Made available in DSpace on 2017-07-10T19:24:28Z (GMT). No. of bitstreams: 1 Gislaine Picollo de Lima.pdf: 510399 bytes, checksum: ea2c2de4321bd8f24facd8e31b533b09 (MD5) Previous issue date: 2008-02-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The cover crop adequacy to the implanted crop together with the adopted soil management system is important in order to obtain improvements on the system s yield and efficiency. Thus, this study aimed at examining the possible allelopathyc interference of black oat remains (Avena strigosa Schreb) and a consortium of black oat, forage turnip (Raphanus sativus L.) and vetch (Vicia sativa L.) on the speed emergency index (SEI) and emergency speed (ES) of seedlings, plants heights, weed incidence (large and narrow leaf), harvested seed quality and soybean yield Glycine max (L.) Merrill; considering different intervals among drying of cover crop using the Glyphosate 480 (3L ha-1) herbicide and the sowing of BRS 232 soybeans. The plots were marked on the field measuring 5 m x 2.5 m, adding 1 m borderline between them to the four treatment distributions for black oat cover, four treatments, the consortium and a control for each cover crop, completely randomized, with five replications. The cover crop was sowed in August, 2006; each row was 0.15m distant from each viii other. Later, the plots were dried on intervals of ten, twenty and thirty days before the soybean sowing, which was installed in November, 2006, with the 13 rows; each row was 0.45 m distant from each other and there were 14 seeds per linear meter. All the tests were submitted to an experimental design, with subdivided plots (split plot), completely randomized; the averages were also compared using Scott and Knott test at 5 % of significance. The study observed possible allelopathyc interference of cover crop on SEI, harvested seed quality, weed as well as the intervals of sowing and drying. / A adequação da cobertura vegetal à cultura agrícola, implantada em conjunto ao sistema de manejo de solo adotado, é importante para obtenção de melhorias na eficiência e produtividade do sistema. Dessa forma, o estudo em questão visou analisar a possível interferência alelopática dos restos vegetais de aveia preta (Avena strigosa Schreb) e consórcio de aveia preta, nabo forrageiro (Raphanus sativus L.) e ervilhaca comum (Vicia sativa L.) no índice de velocidade de emergência (IVE) e velocidade de emergência (VE) de plântulas, altura de planta, incidência de espécies invasoras (folha larga e folha estreita), qualidade da semente colhida e produtividade da cultura de soja Glycine max (L.) Merrill; considerando intervalos diferenciados entre a dessecação da cobertura vegetal com o herbicida Glyphosate 480 (3L ha-1) e a semeadura da soja BRS 232. No campo foi realizada a demarcação das parcelas em 5 m x 2,5 m, acrescido de 1 m de bordadura entre elas, para a distribuição de quatro tratamentos para a cobertura de aveia preta, quatro para o consórcio, e uma testemunha para cada cobertura, ao acaso, com cinco repetições. A cobertura vegetal foi semeada em agosto de 2006 com espaçamento de 0,15 m entre linhas; posteriormente, as parcelas foram dessecadas em intervalos variados de um, dez, vinte e trinta dias anteriores à semeadura da soja, a qual foi instalada em novembro de 2006, com espaçamento entre linhas de 0,45 m, treze linhas de semeadura e 14 sementes por metro linear. O delineamento experimental foi inteiramente casualizado, em esquema de parcela subdividida, comparando-se as médias pelo teste de Scott e Knott ao nível de 5 % de significância. O estudo observou possível interferência alelopática das coberturas vegetais no IVE, qualidade da semente colhida, espécies invasoras, assim como, nos intervalos entre dessecação e semeadura.

