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Efeito da rega com injec o de ar na humidade do solo, dis-ponibilidade de azoto nítrico, condutividade eléctrica e pro-dutividade da alface cultivada em estufa plástica Effects of irrigation with injection of air in soil moisture, nitrate avail-ability, electrical conductivity and lettuce productivity grown in plastic greenhouse  [cached]
C.R. Pivetta,R.M. A. Machado,A. B. Heldwein,L. Dalbianco
Revista de Ciências Agrárias , 2010,
Abstract: Este trabalho teve como objectivo veri-ficar se a injec o de ar junto a água de rega gota-a-gota enterrada, afecta a humi-dade do solo, a disponibilidade de azoto nítrico, a condutividade eléctrica e o cres-cimento e produtividade da alface. Para tal realizou-se um ensaio com a alface variedade “Mention” cultivada em estufa plástica e localizada na Herdade Experi-mental da Mitra-ICAAM, da Universida-de de évora -Portugal. Utilizou-se o deli-neamento experimental blocos ao acaso com quatro repeti es, com os tratamen-tos: rega com injec o de ar (CAR), e rega sem injec o de ar (SAR). O ar foi introdu-zido na água de rega por meio de um injector “Mazzei”. O teor de humidade na camada superficial (0-0,05 m) foi seme-lhante para os dois tratamentos, alcan an-do valores em torno de zero. Em termos de concentra o de azoto nítrico (NO 3-) os valores observados na camada 0,10-0,20 m, aos 35 e 47 dias após a transplan-ta o, foram mais elevados no tratamento CAR. Aos 47 dias após a transplanta o, os níveis médios de NO3-foram de 95,33 e 67,94 ppm nos tratamentos CAR e SAR, respectivamente. A densidade radical no tratamento CAR na camada de 0-0,10 m do solo foi 34 % superior em rela o ao SAR. A produ o comercial n o foi afectada pelo tratamento. A falta de resposta da cultura ao acréscimo de azoto nítrico e da densidade radical pode estar relacionada com o curto ciclo da cultura e/ou com o elevado teor de azoto presente no solo, ou ainda com a profundidade que os goteja-dores foram instalados e n o com a fun-cionalidade do injector de ar. The objective of the present study was to evaluate the effect of the air injection through subsurface drip irrigation (oxyga-tion) in soil moisture, availability of nitro-gen oxide, and electrical conductivity, plant growth and yield of lettuce, variety "Men-tion", cultivated in plastic greenhouse. The experiment was carried out at the Mitra-ICAM, an Experimental Station of the Uni-versity of évora -Portugal. The experiment was arranged in a randomized block design with four replications and the treatments were: irrigation with (CAR) and without (SAR) air injection. The air was introduced into irrigation water through a jet "Mazzei". The soil moisture in the surface layer (0-0.05 m) was similar for the two treatments, reaching values around zero. Concerning NO3-concentration in 0.10-0.20 m soil layer at 35 and 47 days after planting was higher in the treatment CAR. At 47 days after plant-ing, the average levels of NO3-were 95.33 and 67.94 ppm respectively in treatments CAR and SAR. Air injection increased root length densi
Análise Econ mica de Dois Híbridos de Mel o Rendilhado, Cultivados em Ambiente Protegido  [cached]
Marliana Araújo de Sousa,José Wéselli de Sá Andrade,Nelmício Furtado da Silva,Fernando Nobre Cunha
Revista Brasileira de Agricultura Irrigada , 2012, DOI: 10.7127/rbai.v6n100080
