Escola Superior de Agricultura Luiz de Queiroz

São Luís, Brazil

Escola Superior de Agricultura Luiz de Queiroz

São Luís, Brazil
SEARCH FILTERS
Time filter
Source Type

Frazao L.A.,Escola Superior de Agricultura Luiz de Queiroz | Paustian K.,Colorado State University | Pellegrino Cerri C.E.,Escola Superior de Agricultura Luiz de Queiroz
GCB Bioenergy | Year: 2013

As oil palm has been considered one of the most favorable oilseeds for biodiesel production in Brazil, it is important to understand how cultivation of this perennial crop will affect the dynamics of soil organic carbon (SOC) in the long term. The aim of this study was to evaluate the changes in soil C stocks after the conversion of forest and pasture into oil palm production in the Amazon Region. Soil samples were collected in March 2008 and September 2009 in five areas: native forest (NARF), pasture cultivated for 55 years (PAST), and oil palm cultivated for 4 (OP-4), 8 (OP-8) and 25 years (OP-25), respectively. Soils were sampled in March 2008 to evaluate the spatial variability of SOC and nitrogen (N) contents in relation to the spacing between trees. In September 2009, soils were sampled to evaluate the soil C stocks in the avenues (inter rows) and frond piles, and to compare the total C stocks with natural forest and pasture system. Soil C contents were 22-38% higher in the area nearest the oil palm base (0.6 m) than the average across the inter row (0-4.5 m from the tree), indicating that the increment in soil organic matter (SOM) must have been largely derived from root material. The soil C stocks under palm frond piles were 9-26% higher than in the inter rows, due to inputs of SOM by pruned palm fronds. The soil carbon stocks in oil palm areas, after adjustments for differences in bulk density and clay content across treatments, were 35-46% lower than pasture soil C stocks, but were 0-18% higher than the native forest soil C content. The results found here may be used to improve the life cycle assessment of biodiesel derived from palm oil. © 2012 Blackwell Publishing Ltd.


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.


Savio F.L.,Escola Superior de Agricultura Luiz de Queiroz | Da Silva G.C.,Federal University of Goais | Teixeira I.R.,State University of Goiás | Borem A.,Federal University of Viçosa
Semina:Ciencias Agrarias | Year: 2011

The objective of this study was to evaluate the effect of sources of silicon on the agronomic traits and on Si content on B. decumbens cv. Brasilisk and P. maximum, cv. Mombaça cultivated in a B horizon soil collected from a Latosol at the "Zona da Mata Mineira", Brazil. The experimental design was a completely randomized block in a 4 x 2 factorial, with four replications. Treatments consisted of three sources of silicon (sodium silicate, rocksil and potassium silicate, with doses of 40 g L-1 of Si) and a control, all combined with two forage grass species (B. decumbens cv, Basilisk and P. maximum cv. Mombaça). Results showed that Si sprayed on leaves promoted increase in dry biomass content in the second and third harvests of P. maximum. Foliar fertilization with Si also increased silicon absorption in both species, especially in the second and third harvests. The three silicon sources did not differ among them, as a source of silicon applied on leaves.


De Gaspari L.C.,Escola Superior de Agricultura Luiz de Queiroz | Khatounian C.A.,Escola Superior de Agricultura Luiz de Queiroz
Revista de Economia e Sociologia Rural | Year: 2016

The structure of farms is associated with family characteristics and to sale strategy, for a given expectation of income generation and risk exposure. To understand this association, seven cases of settled families were studied in a land reform settlement in Araraquara-SP, Brazil, a region dominated by sugarcane and citrus plantations. The indicators were total aggregated value, the aggregated value per worker, family structure and dynamics and farm-work organization. The cases comprised two farms integrated with agroindustry (sugarcane and chicken, milk and chicken), three vegetable producers (selling in wholesale, semi-wholesale and farmers' market), a family that produced exclusively for household consumption and a family without economic production. Families associated with agroindustry had the highest aggregated values, but had to make greater investments, which increased risk exposure. The world financial crisis of 2008 broke the agroindustries and both integrated properties. Vegetable producers had lower aggregated values than farms integrated with agroindustry, but their investments needs were accordingly lower. The choice for vegetable sale route was associated with family composition and with technologic and market knowledge present in the family.


