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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Using adaptive management and modelling to improve nitrogen and water use efficiency in crop production : a case study using annual ryegrass

Fessehazion, M.K. (Melake Kessete) 07 September 2012 (has links)
Poor management of nitrogen (N) fertilisers and water in agro-ecosystems reduces yield, quality and N-use efficiency, and leads to pollution. The objective of this study was to improve irrigation and N management for planted pastures through adaptive management with simple tools and modelling. Field experiments were conducted in 2007 and 2008 at Cedara (KwaZulu Natal) and Hatfield (Gauteng) using annual ryegrass as a case study under a range of N and irrigation application strategies. Collected data sets were also used to calibrate and validate the SWB-Pro (simple) and SWB-Sci (detailed) model versions. After validation, the model was used to develop irrigation calendars and strategies, and estimate irrigation requirements for annual ryegrass. The highest forage yields were produced when N application rates ranged between 30 to 60 kg N ha-1 for each growth cycle, except for the first 2-3 growth cycles when there was high soil N carryover from the previous season. The current farmers’ recommendation (fixed N application rate of 50 kg ha-1 per growth cycle) maximised biomass but reduced pasture quality. Adaptive strategies based on nitrate concentration in wetting front detectors at different depths, reduced fertiliser N application by 28–32% and reduced potentially leachable residual soil N, while improving forage quality without yield reduction. The rate 30-40 kg N ha-1 per growth cycle provided a compromise between forage yield and quality. The SWB model performed well in simulating ryegrass growth, leaf area index, forage yield, root zone soil water deficit, daily evapotranspiration, biomass N uptake and soil nitrate. Site specific and monthly variable irrigation calendars were developed using the SWB-Pro model, for four major milk producing areas of South Africa. The simpler monthly irrigation calendars can be used in the absence of irrigation monitoring tools or more accurate site specific calendars. The SWB-Pro model requires relatively few and simple inputs. However, irrigation monitoring/scheduling with the aid of real time modelling or measurements is better than calendars developed using the SWB-Pro model with long-term historical weather data. The SWB-Sci model showed ways of improving water use efficiency using ‘room for rain’ and ‘mildly deficit irrigation’ approaches in high rainfall areas. Scenario modelling demonstrated that the best management strategy of achieving maximum yield together with low N leaching is by integrating N and water management. This integrated management can be based on the wetness of the soil and nitrate concentration in the deep root zone using wetting front detectors. The model can be used to generate monitoring protocols such as depth of wetting front detector placement and selecting N thresholds to be used for adaptive management. Setting approximate thresholds for wetting depth and nitrate concentration is a first step in implementing an adaptive management strategy. However, the challenge is to find monitoring tools which allow effective implementation of the strategy. In this study, the wetting front detector proved to be a robust, on-farm water and nitrate monitoring tool which is relatively simple and cost effective. Should it become widely adopted, farmers are expected to improve these thresholds as more experience is gained. The SWB model could also be used to evaluate alternative thresholds for adaptive N and water management. / Thesis (PhD)--University of Pretoria, 2012. / Plant Production and Soil Science / unrestricted
22

Screening for Forage Sorghum Genotypes with Chilling Tolerance

Podder, Swarup January 2019 (has links)
Forage sorghum (FS) [Sorghum bicolor (L.) Moench] is a warm-season biomass crop with the potential to become a bioenergy feedstock. The objective of this study was to screen potential FS genotypes for increased chilling tolerance and biomass productivity. The experiments were conducted in Fargo and Hickson, ND, in 2017 and 2018. Seventy-two genotypes of FS were tested at 24, 12, and 10℃. The genotypes were ranked from high to low vigor index and 12 genotypes were planted on two seeding dates: early (10 May) and late (27 May). Field emergence index values were greater for the late-seeding compared with the early-seeding date. Stand establishment and seed mortality were affected by the seeding date. Biomass yield correlated with emergence index and normalized vegetative index. Some of the genotypes tested had increased chilling tolerance and biomass yield when seeded earlier than normal, and may be used for breeding chilling tolerance into FS.
23

Bioenergy crop production's impact on water quality in the Mississippi River basin using the benefit transfer approach.