Made available in DSpace on 2017-05-12T14:47:46Z (GMT). No. of bitstreams: 1 Gislaine Picollo de Lima.pdf: 510399 bytes, checksum: ea2c2de4321bd8f24facd8e31b533b09 (MD5) Previous issue date: 2008-02-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The cover crop adequacy to the implanted crop together with the adopted soil management system is important in order to obtain improvements on the system s yield and efficiency. Thus, this study aimed at examining the possible allelopathyc interference of black oat remains (Avena strigosa Schreb) and a consortium of black oat, forage turnip (Raphanus sativus L.) and vetch (Vicia sativa L.) on the speed emergency index (SEI) and emergency speed (ES) of seedlings, plants heights, weed incidence (large and narrow leaf), harvested seed quality and soybean yield Glycine max (L.) Merrill; considering different intervals among drying of cover crop using the Glyphosate 480 (3L ha-1) herbicide and the sowing of BRS 232 soybeans. The plots were marked on the field measuring 5 m x 2.5 m, adding 1 m borderline between them to the four treatment distributions for black oat cover, four treatments, the consortium and a control for each cover crop, completely randomized, with five replications. The cover crop was sowed in August, 2006; each row was 0.15m distant from each viii other. Later, the plots were dried on intervals of ten, twenty and thirty days before the soybean sowing, which was installed in November, 2006, with the 13 rows; each row was 0.45 m distant from each other and there were 14 seeds per linear meter. All the tests were submitted to an experimental design, with subdivided plots (split plot), completely randomized; the averages were also compared using Scott and Knott test at 5 % of significance. The study observed possible allelopathyc interference of cover crop on SEI, harvested seed quality, weed as well as the intervals of sowing and drying. / A adequação da cobertura vegetal à cultura agrícola, implantada em conjunto ao sistema de manejo de solo adotado, é importante para obtenção de melhorias na eficiência e produtividade do sistema. Dessa forma, o estudo em questão visou analisar a possível interferência alelopática dos restos vegetais de aveia preta (Avena strigosa Schreb) e consórcio de aveia preta, nabo forrageiro (Raphanus sativus L.) e ervilhaca comum (Vicia sativa L.) no índice de velocidade de emergência (IVE) e velocidade de emergência (VE) de plântulas, altura de planta, incidência de espécies invasoras (folha larga e folha estreita), qualidade da semente colhida e produtividade da cultura de soja Glycine max (L.) Merrill; considerando intervalos diferenciados entre a dessecação da cobertura vegetal com o herbicida Glyphosate 480 (3L ha-1) e a semeadura da soja BRS 232. No campo foi realizada a demarcação das parcelas em 5 m x 2,5 m, acrescido de 1 m de bordadura entre elas, para a distribuição de quatro tratamentos para a cobertura de aveia preta, quatro para o consórcio, e uma testemunha para cada cobertura, ao acaso, com cinco repetições. A cobertura vegetal foi semeada em agosto de 2006 com espaçamento de 0,15 m entre linhas; posteriormente, as parcelas foram dessecadas em intervalos variados de um, dez, vinte e trinta dias anteriores à semeadura da soja, a qual foi instalada em novembro de 2006, com espaçamento entre linhas de 0,45 m, treze linhas de semeadura e 14 sementes por metro linear. O delineamento experimental foi inteiramente casualizado, em esquema de parcela subdividida, comparando-se as médias pelo teste de Scott e Knott ao nível de 5 % de significância. O estudo observou possível interferência alelopática das coberturas vegetais no IVE, qualidade da semente colhida, espécies invasoras, assim como, nos intervalos entre dessecação e semeadura.

<p>U regionu severnog Banata se uglavnom primenjuje<br />konvencionalni način obrade zemlji&scaron;ta, zasnovan na obradi<br />plugom, kao primarna obrada koji je spor, skup i zahteva veliki<br />utro&scaron;ak rada i goriva. Takva obrada je sa ekolo&scaron;kog stanovi&scaron;ta<br />nepovoljna i neodrživa. U poslednjih trideset godina, naučna<br />saznanja o obradi zemlji&scaron;ta u svetu se menjaju u pravcu<br />pojednostavljenja obrade i smanjenja prohoda. Savremeni sistemi<br />obrade su u Srbiji nedovoljno istraženi, a cilj ovoga rada je da se<br />optimizuje obrada zemlji&scaron;ta za date uslove. Za potrebe istraživanja<br />je postavljen ogled u trajanju od tri godine (2011/2012, 2012/2013<br />i 2013/2014), pri čemu je uzgajan kukuruz, p&scaron;enica i kukuruz, tim<br />redosledom. Svaka kultura je uzgajana u tri sistema obrade:<br />konvencionalna obrada bazirana na plugu, direktna setva i<br />konzervacijska obrada bazirana na razrivaču, pri čemu je Ďubrenje<br />bilo uniformno. U radu je analiziran uticaj različitih načina obrade<br />na specifični otpor zemlji&scaron;ta, fizičke i hemijske osobine zemlji&scaron;ta i<br />živi svet u