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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.
1

Foliar nutrition: targeted fertilization to test herbivore preference

Penner, Johan January 2014 (has links)
Abstract   The aim of this study was to increase knowledge of how plants as a whole respond to targeted fertilization and to refine the method of foliar nutrition fertilization. The experiment also aimed to test how herbivores respond when presented with a choice between fertilized and unfertilized Salix leaves in a feeding trial experiment. One major problem that arises when trying to alter the nutrient levels within a specific part of a plant is that adding fertilizer directly to the soil in which the plants grow will have a systemic effect on the plant, causing the plant physiology as a whole to change instead of just changing the properties of the plant part which the study focuses on. The approach chosen for this experiment is to target the leaves directly when applying the fertilizer and therefore try to avoid altering the rest of the plant. Fertilizer in the form of NH3NO4 was added to Salix leaves using a pipette and a brush at two different concentrations. When the leaves had been fertilized they were analyzed and used in a feeding trial experiment to study herbivore response to targeted fertilization. Once all data was analyzed statistically it became clear that both concentrations of the treatment had altered the nitrogen content within the leaves, however only the lower concentration had done so without altering the characteristics of the leaf. The data collected from the feeding trial displayed no statistical evidence for preference between the treated and control leaves in regard to amount consumed by the Phratora beetles, on the other hand when testing for egg laying preference 8/8 of egg clutches were laid on treated leaves.
2

Enhancing deciduous fruit and tree quality through the use of various foliar applications

Hendricks, David Thomas 12 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Fruit trees are exposed to various factors that can adversely affect the production of quality fruit. These factors can directly affect the fruit and the health of the tree and can be classified according to their biotic or abiotic nature, such as pathogenic attacks and drought stress respectively. One of the cultural practices used commercially to address these stresses is the application of fungicides and bactericides. The fruit production industry is under severe pressure from consumers, retailers and environmentalists, locally and internationally, to reduce chemical applications to fruit and fruit trees. The use of natural plant defence elicitor compounds and nutrients offer a potential alternative to fungicide and bactericide sprays and may also increase fruit quality and size as result of a reduction of plant stress. Trials were conducted to evaluate the efficiency of natural plant defence elicitors i.e. salicylic acid (SA) and flavonoids, in addition to mineral nutrients and bactericide/fungicides, on peach (incidence of Xanthomonas infection), plum (induced drought stress and Mg/Mn deficiencies) and apple (Mg/Mn deficiencies) fruit and trees against specified biotic or abiotic stress factors. Trial on Prunus persica cv. ‘Sandvliet’were conducted over two seasons (2008/2009 and 2011/2012) on a commercial site, Protea Farm, in the Worcester area in the Western Cape Province. During the 2008/2009 season the SA (AlexinTM, AlexiboostTM) containing treatments were applied first at 75% petal drop at concentrations of 125 and 250 ml. 100 L-1. The copper (StCu, Cu)-containing treatment was applied at 50% petal drop, while dichlorophen (XanbacTM) treatments were applied at fruit set at concentrations of 150, 300 and 200 ml. 100 L-1. The flavonoid (CroplifeTM) treatment was applied at the start of petal drop at a concentration of 150 ml.100 L-1. During the 2011/2012 season, a new flavonoid (CropbiolifeTM) treatment, as well as potassium (K-MaxTM) treatment, were incorporated into the trial and applied at concentrations of 150 and 500 ml. 100 L-1 respectively. Additionally a SA (AlexinTM) and dichlorophen (XanbacTM) treatments that performed well during the first season, were incorporated into the second season with application times and rates