White, William Tillman 06 August 2021 (has links)
Biofuel production-driven land-use change in agricultural land can have impacts on ecosystem services. Since there is no planned mandate after the Renewable Fuel Standard, there are questions about what implications will future land-use changes have on water quality and how do water quality changes, resulting from potential bioenergy scenarios, affect changes in people's well-being? To answer these questions, I will estimate the value of the predicted changes in water quality under biofuel policy scenarios in counties inside the Mississippi River Basin. From this study, I found that as the percent of land-use changes increase across each county, water quality decreased. I also found that for every unit increase for the change in water quality index, the percentage of individuals' willingness to pay for a change in water quality would increase. The predicted willingness to pay for a change in water quality for a given household varied from -$72 to $143.
24

Agricultural Transformation and Land-Use Change / Evidence on Causes and Impacts from Indonesia / Evidence on Causes and Impacts from Indonesia

Hettig, Elisabeth 24 February 2017 (has links)
No description available.
25

A reestruturação da cotonicultura no Brasil: fatores econômicos, institucionais e tecnológicos / The restructuring of the Brazilian cotton sector: economic, institutional, and technological factors

Alves, Lucilio Rogerio Aparecido 18 September 2006 (has links)
Desde meados dos anos 1970 os preços do algodão vêm caindo no Brasil e, mesmo assim, após a reestruturação dos anos 1990, a produção se expande de forma marcante. Neste trabalho argumenta-se que tal perfomance decorreu de uma conjugação de fatores de ordem tecnológica (do lado da oferta) e mercadológica (do lado da demanda). A capacidade empresarial e empreendedora dos produtores brasileiros foi essencial para aproveitar as oportunidades e superar os obstáculos para que a produção de algodão e derivados alcançasse o elevado padrão de produtividade e eficiência dos dias de hoje. Por um lado, o setor se organizou e se transformou numa ?cotonicultura empresarial?, com o plantio sendo realizado em grandes extensões, num sistema capitalizado e tecnificado. Ao mesmo tempo, a partir dos anos 1990 verifica-se um processo de redefinição institucional. Devido à escassez de recursos estatais a partir dos anos de 1980, a iniciativa privada passa a investir inclusive em pesquisa. Deste processo resultam saltos de produtividade que se viabilizam graças às exportações, que moderavam as quedas de preços que, fatalmente ocorreriam caso a expansão da produção ficasse represada no mercado interno. Desenvolve-se um modelo econômico para aferir o crescimento do setor em termos de choques de oferta e de demanda utilizando as idéias básicas desenvolvidas por Blanchard e Quah (1989), que foram adaptadas ao setor agrícola por Barros; Spolador e Bacchi (2006). Aplica-se a Análise de Auto-Regressão Vetorial ? VAR a dados da renda nacional (PIB), do quantum exportado de algodão em pluma, da produtividade agrícola de algodão em caroço, da área colhida com algodão, da produção de algodão em caroço e do preço recebido pelo produtor no mercado interno. Os resultados do trabalho apontaram que a área colhida com algodão tem uma evolução fortemente marcada por um processo auto-regressivo. Aparentemente, definidas as condições gerais econômicas e tecnológicas, a área da cultura passa a seguir um processo de elevação ou redução em direção ao valor desejado que pode levar uma década ou mais. Entretanto, aproximadamente 30% do crescimento da produção de algodão no Brasil se deveu ao comportamento da produtividade da lavoura. Outros 15% do aumento da produção pode ser atribuído à evolução do preço. Quase um quarto da evolução da exportação de algodão pode ser atribuído ao comportamento da produtividade. Entre trinta e cinco e quarenta porcento se devem a mudanças de produção não associadas diretamente à produtividade e preços. Em síntese, podese dizer que o desenvolvimento da cotonicultura brasileira pode ser atribuído principalmente a mudanças do lado da oferta. / Brazilian cotton prices have been decreasing since the 1970s. Even after the restructuring of the sector, in 1990s, cotton production has been increasing in a great pace. This paper argues that this performance is directly related to technological (supply) and marketing (demand) factors. Entrepreneurial and management abilities were essential to Brazilian growers take opportunities and overcome obstacles. That is why the cotton production has reached the current standard of productivity. The sector has been reorganized, turning into a ?cottonculture business?, with plant activities both in large extensions, as well as capitalized and hi-tech systems. At the same time, from 1990s, it was noted a process of institutional redefinition. Due to scarcity of federal resources starting in 1980s, private companies have also started to invest in cotton research. The result was a big improvement of productivity assisted by increasing exports, which was crucial to support prices. An economic model was developed to measure the growth of the sector in terms of supply and demand disturbances, considering the ideas used by Blanchard and Quah (1989), which were adapted to the agricultural sector by Barros, Spolador, and Bacchi (2006). Analysis of Vector Autoregression ?VAR was applied to data of the national income (Gross Domestic Product ? GDP), the cotton exported volume, the agricultural productivity of cotton, the harvested cotton area, the cotton production, and the price received by growers in the domestic market. The paper concluded that the cotton harvested area showed progress manifested by an Auto Regression (AR) process. Apparently, defined economic and general technological conditions, the area of the culture starts to follow a process of rise or reduction in direction of the desired value that can take one decade or more. However, around 30 percent of the cotton production?s growth in Brazil was related to technical productivity. Another 15 percent of the rise of the production can be attributed to prices? changes. Almost a quarter of development of cotton export can be explained by the productivity. Between 35 and 40 percent is linked to production alterations, not directly linked to productivity and prices. To summarize, the development of Brazilian cotton culture can be associated with supply-side disturbances.
26