Abstract: Este estudo foi desenvolvido na Fazenda de Ensino e Pesquisa da Faculdade de Engenharia – UNESP, Campus de Ilha Solteira - SP. Estudou-se a rentabilidade de dois híbridos de mel o rendilhado (Laurent e Nero), cultivados com cobertura plástica do solo (filme de polietileno de baixa densidade preto) e em solo nu, conduzidos sob duas condi es de ambiente protegido (estufa arco coberta com filme de polietileno normal e estufa arco coberta com filme térmico difusor de luz). Adotou-se o delineamento em blocos ao acaso, em esquema fatorial 23,com cinco repeti es por ambiente. Foram realizados cálculos para o custo de produ o do mel o rendilhado, baseado na estrutura do custo operacional total (COT) de produ o, utilizada pelo Instituto de Economia Agrícola (IEA). As análises econ micas mostraram que todos os tratamentos tiveram taxas de retorno positivas, entre 30,9 e 98,9%
Balan?o de radia??o e energia da cultura de alface em estufa de polietileno
Frisina, Valéria de Almeida;Escobedo, Jo?o Francisco;
Pesquisa Agropecuária Brasileira , 1999, DOI: 10.1590/S0100-204X1999001000003
Abstract: the objective of this paper was to describe the radiation and energy balance, during the lettuce (lactuca sativa, l. cv. ver?nica) crop cycle inside a polyethylene greenhouse. the radiation and energy balance was made inside a tunnel greenhouse with polyethylene cover (100 mm) and in an external area, both areas with 35 m2. global, reflected and net radiation, soil heat flux and air temperature (dry and humid) were measured during the crop cycle. a datalogger, which operated at 1 hz frequency, storing 5 minutes averages was utilized. the global (kˉ) and reflected (k-) radiations showed that the average transmission of global radiation (kˉin / kˉex) was almost constant, near to 79.59%, while the average ratio of reflected radiation (k-in / k-ex) was 69.21% with 8.47% standard-deviation. the normalized curves of short-wave net radiation, in relation to the global radiation (k*/ kˉ), found for both environments, were almost constant at the beginning of cycle; this relation decreased in the final stage of culture. the normalized relation (rn/ kˉ) was bigger in the external area, about 12%, when the green culture covered the soil surface. the long-wave radiation balance average (l*) was bigger outside, about 50%. the energy balance, estimated in terms of vertical fluxes, showed that, for the external area, in average, 83.07% of total net radiation was converted in latent heat evaporation (le), and 18% in soil heat flux (g), and 9.96% in sensible heat (h), while inside of the greenhouse, 58.71% of total net radiation was converted in le, 42.68% in h, and 28.79% in g.
Matura??o da uva niágara rosada cultivada em estufa de plástico e a céu aberto
Schiedeck, Gustavo;Miele, Alberto;Barradas, Carlos Iguassu Nogueira;Mandelli, Francisco;
Ciência Rural , 1999, DOI: 10.1590/S0103-84781999000400010
Abstract: the objective of this work was to evaluate the effect of the plastic greenhouse on the maturation of red niagara (vitis labrusca l.) grapevines. the experiment was carried out in bento gon?alves, rs, brazil, from july 1994 to january 1995. there were two cultural systems (greenhouse and natural condition) and three pruning times for each system (july 21 and august 1st and 11). the variables evaluated in the must were obrix, density, ph, total acidity, and obrix/total acidity. grapevines cultivated in the greenhouse accelerated the process of maturation in all pruning times. grape maturity was anticipated from 17 to 25 days (average of 21 days) when reached 15obrix and from 20 to 33 days (average of 27 days) with 18obrix, varying according to the pruning time. however, considering the greenhouse effect on both the grapevine phenology and the pruning time, grapevines early pruned showed an anticipation of harvest of 32 days when compared to the normal pruning time in the serra gaúcha region. this anticipation of grape maturation could allow prices five times higher when harvested with 15obrix than those obtained with grapes grown in the natural condition.
