• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 11
  • 1
  • 1
  • Tagged with
  • 13
  • 12
  • 11
  • 11
  • 7
  • 4
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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

Role DSE (Dark Septate Endophytes) v rostlinném společenstvu lesního ekosystému / The role of DSE (Dark Septate Endophytes) in plant communities in forest ecosystem

Lukešová, Tereza January 2013 (has links)
10 Abstract All plants live in symbiosis with fungal endophytes - they can form mutualistic, commensal or parasitic symbioses. Symbiosis of root endophytes, called for their darkly pigmented and septated hyphae dark septate endophytes (DSE), and plants has been often overlooked although its role for plant communities can be very important. Despite their ubiquitous presence in roots of terrestrial and also aquatic plants the influence of DSE on their host plants is still unresolved. Results of previous studies are inconsistent - some reported that DSE have positive effects on their host plant growth and some negative. The main reason for this inconsistency might be their complicated taxonomy and difficult identification of different cryptic species which are morphologically indistinguishable. We were able to complete a unique collection of the most common DSE species, mainly members of the Phialocephala fortinii - Acephala applanata species complex. The collection includes the most common DSE species isolated from roots of forest plant communities. The goal of my thesis was to describe behaviour of DSE in roots of typical forest plants and elucidate their physiological influence on host plants. In vitro resynthesis experiments were used to observe root colonization patterns. Nutrient flow between the plant...
12

Estudo agroeconômico do cultivo da couve folha, coentro, alface e cebolinha em sistemas consorciados. / Agricultural economic study of cultivation of cabbage, coriander, lettuce and chives in intercropping systems.

LACERDA, Rodolfo Rodrigo de Almeida. 17 May 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-17T17:18:07Z No. of bitstreams: 1 RODOLFO RODRIGO DE ALMEIDA LACERDA - DISSERTAÇÃO PPGHT 2015..pdf: 1733217 bytes, checksum: 39fb75d0084081bcfe2544bfaf1ae5e1 (MD5) / Made available in DSpace on 2018-05-17T17:18:07Z (GMT). No. of bitstreams: 1 RODOLFO RODRIGO DE ALMEIDA LACERDA - DISSERTAÇÃO PPGHT 2015..pdf: 1733217 bytes, checksum: 39fb75d0084081bcfe2544bfaf1ae5e1 (MD5) Previous issue date: 2015-08-10 / O que pode se esperar dos consórcios é a maximização dos recursos ambientais, econômicos e produtivos das culturas envolvidas no sistema enquanto seu estudo econômico permite a eficiente tomada de decisões. Com o objetivo de avaliar a viabilidade agroeconômica do cultivo da couve folha, coentro, alface e cebolinha, em sistemas consorciados comparados ao seu monocultivo, foi conduzido o experimento no Centro de Ciências e Tecnologia Agroalimentar, da Universidade Federal de Campina Grande, em Pombal-PB, no período de julho a novembro de 2014, em campo aberto. O delineamento experimental foi composto por 11 tratamentos correspondendo a quatro policultivos, três consórcios e quatro monocultivos, distribuídos em delineamento de blocos ao acaso, com quatro repetições. Utilizaram-se, como culturas principais a couve folha 'Manteiga'; coentro 'Verdão'; alface 'Vera' e cebolinha 'Todo ano'. Foram avaliadas para todas as culturas, o número de folhas; altura de planta; massa fresca e seca da parte aérea; produtividade; área foliar; massa fresca e seca da raiz e volume da raiz. Além dessas características também foi avaliado para a alface o diâmetro transversal e, para o coentro, o número de plantas. Nos diferentes sistemas foram mensurados o uso eficiente da terra (UET), índice de área foliar, temperatura externa e interna do solo, os custos operacionais totais (COT), receita bruta, receita líquida, índice de lucratividade e taxa de retorno. Os valores de COTs dos sistemas consorciados foram calculados com os preços do mês de Julho de 2014. Em relação à produtividade, foi no monocultivo da couve que se encontraram as melhores médias (21,2 t ha-1) perdendo, porém em diversidade de alimentos. Por outro lado, o UET foi viável em todos os sistemas estudados chegando a valores que indicam uma eficiência de uso da terra aproximadamente de até 50% a mais nos policultivos e bicultivos. Os COTs de produção dos policultivos da couve com o coentro, alface e cebolinha foram, respectivamente, em R$ 14.711,68 ha-1 (com as quatro espécies) 11.967,66; 11.337,60 e 10.349,21 ha-1(combinações com três espécies). Nos bicultivos da couve folha com o coentro, alface ou cebolinha, os COT foram de R$ 10.921,64; 12.380,15 e 12.403,79 ha-1, respectivamente, valores esses superiores aos do monocultivo das culturas envolvidas nos sistemas em que o COT variou de R$ 8.009,52 a 9.458,90 ha-1. Em todos os sistemas estudados a maior participação foi referente ao custo com mão de obra. Apesar dos acréscimos nos COT dos sistemas em policultivo em relação aos bicultivos se mostrarem viáveis economicamente, pois os valores dessas características não diferiram significativamente dos monocultivos superando-os em alguns casos. Nos policultivos as melhores receitas brutas e líquidas, taxa de retorno e índice de lucratividade, foram constatadas no policultivo da couve com o coentro e alface. No bicultivo, a combinação da couve com a cebolinha obteve as menores taxa de retorno e índice de lucratividade, no monocultivo da alface foram encontradas as maiores receitas brutas e líquidas, taxa de retorno e índice de lucratividade. / What can be expected of the intercropping is the maximization of environmental resources, economic and productive cultures involved in the system while its economic study enables efficient decision making. With the aim to evaluate the agricultural economic viability of the collard cultivation, cilantro, lettuce and chives in intercropping systems compared to their monoculture. The experiment was conducted in the Centro de Ciências e Tecnologia Agroalimentar, of Universidade Federal de Campina Grande in Pombal-PB, in the period from July to November 2014, in the open. The experimental design consisted of 11 treatments corresponding to four polycultures, three intercropping, four monocultures, allotted to a randomized block design with four replications. They were used as main crops collard 'Manteiga'; coriander 'Verdão'; lettuce 'Vera' and chives 'Todo ano'. Were evaluated for all cultures, the number of sheets; plant height; fresh and shoot dry; productivity; leaf area; fresh and dry root and volume root. Besides these characteristics were also evaluated for lettuce transverse diameter and to coriander, the number of plants. In the different systems were measured the efficient use of land (EUL), leaf area index, external and internal temperature of the soil, total operating costs (TOC), gross revenue, net revenue, profitability index and rate of return. The TOCs values of intercropping systems were calculated with the prices of July 2014. With regard to productivity, was the collard monocultures that met the best average (21.2 t ha-1) losing, but in diversity foods. On the other hand, the EUL has been viable in all systems studied reaching values that indicate a land use efficiency of approximately 50% more in policultives and bicultivos. Production of TOCs collard polycultures with cilantro, lettuce and chives were, respectively, R$ 14,711.68 ha-1 (with the four species) 11,967.66; 11,337.60 and 10,349.21 ha-1 (combinations with three species). In bicultivos collard with coriander, lettuce or chives, the TOC were R$ 10,921.64; 12,380.15 and 12,403.79 ha-1, respectively, values higher than the monoculture crops involved in systems where TOC ranged from R$ 8,009.52 to 9,458.90 ha-1. In all systems studied the largest share was related to the cost of labor. Despite increases in TOC systems in polyculture in relation to bicultivos prove economically viable, because the values of these characteristics did not differ significantly from monocultures surpassing them in some cases. In polycultures the highest gross and net income, rate of return and profitability index, were found in polyculture collard with coriander and lettuce. In bicropping, the combination of collard with chives obtained the lower rate of return and profitability index, the lettuce monocultures in which were found the largest gross and net income, rate of return and profitability index.
13