Produção de banana ´Nanicão` (Musa sp. AAA) em clima Cwa / Production of banana cv. Nanicão (Musa sp. AAA) in climate Cwa

Domingues, Andréa Ribeiro 24 January 2012 (has links)
O clima classificado como Cwa é considerado marginal para a cultura da bananeira, pois apresenta inverno típico com baixas temperaturas e deficiência hídrica. O objetivo desse trabalho foi estudar o desenvolvimento da bananeira cv. Nanicão (Musa sp. AAA) em clima Cwa. Foram realizados dois experimentos, o primeiro para verificar a formação do cacho da bananeira desde a emissão da inflorescência até a colheita. No segundo experimento avaliou-se os quatro primeiros ciclos, com o objetivo de verificar a variação da duração do ciclo, produção e rendimento anual de cada ciclo. O experimento foi realizado em bananal com 5 anos de idade localizado no município Tiête SP. O bananal corresponde a uma área de 16,0 hectares com plantas oriundas de mudas micropropagadas, espaçamento de 2,4 m x 2,00m, irrigada por aspersão. Os dados meteorológicos foram retirados do Centro Integrado de Informações Agrometeorológicas. Para a condução do experimento 1 foram avaliadas 1104 famílias, no período de maio de 2010 a julho de 2011. Os fatores em estudo foram: época de emissão da inflorescência, duração do intervalo entre a emergência da inflorescência e colheita (I - C), quantidade de emissão de inflorescência nas diferentes épocas, época de colheita, massas dos cachos e produção. No segundo experimento avaliou-se 16,0 hectares de bananeira no período de setembro de 2005 a agosto de 2011. Avaliou - se a duração do ciclo de produção e o período da colheita de cada ciclo, bem como a produção e rendimento médio anual/ha. Foi observado no estudo que a produção de banana nesse tipo de clima é marcada por oscilações. As maiores taxas de emissões de inflorescências e menores durações de I-C ocorrem na época mais quente e chuvosa e taxas inferiores de emissões e durações de I-C foram maiores na época fria e seca do ano. As massas dos cachos e consequentemente as produções variam ao longo do ano, massas superiores são encontradas na época fria e seca e menores massas ocorrem na época quente do ano. Os quatro primeiros ciclos de produção apresentam variações na duração total do ciclo bem como no período de colheita, em consequência o rendimento médio anual de cada ciclo varia, de modo que, a partir do terceiro ciclo o rendimento médio decresce e estabiliza-se devido à extensão da duração do ciclo de produção. / The climate classificated by Cwa is not considerate totally appropriate for banana crop, because has the typical dry winter with low temperature, conditions that injure the plant development. The objective of this research was to verify the banana development cv. Nanicão (Musa sp. AAA) in Cwa climate. Two experiments were performed, the first one verified the development banana bunch formation, since the inflorescence emission until the harvest. The second experiments evaluated the first four cycles, aimed to verify the cycles variation, production and annual yield per cycle. The experiment was developed in field banana Nanicão with 5 years from planting, localized in Tiête São Paulo city. The total area is 16 ha with plants originated by micropropagated seedlings, spacing of 2,4m x 2,00m, irrigated by sprinkling. The meteorogical data was offered by Integrated Centre of Agrometeorogical Information. For the conduction the experiment 1 was evaluated 1104 families in period from May 2010 to July 2011. The factors studied were: epoch of inflorescence emission, time interval between the inflorescence emissions to harvest (I-H), amounts of inflorescences in different epochs of year, time of harvest, mass of bunch and production. In the second experiments aimed the production in total area of 16 ha, between September 2005 to August 2011. Evaluated the cycle time, the period of harvest, the production and medium annual yield per hectare. It was observed in this study the banana Nanicão production in this kind of climate is characterized for great oscillation in the yield during the production cycle. The higher rates of inflorescence emission and lower duration of I-H occurred in the hottest time of the year. The bunch mass and production vary throughout the year. The bunch mass biggest and production occurred in cooler time of the year. The first four production cycles vary a well as the time interval harvest in consequence the annual yield per cycle, so that from third cycle the medium annual yield decrease due to the extension of cycle duration.
27

