824 resultados para estufa


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Pós-graduação em Agronomia (Horticultura) - FCA

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The soil is one of the main C pools in terrestrial ecosystem, capable of storing significant C amounts. Therefore, understanding the factors that contribute to the loss of CO2 from agricultural soils is critical to determine strategies reducing emissions of this gas and help mitigate the greenhouse effect. The purpose of this study was to investigate the effect of soil tillage and sugarcane trash on CO2 emissions, temperature and soil moisture during sugarcane (re)planting, over a study period of 15 days. The following managements were evaluated: no-tillage with crop residues left on the soil surface (NTR); without tillage and without residue (NTNR) and tillage with no residue (TNR). The average soil CO2 emission (FCO2) was lowest in NTR (2.16 µmol m-2 s-1), compared to the managements NTNR (2.90 µmol m-2 s-1) and TNR (3.22 µmol m-2 s-1), indicating that the higher moisture and lower soil temperature variations observed in NTR were responsible for this decrease. During the study period, the lowest daily average FCO2 was recorded in NTR (1.28 µmol m-2 s-1), and the highest in TNR (6.08 µmol m-2 s-1), after rainfall. A loss of soil CO2 was lowest from the management NTR (367 kg ha-1 of CO2-C) and differing significantly (p<0.05) from the managements NTNR (502 kg ha-1 of CO2-C) and TNR (535 kg ha-1 of CO2-C). Soil moisture was the variable that differed most managements and was positively correlated (r = 0.55, p<0.05) with the temporal variations of CO2 emission from NTR and TNR. In addition, the soil temperature differed (p<0.05) only in management NTR (24 °C) compared to NTNR (26 °C) and TNR (26.5 °C), suggesting that under the conditions of this study, sugarcane trash left on the surface induced an average rise in the of soil temperature of 2 ºC.

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The present study aimed at evaluating the productive performance of Leporinus macrocephalus fed with different levels of inclusion of poultry viscera meal replacing fish meal. The experiment was conducted in a stove located in the Universidade Estadual do Oeste do Paraná during 45 days. We used 200 fish with average initial length of 4.7 ± 0.37 cm and average initial weight of 1.407 ± 0.03 g, distributed in 20 net-cages. The experimental design was randomized with five treatments and five replicates with five levels of replacement of fish meal by poultry viscera meal (0, 25, 50, 75, 100%). The parameters evaluated were the productive performance and the chemical composition of animals. The inclusion of poultry viscera meal in the substitution of fish meal in the feeding of Leporinus macrocephalus can be used without impairing the performance of the animals.

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The aim of this study was to evaluate CO2 emission, canopy characteristics and herbage accumulation in pastures of pensacola bahiagrass under frequencies of defoliation. The experiment was conducted at the Universidade Estadual Paulista Julio de Mesquita Filho, Faculty of Agrarian Sciences and Veterinary of UNESP, Jaboticabal, São Paulo, Brasil. The experimental period was from May 3rd to July 26th 2012. The experimental area comprised 28 m² of pensacola bahiagrass (Paspalum notatum Flügge), divided into 10 plots for allocation of treatment (frequencies of defoliation = 2 or 4 weeks). The following variables were studied: canopy height, light interception, leaf area index, herbage accumulation, tiller density, CO2 emissions, soil temperature and moisture. The frequencies of defoliation in the months of May, June and July slightly affect pensacola bahiagrass characteristics. CO2, soil temperature and moisture are more associated to environmental conditions (months of evaluation) than to the frequencies of defoliation imposed to the canopies.

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O trabalho teve por objetivo determinar, em casa-de-vegetação, a densidade adequada de adultos, a idade ideal das plantas e a distribuição vertical de ovos nas diferentes partes da planta, visando à realização de estudos de resistência e à melhoria das práticas de manejo de Spodoptera frugiperda em algodoeiro. Os experimentos de oviposição de S. frugiperda em relação à densidade de adultos, relação entre plantas de algodoeiro e oviposição de S. frugiperda e não preferência para oviposição de S. frugiperda em variedades de algodoeiro foram realizados com plantas da variedade de algodoeiro BRS Ita 90. A não preferência (antixenose) para oviposição foi acompanhada nas variedades FiberMax 966, FiberMax 977, DeltaOpal, DeltaPenta, Acala 90, Coodetec 408, Coodetec 409, Coodetec 410, BRS Cedro, BRS Ipê, BRS Aroeira, IPR 96, IPR 20, BRS Araçá, IAC 24 e BRS Ita 90. Concluiu-se que S. frugiperda prefere ovipositar em plantas com cerca de 60 dias de idade, na superfície inferior das folhas situadas no terço superior dos testes de plantas sob condições de estufa. Uma densidade de, pelo menos, três pares de adultos S. frugiperda por planta foi suficiente para realizar testes de não preferência para oviposição em casa de vegetação. As variedades Coodetec 408, BRS Aroeira, BRS Araçá, BRS Ita 90 e DeltaPenta apresentaram resistência do tipo não preferência para oviposição de S. frugiperda. Em regiões com altas infestações de S. frugiperda, seria prudente para o cultivo utilizar a variedade de algodão BRS Ita 90.

