Despite the agronomic benefits of exotic grass plantings for pasture and rangeland forage, exotic grass invasions are capable of having dramatic and widespread impacts on native communities and ecosystems. Exotic Old World bluestem grasses (OWBG; Bothriochloa and Dichanthium spp.) have become increasingly invasive throughout the central and southern U.S. Little is known regarding the impacts of OWBG invasion on native grassland and savannah ecology and how to successfully control OWBG invasions in natural areas. Accordingly, this dissertation research had several objectives: 1) Evaluate the efficacy of herbicide and/or disking to control OWBG; 2) Assess the relative competitive ability of the OWBG, Kleberg bluestem (Dichanthium annulatum); 3) Evaluate herbicide application and native grass seeding to rehabilitate an OWBG invaded coastal prairie; 4) Examine whether ecosystem function differs between areas dominated by OWBG vs. native coastal prairie; and 5) Characterize the germinable soil seed bank of an OWBG invaded coastal prairie. Herbicide treatments of imazapyr, glyphosate, and imazapyr + glyphosate were found to provide effective, albeit temporary, OWBG control (often less than six months). A combination regimen of disking followed by herbicide treatments, regardless of herbicide active ingredient or application rate, controlled OWBG more effectively than herbicide alone or herbicide followed by disking. Herbicide treatments followed by native grass seeding did not markedly rehabilitate coastal prairie invaded by OWBG. OWBG appeared to reinvade from the seed and/or bud bank suggesting the restoration of OWBG invaded grasslands will likely require aggressive and repetitive control methods to completely extirpate OWBG at a given site before native plantings occur. A seed bank survey revealed the density of OWBG germinable seeds increases dramatically with increasing OWBG invasion (i.e., canopy cover) while the native grass seed bank is generally depauperate even when levels of OWBG invasion were low. Dominance of OWBG appears to have altered native coastal prairie ecosystem function; yet the directionality and extent of OWBG effects were strongly soil texture dependent. Here, ecosystem function parameters between areas dominated by OWBG compared to native prairie differed most often on sandy loam vs. clay soil. Moreover, DeWit replacement series experiments revealed the relative competitive ability of Dichanthium annulatum was significantly greater than the native grass, little bluestem (Schizachyrium scoparium). OWBG will likely persist throughout the central and southern Great Plains, USA, for years to come and intensive management efforts will be necessary to keep OWBG invasions under control in natural areas of high conservation value.

2 pp. / The most difficult part of conversion from a lawn to a low water (xeriscape) landscape is the removal of a lawn. By removing a Bermuda grass lawn, it is estimated that water savings of 50 -75% is possible. Potential water savings comes from the fact that water is applied to a limited amount of total yard space, compared to the greater water needs of a continuous grass-covered area. Also, by planting low water use plants, less maintenance is required and substantial cost savings can be realized. Turf removal and subsequent weed suppression is achievable using readily available herbicides.

5 pp. / Precision herbicide application is an effective tool for placing soil incorporated herbicides which have a tendency for soil adherence. And while field implementation depends on previous knowledge of soil textural variability (soil test and texture evaluations), site-specific technologies show promise for Arizona vegetable producers in non-uniform soils. Regardless of the method used for textural characterization, growers should keep in mind that textural differences do not change in the short/medium term, so the costs associated with defining texture-based management zones can be spread over many years.