Tecnologia de produção de maxixe paulista (Cucumis anguria L.). / Paulista gherkin technologic production (Cucumis anguria l.).

Modolo, Valéria Aparecida 06 September 2002 (has links)
Maxixe Paulista é um novo tipo de maxixe obtido a partir do cruzamento de Cucumis anguria x Cucumis longipes. Após ciclos de seleção massal intercalados a ciclos de endogamia, foram obtidas linhagens que diferem do tipo comum pelas suas características de ausência de espiculosidade, tamanho de fruto e formato de folha não lobulada semelhante ao pepino. Em três ensaios de campo, linhagens e híbridos de Maxixe Paulista foram avaliados quanto ao comportamento e produção de frutos em três sistemas de cultivo: a) com cobertura de polietileno e fertirrigação; b) cultivados em vasos com substrato, com tutoramento e podas e em ambiente protegido; c) no sistema de cultivo tutorado em rede agrícola. No primeiro ensaio, foram avaliadas dez linhagens de Maxixe Paulista e uma cultivar do Maxixe Comum. As linhagens de Maxixe Paulista apresentaram um peso médio de fruto de 66 a 91% maior que o tipo Comum. A produção em peso total de frutos não diferiu entre os dois tipos de maxixe. O cultivo em canteiros com cobertura de polietileno e fertirrigação por gotejamento proporcionou uma produtividade estimada de 51,89t.ha -1 . No segundo ensaio, três linhagens do Maxixe Paulista e o tipo Comum foram cultivados em vasos com substrato, em ambiente protegido, com tutoramento e podas. As linhagens de Maxixe Paulista apresentaram um peso médio de fruto de 62 a 84% maior que o tipo Comum. A linhagem 2 foi tão produtiva, em termo de peso total, quanto o tipo Comum porém seu peso médio de fruto foi 75% maior. A planta de maxixe mostrou ser inadequada para condução no protocolo de tutoramento e podas da cultura do pepino. No terceiro ensaio, foram avaliadas quatro linhagens e seis híbridos simples, quanto ao comportamento e produção de frutos no sistema de cultivo tutorado em rede agrícola. A produção e a qualidade dos frutos dos híbridos foi equivalente a das linhagens. A rede agrícola se mostrou adequada para o cultivo de Maxixe Paulista na forma tutorada. A concentração da frutificação ocorreu nas hastes secundárias e terciárias, cujas gavinhas mantiveram as plantas presas à rede. Esta técnica de condução facilitou a colheita e incrementou a qualidade dos frutos. / Paulista Gherkin is a new gherkin type derived from Cucumis anguria x Cucumis longipes. After mass selection cycles intercalated with inbreeding cycles, lines were obtained that differ from the common types by their greater fruit size, spine abscence and non-lobular shaped leaves, similar to cucumber ones. In three experiments, Paulista gherkin lines and hybrids were evaluated for their yield and fruit production in three production systems: a) under polyethylene mulching and fertigation crop system; b) trellised and pruned plants grown in pots with substrate under high plastic tunnel; c) under the trellised net crop system. In the first experiment, ten lines of Paulista Gherkin and one type of Common Gherkin were evaluated. Paulista Gherkin fruits were, in average, 66 to 91% heavier than the Common Gherkin ones. Total fruit weight, of two gherkin types did not differ. Polyethylene-covered bed and drip fertigation use promoted an estimate yield of 51,89 t.ha -1 . In the second experiment, three Paulista Gherkin lines and Common Gherkin were cultivated in pots with substrate, under high plastic tunnel and they were trellised and pruned. Paulista Gherkin fruits were, in average, 62 to 84% heavier than the Common Gherkin ones. Paulista Gherkin line number 2 was productive as the Common type, considering the total fruits weight. However, its average fruit weight was 75% higher. Gherkin plants showed to be inadequate for to be conducted as suggested for the greenhouse cucumber crop protocol. In the third experiment, four lines and six single hybrids performance were evaluated for their yield and fruit production under trellised net crop system. Hybrids and lines were similar for yield and fruit quality. The trellised net crop system showed to be suitable to support Paulista Gherkin plants. Fruit concentration occurred in the secondary and tertiary lateral branch and plants was hold by tendrils on the net. Trellised gherkin in net mate harvest easier and enhance fruit quality.
28