Conserva??o do jiló em fun??o da temperatura de armazenamento e do filme de polietileno de baixa densidade
Neres, Cláudio Rodrigo Lacerda;Vieira, Gerival;Diniz, Ellen Rúbia;Mota, Wagner F. da;Puiatti, Mário;
Bragantia , 2004, DOI: 10.1590/S0006-87052004000300013
Abstract: the research work was aimed at evaluating the effect of storage temperatures and plastic packing on jilo (solanum gilo raddi) cv. 'tinguá' conservation. the experiment was set up in a complete randomized design with three replications and five fruit/replications. the fruits were stored at 25 °c (openenvironment); 13 °c and 5 °c), wrapped or not wrapped in bags of low density polyethylene (ldpe) with 80 μm thickness. loss of fresh mass, chilling injury, peel color, total soluble solids content (tss) and tritable total acidity (tta) were evaluated. daily losses of fresh mass reached 2.37%, 0.91% and 0.84% in the fruits stored without ldpe protection at 25 °c, 13 °c and 5 °c, respectively while the same losses in wrapped fruits were significantly smaller, in the same temperature conditions (0.079%, 0.037% and 0.029% respectively). fruits stored at 25 °c, with no plastic packing presented the smallest tss contents, while those with ldpe showed the highest values for the trait. a linear increase of tta values was observed in wrapped fruits (5 °c and 13 °c) and a quadratic one at 25 °c; in the unwrapped ones, the smallest tta values were detected at 25 oc along with fast changes in peel color. chilling injury symptoms were present in fruits stored at 5 °c, in all cases, after six days of storage.
Cobertura do solo, produ o de biomassa e teores de Mn e Zn de alface no sistema organico = Soil covering, biomass production, and Mn and Zn content of lettuce in organic system
átila Francisco Mógor,Francisco Luiz Araújo Camara
Acta Scientiarum : Agronomy , 2009,
Abstract: O objetivo deste trabalho foi avaliar o efeito da cobertura do solo com aveia preta e manuten o da palha sobre o terreno, bem como cobertura do solo com filme de polietileno preto, sobre a produ o de biomassa e teores de Mn e Zn em alface cultivada no sistema organico, por dois anos consecutivos. Utilizaram-se cinco tratamentos: solo sem cobertura, coberto com filme de polietileno preto, coberto com aveia acamada, coberto com aveia ceifada e solo coberto com aveia na sua forma natural,para o cultivo de três cultivares de alface. O experimento seguiu delineamento experimental de blocos ao acaso, com quatro repeti es e análise estatística com parcelas subdivididas. Concluiu-se que o cultivo de alface em sucess o à aveia preta,sobre a palha, promoveu produ o satisfatória e apresentou adequados teores demanganês e zinco, equivalentes àqueles encontrados na literatura em diferentes sistemas de cultivo, e a cobertura do solo com plástico preto promoveu produ o satisfatória com maior acúmulo de Zn no primeiro ano e menor de Mn no segundo. The goal of this research was to evaluate the effect of soil covering with black oat straw, as well as soil covered with black plastic, on the production of biomass and levels of Mn and Zn in lettuce produced in an organic system, over two consecutive years. Five treatments were used: soil without cover, covered with black plastic,covered with laying oats, covered with harvested oats, and covered with oat straw in natural form, for growing three cultivars of lettuce. A randomized blocks design was used in a splitplot system, with four replications. It was concluded that soil covered with oat straw promoted satisfactory lettuce production, as well as adequate Mn and Zn content in plants,equivalent to those found in studies conducted under different growing systems; the soil covered with black plastic promoted satisfactory production and higher Zn content after thefirst year, and lower Mn content after the second year.
Desempenho da cultura da rúcula cultivada em época de ver?o em túneis baixos de polietileno perfurado
Pereira, Edilaine R.;Silva, Iran J. O.;Moura, Daniella J.;Piedade, Sonia M. S.;
Engenharia Agrícola , 2004, DOI: 10.1590/S0100-69162004000200006
Abstract: low tunnels is a type of greenhouse that is used for cultivation of species of small load, as lettuce, strawberry, sweet pepper, rocket press and cucumber. this type of greenhouse has a smaller cost of installation than other because its lower high. the plastic covering allows the gain of temperature during the day improving plant growth, protecting the crop from the impact of the rain, cold wind and low temperature. the purpose of this research was to decide the atmosphere changes with the use of polyethylene film with density fall, in low tunnel with perforated area at 0; 5; 10; 15, and 20% in the plastic in the development of the rocket press culture (eruca vesicaria sativa (mill) thell). the results showed different productivity between the tunnel with different holes and significative differences in physics characteristics of plants between some different treatments. as for the inside atmosphere of the tunnel it could see by statistic analysis, that the air temperature in review schedule of the day had significative difference between 0% of perforation and soil without covering, and, the air absolute humidity is higher as much less is the perforated plastic covering.