similar to the first season’s protocol. In addition to fruit size and quality measurements, the percentage Xanthomonas infection was determined on the leaves and fruit of the experimental trees. The SA (AlexinTM) containing treatment significantly reduced the incidence of Xanthomonas infection on leaves and fruit compared to the control in the first season. However, results varied between the two seasons, as no significant difference from the control could be obtained in the following season. The AlexinTM treatments also significantly increased the fruit size and quality. The flavonoid (CropbiolifeTM) and K (K-MaxTM) containing treatments similarly reduced the Xanthomonas infection on leaves and fruit, as well as increasing the fruit size and quality in the second season. The dichlorophen (XanbacTM) containing treatment recorded varying results as it significantly reduced the Xanthomonas infection on the fruit only in the second season. The plum trials were conducted over the 2011/2012 season on ‘Laetitia’ and ‘Songold’ plum trees, Welgevallen Experimental Farm, Stellenbosch University. Three SA (AlexinTM, AlexSal and RezistTM) containing foliar treatments were applied on the ‘Laetitia’ trees. Only two SA (AlexinTM, AlexSal) containing foliar treatments were applied on the ‘Songold’ trees. Additionally, a foliar treatment containing only K, Ca, Mg and B, was applied in both the ‘Laetitia’ and ‘Songold’ trials. All the treatments were first applied at 75% petal drop, at the same concentration of 250 ml. 100 L-1. Additionally to fruit size and quality, the mineral nutrient content of the leaves and fruit was determined. The ascorbic acid and glutathione content was determined in fruit at harvest and again after storage. None of the treatments had a positive effect on the parameters measured, except the SA (AlexinTM) containing treatments which increased the titratible acidity (TA) in both at harvest and after storage. The treatments also did not alleviate the induced stress compared to the control. The apple and plum tree trials were conducted over the 2011/2012 season in a semi-closed greenhouse, at the Welgevallen Experimental Farm, Stellenbosch. Magnesium (Mg) and Manganese (Mn) deficiencies were induced in one-year-old ‘Royal Beaut’ apple and ‘Laetitia’ plum trees planted in 10 L nursery bags, by omitting these nutrients from a standard Long Ashton soil application. Foliar treatments of Mg (MagMaxTM) and Mn (ManMaxTM) containing sprays were subsequently applied at concentrations of 250 and 75 ml. 100 L-1 respectively, after deficiency symptoms for these nutrients were visually observed. Mineral nutrient analysis of the leaves were analysed on the 13th of February for the plums and 30th of March 2012, for the apples. The Mn (ManMaxTM) containing treatment successfully overcame the Mn induced deficiency. The Mg (MagMaxTM) containing treatment did not overcome the induced Mg deficiency and was probably due to the deficient nitrogen levels in the plants, caused by an error in the initial Long Ashton nutrient solution formulation. In conclusion AlexinTM, K-MaxTM and CropbiolifeTM have shown their ability to decrease Xanthomonas infection in peaches. Additionally to their positive effect on fruit size and quality on the peaches. SA was not able to overcome the induced stress on plums, but had a positive effect on the fruit quality and size. The ManMaxTM been proven to overcome the induced Mn deficiency, while MagMaxTM was unsuccessful to overcome the Mg deficiency. / AFRIKAANSE OPSOMMING: Vrugtebome word blootgestel aan verskeie faktore wat die produksie van kwaliteit vrugte nadelig kan beïnvloed. Hierdie faktore kan ‘n direkte invloed hê op die vrugte en op die gesondheid van die boom en kan geklassifiseer word op grond van hulle biotiese of abiotiese natuur, soos patogeen infeksie en droogte stres onderskeidelik. Van die produksie praktyke wat gebruik word sluit in die toepassing van verskillende swamdoders en bakterisiede. Die vrugtebedryf is onder geweldige druk van verbruikers, die kleinhandel en omgewingsbewustes om die toediening van chemikalieë aan vrugte en vrugtebome te verminder. Die gebruik van natuurlike plant verdediging stimulerende verbindings en nutriënte, bied 'n moontlike alternatief tot die spuit van swamdoders en bakterisiede, en kan ook