Tecnologia de produção de maxixe paulista (Cucumis anguria L.). / Paulista gherkin technologic production (Cucumis anguria l.).

Valéria Aparecida Modolo 06 September 2002 (has links)
Maxixe Paulista é um novo tipo de maxixe obtido a partir do cruzamento de Cucumis anguria x Cucumis longipes. Após ciclos de seleção massal intercalados a ciclos de endogamia, foram obtidas linhagens que diferem do tipo comum pelas suas características de ausência de espiculosidade, tamanho de fruto e formato de folha não lobulada semelhante ao pepino. Em três ensaios de campo, linhagens e híbridos de Maxixe Paulista foram avaliados quanto ao comportamento e produção de frutos em três sistemas de cultivo: a) com cobertura de polietileno e fertirrigação; b) cultivados em vasos com substrato, com tutoramento e podas e em ambiente protegido; c) no sistema de cultivo tutorado em rede agrícola. No primeiro ensaio, foram avaliadas dez linhagens de Maxixe Paulista e uma cultivar do Maxixe Comum. As linhagens de Maxixe Paulista apresentaram um peso médio de fruto de 66 a 91% maior que o tipo Comum. A produção em peso total de frutos não diferiu entre os dois tipos de maxixe. O cultivo em canteiros com cobertura de polietileno e fertirrigação por gotejamento proporcionou uma produtividade estimada de 51,89t.ha -1 . No segundo ensaio, três linhagens do Maxixe Paulista e o tipo Comum foram cultivados em vasos com substrato, em ambiente protegido, com tutoramento e podas. As linhagens de Maxixe Paulista apresentaram um peso médio de fruto de 62 a 84% maior que o tipo Comum. A linhagem 2 foi tão produtiva, em termo de peso total, quanto o tipo Comum porém seu peso médio de fruto foi 75% maior. A planta de maxixe mostrou ser inadequada para condução no protocolo de tutoramento e podas da cultura do pepino. No terceiro ensaio, foram avaliadas quatro linhagens e seis híbridos simples, quanto ao comportamento e produção de frutos no sistema de cultivo tutorado em rede agrícola. A produção e a qualidade dos frutos dos híbridos foi equivalente a das linhagens. A rede agrícola se mostrou adequada para o cultivo de Maxixe Paulista na forma tutorada. A concentração da frutificação ocorreu nas hastes secundárias e terciárias, cujas gavinhas mantiveram as plantas presas à rede. Esta técnica de condução facilitou a colheita e incrementou a qualidade dos frutos. / Paulista Gherkin is a new gherkin type derived from Cucumis anguria x Cucumis longipes. After mass selection cycles intercalated with inbreeding cycles, lines were obtained that differ from the common types by their greater fruit size, spine abscence and non-lobular shaped leaves, similar to cucumber ones. In three experiments, Paulista gherkin lines and hybrids were evaluated for their yield and fruit production in three production systems: a) under polyethylene mulching and fertigation crop system; b) trellised and pruned plants grown in pots with substrate under high plastic tunnel; c) under the trellised net crop system. In the first experiment, ten lines of Paulista Gherkin and one type of Common Gherkin were evaluated. Paulista Gherkin fruits were, in average, 66 to 91% heavier than the Common Gherkin ones. Total fruit weight, of two gherkin types did not differ. Polyethylene-covered bed and drip fertigation use promoted an estimate yield of 51,89 t.ha -1 . In the second experiment, three Paulista Gherkin lines and Common Gherkin were cultivated in pots with substrate, under high plastic tunnel and they were trellised and pruned. Paulista Gherkin fruits were, in average, 62 to 84% heavier than the Common Gherkin ones. Paulista Gherkin line number 2 was productive as the Common type, considering the total fruits weight. However, its average fruit weight was 75% higher. Gherkin plants showed to be inadequate for to be conducted as suggested for the greenhouse cucumber crop protocol. In the third experiment, four lines and six single hybrids performance were evaluated for their yield and fruit production under trellised net crop system. Hybrids and lines were similar for yield and fruit quality. The trellised net crop system showed to be suitable to support Paulista Gherkin plants. Fruit concentration occurred in the secondary and tertiary lateral branch and plants was hold by tendrils on the net. Trellised gherkin in net mate harvest easier and enhance fruit quality.
29

