Weed control is essential in managing high quality turfgrasses. Some preemergent (PRE) herbicides may pose a negative effect on rooting architecture (total length, surface area, diameter, and mass) of desirable species. Several PRE herbicides work by negatively affecting normal cell division and development. Evaluations were performed to determine the effects of four PRE herbicides (dithiopyr, oxadiazon, pendimethalin, and quinclorac) on hybrid bermudagrass (Cynodon dactylon L. X C. transvaalensis Burtt-Davy) (BG) root architecture. Herbicide treatments were applied to field grown dormant BG in Mid-March of 2008 and 2009. A decrease in root length, and in surface area, was observed at 8 WAT by pendimethalin (55% of control). Twelve WAT the greatest decrease occurred in dithiopyr (40%) and pendimethalin (20%). Sixteen WAT, the greatest decrease was observed by dithiopyr (50%). The results indicate that the PRE’s tested can have a negative influence on BG root parameters and possibly water use efficiency.

Using Radioautography 14C simazine, 14C EPTC, 14C 2,4-D, 1414 DCPA and 14C pyrazon absorption by seeds of bean (Phaseolus vulgaris L.), squash (Cucurbita maxima), corn (Zea mays), onion (Allium cepa) and oat (Avena sativa) was studied. Simazine, EPTC, 2,4-D and pyrazon were absorbed through the seed coat of bean, squash, corn and onion, the amount increasing with time. Little DCPA was absorbed by seeds of bean, squash, onion and oat. Distribution and translocation of 14C simazine, 14C EPTC and 14C pyrazon occurred in the young plants of bean, squash, corn and onion. Simazine and pyrazon accumulated in the leaf margins of bean, EPTC and pyrazon were found in the cotyledon margins of squash, and pyrazon was found in the coleoptile tips and leaf tips of corn. The translocation of 14C 2,4-D in bean, onion and squash showed a characteristic fixation along the path of the translocation. Very little translocation or distribution of 14C DCPA were found in bean, squash, onion or oat. In bean leaf, 14C pyrazon was absorbed and moved acropetally in the apoplast. Basipetal movement of 14C pyrazon was limited. Microadioautography was used to determine the tissues involved in the translocation of 14C simazine, 14C EPTC, 14C 2,4-D and 14C pyrazon. Simazine and EPTC were found in the vascular bundle tissues of bean leaf. EPTC was found in the cortex of squash root. 2,4-D was found in the vascular tissues and surrounding the vascular bundle of squash cotyledon and onion hypocotyl. Pyrazon was found intercellularly and intracellularly in bean cotyledon.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-04-26T10:41:11Z No. of bitstreams: 2 Tese - Lara Cristina Pereira da Silva Pacheco - 2017.pdf: 3161074 bytes, checksum: 69afc236d4b1540e17072504bc7db6b9 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-04-26T11:21:24Z (GMT) No. of bitstreams: 2 Tese - Lara Cristina Pereira da Silva Pacheco - 2017.pdf: 3161074 bytes, checksum: 69afc236d4b1540e17072504bc7db6b9 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-04-26T11:21:24Z (GMT). No. of bitstreams: 2 Tese - Lara Cristina Pereira da Silva Pacheco - 2017.pdf: 3161074 bytes, checksum: 69afc236d4b1540e17072504bc7db6b9 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-06-29 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The behavior of the herbicides in the environment is not determined solely by the physicochemical characteristics of the products (pKa, Kow, vapor pressure, water solubility and etc.). Soil attributes (CTC, organic matter, texture, mineralogy, pH, etc.), environmental factors (temperature, rainfall, winds) and the practices adopted in the production systems (cropping system, vegetation cover, chemical fertilization Or organic) also affect the behavior of herbicides in the environment. The objective of this work was to evaluate: 1 - The effect of the soil type on the activity of the herbicides clomazone, diclosulam, oxyfluorfen and sulfentrazone and to determine the ideal dose of this herbicide in each type of soil, through dose- answer; 2 - The activity of the herbicide Oxyfluorfen in soil with addition of biochar of sewage sludge; 3 - The activity of pre-emergent herbicides, in the absence and presence of Pennisetum glaucum straw. The soil type affected the the herbicides activities and, therefore, should be considered when deciding the herbicide applied doses. In Cerrado soils CEC is the most suitable soil attribute to predict the ideal herbicides doses of oxyfluorfen. The addition of biochar from sewage sludge obtained by pyrolysis at 500 ° C increased the sorption of the herbicide Oxyfluorfen to the soil, reducing its availability to the plants. The herbicide efficacy of the herbicides atrazine, clomazone and diclosulam is negatively affected by the presence of straw of Pennisetum glaucum. The presence of straw of Pennisetum glaucum does not affect the effectiveness of the herbicides Oxyfluorfen and Sulfentrazone. / O comportamento dos herbicidas no ambiente não é determinado, somente, pelas características físico-químicas dos produtos (pKa, Kow, pressão de vapor, solubilidade em água e etc). Os atributos do solo (CTC, teor de matéria orgânica, textura, mineralogia, pH, etc), os fatores ambientais (temperatura, precipitação pluviométrica, ventos) e as práticas adotadas nos sistemas de produção (sistema de cultivo, cobertura vegetal, adubação química ou orgânica) também afetam o comportamento dos herbicidas no ambiente. Diante disso, objetivou-se com este trabalho avaliar: 1 – O efeito do tipo de solo na atividade dos herbicidas clomazone, diclosulam, oxyfluorfen e sulfentrazone e determinar a dose ideal desse herbicida em cada tipo de solo, por meio de curvas de dose-resposta; 2 – A atividade do herbicida Oxyfluorfen em solo com adição de biochar de lodo de esgoto; 3 – A atividade de herbicidas pré-emergentes, na ausência e presença de palhada de Pennisetum glaucum. O tipo de solo afeta a atividade dos herbicidas estudados e, portanto, deve ser considerado quando da tomada de decisão das doses aplicadas dos herbicidas. Nos solos de Cerrado, a CTC é o atributo do solo mais indicado para predição das doses a serem aplicadas do herbicida oxyfluorfen. Quanto ao impacto de resíduos orgânicos na atividade de herbicidas, a adição de biochar de lodo de esgosto, obtido pela pirólise a 500°C, aumentou a sorção do herbicida Oxyfluorfen ao solo, reduzindo sua disponibilidade às plantas. A eficácia no controle de plantas daninhas dos herbicidas atrazina, clomazone e diclosulam, éafetada negativamente pela presença de palhada de Pennisetum glaucum. A presença de palhada de Pennisetum glaucum não afeta a eficácia dos herbicidas Oxyfluorfen e Sulfentrazone.

Weed competition occurs during potato planting and development, demanding for the application of specific herbicides, especially pre-emergent ones. There are few herbicides registered for this crop and the cultivars present different selectivity levels to them. Thus, the study of selectivity and weed management are fundamental for obtaining high yields. This study evaluated the selectivity and weed control with the use of pre-emergent herbicides on potatoes. Two experiments were done in Perdizes-MG, using the cultivar Innovator. The first one was installed on August 2014 to evaluate pre-emergent herbicide selectivity to potatoes. Treatments consisted of a control, a hoed control, metribuzin (240 g ha-1), metribuzin (480 g ha-1), linuron (450 g ha-1), linuron (990 g ha-1), diclosulan (25.2 g ha-1), imazetapir (700 g ha-1), prometrine (1000 g ha-1), clomazone (360 g ha-1), clomazone + carfentrazone (300 + 7.5 g ha-1), clomazone + carfentrazone (600 + 15 g ha-1) and sulfentrazone (125 g ha-1). The second experiment was installed on March 2015 using pre-emergent herbicides to evaluate the control of weeds. Treatments consisted of a control, a hoed control, clomazone (360 g ha-1), metribuzin (480 g ha-1), linuron (990 g ha-1), clomazone + metribuzin (360 + 480 g ha-1), and clomazone + linuron (360 + 990 g ha-1). Both experiments were done as randomized blocks with four replications. Plant vegetative development, phytotoxicity and weed control were evaluated 10 and 30 days after shoot emergence (DAE), while total soluble solids, yield and classification were evaluated after harvest. Averages were compared by the Tukey test at 5% significance. The herbicides evaluated for selectivity, in the first trial, did not affect plant development. The herbicides metribuzin, diclosulan and imazetapir presented high phytotoxicity, lowe soluble solids contents and lower yield, and were considered as less selective. In contrast, the herbicides linuron and clomazone were not phytotoxic, did not affect soluble solids contents and did not cause crop yield reduction, and were considered more selective to this potato cultivar. The herbicides evaluated for weed control, in the second experiment, alone or in association, provided 100% control for the species Eleusine indica and Digitaria horizontalis. The best control of Commelina benghalensis, was obtained with clomazone alone or in association with metribuzin or linuron. Plots treated with clomazone presented phytotoxicity at 10 DAE; however, plants recovered from it at the 30 DAE evaluation. . The greatest yields were observed in treatments with clomazone and metribuzin applied by themselves. However, metribuzin reduced total solids contents, which affects potato industrial yield. Therefore, for this potato cultivar, the herbicides conserved more selective were clomazone and linuron, applied alone or in association. / Durante a implantação e o desenvolvimento da cultura da batata ocorre competição por plantas infestantes, exigindo aplicações de herbicidas específicos, principalmente pré-emergentes. Existem poucos herbicidas registrados para esta cultura e as cultivares apresentam diferentes níveis de seletividade a esses herbicidas. Por tanto, o estudo da seletividade e o manejo das plantas infestantes são fundamentais para obtenção de elevadas produtividades. O objetivo deste trabalho foi avaliar a seletividade e o controle de plantas infestantes com a utilização de herbicidas pré-emergentes