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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.
11

Gergelim irrigado em função da adubação nitrogenada em duas safras agrícolas / Sesame irrigated due to nitrogen fertilization in two agricultural crops

Santos, Manoel Galdino dos 17 February 2017 (has links)
Submitted by Socorro Pontes (socorrop@ufersa.edu.br) on 2017-07-19T14:21:23Z No. of bitstreams: 1 ManoelGS_DISSERT.pdf: 1850481 bytes, checksum: 38ebeeaccd9b0ab617bb5bba4c837f81 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-07-25T14:44:21Z (GMT) No. of bitstreams: 1 ManoelGS_DISSERT.pdf: 1850481 bytes, checksum: 38ebeeaccd9b0ab617bb5bba4c837f81 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-07-25T14:44:49Z (GMT) No. of bitstreams: 1 ManoelGS_DISSERT.pdf: 1850481 bytes, checksum: 38ebeeaccd9b0ab617bb5bba4c837f81 (MD5) / Made available in DSpace on 2017-07-25T14:45:12Z (GMT). No. of bitstreams: 1 ManoelGS_DISSERT.pdf: 1850481 bytes, checksum: 38ebeeaccd9b0ab617bb5bba4c837f81 (MD5) Previous issue date: 2017-02-17 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Sesame is an oleaginous that presents great economic potential, due to the possibilities of exploration. It is a crop of low productivity, and may be superior when management in fertilization is appropriate. However, more information about the nutrition of the crop is needed. Nitrogen is one of the nutrients that most limits the production of sesame because it is responsible for important functions of metabolism and nutrition of the crop. Therefore, the objective of this work was to evaluate the cultivars of irrigated sesame in the function of nitrogen fertilization in two agricultural crops. Experiments were conducted at the Experimental Farm Rafael Fernandes, belonging to the Federal Rural Semi-Arid University, Mossoró-RN, from February to May (1st crop) and July to October (2nd crop) in 2016. The experimental design was in randomized complete blocks with four replications in a subdivided plots scheme, being allocated in the plots five nitrogen doses (0, 30, 60, 90 and 120 kg ha-1), and the four sesame cultivars in the subplots (CNPA G2 , CNPA G3, CNPA G4 and BRS Silk). The variables evaluated were: nitrogen content in the leaf diagnosis, plant height, stem diameter, number of leaves and capsules, dry mass (leaf, stem, capsules and plants), seed productivity, agronomic efficiency, oil and protein content. The dose of 120 kg ha-1 of nitrogen provided the best agronomic performance for sesame. The cultivar CNPA G4 had the highest productive performance. The cultivar BRS Silk had a higher oil content. The second crop provided better agronomic performance to the sesame crop / O gergelim é uma oleaginosa que apresenta grande potencial econômico, devido às possibilidades de exploração. É uma cultura de baixa produtividade, podendo ser superior quando há manejo adequado na adubação. Contudo, maiores informações sobre a nutrição da cultura precisam ser obtidas. O nitrogênio é um dos nutrientes que mais limitam a produção do gergelim, por ser responsável por importantes funções do metabolismo e da nutrição da cultura. Diante disso, o objetivo deste trabalho foi avaliar cultivares de gergelim irrigado em função de adubação nitrogenada em duas safras agrícolas. Os experimentos foram conduzidos na Fazenda Experimental Rafael Fernandes, pertencente à Universidade Federal Rural do Semi-Árido, Mossoró-RN, no período de fevereiro a maio (1ª safra agrícola) e julho a outubro (2ª safra agrícola) de 2016. O delineamento experimental foi em blocos completos casualizados com quatro repetições em esquema de parcelas subdivididas, sendo alocadas nas parcelas cincos doses de nitrogênio (0, 30, 60, 90 e 120 kg ha-1), e nas subparcelas as quatros cultivares de gergelim (CNPA G2, CNPA G3, CNPA G4 e BRS Seda). As variáveis avaliadas foram: teor de nitrogênio na folha diagnóstico, altura de plantas, diâmetro do caule, número de folhas e cápsulas, massa seca (folha, caule, cápsulas e plantas), produtividade de sementes, eficiência agronômica, teor de óleo e proteína. A dose de 120 kg ha-1 de nitrogênio propiciou o melhor desempenho agronômico para o gergelim. A cultivar CNPA G4 teve o maior desempenho produtivo. A cultivar BRS Seda teve maior teor de óleo. A 2ª safra agrícola proporcionou melhor desempenho agronômico à cultura do gergelim / 2017-07-19
12