Ação de produtos fitossanitários utilizados na agricultura orgânica sobre Ascia monuste orseis (Godart, 1818) Lepidoptera: Pieridae / Action of pesticides used in organic farming on Ascia monuste orseis (Godart, 1818) Lepidoptera: Pieridae

Pizzatto, Mariana 20 May 2013 (has links)
Made available in DSpace on 2017-07-10T17:36:51Z (GMT). No. of bitstreams: 1 Mariana_Pizzatto.pdf: 1590245 bytes, checksum: a1210a7b77fed4e9a83c1f6159970110 (MD5) Previous issue date: 2013-05-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The kale (Brassica oleracea var. Acephala), is an important vegetable among the hardwoods, which is attacked by many pests, especially the cabbage leafworm Ascia monuste orseis (Godart, 1818) (Lepidoptera: Pieridae), whose damage occurring directly in the consumption product. Vegetables like cabbage, are important sources of income for family farming in Brazil and can be cultivated in a traditional way or through organic production thus the objective of this study was to evaluate the effects of pesticides used in organic production system on the A. monuste orseis. For this, we used the commercial products Azamax, DalNeem and Dipel, beyond grout sulfur and Bordeaux mixture at recommended concentrations by the manufacturer carrying out tests as the insecticidal activity. The applications were made in cabbage leaf sections (4 × 5 cm) with sprayer. For assessing the effect of treatments on the development of caterpillars offered the leaf sections to first instar larvae for 24 h, after which the larvae were fed leaf sections for free treatment. To check the action of neem-based products on A. monuste orseis in different instars were offered cabbage leaf sections 24 h to sprayed caterpillars of the first, second, third, fourth and fifth instar. A test was also performed to assess the systemic effects of neem on the insect, therefore, kale plant water stress presented received two irrigations, with products based on neem leaves were cut and offered to the caterpillars that received treated leaves throughout the development. In all trials were assessed daily, mortality, duration of instars, total duration of larval, pupal weight male and female pupal with four days of age, duration and pupal viability observing the percentage of adult emergence. Products Azamax, DalNeem and Dipel showed 100% mortality of the first instar, however the grout caused little influence on the development of A. monuste orseis. When tested in different instars Products Azamax, DalNeem presented mortality in all instars tested, and for Azamax did not observe significant difference in mortality between instars, referring to TL 50 and TL 80 is observed that there is increase in time according the age of the oldest caterpillar tracks which require more time to achieve the desired mortality. When applied to soil the product Azamax, presented higher translocation capacity of the plant causing higher mortality, and prolong the larval stage and pupal derail / A couve manteiga (Brassica oleracea var. acephala), é uma importante olerícola dentre as folhosas, que sofre o ataque de várias pragas, destacando-se o curuquerê da couve, Ascia monuste orseis (Godart, 1818) (Lepidoptera: Pieridae), cujos danos ocorrem diretamente no produto de consumo. Hortaliças como a couve, são de importantes fontes de renda para agricultura familiar no Brasil, podendo ser cultivada de maneira tradicional ou através da produção orgânica, sendo assim, o objetivo deste trabalho