na cultura da batata. Para isto, foram instalados dois experimentos em Perdizes-MG utilizando a cultivar Innovator. O primeiro foi instalado em agosto de 2014 com o objetivo de avaliar a seletividade dos herbicidas pré-emergentes na cultura da batata. Os tratamentos consistiram em testemunha, testemunha capinada, metribuzin (240 g ha-1), metribuzin (480 g ha-1), linuron (450 g ha-1), linuron (990 g ha-1), diclosulan (25,2 g ha-1), imazetapir (700 g ha-1), prometrina (1000 g ha-1), clomazone (360 g ha-1), clomazone + carfentrazone (300 + 7,5 g ha-1), clomazone + carfentrazone (600 + 15 g ha-1) e sulfentrazone (125 g ha-1). O segundo experimento foi instalado em março de 2015 utilizando os herbicidas pré-emergentes com objetivo de avaliar o controle de plantas infestantes. Os tratamentos consistiram em testemunha, testemunha capinada, clomazone (360 g ha-1), metribuzin (480 g ha-1), linuron (990 g ha-1), clomazone + metribuzin (360 + 480 g ha-1), clomazone + linuron (360 + 990 g ha-1). Os dois experimentos foram realizados em delineamento de blocos casualizados com quatro repetições. Foram realizadas avaliações de desenvolvimento vegetativo, fitotoxicidade e controle de plantas infestantes aos 10 e 30 dias após emergência das hastes (DAE), teor de sólidos solúveis, produtividade e classificação após a colheita. As médias foram comparadas pelo teste de Tukey a 5% de significância. Com relação à seletividade avaliada no primeiro ensaio, os herbicidas não afetaram desenvolvimento das plantas. Os herbicidas metribuzin, diclosulan e imazetapir apresentaram elevada fitotoxicidade, menor teor de sólidos solúveis e menor produtividade, sendo assim considerados menos seletivos. Ao passo que linuron e clomazone, não proporcionaram fitotoxicidade, não afetaram o teor de sólidos solúveis e não proporcionaram redução de produtividade, sendo dessa forma considerados mais seletivos para esta cultivar. Já no segundo ensaio, no qual objetivou-se avaliar o manejo de plantas infestantes, os herbicidas tanto isolados como em associação apresentaram controle de 100% para as espécies Eleusine indica e Digitaria horizontalis. Para o controle de Commelina benghalensis, clomazone isolado ou em associação com metribuzin ou linuron proporcionaram melhor controle. Parcelas tratadas com clomazone apresentaram sintomas de fitotoxicidade aos 10 DAE, porém as plantas se recuperaram aos 30 DAE. Os maiores níveis de produtividade foram observados nos tratamentos com clomazone e metribuzin aplicados isolados. No entanto, metribuzin reduziu o teor de sólidos solúveis, o que afeta o rendimeno industrial. Dessa forma, para esta cultivar os herbicidas considerados mais seletivos foram clomazone e linuron, aplicados isolados ou em associação. / Mestre em Agronomia

Bare-root Nuttall oak, Shumard oak, and swamp chestnut oak seedlings were planted on former agricultural fields in Mississippi to evaluate growth and survival following treatment by different combinations of mechanical site preparation and pre-emergent Oust XP® applications. Mechanical treatments included: (1) controls, (2) subsoiling treatment, (3) bedding treatment, and (4) combination plowing. Pre-emergent Oust XP® treatments included: (1) one-year Oust XP® applications and (2) two-year Oust XP® applications. Evaluations and measurements were performed over the course of three years. Results within this dissertation should be considered in the context of high quality former agricultural sites with silt loam soils. Seedling height and GLD increased each growing season. Height and GLD of seedlings were greater in bedded and combination plowed areas compared to control and subsoiled areas. Height and GLD were not different by Oust XP® application. However, seedling survival in two-year Oust XP® application areas was reduced compared to one-year Oust XP® application areas. Nuttall oak seedlings planted in bedded and combination plowed areas exhibited greater stem biomass compared to those planted in control or subsoiled areas. Seedlings planted in two-year Oust XP® areas exhibited greater stem and root biomass compared to those planted in areas receiving the one-year treatment. Better growth and biomass production in bedded and combination plowed areas would promote their use for site preparation on similar sites. While survival was lower in two-year Oust XP® treatment areas compared to one-year treatment areas, the difference would not warrant change in management strategy. Additionally, woody biomass was much greater in two-year Oust XP® areas. Thus, if cost is not prohibitive, treatment with two years of Oust XP® is recommended. The objective of the mixed species study was to establish baseline growth and survival data for mixed Nuttall oak and green ash plantations on former agricultural areas. Height and GLD for both species increased each growing season. Third-year survival was excellent at 96.0 percent. In conclusion, the mixture performed satisfactorily. Growth and survival were excellent, which indicates this mixture would be useful in afforesting similar former agriculture sites.