Statistical Estimation of Vegetation Production in the Northern High Latitude Region based on Satellite Image Time Series

Shen, Meicheng 24 October 2019 (has links)
No description available.
13

Změny délek odobí s charakteristickými teplotami vzduchu / Changes of length of periods with characteristic temperatures

Černochová, Eva January 2006 (has links)
Title: Changes of lengths of periods with characteristic air temperatures Author: Eva Černochová Department: Department of Meteorology and Environment Protection Supervisor: doc. RNDr. Jaroslava Kalvová, CSc. Supervisor's e-mail address: jaroslava.kalvova@mff.cuni.cz Abstract: Lengths of periods with characteristic air temperatures were derived using two different methods (linear interpolation, robust locally weighted regression) for 10 stations in the Czech Republic and for output data of regional climate models HIRHAM and RCAO in 4 grid points. Averages for a forty-year period (1961-2000) and for a thirty-year period (1961-1990) were computed as well as averages for every decade. Considerable attention was also paid to the analysis of methods used in the research. Most stations showed lengthening of growing season and summer during the twentieth century. Decennary average length of growing season and summer shortened in the years 1971-1980. The comparison of output data of regional climate models HIRHAM and RCAO and measured station data showed that the thirty-year average lengths of growing season and summer estimated by the two models were reasonably accurate approximately half of all cases. The models' estimates were not accurate at all concerning decennary averages. Keywords: robust locally...
14

Determinação dos regimes de precipitação, estação de cultivo e épocas de plantio no Estado da Paraíba. / Determination of precipitation regimes, growing season and planting seasons in the State of Paraíba.

BASTOS, Eduardo Jorge de Brito. 01 October 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-10-01T15:36:19Z No. of bitstreams: 1 EDUARDO JORGE DE BRITO BASTOS - DISSERTAÇÃO PPGMet 1986..pdf: 20375801 bytes, checksum: ff9bb773d868a10b480b4ad31add8635 (MD5) / Made available in DSpace on 2018-10-01T15:36:19Z (GMT). No. of bitstreams: 1 EDUARDO JORGE DE BRITO BASTOS - DISSERTAÇÃO PPGMet 1986..pdf: 20375801 bytes, checksum: ff9bb773d868a10b480b4ad31add8635 (MD5) Previous issue date: 1986-04-30 / Analisando as distribuições anuais da precipitação média semanal, determinadas com base nas séries dos totais diários de precipitação de 71 postos p1uviométricos do Estado da Paraíba, com mais de trinta anos de observação, identificaram-se cinco regimes pluviais com um total de 12 sub-regimes. Estes regimes de precipitação delimitam regiões com características c1 ima to 1ogicamente semelhantes do ponto de vista da distribuição temporal das chuvas. Com base na curva média da distribuição da precipitação de cada sub-regime, determinaram-seas estações "chuvosa" e "úmida" pelo método dos percentuais relativos ã semana mais chuvosa. Estimaram-se valores de temperatura médias mensais para aquelas Estações onde apenas disponham de dados de precipitação, através de regressão múltipla onde a temperatura é uma função das coordenadas geográficas: latitude (Ø) , longitude (λ) e altitude (Z). A temperatura média anual foi obtida pela média aritmétrica das temperaturas médias mensais. Utilizando-se dessas temperaturas médias anuais, estimou-se a temperatura média diária pelo método da análise harmônica, cujos coeficientes harmônicos são estimados com base nas séries de temperatura diária compensada das cinco Estações com dados disponíveis. A evapotranspiração potencial foi então estimada, para períodos semanais, com base no método proposto por THORNTHWAITE & MATHER (1955) . Com as curvas anuais médias de evapotranspiração potencial e precipitação, representativas de cada sub-regime,determinou-se as estações de cultivo potencial (ECP) e a época de plantio (EP) para as culturas de arroz, milho e sorgo, levando-se em consideração o GDA(ECP) para uma temperatura base de 10°C e as faixas de requerimentos térmicos de cada uma dessa s culturas. / Using the annual distribution of weekly mean precipitation, obtained from the daily precipitation data with more than 30 years of observations for Paraíba state, five regi mes and twelve sub-regimes of precipitation were identified. These precipitation regimes are characterized by limiting re gions c1 ima to 1ogica 11y similar from the point of view of the temporal rain distribution. The precipitation mean curve for each regime was used for determining the so called "rainy" and "humid" seasons by the method of the percentages relatives to the most rainy week. Mean monthly temperatures, for these stations having precipitation data only, were estimated through a multi pie regression in which the temperature is a function of the local coordenates: latitude (Ø) , longitude (λ) and altitude (Z). The annual mean temperature was obtained as the arithmetic mean of the monthly mean values. These annual mean temperatures were used for estimating the corresponding daily values, em ploying the harmonic analysis method. The harmonic coefficients were estimated on the basis of the daily temperature data a_ vailable for five stations. The weekly potencial evapotranspira tion values were then estimated by the method proposed by THORNTHWAI TE & MATHER, 1955.
15