foi avaliar a ação de produtos fitossanitários utilizados no sistema de produção orgânico sobre A. monuste orseis. Para tanto, foram utilizados os produtos comerciais Azamax, DalNeem e Dipel, além das caldas sulfocálcica e bordalesa, nas concentrações recomendadas pelo fabricante realizando-se testes quanto a atividade inseticida. As aplicações foram realizadas em secções foliares de couve (4 × 5 cm) com pulverizador manual. Para avaliação da ação dos tratamentos no desenvolvimento das lagartas ofereceu-se as secções foliares à lagartas de primeiro ínstar por 24 h, após este período as lagartas foram alimentadas por secções foliares isentas de tratamento. Para verificar a ação dos produtos à base de nim sobre A. monuste orseis nos diferentes ínstares, foram oferecidas secções foliares de couve pulverizadas por 24 h para lagartas de primeiro, segundo, terceiro, quarto e quinto ínstar. Foi também realizado ensaio para avaliar do efeito sistêmico do nim sobre o inseto, para tanto, plantas de couve apresentado estresse hídrico receberam duas irrigações, com os produtos à base de nim e as folhas foram cortadas oferecidas as lagartas, que receberam folhas tratadas durante todo o desenvolvimento. Em todos os ensaios foram avaliados diariamente, mortalidade, duração dos ínstares, duração total da fase larval, peso de pupa macho e pupa fêmea com quatro dias de idade, duração e viabilidade de pupa observando-se a porcentagem de emergência dos adultos. Os produtos Azamax, DalNeem e Dipel, apresentaram 100% de mortalidade de lagartas de primeiro ínstar, no entanto as caldas causaram baixa influência sobre o desenvolvimento de A. monuste orseis. Quando testados nos diferentes ínstares os produtos Azamax e DalNeem apresentaram mortalidade em todos os ínstares testados, sendo que para Azamax não observou-se diferença significativa na mortalidade entre os ínstares, referente ao TL 50 e TL 80 observa-se que há aumento do tempo de acordo com a idade da lagarta onde lagartas mais velhas necessitam de maior tempo para alcançar a mortalidade desejada. Quando aplicados via solo o produto Azamax, presentou maior capacidade de translocação na planta causando maior mortalidade, além de prolongar a fase larval e inviabilizar as pupas
30

Atmospheric Inversion of the Global Surface Carbon Flux with Consideration of the Spatial Distributions of US Crop Production and Consumption

Fung, Jonathan Winston 22 November 2012 (has links)
Carbon dioxide is taken up by crops during production and released back to the atmosphere at different geographical locations through respiration of consumed crop commodities. In this study, spatially distributed county-level US cropland net primary productivity, harvested biomass, changes in soil carbon, and human and livestock consumption data were integrated into the prior terrestrial biosphere flux generated by the Boreal Ecosystem Productivity Simulator (BEPS). A global time-dependent Bayesian synthesis inversion with a nested focus on North America was carried out based on CO2 observations at 210 stations. Overall, the inverted annual North American CO2 sink weakened by 6.5% over the period from 2002 to 2007 compared to simulations disregarding US crop statistical data. The US Midwest is found to be the major sink of 0.36±0.13 PgC yr-1 whereas the large sink in the US Southeast forests weakened to 0.16±0.12 PgC yr-1 partly due to local CO2 sources from crop consumption.

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