Doctor of Philosophy / Department of Agronomy / Phillip W. Stahlman / Kochia [Kochia scoparia (L.) Schrad.] is a weed of great economic importance in the Great Plains and western United States and Canada. This weed is prone to evolving resistance to herbicides. Glyphosate is the most widely used herbicide in glyphosate-resistant crops and chemical fallow, and is extremely valuable to crop production. Anecdotal reports of kochia control failure with glyphosate in western Kansas arose during the mid-2000’s. The objectives of this research were to (1) confirm and characterize glyphosate resistance in kochia and measure its impact in western Kansas, (2) gather information on grower weed management practices before and since glyphosate resistance in kochia was confirmed, and (3) determine if altered absorption and translocation of glyphosate contributes to glyphosate resistance in kochia. Dose-response studies on greenhouse and outdoor grown plants, and shikimate accumulation assays confirmed one kochia population collected in 2007 and eight populations collected in 2010 tolerated three- to eleven-times more glyphosate compared to a known glyphosate-susceptible (GS) population. Furthermore, 40 kochia populations collected in 2012 showed varied response, from slightly elevated tolerance to resistance to 0.84 kg ae ha-1 glyphosate. Further analysis suggested these populations were at different stages of resistance evolution. An online survey revealed that growers increased glyphosate use rate and application frequency, but decreased exclusive use of glyphosate and diversified weed management practices during post- compared to pre-glyphosate confirmation periods. Most survey respondents reported presence of glyphosate-resistant (GR) kochia in at least in few fields, and half reported GR kochia in a majority of fields. Thus, together with the resistance confirmation studies, it is estimated that at least one-third of western Kansas kochia populations have evolved resistance to glyphosate. Nominal differences in absorption and translocation of 14C-glyphosate observed between GS and GR kochia populations likely do not contribute to differential response of these populations to glyphosate. Glyphosate-resistant kochia has become widespread in western Kansas in a short period of time. Use of weed resistance best management practices (BMP) is imperative to sustain the utility of glyphosate in the region.

O emprego de mudas pré-brotadas (MPB) de cana-de-açúcar, no sistema canavieiro, cresceu imensamente nos últimos anos. Entretanto, a carência de informações no manejo com herbicidas no sistema pode comprometer a tecnologia. Com o objetivo de compreender melhor os efeitos causados por diferentes herbicidas aplicados em pré e pós-transplantes das MPBs de cana-de-açúcar da variedade CTC4, este estudo foi conduzido em duas etapas em diferentes condições. Os tratamentos foram definidos com base nos herbicidas mais usuais do setor. Ambos os experimentos foram conduzidos no centro de pesquisa da FMC em Paulínia (SP), onde efeitos como fitotoxicidade, altura, produtividade, número de perfilhos, número de colmos e germinação foram avaliados. Para o experimento de campo, observou-se que apesar de injúrias iniciais causadas por diversos herbicidas, apenas o sulfentrazone promoveu redução de produtividade, entretanto todos tratamentos aos 60 dias após à aplicação não apresentavam sintomas de fitotoxidez. A partir desse primeiro estudo, foi realizado em casa de vegetação outro experimento, buscando analisar os mesmos herbicidas em diferentes posicionamentos de aplicação e em dois tipos de solo. Quando posicionado em pré transplante os sintomas de injúrias foram mais elevados, comprometendo o desenvolvimento de alguns tratamentos. Neste caso, o diclosulam mostrou-se o menos seletivo independentemente do tipo de solo estudado, seguido pelo clomazone. Entretanto, a literatura mostra que resultados de seletividade variam de acordo com as condições empregadas e principalmente variedades da cultura, assim, repetições deste estudo devem ser realizadas para possibilitar uma melhor compreensão e validação dos dados. / The use of pre-sprouted seedlings (PSS) of sugarcane in the sugarcane\'s system has grown immensely in recent years. However, lack of information on herbicide management in the system may compromise the technology. In order to better understand the effects caused by different herbicides applied in pre and post-transplantation of sugarcane MPBs variety CTC4, this study was conducted in two stages under different conditions. The treatments were defined based on the herbicides most common in the industry. Both experiments were conducted at the FMC research center in Paulínia (SP), where effects such as phytotoxicity, height, yield, number of tillers, number of stems and germination were evaluated. For the field experiment, it was observed that in spite of initial insults caused by several herbicides, only sulfentrazone promoted a reduction of productivity, however all treatments at 60 days after application did not present phytotoxicity symptoms. From this first study, another experiment was carried out in a greenhouse, trying to analyze the same herbicides in different application positions and in two types of soil. When positioned in pretransplantation the symptoms of injuries were higher, compromising the development of some treatment. In this case, diclosulam showed to be the least selective independent of the type of soil studied, followed by clomazone. However, the literature shows that selectivity results vary according to the conditions employed and mainly the crop varieties, thus, repetitions of this study should be performed to enable better understanding and validation of the data.