Ekologie populací jednoletého poloparazitického druhu \kur{Melampyrum pratense.} / [Population ecology of annual hemiparasitic species \kur{Melampyrum pratense.}

PRŮŠOVÁ, Monika January 2010 (has links)
The thesis deals with the hemiparasitic species Melampyrum pratense. This species was monitored during the growing season 2009 and the relationship between morphological characteristics and reproductive success of plant individuals was assessed. The relationships between population density, the vegetative biomass and the investments in generative reproduction were investigated. Identity of the host species was determined using the DNA barcoding method.
16

Adaptation to growing season length in the perennial <em>Arabidopsis lyrata</em>

Kemi, U. (Ulla) 03 December 2013 (has links)
Abstract Adaptation to local environment is important for all organisms to guarantee survival and to maximize reproduction. Populations of the same species may live in environments that differ markedly. Due to differential selection pressures this can lead to population differentiation, which can be studied both at the phenotypic and at the gene level. The growing season cued by long days is typically short in the north, whereas southern populations have long growing seasons and are adapted to short days. Seasonal fluctuations in temperature also differ between northern and southern environments. Daylength and temperature regulate the timing of flowering in plants. Environmental regulation of flowering and its genetic basis has been extensively studied in the annual model species Arabidopsis thaliana. The perennial growth and flowering habit has been studied especially in trees, but studies on herbaceous plants species have been lacking. In this thesis, I have studied adaptation to growing season length in a perennial herbaceous model species Arabidopsis lyrata. Individuals from populations adapted to northern and southern environments in Europe were grown in same conditions in the growth chambers and in the field. Differentiation between the populations was studied by observing their flowering phenotypes and by studying the expression of genes that are candidates for governing the phenotypic differentiation. The main result in the thesis was that adaptation to short growing season in north can be seen as long daylength requirement for flowering and as fast developmental rate. Critical daylength for flowering likely regulates especially the timing of flowering cessation in the end of the growing season. Flowering time of individuals from northern populations also responded more strongly to cold treatment (representing winter) than that of the southern population. The cold requirement for flowering guarantees that the plants only flower after the winter in the spring with suitable conditions. Expression studies indicated that population differentiation in flowering could be at least partly governed by the expression variation in a few candidate genes. The results in this thesis are valuable for instance for understanding perennial species in general, including tree and crop species, and for predicting how plants response to changing climate. / Tiivistelmä Ympäröiviin oloihin sopeutuminen on tärkeää kaikille organismeille selviytymisen ja jälkeläistuoton kannalta. Saman lajin eri populaatiot saattavat elää ympäristöissä, joiden olosuhteet poikkeavat toisistaan huomattavasti. Tällöin populaatioihin kohdistuvat erilaiset valintapaineet ja populaatiot erilaistuvat. Erilaistuminen havaitaan tarkastelemalla yksilöiden ilmiasuja ja geenejä. Kasvukauden pituus määrittää eteläisten ja pohjoisten kasvuympäristöjen valintapaineita. Pohjoisessa kasvukausi on lyhyt ja sen alkamisesta ja loppumisesta kertoo pitkä päivänpituus. Etelässä on pitkä kasvukausi ja siellä elävät populaatiot ovat sopeutuneet lyhyeen päivänpituuteen. Myös vuodenaikaiset lämpötilavaihtelut eroavat pohjoisten ja eteläisten alueiden välillä. Muutokset päivänpituudessa ja lämpötilassa säätelevät kasveilla kukkimisen ajankohtaa. Kukkimiseen vaikuttavia ympäristötekijöitä ja kukkimista sääteleviä geenejä on tutkittu paljon yksivuotisella mallilajilla lituruoholla (Arabidopsis thaliana). Monivuotisten kasvien kasvun ja kukkimisen säätelyä on tutkittu etenkin puilla, mutta hyvin vähän ruohovartisilla kasveilla. Tässä väitöskirjatyössä tutkin kasvukauden pituuteen sopeutumista monivuotisella ruohovartisella lajilla, idänpitkäpalolla (Arabidopsis lyrata). Pohjoisiin ja eteläisiin ympäristöoloihin sopeutuneiden eurooppalaisten populaatioiden yksilöitä kasvatettiin samanlaisissa olosuhteissa kontrolloiduissa kasvatushuoneissa ja kenttäolosuhteissa. Populaatioiden erilaistumista tarkkailtiin kukkimiseen liittyvissä ominaisuuksissa sekä eroja selittävien kandidaattigeenien ekspressiossa. Tutkimuksen päätulos oli, että pohjoisen populaation lyhyeen kasvukauteen sopeutuminen voidaan havaita pitkän päivän vaatimuksena kukkimiselle ja nopeana kehityksenä. Kenttäolosuhteissa päivänpituus sääteli etenkin kukkimisen lopetusta kasvukauden lopussa. Pitkä kylmäkäsittely nopeutti kukkimista etenkin pohjoisessa populaatiossa. Kukkimista edeltävä kylmävaatimus takaa, etteivät kasvit kuki syksyllä epäsuotuisissa olosuhteissa, vaan vasta keväällä talven jälkeen. Populaatioiden erilaistuminen kukkimisen päivänpituus- ja kylmävaatimuksessa selittyy todennäköisesti ainakin osittain kandidaattigeenien ekspressioeroilla. Tämän väitöskirjatyön tuloksia voidaan soveltaa monivuotisten viljelykasvien jalostuksessa tai ennustettaessa kasvipopulaatioiden sopeutumista ilmastonmuutokseen.
17

Effect of phosphorus application on the performance of four cowpea varieties and two maize varieties under strip intercropping in Limpopo Province