moontlik ʼn bydrae maak tot verbeterde vrugkwaliteit en -grootte. Proewe is uitgevoer om die effektiwiteit van die natuurlike plant verdediging stimulante, salisielsuur (SA) en flavonoïede, addisioneel tot verskillende voedingstowwe en bakterieële / swamdoders op perske, pruim en appels teen Xanthomonas infeksie, droogte stres en Mg / Mn tekorte as biotiese en abiotiese stres faktore onderskeidelik te evalueer. Die Prunus persica ‘Sandvliet’ proewe is oor twee seisoene (2008/2009 en 2011/2012) op 'n kommersiële perseel, Protea Farm, in die Worcester-area in die Wes-Kaap Provinsie, uitgevoer. Gedurende die 2008/2009 seisoen is die SA (AlexinTM, AlexiboostTM) bevattende behandelings eers toegedien by 75% blomblaarval teen konsentrasies 125 en 250 ml. 100 L-1. Die koper (StCu, Cu) bevattende behandeling is toegedien by 50% blomblaarval, terwyl die dichlorofen (XanbacTM) bevattende behandelings toegedien is by vrugset, teen konsentrasies van 150, 300 en 200 ml. 100 L-1. Die flavonoïde (CroplifeTM) behandeling is toegedien by die begin van blomblaarval teen 'n konsentrasie van 150 ml. 100 L-1. Gedurende die 2011/2012 seisoen was 'n nuwe flavonoïd (CropbiolifeTM) en ‘n kalium (K-MaxTM) behandeling toegevoeg tot die eksperiment, met ʼn toediening teen konsentrasies van onderskeidelik 150 en 500 ml. 100 L-1. Daarbenewens is die SA (AlexinTM) en dichlorofen (XanbacTM) behandeling van die 2008/2009 seisoen herhaal teen dieselfde konsentrasies en toedieningstye soos in die protokol van die eerste seisoen. Behalwe vir die bepaling van vruggrootte en –kwaliteit, is die persentasie Xanthomonas infeksie op blare en vrugte ook bepaal. Die SA (AlexinTM) bevattende behandeling het die voorkoms van Xanthomonas infeksie op die blare en vrugte betekenisvol verminder in vergelyking met die kontrole. Resultate het egter gewissel in die daaropvolgende seisoen en geen beduidende verskille tussen die behandelings is waargeneem nie. Hierdie SA-bevattende behandelings het ook tot ‘n toename in vruggrootte en -kwaliteit gelei. Die flavonoïde bevattende behandelings, (CropbiolifeTM) en K (K-MaxTM), het soortgelyke afnames in Xanthomonas infeksie op die blare en vrugte in die tweede seisoen getoon, sowel as ‘n toename in vruggrootte en -kwaliteit. Die dichlorofen (XanbacTM) bevattende behandeling het variërende resultate getoon aangesien dit slegs tot ‘n beduidende afname in Xanthomonas infeksie op die blare en vrugte in die tweede seisoen kon lei. Pruim proewe is uitgevoer in die 2011/2012 seisoen op ‘Laetitia’ en ‘Songold’ pruimbome te Welgevallen Proefplaas, Universiteit van Stellenbosch. Drie SA (AlexinTM, AlexSal en RezistTM) bevattende blaar behandelings is toegedien op die ‘Laetitia’ bome. Slegs twee SA (AlexinTM, AlexSal) blaar behandelinge is toegedien op die ‘Songold’ bome. ʼn Verdere K, Ca, Mg en B blaar behandeling is ook toegedien in beide die ‘Laetitia’ en ‘Songold’ proewe. Al die behandelings se eerste toediening het saamgeval met 75% blomblaarval, teen dieselfde konsentrasie van 250 ml. 100 L-1. Addisioneel tot vruggrootte en –kwaliteit, is die mineraal element inhoud van die blare en vrugte bepaal. Die askorbiensuur en glutatioon inhoud is bepaal in die vrugte met oes asook na opberging. Geen behandeling het 'n positiewe uitwerking op die parameters wat gemeet is getoon nie, behalwe een van die SA (AlexinTM) bevattende behandelings wat die titreerbare sure (TS) verhoog het in beide kultivars. Die behandelings kon ook nie die geïnduseerde stres verlig in vergelyking met die kontrole nie. Die appel- en pruim proewe is uitgevoer gedurende die 2011/2012 seisoen in 'n semi-geslote glashuis te Welgevallen Proefplaas, Universiteit van Stellenbosch. Magnesium (Mg) en Mangaan (Mn) tekorte is geïnduseer in een-jaar-oue ‘Royal Beaut’ appel en ‘Laetitia’ pruim bome, aangeplant in 10L kwekerysakke, deur dié elemente uit ʼn toediening van standaard Long-Ashton voedingsoplossing aan die grond weg te laat. Mg (MagMaxTM) en Mn (ManMaxTM) bevattende blaarspuite is daarna toegepas teen onderskeidelik konsentrasies van 250 en 75 ml. 100 L-1. ʼn Minerale analise van die blare is uitgevoer op 13 Februarie, op die pruime en 30 Maart 2012, op die appels. Die Mn (ManMaxTM) bevattend behandeling het die Mn-geïnduseerde tekort verlig. Die Mg (MagMaxTM) bevattende behandeling het nie die geïnduseerde Mg-tekort verlig nie. Dit is moontlik toe te skryf aan die stikstof tekort in die plante wat te wyte was aan ʼn foutiewe Long Ashton voedingsoplossing formulasie wat aanvanklik toegedien is. Ten slotte het AlexinTM, K-MaxTM en CropbiolifeTM getoon dat hul die vermoë het om Xanthomonas infeksie te verminder, asook om vruggrootte en kwaliteit in perskes te verbeter. SA was nie in staat om die geïnduseerde stres op pruime te oorkom nie, maar het 'n positiewe uitwerking op die vruggroote en kwaliteit gehad. ManMaxTM het getoon dat dit ʼn geïnduseerde, visuele Mn tekort kan oorkom, terwyl MagMaxTM onsuksesvol was om die Mg-tekort te oorkom