Resumo: Avaliou-se a eficiência de surfactantes e espalhantes adesionantes na homogeneização da calda de pulverização, constituída por óleo fúsel e água. Para o teste, utilizou-se de Energic, detergente neutro, álcool e Haiten. Para erradicação da cana-de-açúcar comparou-se o óleo fúsel isolado e em mistura com glifosato, em vasos de 22 L, em delineamento inteiramente casualizado, com 12 tratamentos em 4 repetições. Em outro experimento, o óleo fúsel isolado foi aplicado em plantas daninhas em pré-plantio incorporado, em delineamento inteiramente casualizado, com 25 tratamentos em quatro repetições, analisado em esquema fatorial 5x5 (concentrações e espécies); em pós-emergência das plantas daninhas houve a mistura do óleo fúsel e glifosato, em diferentes concentrações. Por último, avaliou-se a eficiência do óleo fúsel isolado e em mistura com glifosato, aplicados em pós-emergência tardia de plantas daninhas, em delineamento em blocos casualizados com 13 tratamentos em 4 repetições. Na mistura do óleo à calda de pulverização, Energic e detergente neutro proporcionaram melhores resultados, enquanto álcool e Haiten mostraram-se ineficientes. O óleo fúsel isolado não dessecou a cana-de-açúcar e, em mistura com o glifosato, dessecou os perfilhos principais. Em pré-plantio incorporado, o óleo fúsel não apresentou interferência sobre a germinação e viabilidade das sementes; em pósemergência, os resultados mostraram controle parcial com a mistura do óleo fúsel e glifosato. Na pós-emergência tardia, em mistura com glifosato apresentou vantagens, por reduzir a massa seca das plantas e custos com a aplicação. / Abstract: The studies aimed to evaluate the fusel oil efficiency in sugarcane desiccation and weed control. The first study evaluated the efficacy of Energic, neutral detergent, alcohol and Haiten in fusel oil and water mixture. The second study evaluated the sugarcane desiccation compared with rates of fusel oil and glyphosate. The experimental design was completely randomized with 12 treatments and four replications in 22 L pots. At other study, isolated fusel oil was applied in incorporate preplanting of weeds, in experimental design completely randomized with 25 treatments and four replications analysed in a factorial arrangement 5x5 (concentrations and weed species); in weed post-emergence there were the fusel oil mixture with glyphosate, in different concentrations. The isolated fusel oil efficiency was evaluated and in mixture with glyphosate, applied in weed late post-emergence, in randomized blocks with 13 treatments in four 4 replications. The fusel oil mixture with water, Energic and neutral detergent provided better results, while alcohol and Haiten showed inefficient. The isolated fusel oil didn’t promote the complete sugarcane desiccation and when in mixture with glyphosate desiccated the sugarcane main shoot population. In incorporate pre-planting, the fusel oil didn't present interference about the seed germination and viability; in weed late post-emergence, the results showed partial control with fusel oil and glyphosate mixture. In weed late post-emergence, fusel oil mixture with glyphosate presented advantages, for reducing the plant dry mass and costs with the application. / Orientador: Marcos Omir Marques / Coorientador: Maria do Carmo Morelli Damasceno Pavani / Banca: Luciano Soares de Souza / Banca: Maria do Carmo de Salvo Soares Novo / Banca: Miguel Ângelo Mutton / Banca: Pedro Luís da Costa Aguiar Alves / Doutor

Orientador: Edivaldo Domingues Velini / Banca: Leandro Tropaldi / Banca: Lucas Perim / Resumo: Devido ao uso frequente do glyphosate na agricultura, o capim-amargoso (Digitaria insularis) tornou-se uma das plantas daninhas mais problemáticas no Brasil, por adquirir resistência a esse herbicida. Biótipos resistentes em estádios iniciais são facilmente controlados por graminicidas, porém em estádio mais avançado o controle é reduzido. O herbicida clethodim é um graminicida com alta eficiência, portanto, verificar o controle de biótipos resistentes ao glyphosate em diferentes estádios, com o uso isolado de clethodim e em mistura com o glyphosate é fundamental para auxiliar no manejo desta invasora. Assim o presente trabalho teve como objetivo avaliar o desempenho de glyphosate, clethodim e glyphosate + clethodim, em biótipo de D. insularis resistente e suscetível. O ensaio foi realizado em casa de vegetação, inteiramente casualizado, com quatro repetições e repetido em duas épocas do ano. As aplicações foram realizadas em estádio inicial (15 - 20 cm) e em florescimento. Avaliou-se o controle aos 21 dias e o peso da biomassa seca. Para a mistura dos produtos, foi verificada a interação entre os herbicidas: efeito sinérgico, antagônico ou aditivo. No ensaio com plantas em estádio inicial, avaliou-se a concentração de lipídeos na biomassa seca. De forma geral, a aplicação de clethodim aplicado isoladamente controlou o biótipo resistente em estádio inicial, porém em florescimento a eficácia foi reduzida. A mistura mostrou-se eficiente para controle de biótipo resistente em es... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Due to frequent use of glyphosate in agriculture, sourgrass (Digitaria insularis) has become one of the most problematic weeds in Brazil for purchase resistance to this herbicide. Resistant biotypes in initial stages are easily controlled by graminicides, but in a more advanced stage the control is reduced. The herbicide clethodim is a graminicide with high efficiency, therefore, to check the control of resistant biotypes of glyphosate in different stages, with the isolated use of clethodim and in mixture with the glyphosate is fundamental to assist in the management of this weed. Thus the experiment was aimed at evaluate the action of glyphosate, clethodim and glyphosate + clethodim, in a resistant and susceptible biotype of D. insularis. The experiment was carried out in a greenhouse, completely randomized, with four replications and repeated at two times of the year. The applications were performed in the initial stage (15 - 20 cm) and flowering. Plants were evaluated at 21 days after application (DAA) and dry biomass weight. For the mixture of products, the interaction between the herbicides was also verified: synergistic, antagonistic or additive effect. In the experiment with plants at the initial stage, was evaluated the lipid concentration in the dry biomass. In general, the application of clethodim applied alone controlled the resistant biotype at the initial stage, but in flowering the efficiency was reduced. The mixture showed to be efficient for control of resistant biotype in initial and flowering stages. Considering the visual evaluations of control, the interaction between glyphosate and clethodim showed synergic effect for intermediate doses and additive for the highest doses considering the initial stage; in flowered plants, with the additive effects predominating for all as doses, the additive effect prevailed for all doses. For dry mass, the mixture had synergistic interaction ... / Mestre

As indústrias de papel e celulose geram enormes quantidades de cinzas de caldeira todos os anos. A disposição final dessas cinzas em aterros costumava ser prática comum, porém a sua utilização em solos florestais e agrícolas merece consideração devido ao seu potencial de corrigir a acidez e de fertilizar os solos, minimizando assim a pressão sobre sua forma de descarte no ambiente. No entanto, o uso desse resíduo pode afetar diretamente a dinâmica de pesticidas no solo, além de adicionar metais pesados. Desta forma, o presente trabalho avaliou o efeito de três cinzas de biomassa florestal (C-1, C-11 e C-27) na fertilidade e na sorção do herbicida imazetapir em três solos com atributos físico-químicos distintos (RQd, LVd e LVAd). Além das três cinzas, calcário e o controle compuseram os tratamentos, os quais foram incubados por três meses. Posteriormente, estudos de sorção do herbicida imazetapir foram realizados nos diferentes tratamentos. As cinzas C-11 e C-27 aumentarem o valor do pH dos solos e os teores de macroelementos, mas reduziram os teores de microelementos catiônicos. A C-1 mostrou ser boa fonte de K para os solos. Nenhuma cinza mostrou-se limitante quanto ao teor de metais pesados. De forma geral, o imazetapir apresentou baixo potencial de sorção nos solos e seus respectivos tratamentos (Kd < 1,8 L kg-1). A C-11 e a C-27 reduziram enquanto que a C-1 aumentou o potencial de sorção do imazetapir nos solos, o que foi devido às alterações nos valores de pH do solo. A sorção foi ligeiramente maior