Processos de prote o dos garfos na enxertia da mangueira  [cached]
Jacomino Angelo Pedro,Minami Keigo,Scarpare Filho Jo?o Alexio,Kluge Ricardo Alfredo
Scientia Agricola , 2000,
Abstract: Diferentes processos de prote o dos garfos foram pesquisados na produ o de mudas por enxertia, da mangueira ?Tommy Atkins?. Os tratamentos utilizados foram os seguintes: saquinho de polietileno (testemunha), filme de PVC, parafilme, cera de abelha, parafina e parafina + vaselina. Verificou-se que o filme de PVC e o parafilme proporcionaram pegamentos de enxertia semelhantes à testemunha (40,60%, 56,62% e 48,33%, respectivamente), enquanto que para os demais tratamentos, os percentuais de pegamento foram muito baixos (< 10%). Conclui-se que o filme de PVC e o parafilme podem ser empregados como op o aos saquinhos plásticos, na prote o dos garfos da mangueira, no procedimento da enxertia.
Compara??o do crescimento e desenvolvimento da alface (Lactuca sativa L.) no interior e no exterior de uma estufa de polietileno em Santa Maria, RS
Segovia, Jorge Frederico Orellana;Andriolo, Jer?nimo Luís;Buriol, Galileo Adeli;Schneider, Flávio Miguel;
Ciência Rural , 1997, DOI: 10.1590/S0103-84781997000100007
Abstract: growth and development of lettuce cultivar brasil- 202, white boston and regina inside and outside of a polyethylene greenhouse were compared in santa maria, rs. during a winter period of 50 days the greenhouse caused an increase in about 256 degree-days in the temperature values above the base temperature for growth (estimated in 10°c). mean soil temperature was also 5.3°c higher inside the greenhouse. the growth patterns of plants cultivated inside the greenhouse were similar to those cultivated outside. growth parameters of leaf surface, shoot fresh weight, dry weight of leaves. stem and roots and the shoot/root ratio were lower outside the greenhouse. the number of leaves per plant was similar in both conditions. brasil-202 showed earlier growth and higher dry matter accumulation. protection of plants with polyethylene greenhouses is an efficient technique to improve lettuce crop production in winter.
Variabilidade da produ o de frutos de piment o em estufa plástica  [cached]
Lorentz Leandro Homrich,Dal?Col Lúcio Alessandro,Boligon Alexandra Augusti,Lopes Sidinei José
Ciência Rural , 2005,
Abstract: As estufas plásticas s o consideradas como um ambiente homogêneo. No entanto, essa afirmativa n o é comprovada, pois existem varia es de produ o entre plantas, causada por diversos fatores externos. S o escassas as informa es relacionadas a técnicas experimentais de planejamento de experimento nestes ambientes. Dessa forma, foram instalados experimentos no Departamento de Fitotecnia/UFSM com a cultura do piment o em estufa plástica nas esta es sazonais de cultivo ver o/outono e inverno/primavera com o objetivo de determinar a variabilidade da produ o, em torno da média, para cada colheita e no total produzido, em diferentes tamanhos de parcela dispostos no sentido da linha. Pelo teste de homogeneidade de variancias, em cada colheita e para produ o total e através da dispers o da produ o média, verificou-se que existe alta heterogeneidade na distribui o da produ o entre as parcelas experimentais de piment o em estufa plástica e que parcelas de 14 plantas na linha de cultivo amenizaram as varia es de solo existentes. O delineamento de blocos ao acaso no sentido das linhas se mostrou adequado para estes ambientes.
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