3

Titânio via foliar no metabolismo, absorção de nutrientes e produtividade de batata / Titanium foliar spray in metabolism, nutrient uptake and potato productivity

Bacilieri, Fernando Simoni 03 March 2015 (has links)
The potato (Solanum tuberosum L.) has great importance in human nutrition where it occupies the fourth place among the most consumed foods in the world. It is a highly demanding culture technology especially in the nutritional point of view. Despite the titanium (Ti) is not considered a nutrient, studies have shown beneficial effects of this element when applied to plants. The application of Ti leaf can be an alternative for this element is slightly movable in the soil and is generally present in insoluble forms. Thus, the objective was to evaluate the influence of application rates of Ti foliar in the potato crop. We conducted an experiment in the period from August to November 2014, installed at the experimental station Udi Pesquisa e Development in Uberlândia-MG, with kind Ágata. Variables related to metabolism were evaluated: SPAD chlorophyll content, nitrate reductase activity (NRA), lipid peroxidation (LP), urease, proline, catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD). Nutritional factors such as levels of nutrients nitrogen (N), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) present in leaves and tubers were measured stages of growth, tuber and tuber filling. At the end of the crop cycle was quantified the average mass, diameter, commercial classification and productivity of tubers. The design was a randomized block design with four replications and six treatments. The supply of the Ti compound fertilizer was through for 5% of magnesium oxide, 10% sulfur trioxide and 0,85% titanium complex and the treatments was: T1 - without the application of Ti, T2 -10.2; T3 - 15.3; T4 - 20.4; T5 - 22.9 and T6 - 25.5 g Ti ha-1 divided into three equal applications during the growth phase, tuber and tuber filling. It was concluded that in the growth phase the foliar application of Ti reduces the Mn content in the leaves and there is increased activity of POD and ANR and reduced urease activity. In the tuberization phase the Fe absorption, SOD activity and POD response to increasing Ti dose. In tubers filling stage foliar application of Ti increases chlorophyll levels (Spad value). The application of Ti in the leaf growth stages, tuber and tuber filler results in a lower Zn content in the tubers. The average tuber weight, the average diameter of tubers and the total productivity of tubers are affected by foliar application of Ti. The dose Ti foliar applied for further tuber yield is 5.74 g Ti ha-1. / A batata (Solanum tuberosum L.) tem grande importância na alimentação humana onde ocupa o quarto lugar entre os alimentos mais consumido no mundo. É uma cultura altamente exigente em tecnologias especialmente sob o ponto de vista nutricional. Apesar do titânio (Ti) não ser considerado um nutriente, trabalhos demonstram efeitos benéficos deste elemento quando aplicado às plantas. A aplicação de Ti foliar pode ser uma alternativa pois este elemento é pouco móvel no solo e geralmente está presente em formas insolúveis. Desta forma, objetivou-se avaliar a influência da aplicação de doses de Ti via foliar na cultura da batata. Realizou-se um experimento no período de agosto a novembro de 2014, instalado na estação experimental Udi Pesquisa e Desenvolvimento em Uberlândia-MG, com utilização da cultivar Ágata. As variáveis relacionadas ao metabolismo avaliadas foram: teor clorofila SPAD, atividade da nitrato redutase (ANR), peroxidação lipídica (PL), urease, prolina, catalase (CAT), superóxido desmutase (SOD) e peroxidase (POD). Aspectos nutricionais como os teores dos nutrientes nitrogênio (N), cobre (Cu), ferro (Fe), manganês (Mn) e zinco (Zn) presentes em folhas e tubérculos foram mensurados fases de crescimento, tuberização e enchimento de tubérculos. Ao final do ciclo da cultura foi quantificada a massa média, diâmetro médio, classificação comercial e a produtividade dos tubérculos. O delineamento foi o de blocos casualizados, com quatro repetições e seis tratamentos. O fornecimento do Ti foi através de fertilizante composto por 5% de óxido de magnésio, 10% de trioxido enxofre e 0,85% de complexo de titânio com os seguintes tratamentos: T1 sem aplicação de Ti, T2 -10,2; T3 -15,3; T4 - 20,4; T5 - 22,9 e T6 - 25,5 g de Ti ha-1 divididos em três aplicações iguais durante a fase de crescimento, tuberização e enchimento de tubérculos. Concluiu-se que os teores de Cu não são influenciados pelas doses de Ti nas fases avaliadas. Na fase de crescimento a aplicação foliar de Ti reduz o teor de Mn nas folhas e há aumento da atividade da POD e ANR e redução da atividade da urease. Na fase de tuberização a absorção de Fe e atividade de enzimas SOD e POD tem resposta ao aumento da dose de Ti. Na fase de enchimento de tubérculos a aplicação foliar de Ti incrementa os teores de clorofila (valor Spad). A aplicação de Ti foliar nas fases de crescimento, tuberização e enchimento de tubérculos resulta em menor teor de Zn nos tubérculos. A massa média de tubérculos, o diâmetro médio de tubérculos e a produtividade total de tubérculos são influenciados pela aplicação foliar de Ti. A dose de Ti aplicada via foliar para maior produtividade de tubérculos é de 5,74 g de Ti ha-1. / Mestre em Agronomia
4

Atividade microbiana e interferência de plantas daninhas na cultura do milho em solo com diferentes manejos de fertilidade / Microbial activity and weed interference on corn in soil with different fertility managements

Melo, Christiane Augusta Diniz 16 February 2012 (has links)
Made available in DSpace on 2015-03-26T13:39:47Z (GMT). No. of bitstreams: 1 texto completo.pdf: 739809 bytes, checksum: 69524346956f11b5bb2a849577857347 (MD5) Previous issue date: 2012-02-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The competitive ability of crops and weeds is related to the efficient use of environmental resources. However, it may also be related to the associations of these species with soil microbiota and the ability to change it to minimize interference. The objective of this study was to evaluate the effects of the interference of five weeds in dry matter accumulation of corn plants and in the relative content of nutrients, as well as evaluate the biomass and microbial activity associated with weeds and corn in monoculture and in competition, in soils with diferent fertility managements. The experiment was conducted in a protected environment, considering four soil fertility managements (with calcium and magnesium silicate and fertilization; with limestone and fertilization; without correction of acidity, but with fertilization; without correction of acidity and without fertilization) and five arrangements competition between Zea mays and the weeds Brachiaria brizantha, Ipomoea grandifolia, Conyza canadensis, Bidens pilosa and Hyptis suaveolens, addition of species in monoculture and soils without plants. The coexistence of corn with weeds caused average reductions of 43.9%, 39.8% and 41.9% in dry matter of shoot, root and total culture, respectively. Under interference of B. brizantha, the corn had reductions exceeding 50% in the content of all macronutrients, being this weed the most damaging to the culture. Additionally, B. brizantha and B. pilosa in competition with corn stood out among the other weeds and has high ability to extract and use macronutrients in the four soil conditions. There was a tendency of reduction of microbial biomass carbon (MBC) in soils that receive were not correction acidity. B. pilosa and the arrangement formed by Z. mays and B. brizantha, showed high values of MBC, regardless of soil management. Low biological activity was observed in soil without acidity correction and without fertilization. In soil with calcium and magnesium silicate and maize plants in monoculture, the metabolic quotient (qCO2) was higher than the value observed with the weeds in monoculture