zemlji&scaron;tu (brojnost glista). Uspe&scaron;nost poljoprivredne<br />proizvodnje se ogleda kroz ostvareni prinos i utro&scaron;ena sredstva,<br />zbog čega je utvrĎen najprinosniji i ekolo&scaron;ki najprihvatljiviji način<br />obrade zemlji&scaron;ta. Pored navedenog, analiziran je uticaj različitih<br />rasprskivača pri tretiranju useva pesticidima na prisustvo ostataka<br />pecticida u zemlji&scaron;tu</p> / <p>Conventional tillage is the most frequently applied tillage method in the<br />area of northern Banat. It is based on ploughing as the primary tillage<br />operation, which is slow, costly, and requires large expenditure of labour<br />and fuel. Such treatment can be ecologically unfavourable, and it is not<br />sustainable. In the last thirty years, global knowledge about soil tillage<br />has been changing towards simplification and reduced soil tillage.<br />Contemporary tillage systems in Serbia are not studied thoroughly<br />enough, but the goal of this work was to optimize soil tillage for the given<br />conditions. The trial was set up during the period of three years<br />(2011/2012, 2012/2013, and 2013/2014), in which corn, wheat, and corn<br />were cultivated, respectively. Each crop was grown using three tillage<br />systems - conventional tillage based on ploughing, direct seeding, and<br />conservation tillage based on tine cultivator, whereas fertilization was<br />uniform in all the systems. This dissertation analyzes the impact of<br />different tillage on soil resistance, physical and chemical properties of<br />soil, as well as biota in the soil (number of earthworms). Success of<br />agricultural production is reflected in yield and expenses, therefore this<br />dissertation determins the highest yielding and most environmentally<br />friendly system of tillage. In addition, it analyzes the impact of using<br />different kinds of nozzles in treating crops on the pesticide residues in the<br />soil.</p>

Orientador: Itamar Andrioli / Banca: Itamar Andrioli / Banca: Renato de Mello Prado / Banca: Adilson Pelá / Resumo: Os resíduos produzidos pelas culturas comerciais, geralmente, são insuficientes para proporcionarem uma adequada cobertura do solo. Portanto, é necessário introduzir ao sistema, plantas capazes de produzirem grandes quantidades de fitomassa com rápido desenvolvimento inicial e de ciclo curto. O objetivo deste trabalho foi avaliar a produção de matéria seca e o N acumulado pelas plantas de cobertura, a produção de matéria seca do milho, o fornecimento de N ao milho e o rendimento de grãos da cultura devido aos sistemas de sucessão de plantas de cobertura em pré-safra ao milho. O experimento foi conduzido na área experimental da FCAV - Unesp Jaboticabal SP, (21º15'27"S e 48º18'58"W; 595 m de altitude) nos anos agrícolas 2006/07 e 2007/08. O delineamento experimental adotado foi o de blocos ao acaso, em parcelas subdivididas, com quatro repetições, em que os tratamentos principais foram constituídos por seis sistemas de sucessão (S1=crotalária/milho; S2=feijão-deporco/ milho; S3= lablabe/milho; S4=milheto/milho, S5=mucuna-preta/milho e S6=pousio/milho). Nas subparcelas foram aplicadas quatro doses de nitrogênio em forma de uréia em cobertura nas doses de 0, 60, 120 e 180 kg ha-1. Pode-se concluir que: as espécies de cobertura que produziram mais fitomassa foram milheto e crotalária (2007/08) e as que mais acumularam nitrogênio foram mucuna-preta (2006/07) e milheto e crotalária (2007/08). No ano agrícola 2007/08 a sucessão S1 apresentou os maiores teores de N no tecido foliar e maior MS do sabugo na ausência de adubação nitrogenada. Quando aplicado 60 kg ha-1 de N a sucessão S5 obteve maior teor de N foliar no milho. A maior produção de MS de grãos na ausência de adubação nitrogenada no ano 2007/08 ocorreu nas sucessões S1 e S3. O maior acúmulo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The residues produced by commercial crops usually are insufficient to produce a good soil cover. Therefore, it is necessary to introduce the system, plants capable of producing large quantities of biomass with rapid initial development and short cycle. The objective of this work was to evaluate the production of biomass and N accumulation by the plants cover, the dry biomass of corn, the N supply of corn and the grain yield of the crop due to the succession systems of plant cover in pre-safra to the corn. The experiment was conducted in the experimental area of FCAV - Unesp Jaboticabal SP, (21 º 15 'S and 48 º 18' W, 595 m altitude). The experimental design was randomized blocks, in split plots with four replications, where the main treatments were consisted of six succession systems (S1 = sunn hemp/corn; S2 = pig-bean/corn, S3 = lablab/corn; S4 = millet/corn, S5 = velvetbean /corn and S6 = fallow/maize). In the subplots were applied four rates of nitrogen as urea in coverage at doses of 0, 60, 120 and 180 kg ha-1. It can be concluded that the species