no solo com maiores teores de argila e carbono orgânico (LVd), enquanto a dessorção foi maior no solo de teores intermediários (LVAd). Houve histerese em todos os solos, sugerindo irreversibilidade de parte do herbicida sorvido. / The pulp and paper industries generate huge amounts of wood ash every year. The ashes disposals in landfills used to be a common practice, but their use in agricultural and forest soils deserves special attention due to their potential to neutralize acidity and to fertilize soils, thus decreasing pressure about their environmental disposal. However, the use of this residue may directly impact the dynamic of pesticides as well as add heavy metals to the soils. Therefore, this study evaluated the effects of three wood ashes (C-1 , C-11, and C-27 ) in the fertility and sorption of imazethapyr in three soils (RQd, LVd, LVAd), with contrasting physical-chemical attributes. Besides the ashes, lime and control treatments were added, all of them incubated for three months. Afterwards, batch sorption isotherms for imazethapyr were performed for all treatments. The C-11 and C-27 enhanced soil-pH and macroelement contents, but decreased cationic microelement contents. The C-1 was a good source of K to the soils. There is little risk of contamination by heavy metals. Overall, imazethapyr sorption was low in all soils and their respective treatments (Kd < 1,8 L kg-1). The C-11 and the C-27 decreased whereas C-1 enhanced sorption of imazethapyr to the soils, most likely due to changes in soil-pH. Sorption was slightly higher in the soil with higher clay and organic carbon contents (LVd) whereas desorption was higher in the soil with intermediate values (LVAd). There was hysteresis, suggesting irreversibility during sorption/desorption processes.

No cenário olerícola nacional, a produção de batata está em crescimento. Nas áreas produtoras de batata das regiões Sul e Sudeste é comum encontrar essa cultura em rotação com milho e trigo. O uso de alguns herbicidas do grupo químico das sulfoniluréias nas culturas anteriores tem causado sintomas de fitointoxicação nas lavouras de batata. As deformações dos tubérculos ocorrem no inicio da fase de tuberização, quando se nota numerosas rachaduras relacionadas à contaminação por sulfoniluréias. O objetivo deste trabalho de pesquisa foi avaliar a resposta de plantas de batata das cultivares Atlantic e Lady Rosetta, quanto à produtividade e qualidade dos tubérculos, submetidas a aplicação de subdoses dos herbicidas metsulfuron-methyl e nicosulfuron, utilizados nas culturas do trigo e milho respectivamente. O experimento foi instalado em condições de campo. Os herbicidas foram aplicados nas plantas de batata no início da fase de tuberização. A fitointoxicação causada pelos herbicidas foi avaliada na parte aérea, na produtividade e qualidade dos tubérculos. Ambas as sulfoniluréias, metsulfuron-methyl e nicosulfuron, causaram injúrias foliares nas cultivares de batata, sendo que na cultivar Atlantic esses sintomas não predizem os danos nos tubérculos, que foram inferiores aos esperados. As sulfoniluréias reduziram a produção de tubérculos de maior diâmetro em ambas as cultivares. A cultivar Atlantic teve redução na produção e produtividade causadas pela pulverização de nicosulfuron na dose recomendada para a cultura do milho, e não foi afetada pelas pulverizações de metsulfuron-methyl. A cultivar Lady Rosetta foi afetada por ambas as sulfoniluréias nas maiores doses e pelo nicosulfuron também em dose 10 vezes menor àquela recomendada para a cultura do milho. A produção de tubérculos inviáveis na cultivar Atlantic foi devido à incidência de rachaduras, podendo chegar a 16,11% com a pulverização de metsulfuron-methyl e até 91,33% com nicosulfuron. Na cultivar Lady Rosetta a produção de tubérculos inviáveis caracterizou-se por sintomas de distúrbios fisiológicos, chegando até 78,26% e 88,44% com pulverização de metsulfuron-methyl e nicosulfuron respectivamente. As cultivares Atlantic e Lady Rosetta não perderam produtividade nem qualidade dos tubérculos após aplicação de metsulfuron-methyl ou nicosulfuron nas subdoses testadas. / Potato production increases in the brazilian horticultural scene. Its common to find this crop in rotation with wheat and maize in the south and southeast