and in competition arrangements, suggesting greater susceptibility of this system for carbon losses. Z. mays in competition with H. suaveolens was the arrangement that had greater preservation of organic matter (<qCO2) in the four soils. The weeds showed different competitive abilities causing reductions in the dry matter and nutrients accumulation in the corn plants, and showed distinct potential for nutrient cycling, depending on soil condition. Calcium and magnesium silicate and limestone did not differ in the weed interference on the dry biomass of corn plants, being the influence of these sources variable on nutrient accumulation by plants in monoculture or under interference. The microbial biomass and activity were altered by plant species, interference and managements of soil fertility. The manipulation of soil microorganisms may be a strategy used by corn and, or the weeds to minimize the competition in a given soil. / A habilidade competitiva das culturas e das plantas daninhas está relacionada à utilização eficiente dos recursos do meio na qual se encontram. No entanto, pode também estar relacionada com as associações dessas espécies com a microbiota do solo e a capacidade de alterá-la para minimizar a interferência. Objetivou-se com este trabalho avaliar os efeitos da interferência de cinco plantas daninhas no acúmulo de matéria seca e no conteúdo relativo de macronutrientes de plantas de milho, bem como a biomassa e a atividade microbiana associada às plantas daninhas e de milho em monocultivo e em competição, em solos com diferentes manejos de fertilidade. O experimento foi realizado em casa de vegetação, considerando-se como primeiro fator quatro manejos de fertilidade do solo (com silicato de cálcio e magnésio e adubação; com calcário e adubação; sem correção de acidez, mas com adubação; sem correção de acidez e sem adubação) e como segundo fator cinco arranjos de competição entre Zea mays e as plantas daninhas Brachiaria brizantha, Ipomoea grandifolia, Conyza canadensis, Hyptis suaveolens e Bidens pilosa, acrescido das seis espécies em monocultivo e de solo sem cultivo. A convivência do milho com plantas daninhas provocou reduções médias de 43,9%, 39,8% e 41,9% na massa da matéria seca da parte aérea, do sistema radicular e total da cultura, respectivamente. Sob interferência de B. brizantha, o milho apresentou reduções superiores a 50% no conteúdo de todos os macronutrientes, sendo esta a planta daninha mais danosa a cultura. Adicionalmente, B. brizantha e B. pilosa em competição com o milho se destacaram entre as demais plantas daninhas, apresentando elevada habilidade de extração e utilização de macronutrientes nas quatro condições de solo. Observou-se tendência de redução do carbono da biomassa microbina (CBM) nos solos que não tiveram correção de acidez. B. pilosa e o arranjo formado por Z. mays e B. brinzantha, independente do solo, apresentaram elevados valores de CBM. Baixa atividade biológica foi verificada no solo sem correção de acidez e sem adubação. No solo corrigido com silicato de cálcio e magnésio e cultivado com milho livre de interferência, o quociente metabólico (qCO2) foi maior do que com as plantas daninhas em monocultivo e arranjos de competição, sugerindo maior suscetibilidade desse sistema a perdas de carbono. Z. mays em competição com H. suaveolens mostrou ser o sistema misto mais conservativo da matéria orgânica (<qCO2) nos quatro manejos de fertilidade do solo. As plantas daninhas apresentaram não só habilidades competitivas distintas, provocando reduções consideráveis no acúmulo de matéria seca e nutrientes das plantas de milho, como também potencial diferenciado para ciclagem dos nutrientes estudados, a depender da condição de solo. Silicato de cálcio e magnésio e calcário não diferiram quanto à interferência das plantas daninhas sobre o acúmulo de biomassa seca das plantas de milho, sendo variável a influência dessas fontes sobre o acúmulo de nutrientes pelas plantas em monocultivo ou sob interferência. A biomassa e atividade microbiana foram alteradas pelas espécies de plantas, pela convivência e pelos manejos de fertilidade do solo, e a manipulação dos microrganismos do solo pode ser uma estratégia utilizada pela cultura do milho e, ou pelas plantas daninhas para minimizar a competição em determinado ambiente.