Nkuna, Mzamani Knowledge January 2019 (has links)
Thesis (M.Sc. Agriculture (Agronomy)) -- University of Limpopo, 2019 / Limpopo Province is a semi-arid region prone to drought. Crop yields continue to decline due to low soil fertility and poor cropping systems. Cowpea is nutritionally rich in proteins essential for human consumption and livestock feeding. It fixes N2 which becomes available for the succeeding crop in rotation. For this reason, it is used as a companion crop in cereal-legume intercropping systems. Maize is one of the most important grain crops in South Africa, it serves as the major staple food for many households. Phosphorus is one of the macro-nutrient elements required by crops to produce satisfactory yields. The interactions between different rates of P fertilisation and cowpea-maize strip intercropping have not been studied in detail under rain-fed maize-cowpea strip intercropping in Limpopo Province. Many smallholder farmers in Limpopo Province obtain low yields due to the practice of mixed intercropping. Two season (2014/15 and 2015/16) experiments were laid out in a split-split plot design at Syferkuil farm to determine the performance of cowpea and maize varieties in cowpeamaize strip intercropping at varying P application rates. Treatments consisted of factors namely, P levels (0, 15, 30, 45 kg/ha), cropping system (monocropping and intercropping), maize varieties (WE3127 and ZM1423) and cowpea varieties (PAN311, TVu13464, IT86D-1010 and IT82D-889). Data were collected from growth and yield parameters that included (number of days to flowering, plant height, number of days to physiological maturity, root weight, number of pods per plant, unshelled net pod weight, number of cobs per plant, unshelled net cob weight and grain yield) in order to determine their performance. Results obtained revealed that P application levels significantly influenced most of the measured growth and yield parameters of both crops. PAN311 flowered earliest (49 days) across P levels. Increasing P application hastened the maturity of the varieties of PAN 311 and TVu13464 in both seasons. The P levels of 30 and 45 kg/ha reduced the number of days to maturity as compared to 0 and 15 kg/ha. TVu13464 variety produced more pods per plant (30) than other varieties. PAN311 yielded more grains (2491 kg/ha) than other varieties. Maize varieties performed well between P applications of 30 and 45 kg/ha. WE3127 yielded 3462 kg/ha whereas ZM1423 yielded 3306 kg/ha. Intercropping vi system performed better than monocropping system based on the measured growth and yield parameters. Two promising cowpea varieties (PAN311 and TVu13464) performed well and were selected based on their early maturity, drought tolerance and high yielding. Increasing P application levels increased crop yield. Optimum P levels for cowpea-maize strip intercropping were between 30 and 45 kg/ha. The calculated LER values were greater than one which indicates that intercropping was advantageous in land utilisation. The study showed the importance of P application in improving cowpea yield in cowpeamaize strip intercropping. / National Research Foundation (NRF) and University of Missouri, USA
18

Cooling Capacity Assessment of Semi-closed Greenhouses

Lee, Wee Fong 22 June 2010 (has links)
No description available.
19

Biochemistry and genetics of carotenoid composition in potato tubers

Othman, Rashidi January 2009 (has links)