Ferraz S.F.B.,Escola Superior de Agricultura Luiz de Queiroz | Lima W.D.P.,Escola Superior de Agricultura Luiz de Queiroz | Rodrigues C.B.,IPEF Institute of Forestry Research and Studies
Forest Ecology and Management | Year: 2013

Forest ecosystems play an important role in water conservation yet forest plantations are considered detrimental because of their high water use. The current worldwide trends of reduction in natural forest and expansion of forest plantations increases the need for forest managers to contribute to water conservation, implementing management plans that integrate economic (productivity and growth), social (equity of access to water and land-use conflicts) and environmental (climate change and biodiversity impacts) factors. In this paper, we show examples of forest management alternatives at macro- and meso-scales that could contribute to improve water conservation in forest plantation landscapes. At the macroscale, we assess water use in different forest plantation areas in Brazil by analyzing the theoretical thresholds for the management of evapotranspiration. Then, using data from an experimental catchment, we modeled water yield reduction by a forest plantation over multiple years and assessed how different meso-scale forest plantation management alternatives affected water flow regulation. Results show that at a macroscale it is important to consider the natural climatic constraints of water availability. Evidence shows that forest plantations in the tropics use water according to its availability, and the appropriate choice of species/varieties and associated forest management options are crucial for water conservation. At the meso-scale we found that the proportion of native forest plays an important role in the reduction and regulation of water use, and therefore a system of mosaic management may be able to stabilize water flow across plantation landscapes. © 2012 Elsevier B.V.


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.


Andrade S.A.L.,University of Campinas | Gratao P.L.,Escola Superior de Agricultura Luiz de Queiroz | Azevedo R.A.,Escola Superior de Agricultura Luiz de Queiroz | Silveira A.P.D.,Instituto Agronomico | And 2 more authors.
Environmental and Experimental Botany | Year: 2010

The influence of jack bean [Canavalia ensiformis (L.) D.C.] mycorrhization, by the arbuscular mycorrhizal (AM) fungus Glomus etunicatum, in response to increasing Cu concentrations in soil (0, 50, 150 and 450 mg dm-3) was studied. In the highest Cu dose, mycorrhiza decreased Cu concentrations in plant organs and promoted biomass accumulation. In addition, mycorrhizal colonization was not affected by Cu suggesting certain tolerance of the inoculated AM fungus to this metal. Cu-induced proline accumulation and an increase in soluble amino acid contents in leaves, with higher proline contents in AM plants. Marked differences in foliar soluble amino acid composition were also observed in response to Cu in the soil. The activity of key antioxidant enzymes increased mainly in the leaves of non-AM plants, indicating increased production of reactive oxygen species. However, changes in malondialdehyde content were not observed suggesting an effective antioxidant system. Independent of mycorrhization, glutathione content in leaves decreased as Cu increased in the soil. Phytochelatins were detected in the leaves of both Cu treated and untreated plants, and quantitative and qualitative differences were observed due to mycorrhization. In summary, the AM fungus was able to maintain an efficient symbiosis with jack bean plants in soil containing high Cu concentrations. A combination of physiological and nutritional changes caused by the symbiotic association that might be of interest for phytoremediation strategies in Cu-contaminated soils. © 2009 Elsevier B.V. All rights reserved.


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.


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.


Medeiros J.C.,University of Sao Paulo | Figueiredo G.C.,Escola Superior de Agricultura Luiz de Queiroz | Mafra A.L.,Santa Catarina State University
Revista Brasileira de Ciencia do Solo | Year: 2010

To express the negative effects of soil compaction, some researchers use critical values for soil mechanical strength that severely impair plant growth. The aim of this study was to identify this critical compaction depth, to test the functionality of a new, portable penetrometer developed from a spring dynamometer, and compare it to an electronic penetrometer traditionally used in compaction studies of agricultural soils. Three soils with distinct texture were conventionally tilled using a disk plow, and cultivated with different plant species. The critical soil resistance defined to establish critical compaction depth was equal to 1.5 MPa. The results of the new equipment were similar to the electronic penetrometer, indicating its viability as a tool for assessing the soil physical conditions for plant growth.

Loading Escola Superior de Agricultura Luiz de Queiroz collaborators
Loading Escola Superior de Agricultura Luiz de Queiroz collaborators