Time filter

Source Type

Lara M.A.S.,Federal University of Lavras | Pedreira C.G.S.,Escola Superior de Agricultura Luiz de Queiroz
Pesquisa Agropecuaria Brasileira | Year: 2011

The objective of this work was to evaluate structural and morphogenetic responses of two species and five cultivars of brachiaria to defoliation intensities. The cultivars Marandu, Xaraés, Arapoty, Capiporã (Urochloa brizantha), and Basilisk (U. decumbens) were mechanically defoliated at 15 and 7.5 cm, in mid-summer and mid-winter. The experimental units (9x4 m plots) were irrigated and fertilized with 220 kg ha -1 per year of N and K 2O. Morphogenetic characteristics measured were: phyllochron, leaf senescence and life span, and leaf appearance and elongation rate. The structural characteristics evaluated were: number of leaves per tiller, final leaf length of fully expanded leaves, stems length, senescence/growth ratio, and tiller density. Variations in meteorological conditions of each season promoted increasing of the appearance rates and leaf elongation, and decreasing of the phyllochron and leaf life span. The structural features most responsive to the gradient promoted by harvesting heights were the final leaf length of expanded leaves and tiller density. The lower harvest height had the greatest impact on growth dynamics in comparison to senescence, in individual tillers. The cultivars Xaraés and Capiporã were more productive due to higher leaf elongation rates and higher tiller density. Source

Cerri C.E.P.,Escola Superior de Agricultura Luiz de Queiroz
Agriculture, Ecosystems and Environment | Year: 2010

The Brazilian Cerrado soils were incorporated into the agricultural production process in the 1970s. The introduction of pastures and/or annual crops utilizing different management systems produced changes in the dynamics of soil organic matter. This study evaluated the microbial attributes of a Typic Quartzipsamment (Arenosols in FAO classification) in native vegetation, pastures, and soybean cultivation under conventional (CT) and no-till (NT) systems. The soil samples (0-5, 5-10 and 10-20 cm layers) were collected in July 2005 and February 2006 from different systems: native Cerrado (CE), CT for 4 years with soybean (CT4 S), CT for 4 years with soybean in rotation with millet (CT4 S/M), an area that has been under pasture for 22 years (PA22), and an area that remained under pasture for 13 years, followed by NT with soybean in rotation with millet for 5 years (NT5). Soil inorganic N (nitrate and ammonium), microbial C and N and basal respiration were determined. The soil metabolic quotient (qCO 2) and the C mic:C org ratios were calculated. The predominant form of inorganic N in the native Cerrado (CE) and in the pasture area (PA22) was ammonium, while the conventional system (CT4 S/M) and no-till system (NT5) areas presented higher nitrogen availability for crops in the form of nitrate. The microbial C and N concentrations increased in the wet season, and the highest values were found in the Cerrado (CE) and in pasture (PA22) areas, where the permanent soil cover and the lack of soil disturbance by agricultural practices allowed more favorable conditions for microbial development. The CT4 S area presented the highest qCO 2 index and the lowest C mic:C total ratio, indicating that the conversion of total carbon into microbial carbon is less efficient in this system. Since sandy soils are more susceptible to degradation, the use of more conservationist management systems promotes more favorable conditions to microbial development and maintenance. © 2009 Elsevier B.V. All rights reserved. Source

Campos C.R.,Federal University of Lavras | Silva C.F.,Federal University of Lavras | Dias D.R.,Unilavras Centro Universitario Of Lavras | Basso L.C.,Escola Superior de Agricultura Luiz de Queiroz | And 2 more authors.
Journal of Applied Microbiology | Year: 2010

Aims: To evaluate the dominance and persistence of strains of Saccharomyces cerevisiae during the process of sugar cane fermentation for the production of cachaça and to analyse the microbial compounds produced in each fermentative process. Methods and Results: Three S. cerevisiae strains were evaluated during seven consecutive 24-h fermentation batches using recycled inocula. The UFLA CA 116 strain had the largest population of viable organisms, and the maximum population was achieved in the fourth batch after 96 h of fermentation. The UFLA CA 1162 and UFLA CA 1183 strains grew more slowly, and the maximum population was reached in the seventh batch. Molecular characterization of isolated yeast cells using PFGE (pulse field gel electrophoresis) revealed that more than 86% of the isolates corresponded to the initially inoculated yeast strain. The concentration of aldehydes, esters, methanol, alcohol and volatile acids in the final-aged beverages were within the legal limits. Conclusions: Cachaça produced by select yeast strains exhibits analytical differences. UFLA CA 1162 and UFLA CA 116 S. cerevisiae isolates can be considered the ideal strains for the artisanal production of cachaça in Brazil. Significance and Impact of the Study: The use of select yeast strains can improve the quality and productivity of cachaça production. Our findings are important for the appropriate monitoring of yeast during sugar cane fermentation. In addition, we demonstrate that UFLA CA 116 and UFLA CA 1162, the ideal yeast strains for cachaça production, are maintained at a high population density. The persistence of these yeast strains in the fermentation of sugar cane juice promotes environmental conditions that prevent or decrease bacterial contamination. Thus, the use of select yeast strains for the production of cachaça is a viable economic alternative to standardize the production of this beverage. © 2009 The Society for Applied Microbiology. Source

Santos Junior J.L.C.,Instituto Federal Of Educacao | Frizzone J.A.,Escola Superior de Agricultura Luiz de Queiroz | Paz V.P.S.,Federal University of Reconcavo da Bahia
IRRIGA | Year: 2014

The optimization of water use has been a challenge for managers, as irrigation planning requires special care, in order to reconcile water balance and demand in terms of quantity as well as spatial and temporal distribution. The objective of this study was to set an optimum crop plan using a linear programming model, with maximum depths of water, to maximize the farmer's income and optimize the use of water resources in Formoso Irrigated District. Maximization of the net revenue in Formoso Irrigated District was R$ 67.643.676,78. The following crop-growing pattern was used: 30 ha squash, 30 ha Phaseolus beans, 1243 ha watermelon, 1542 ha banana, 1200 ha papaya and 300 ha Tahiti lime for the annual volume of 79,649,300 m3. Source

de Souza Jr C.L.,Escola Superior de Agricultura Luiz de Queiroz
Crop Breeding and Applied Biotechnology | Year: 2011

Objectives of this review were to present the state of the art of the technologies used to develop cultivars in allogamous species, excluding the perennial and asexually propagated species. It was reviewed the genetic structure of these species and its relationship with the development of cultivars, the technologies used to develop hybrids and improved open-pollinated varieties and their F1's, and the impact of the biotechnology and the mixed models on the development of cultivars. A summary of results from the researches developed in the maize breeding project at the Department of Genetics of the Agriculture College "Luiz de Queiroz" will be presented. Source

Discover hidden collaborations