Since weed killers were developed in the early part of the decade beginning in 1940, herbicides have been increasing in use until they are now widely used to control weeds . The application of herbicides has thus become a regular agricultural and ecological practice. Some of the herbicides are applied directly to soils and accompanied by a light irrigation to wash them into the soil in order to increase their efficiency . Some of these chemicals accumulate in the soil and should be removed in order to avoid toxic effect on succeeding plants (Klingman, 1961) . The toxic effect of herbicidal residues in soil and water to human subjects , livestock , and wildlife has been repor•ted (Paynter et al., 1960; Carpenter et al., 1961). When these materials are leached out of the soil , they may pollute the water supply. The movement of water and herbicides in soils is thus closely connected to both their herbicidal and toxic effect and is becoming a serious economic problem. It is the purpose of this investigation to study the simultaneous movement of water and herbicides in unsaturated soils by using the thermodynamic theory of irreversible processes. The adsorption of herbicides, the energy of adsorption, and the break-through curve will also be studied.

Orientador: Edivaldo Domingues Velini / Coorientador: Ivana Paula Ferraz Santos de Brito / Banca: Caio Antonio Carbonari / Banca: Leandro Tropaldi / Resumo: Com a proibição da realização de queimadas para a colheita da cana-de-açúcar, e a implantação da colheita mecanizada, foi originado o sistema de produção denominado cana crua. Nele há o acúmulo de grandes quantidades de resíduos na superfície do solo após a colheita, sendo a cultura implantada sobre essa palhada. Nesse sistema a camada de palha pode interferir na dinâmica dos herbicidas, pois é uma barreira a ser transposta até atingir o solo. Visando obter informações acerca da dinâmica de diferentes produtos, o objetivo desse trabalho foi avaliar a transposição de herbicidas simulando aplicações direto na palha e diluída na água de chuva em palha de cana- de-açúcar. O estudo realizado no NUPAM, visando determinar a dinâmica de transposição dos herbicidas atrazine, diuron, fomesafen, glyphosate, haloxyfop-p- methyl, hexazinone, indaziflam, S-metolachlor e sulfentrazone em palha de cana-de- açúcar. Utilizou-se delineamento inteiramente ao acaso, com quatro repetições, sendo a palha utilizada cortada em 0,5 x 0,5 cm e acondicionada em cápsulas de polietileno. Tendo 9 tratamentos x 3 épocas experimentais x 2 condições. Sendo a primeira condição, a simulação da chegada do herbicida na superfície da palha após a aplicação direta da calda com pipeta de repetição de 40 μL do volume de calda de cada produto por unidade experimental, enquanto na segunda condição, foi simulada a chegada do herbicida na palha após a ocorrência de chuvas, com 40 μL do volume de calda de cada produto apl... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: With the burning fires prohibition for the sugarcane harvesting, and the mechanized harvest implantation, the production system called raw cane was originated. There is accumulation of large amounts of residues on the soil surface after harvest, and the crop is implanted on this straw. In this system the straw layer may interfere with herbicide dynamics, since it is a barrier to be transposed until reaching the ground, and in order to obtain information about the dynamics of different products, the objective of this work was to evaluate the herbicides transposition simulating direct applications in straw and diluted in rainwater in sugarcane straw. The study was carried out at NUPAM, aimed to determine the transposition dynamics of the herbicides atrazine, diuron, fomesafen, glyphosate, haloxyfop-p-methyl, hexazinone, indaziflam, S- metolachlor and sulfentrazone in sugarcane straw. A completely randomized design with four replications was used, the straw being cut into 0.5 x 0.5 cm and packed in polyethylene capsules. Having 9 treatments x 3 times experimental x 2 conditions. Being the first condition, the simulation of herbicide arrival on the straw surface after the direct application of the syrup with a 40 μL repeating pipette of each product volume per experimental unit, while in the second condition, the herbicide arrival was simulated in the straw after the occurrence of rain, with 40 μL of the volume of syrup of each product applied per experimental unit during the 25 mm rainfall simulation. Soon after, 25, 50, 75 and 100 mm accumulated rain blades and 50, 75 and 100 mm were simulated for the first and second experiments, respectively. The herbicides determination in the solutions was performed by means of chromatographic analyzes using the LCMS / MS system. Data were submitted to normality and homogeneity tests and were subsequently submitted to variance analysis by the F test, with the ... / Mestre

Flumetsulam … is a member of the triazolopyrimidine sulfonanilide family of herbicides. It is used for pre or post-emergence broadleaf weed control in wheat, corn, barley and soybean. It has low toxicity and is readily degradable. A HPLC-UV method for the analysis of flumetsulam with the use of a surrogate and internal standard was developed and validated for soybean. The surrogate and internal standards are diclosulam and benzoic acid respectively. A LC-ESI-MS/MS confirmation method in the positive ion mode was also developed for flumetsulam. In the solvent-solvent extraction method, flumetsulam was extracted from the soybean with MeOH and the extract partitioned with a hexane:MTBE mixture (which was discarded). In the solid phase extraction and clean up method, C-18, SAX and SCX cartridges were used. Flumetsulam was extracted from the soybean as for the solvent-solvent extraction method. The solvent-solvent extraction method was used for flumetsulam determination at fortification levels of 10, 20, 50 and 100 ng -g soybean -1. The method has average absolute recoveries of 80% (range 72 to 90%). The absolute precision of recovery is about 16% and the detection limit is 4.8 ng g-1.The solid phase extraction method was used for flumetsulam determination at fortification levels of 20, 50, and 100 ng (ng soybean )-1. The precision of recovery is about 11%. The detection limit is 7.2 ng g-1. The MRL for flumetsulam recommended by the Australian Pesticides and Veterinary Medicines Authority is 50 ng g-1 for pulses. / Doctor of Philosophy (PhD)