5

Épandage de biosolides papetiers et de boues de chaux dans une plantation de peuplier hybride : effets sur la nutrition foliaire et la croissance

Miquel, Jean-Charles 05 1900 (has links)
L’utilisation de matières résiduelles fertilisantes (MRF) dans les plantations de peupliers hybrides (PEH) au Québec pourrait en maximiser la productivité et le volume marchand. Elle présenterait aussi l’avantage de minimiser l’enfouissement ou l’incinération des MRF. Cependant, le dosage des MRF doit être calibré en fonction de la réponse optimale des arbres. L’étude a été réalisée dans une plantation de PEH en Estrie. Un dispositif expérimental comprenant deux blocs (répétitions) de cinq parcelles - un témoin et quatre traitements de combinaisons de biosolides papetiers et de boue de chaux - y a été mis en place à l’automne 2012 et au printemps 2013, soit trois ans avant l’échantillonnage (été 2015). Les traitements représentaient les doses suivantes : 140 et 15 t ha-1 (humides), 140 et 30 t ha-1, 240 et 15 t ha-1 et 240 et 30 t ha-1 de biosolides et de boue de chaux, respectivement. Les propriétés physico-chimiques du sol et la morphologie et la nutrition des PEH ont été évaluées. Nous avons observé un effet très significatif des traitements de MRF sur la croissance des PEH par rapport aux parcelles non traitées. La hauteur des arbres a augmenté de 1,6 à 2 fois, le diamètre de 2,5 à 4 fois, la surface foliaire de 3 à 8 fois et le poids foliaire de 2,7 à 9 fois dans les parcelles traitées comparativement aux arbres des parcelles non traitées. Toutefois, aucune différence significative n’a pu être constatée entre les différents amendements. Les analyses de nutrition foliaire ont, quant à elles, démontré que la fertilisation avec les MRF permettait de pallier la faible disponibilité des nutriments dans le sol. Ainsi, avec l’ajout de MRF, les macronutriments N, P, K et Ca dans les feuilles se situaient à l’intérieur des plages de concentrations optimales, alors que sans MRF, les feuilles montraient des concentrations sous ces seuils. Malgré les faibles différences observées entre les quatre amendements, le traitement combinant 240 t ha-1 de biosolides et 15 t ha-1 de chaux est celui qui se rapprochait le plus d’une nutrition optimale pour le PEH. Les biosolides papetiers en combinaison avec la boue de chaux donnent des résultats très encourageants en ce qui a trait à la nutrition foliaire et le rendement des plantations du PEH lors des premières années d’établissement. / The use of fertilizing residual materials (FRM) in hybrid poplar (HP) plantations in Quebec could maximize yields and merchantable volumes. It would also have the advantage of minimizing the burial (landfill) or incineration of FRM. However, applications rates of FRM must be calibrated for an optimal response of the trees. The study was conducted in a PEH plantation in the Eastern Townships. An experimental design comprising two blocks (repetitions) of five plots - one control and four combinations of papermill biosolids and lime sludge - was established in fall 2012/spring 2013 and sampling was conducted three years later (summer 2015). The treatments represented the following application rates: 140 and 15 t ha-1 (wet), 140 and 30 t ha-1, 240 and 15 t ha-1 and 240 and 30 t ha-1 of biosolids and lime, respectively. Soil properties as well as morphology and nutrition of HP were evaluated. We observed a highly significant treatment effect on HP growth compared to untreated plots. The height of HP trees in the treated plots increased by 1.6 to 2 times, diameter by 2.5 to 4 times, leaf area by 3 to 8 times and the foliar weight by 2.7 to 9 times compared to the trees in the untreated plots. However, there was no significant difference among the various treatments. Foliar nutrition analyses showed that fertilization with FRM was sufficient to compensate for the low availability of nutrients in the soil. Thus, with FRM application, the macronutrients N, P, K and Ca in the leaves were within the optimal concentration ranges, whereas without FRM, the leaves showed concentrations below these thresholds. Despite the small differences observed among the four amendments, the treatment combining 240 t ha-1 of biosolids and 15 t ha-1 of lime was the one the closest to the optimal nutrition for HP. Papermill biosolids in combination with lime sludge provide very encouraging results in regard to foliar nutrition and yields of HP plantations.

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