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AIM: In this paper we estimate the sediment yield and other related information for a small urbanized watershed, located in Sorocaba, São Paulo State. The driving forces that produce the observed scenario are presented and discussed; METHODS: Over a year, water samples and hydrologic information concerning the river channel were collected monthly at one sampling site. In the laboratory, water samples were oven dried (80 ºC) and the total suspended solid weighed for each sample. To estimate sediment yield we used Colby's simplified method. The sediment delivery ratio (SDR) was estimated using two methods: the relief - length ratio and the bifurcation ratio; RESULTS: The annual sediment yield estimated for the period was 1,636.1 t. The total specific sediment yield was 541.7 t.km -2.y-1. Bedload was the predominant fraction. The SDR changed between 60 and 66% according to the method employed. CONCLUSIONS: The main driving forces of hydrosedimentological disequilibrium are the lack of riparian vegetation, the dumping of construction wastes at inadequate sites, and the launching of untreated sewage. Hence, if these three factors were controlled, a significant improvement in the environmental quality, particularly water quality, might be achieved.

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Making bioproducts available to the market requires finding appropriate processes for mass production and formulation of biological agents. This study aimed at evaluating the Bipolaris euphorbiae production in a solid medium (fermentation in solid substrate) and in a biphasic system (growth in a liquid medium followed by growth in a solid medium), as well as determining the processes for collecting and drying conidia, under laboratory conditions. The influence of the incubation period and inoculum quantity were also investigated. The conidia were dried by using an oven (30ºC, 35ºC, 40ºC, 45ºC, 50ºC, 55ºC and 60ºC), and laminar flow, continuous air flow and aseptic chamber at room temperature. Dry conidia were obtained by sieving and grinding in a ball mill, hammer mill or grain grinder. The conidia viability and sporulation efficiency were evaluated in the solid medium and in the biphasic system. For growth period, the best sporulation on solid medium was obtained after 10 days of incubation, reaching 8.3 x 10(7) conidia g-1 of substrate. The biphasic system did not increase the B. euphorbiae sporulation (4.5 x 10(7) conidia g-1 of substrate), after 14 days, and the amount of liquid inoculum used in this system was not an important factor for increasing its production. The continuous air flow and laminar flow preserved the conidial viability (94.6% and 99.1%, respectively), while promoting a great moisture loss (62.6% and 54.0%, respectively). All the grinding processes reduced the conidia germination (86.2%, 10.5% and 12%, respectively), while sieving allowed the collecting of powdered conidia with high viability (94.8%).

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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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Physic nut (Jatropha curcas L.) is a perennial oilseed species that has aroused economic interest for biodiesel production. Among other factors, it is essential to determine the nutritional demands of this species to facilitate raising it as a crop. This study aimed to evaluate the early growth and mineral nutrition of physic nut, as well as soil fertility, as affected by phosphorus fertilization. The study was carried out in a plastic greenhouse in a completely randomized block experimental design with four replicates. The plants were grown in plastic pots filled with 50 dm³ of Latossolo Vermelho (Rhodic Hapludox). Application rates of 0, 50, 100, 150 and 200 mg dm-3 of P were tested, plus a control. Evaluations of plant height and root collar diameter were performed monthly. The experiment was ended 150 days after transplant of the seedlings, at which time leaf area, dry weight, leaf contents and total accumulation of macro- (N, P, K, Ca, Mg and S) and micronutrients (B, Cu, Fe, Mn and Zn) were performed, and soil chemical properties were analyzed. We concluded that absence of P fertilization alone is as limiting to early growth of physic nut as simultaneous absence of soil amendment and fertilization. The rate of 57 mg dm-3 of P may be recommended for initial growth of physic nut. The total accumulation of nutrients in physic nut seedlings exhibited the following order: K>N>Mg>Ca>P>S>Fe>Mn>B>Zn>Cu. Phosphorus fertilization resulted in increased soil cation exchange capacity (CEC).

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Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV

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Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)