Growth and development of 'Pasja' and kale crops with two methods and four rates of phosphorus (P) application

Chakwizira, Emmanuel January 2008 (has links)
*‘Pasja’ (Brassica campestris x napus) and kale (Brassica oleracea var. acephala L.) were grown at Lincoln, Canterbury, New Zealand in 2008 with different levels of phosphorus (P) fertiliser. Banded or broadcast P fertiliser was applied at 0, 20, 40 and 60 kg P/ha at establishment. Total dry matter (DM) production, the proportion of the leaf and stem and leaf area development were measured over time and related to the biophysical environment. For ‘Pasja’, final DM increased with P rate from 3730 kg DM/ha to ~4900 kg DM/ha at 60 kg P/ha. For kale the increase was from 8710 kg DM/ha for the control to ~11000 kg DM/ha for all P treatments. The leaf to stem ratio declined from 22-31 at 17 days after emergence to 10.4 at the final harvest for ‘Pasja’, which meant the crop was effectively made up mainly of leaf (~90%). The ratio for kale declined from 2.7 at 24 days after emergence to 0.64 at the final harvest. The leaf to stem ratio for both species did not respond to either the method of application or rate of P. Seedling DM accumulation increased with applied P over the first 10 to 17 DAE for ‘Pasja’ and kale respectively. The crops went from shoot growth priority to root growth. The phyllochron of both species was unaffected by P application but responded linearly to the temperature above 0°C. For ‘Pasja’ the phyllochron was 60°Cd compared with 109°Cd for kale. As a consequence ‘Pasja’ developed its canopy and reached critical leaf area index (LAIcrit) earlier than kale. Leaf area index (LAI) for the control crops of both species was lower than for P fertiliser treatments with a maximum of 3.6 for ‘Pasja’ and 3.8 for kale. There was no difference in leaf area indices among the P fertiliser treatments for ‘Pasja’, while kale LAI differed with the rate of P application up to 40 kg P/ha. Total accumulated intercepted solar radiation (RIcum) was 8 and 11% greater for ‘Pasja’ and kale crops respectively when P was applied compared with the control. Thus, the difference in total dry matter yield due to P application was attributed to the difference in RIcum. Neither the method of application or rate of P applied affected the radiation use efficiency (RUE) of either crop. For ‘Pasja’ the RUE was 1.1 g DM/MJ PAR and for kale 1.33 g DM/MJ PAR. Based on this research, it was concluded that P application increased RIcum as a result of increased LAI. The difference in total DM yield was attributed to differences in RIcum. It is recommended that farmers growing ‘Pasja’ and kale under similar conditions to this experiment should apply 40 kg P/ha for ‘Pasja’ and band 20 kg P/ha for kale. *‘Pasja’ is considered both as a species and cultivar in this document as it marketed as such in New Zealand. Technically ‘Pasja’ is a leaf turnip.

Page generated in 0.0535 seconds