground to 10 cm presented peaks around-135 W/m2 and 55 W/m2 (7 the 18 h) and to 20 cm he presented peaks around-25 W/m2 and 45 W/m2 (7 the 18 h). The positive sign represents transfer of heat of the air for the ground and the flow was of the surface for the most internal layers of the ground. When we analyse the appreciated evapotranspiration we notice what was inferior of what the evapotranspiration when 4,0 mm⁄dia was appreciated and the measured evapotranspiration 8,8 mm⁄dia. When we analyse the linear regression to appreciated evapotranspiration the measured evapotranspiration was lower.
Acesso aberto (Open Access)
Edge effects and the impact of wildfires on populations of small non-volant mammals in the forest-savanna transition zone in Southern Amazonia
(2012) FREITAS, Tiago Magalhães da Silva; ALMEIDA, Vitor Hudson da Consolação; VALENTE, Roberta de Melo; MONTAG, Luciano Fogaça de Assis
The impact of fire and edge effects on the community of small non-volant mammals was investigated in transitional Amazon forest within a matrix of soybean plantations. The animals were live trapped on 24 line transects, of which 16 were distributed in unburned areas and 8 in a burned area. A total of 11 species was recorded, including six rodents and five marsupials. The abundance and richness of small mammals appeared to decrease in burned areas, although this impact appeared to mask edge effects. In the absence of fire impacts, a positive relationship was found between mammal abundance and the distance from the forest edge. The impact of the edge effect on the diversity of small mammals appears to be influenced by the type of anthropogenic matrix and the ecological characteristics of the different species.