Potato cultivars exhibit a wide variation in skin and flesh colour due to the presence of pigments. This study established that potato cultivars differ greatly with respect to types and concentrations of carotenoids in tubers. A total of 46 cultivars were evaluated for quantitative and qualitative carotenoid composition in different growing seasons, locations, storage conditions and disease symptoms. Factors controlling carotenoid accumulation were also tested by developing an in vitro minituber system as a new high-throughput model system for carotenogenesis in potato tubers. Tuber flesh colour was found to correlate with total carotenoid content in potato cultivars grown in both New Zealand and Netherlands. The main carotenoids identified in 32 potato cultivars in New Zealand were lutein, neoxanthin, violaxanthin and β-carotene. The ratio of these carotenoids varies between cultivars. Neoxanthin was detected in only 13 cultivars (10.59 to 69.21µg/g DW); violaxanthin was found only in 1 cultivar (32.76 µg/g DW). Whereas lutein and β-carotene were found in most of the cultivars but the concentration varied from (0.00 to 160.63 µg/g DW) and (0.00 to 13.62 µg/g DW) respectively. The main carotenoids identified in 12 cultivars grown in the Netherlands were neoxanthin, violaxanthin and lutein, whereas zeaxanthin was not found in any of the cultivars analysed. Marked differences were observed between the same potato cultivars grown in New Zealand and the Netherlands. Therefore cultivars were analysed over a second growing season to assess stability in carotenoids composition. The carotenoid profiles of the potato tubers grown for two different seasons showed highly significant differences between the cultivars, the seasons, the carotenoid pigments, and all combinations of interactions, indicating the complex nature of factors influencing carotenoid composition. Reflectance colorimeter measurement of yellow hue component in this study confirmed that the higher the total carotenoid content, the greater the yellow intensity colour. Eight cultivars were grown at three locations in New Zealand and Agria and Desiree were grown at eight locations in the Netherlands to further investigate the stability of carotenoid composition. Highly significant differences were observed between the cultivars, the locations, the carotenoid pigments, and all combinations of interactions, which emphasises that changes in carotenoid composition are complex and the responses are not consistent across cultivars. Reflectance colorimeter measurement of yellow hue component confirmed the relationship between the yellow colour intensity of tuber flesh, as well as confirming the interaction between colour and locations. Disease and post harvest storage conditions markedly influenced the levels of total carotenoid, neoxanthin, violaxanthin, zeaxanthin, lutein and β-carotene in potatoes. The magnitude of these effects depends on the cultivar, time of storage, and the intensity of powdery scab symptoms. Results showed that long term storage resulted in the accumulation of neoxanthin, violaxanthin and zeaxanthin with a concomitant decreased of lutein, β-carotene and total carotenoid content. Genotypes infected with disease (lower and higher scab score) resulted in accumulation of violaxanthin, β-carotene and total carotenoid with a concomitant decreased in neoxanthin and lutein. A high-throughput model system for investigating carotenoid biogenesis in potato tubers was developed. This involved in vitro potato minitubers and was validated by assessing the effects of environmental variables, such as drought stress, light intensity and nutrient availability on carotenoid accumulation. Light influenced the presence of zeaxanthin, whereas water stress and nutrient strength influenced the accumulation of neoxanthin and violaxanthin. Although these factors had an effect on the carotenoid content and profile, the most influential factor appeared to be cultivar selection.
20