production areas in Brazil. The use of some sulfonylureas herbicides in previous crops might cause phytotoxicity symptoms in potato. Tuber malformation take place in the beginning of tuberization, when can be noted tuber cracking related to sulfonylureas contamination. This trial aimed to assess the tuber quality and productivity of potato cultivars Atlantic and Lady Rosetta, subjected a application of low ates of metsulfuron-methyl and nicosulfuron, used previously in wheat and maize crops respectively. The trial was carried out in field conditions. The herbicides were sprayed in potato plants in the beginning of the tuberization phase in different rates. The sulfonylureas phytotoxicity was evaluated in the vegetative part and in the tuber quality and yield. Sulfonylureas, metsulfuron-methyl and nicosulfuron, caused foliar injuries in the potato cultivars, being that in Atlantic cultivar these symptoms do not predict tuber damages, that was below expectations. The sulfonylureas also reduced the production of tubers with larger caliber. The Atlantic cultivar decreased the production and the yield because of the nicosulfuron sprayed in maize recommended dose but was not affected by metsulfuronmethyl treatments. The Lady Rosetta cultivar was affected by both of sulfonylureas in the highest doses, such recommended for other crops, and also by nicosulfuron ten times diluted. The production of tuber unachievable for commercialization by the Atlantic cultivar was due to cracking, leading to 16.11% of cracked tubers after metsulfuronmethyl spray and 91.33% with nicosulfuron. In the Lady Rosetta cultivar it was characterized by malformation and second growth, achieving 78.26% and 88.44% of deformed tubers after metsulfuron-methyl and nicosulfuron sprays respectively. Both of the cultivars did not reduce tuber quality and yield after pulverization of metsulfuronmethyl or nicosulfuron in those low rates tested.

Problemas causados pelo herbicida glyphosate na cultura da soja RR, constituem um tema bastante atual. No entanto, grande parte dos estudos disponíveis atualmente revelam os possíveis efeitos negativos do glyphosate ao crescimento e ao desenvolvimento da soja RR. Com o contínuo aumento da área de soja RR no mundo, muitos produtores relatam que algumas variedades apresentam sintomas de injúrias após a aplicação, sendo estás cultivadas em áreas que apresentam plantas daninhas de difícil controle. Objetivou-se com este trabalho avaliar os efeitos de doses crescentes do herbicida glyphosate nos caracteres agronômicos e parâmetros fotossintéticos da soja RR em condições de várzea sistematizada. Foram avaliados os determinados caracteres agronômicos: Densidades de plantas daninhas aos 0 DAA e 21 DAA, Controle de Plantas Daninhas aos 7, 14, 21 DAA, Fitotoxicidade aos 7,14 e 21 DAA, massa seca da parte planta-1, massa seca de raiz palnta-1, altura de plantas, inserção da primeira vagem, números de vagens planta-1, massa de 1.000 grãos e produtividade de grãos. Para os parâmetros fisiológicos avaliou-se a fotossíntese (A), condutância estomática (Gs), concentração interna de CO2 (Ci) e transpiração (E) em condições de várzea sistematizada. / Problems caused by glyphosate herbicide in RR soybean crop are a very current issue. However, much of the currently available studies reveal the possible negative effects of glyphosate on the growth and development of RR soybeans. With the continual increase of the RR soybean area in the world, many farmers report that some varieties show signs of injury after application, and are grown in areas with difficult to control weeds. The objective of this work was to evaluate the effects of increasing doses of glyphosate herbicide on agronomic traits and photosynthetic parameters of RR soybean under conditions of lowland systematized. The following agronomic characters were evaluated: Weed densities at 0 DAA and 21 DAA, Control of weeds at 7, 14, 21 DAA, Phytotoxicity at 7,14 and 21 DAA, dry mass of plant-1 part, dry mass of palnta-1 root, height of Plants, first pod insertion, plant-1 pod numbers, 1,000 grain mass and grain yield. For the physiological parameters photosynthesis, stomatal conductance, internal carbon, transpiration, water use efficiency and intrinsic efficiency were evaluated in lowland conditions.