Periódicos
URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
Navegar
3 resultados
Resultados da Pesquisa
Item Coffee water use in agroforestry system with rubber trees(Sociedade de Investigações Florestais, 2008) Righi, Ciro Abbud; Lunz, Aureny Maria Pereira; Bernardes, Marcos Silveira; Pereira, Carlos Rodrigues; Teramoto, Edson Roberto; Favarin, José LaercioWater uptake and use by plants are essentially energy processes that can be largely modified by percentage of soil cover, plant type; foliage area and its distribution; phenological stage and several environmental factors. Coffee trees (Coffea arabica - cv. Obatã IAC 1669-20) in Agrforestry System (AFS) spaced 3.4x0.9m apart, were planted inside and along rows of 12- year-old rubber trees (Hevea spp.) in Piracicaba-SP, Brazil (22 42'30" S, 47 38'00" W - altitude: 546m). Sap flow of one-year-old coffee plants exposed to 35; 45; 80; 95 and 100% of total solar radiation was estimated by the heat balance technique (Dynamax Inc.). Coffee plants under shade showed greater water loss per unit of incident irradiance. On the other hand, plants in monocrop (full sun) had the least water loss per unit of incident irradiance. For the evaluated positions average water use was (gH2O.m-2Leaf area.MJ-1): 64.71; 67.75; 25.89; 33.54; 27.11 in Dec./2002 and 97.14; 72.50; 40.70; 32.78; 26.13 in Feb./2003. This fact may be attributed to the higher stomata sensitivity of the coffee plants under more illuminated conditions, thus plants under full sun presented the highest water use efficiency. Express transpiration by leaf mass can be a means to access plant adaptation to the various environments, which is inaccessible when the approach is made by leaf area.Item Measurement and simulation of solar radiation availability in relation to the growth of coffee plants in an agroforestry system with rubber trees(Sociedade de Investigações Florestais, 2007) Righi, Ciro Abbud; Bernardes, Marcos Silveira; Lunz, Aureny Maria Pereira; Pereira, Carlos Rodrigues; Dourado Neto, Durval; Favarin, José LaercioSolar radiation is an important factor for plant growth, being its availability to understory crops strongly modified by trees in an Agroforestry System (AFS). Coffee trees (Coffea arabica – cv. Obatã IAC 1669-20) were planted at a 3.4 x 0.9 m spacing inside and aside rows of monocrops of 12 year-old rubber trees (Hevea spp.), in Piracicaba-SP, Brazil (22°42’30” S, 47°38’00” W – altitude: 546m). One-year-old coffee plants exposed to 25; 30; 35; 40; 45; 80; 90; 95 and 100% of the total solar radiation were evaluated according to its biophysical parameters of solar radiation interception and capture. The Goudriaan (1977) adapted by Bernardes et al. (1998) model for radiation attenuation fit well to the measured data. Coffee plants tolerate a decrease in solar radiation availability to 50% without undergoing a reduction on growth and LAI, which was approximately 2m2.m-2 under this condition. Further reductions on the availability of solar radiation caused a reduction in LAI (1.5m2.m-2), thus poor land cover and solar radiation interception, resulting in growth reduction.Item Crescimento e características anatômicas de cafeeiro (Coffea arabica L.) e seringueira (Hevea brasiliensis Muell. Arg.) em diferentes sistemas de cultivo: monocultivo e consórcio(Editora UFLA, 2004-03) Oliveira, Cláudio Roberto Meira de; Soares, Angela Maria; Oliveira, Luiz Edson Mota de; Castro, Evaristo Mauro de; Barbosa, João Paulo R. Alves DelfinoObjetivou-se avaliar neste trabalho as influências do sistema de cultivo em plantas de seringueiras (Hevea brasiliensis Muell Arg.) e de cafeeiros (Coffea arabica L.) na fase de estabelecimento do plantio. Foram avaliadas características de cresci- mento das plantas de seringueira e a estrutura foliar de cafeeiros e seringueiras em condições de monocultivo e dois tipos de consórcio: renque e margem. Pela análise dos resultados obtidos evidenciou-se que o sistema de cultivo não influenciou o padrão de crescimento das plantas de seringueira. Em geral, o sistema de cultivo não influenciou a anatomia foliar dos cafeeiros nessa fase do cultivo.