Bibliography: leaves 203-220. / xii, 220 leaves : ill., map ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Crop Protection, 1993

The introduction of glyphosate resistance into Australian cotton systems will have an effect on conventional weed management practices, the weed species present and the risk of glyphosate resistance evolving in weed species. Therefore, it is important that the effects of these management practices, particularly a potential reduction in Integrated Weed Management (IWM) practices, be examined to determine their impact on weed population dynamics and resistance selection. The study began in 2003 with a survey of 40 growers in four major cotton growing regions in Australia to gain an understanding of how adoption of glyphosate resistance had influenced the weed spectrum, weed management practices and herbicide use after three years of glyphosate-resistant cotton being available. The 10 most common weeds reported on cotton fields were the same in glyphosate-resistant and conventional fields. In this survey, herbicide use patterns were altered by the adoption of glyphosate-resistant cotton with up to six times more glyphosate being applied and with 21% fewer growers applying pre-emergence herbicides in glyphosate-resistant cotton fields. Other weed control practices, such as the use of post-emergence herbicides, inter-row cultivation and hand hoeing, were only reduced marginally. A systems experiment was conducted to determine differences in the population dynamics of Echinochloa crus-galli (barnyardgrass) and Urochloa panicoides (liverseed grass) under a range of weed management regimes in a glyphosate-resistant cotton system. These treatments ranged from a full IWM system to a system based soley on the use of glyphosate. The experiment investigated the effect of the treatments on the soil seed bank, weed germination patterns and weed numbers in the field. All applied treatments resulted in commercially acceptable control of the two grass weeds. However, the treatments containing soil-applied residual herbicides proved to be more effective over the period of the experiment. The treatment with a reduced residual herbicide program supplemented with glyphosate had a level of control similar to the full IWM treatments with less input, providing a more economical option. The effectiveness of these treatments in the long-term was examined in a simulation model to determine the likelihood of glyphosate resistance evolving using barnyardgrass and liverseed grass as model weeds. Seed production and above-ground biomass of barnyardgrass and liverseed grass in competition with cotton were measured. In all experiments, seed production and biomass plant⁻¹ decreased as weed density increased while seed production and biomass m⁻¹ tended to increase. Seed production m⁻¹ reached 40,000 and 60,000 for barnyardgrass and liverseed grass, respectively. In 2004-05, weeds were also planted 6 weeks and 12 weeks after the cotton was planted. Biomass and seed production of the two weeds planted 6 weeks after cotton were significantly reduced with seed production declining to 12,000 and 2,500 seeds m⁻¹ row for barnyardgrass and liverseed grass, respectively. Weeds planted 12 weeks after cotton planting failed to emerge. This experiment highlighted the importance of early season weed control and effective management of weeds that are able to produce high seed numbers. A glyphosate dose-mortality experiment was conducted in the field to determine levels of control of barnyardgrass and liverseed grass. Glyphosate provided effective control of both species with over 85% control when the rate applied was greater than 690 g ae ha⁻¹. Dose-mortality curves for both species were obtained for use in the glyphosate resistance model. Data from the experimental work were combined to develop a glyphosate resistance model. Outputs from this model suggest that if glyphosate were used as the only form of weed control, resistance in weeds is likely to eventuate after 12 to 17 years, depending on the characteristics of the weed species, initial resistance gene frequencies and any associated fitness penalties. If glyphosate was used in conjunction with one other weed control method, resistance was delayed but not prevented. The simulations suggested that when a combination of weed control options was employed in addition to glyphosate, resistance would not evolve over the 30-year period of the simulation. These simulations underline the importance of an integrated strategy in weed management to prevent glyphosate resistance evolving from the use of glyphosate-resistant cotton. Current management conditions of growing glyphosate-resistant (Roundup Ready &reg) cotton should therefore prevent glyphosate resistance evolution. / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2006.

Bibliography: leaves 203-220.

Bibliography : leaves 159-184. This study found at least three mechanisms of resistance to the acetyl coenzyme A carboxylase (ACCase)-inhibiting herbicides. A modified target -site was responsible for moderate and high resistance to herbicides at the whole plant level. Enhanced herbicide metabolism and reduced translocation of herbicide to the target site was observed in one resistant biotype each.

Bibliography: leaves 209-254. Experiments detailed in this thesis, evaluate the impact of various herbicides and herbicide mixtures on the growth, nodulation and nitrogen fixation of annual pasture legumes, the efficacy of the herbicides for weed control, and the potential role of mechanical defoliation to replace herbicides, leading to lower cost and more sustainable farming systems.

Bibliography: leaves 128-146. Study was undertaken to determine the occurence and species incidence of wild oats in a major cropping region of southern Australia. Population dynamic studies were undertaken at two sites to define the seed bank decline and emergence pattern of several wild oat populations over a three year period. Management studies were conducted to determine appropriate strategies for the control of wild oats in southern Australian farming systems.

Graduation date: 1999