The signature of sea surface temperature anomalies on the dynamics of semiarid grassland productivity

Chen, Maosi, Parton, William J., Del Grosso, Stephen J., Hartman, Melannie D., Day, Ken A., Tucker, Compton J., Derner, Justin D., Knapp, Alan K., Smith, William K., Ojima, Dennis S., Gao, Wei 12 1900 (has links)
We used long-term observations of grassland aboveground net plant production (ANPP, 19392016), growing seasonal advanced very-high-resolution radiometer remote sensing normalized difference vegetation index (NDVI) data (1982-2016), and simulations of actual evapotranspiration (1912-2016) to evaluate the impact of Pacific Decadal Oscillation (PDO) and El Nino-Southern Oscillation (ENSO) sea surface temperature (SST) anomalies on a semiarid grassland in northeastern Colorado. Because ANPP was well correlated (R-2 = 0.58) to cumulative April to July actual evapotranspiration (iAET) and cumulative growing season NDVI (iNDVI) was well correlated to iAET and ANPP (R-2 = 0.62 [quadratic model] and 0.59, respectively), we were able to quantify interactions between the long-duration (15-30 yr) PDO temperature cycles and annual-duration ENSO SST phases on ANPP. We found that during cold-phase PDOs, mean ANPP and iNDVI were lower, and the frequency of low ANPP years (drought years) was much higher, compared to warm-phase PDO years. In addition, ANPP, iNDVI, and iAET were highly variable during the cold-phase PDOs. When NINO-3 (ENSO index) values were negative, there was a higher frequency of droughts and lower frequency of wet years regardless of the PDO phase. PDO and NINO-3 anomalies reinforced each other resulting in a high frequency of above-normal iAET (52%) and low frequency of drought (20%) when both PDO and NINO-3 values were positive and the opposite pattern when both PDO and NINO-3 values were negative (24% frequency of above normal and 48% frequency of drought). Precipitation variability and subsequent ANPP dynamics in this grassland were dampened when PDO and NINO-3 SSTs had opposing signs. Thus, primary signatures of these SSTs in this semiarid grassland are (1) increased interannual variability in ANPP during cold-phase PDOs, (2) drought with low ANPP occurring in almost half of those years with negative values of PDO and NINO-3, and (3) high precipitation and ANPP common in years with positive PDO and NINO-3 values.

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