of coverage that were produced more biomass were millet and sunn hemp (2007/08) and that accumulated more nitrogen was velvetbean (2006/07) and millet and sunn hemp (2007/08). In the year 2007/08 the succession S1 showed the highest levels of N in leaf tissue and increased MS of root in the absence of nitrogen fertilization. When applied 60 kg ha-1 of N the S5 succession was higher N level leaf and S1 succession higher of root MS. The highest production of MS grain in the absence of nitrogen fertilization in the year 2007/08 was in S1 and S3 successions. The highest accumulation of N in grain in the absence of nitrogen fertilization were found in S1, S3 and S5 successions. The S3 succession promoted the highest accumulation of N in biomass of corn in the year 2007/08. / Mestre

Soil is a critical component of the global sulfur (S) cycle acting as source and a sink for various S species and mediating changes of S oxidation states. However, very little is known about the identities of these specific organic and inorganic S containing molecules, especially in Brazilian soils under no-tillage (NT) system. Thus, the objectives of this study were: (i) to report long and medium term effects of the application of lime and up to 12 t ha-1 of phosphogypsum (PG) in samples from two Oxisols collected in field experiments carried out under no-tillage (NT) systems; (ii) to assess the effect of PG application on the amount, form and distribution of organic and inorganic S pools in soils under NT comparing to a natural forest ; (iii) to investigate C, N and S mineralization/immobilization in soil samples affected by plant residues and biochar, thus identifying the major transformations in the S fractions. After 13 years of lime application in a loamy Oxisol, changes in soil acidity and exchangeable Ca2+ ad Mg2+ supply were visible up to 80 cm depth. The effect of PG providing Ca2+ and S-SO4 2- were more pronounced at lower depths. S-SO4 2- distribution in the soil profile was mostly correlated with contents of free dithionite extractable Fe (Fed) and amorphous dithionite extractable Fe minus oxalate extractable Fe (Fed-Feo). There was no effect of lime and PG in maize grain yield, showing that the plants were unable to benefit of the soil ameliorations. An appreciable movement of sulfate to the subsoil was observed in soil samples from a clayey Oxisol, even in a medium-term (after 3.5 years), despite the fact that the soil had presented high SO4 2- adsorption capacity. In this area, PG had positive benefits in cereal crop yield due to the supply of Ca2+ and S-SO4 2-. PG application and changes in landuse practice alters both quantitative (evaluated by the wet-chemical technique) and qualitative (evaluated by means of X-Ray Near Edge Structure - XANES spectroscopy) composition of S functional groups in this wet subtropical Brazilian soil under NT. Compared to the forest site, soils under NT system had lower amounts of organic C, total N and total S Sulfur losses due to cultivation were higher than losses of C and N, and the use of fertilizers containing S seems to be vital for the recovery of S moieties. The dynamics of the plant materials decomposition was mostly governed by the C/S ratio. Sulfur mineralization was driven by the form of S in the starting materials rather than S concentration in the tissue, as revealed by XANES. The incorporation of plant residues and biochar led to an increase in the amount of ester sulfate in the early stage of incubation, which was further mineralized and had a steady decline at the end of evaluation. These findings encourage further investigations of biochar as S source, involving particularly chars produced from different feedstocks and pyrolysis temperatures. / O solo é um componente crítico do ciclo global de enxofre (S), agindo como fonte e dreno das várias espécies de S e mediando mudanças nos seus estados de oxidação. No entanto, pouco se sabe sobre as identidades dos compostos orgânicos e inorgânicos de S, especialmente em solos brasileiros sob plantio direto (PD). Assim, os objetivos deste estudo foram: (i) relatar os efeitos a longo e médio prazo da aplicação de calcário e de até 12 t ha-1 de fosfogesso (FG) em amostras de dois Latossolos coletadas em experimentos de campo realizados sob PD; (ii) avaliar o efeito da aplicação de PG na quantidade, forma e distribuição das frações orgânicas e inorgânicas de S em solos sob PD em comparação com uma floresta natural; (iii) investigar a mineralização/imobilização de C, N e S em amostras de solo afetadas por fontes de resíduos vegetais e biocarvão, identificando as transformações nas frações de S. Após 13 anos de aplicação de calcário em um Latossolo Vermelho distrófico de textura média, foi verificado efeito na correção da acidez do solo e no fornecimento de Mg2+ até 80 cm de profundidade enquanto os efeitos do FG fornecendo Ca2+ e S-SO4 2- foram mais pronunciados em profundidade. A distribuição de S-SO4 2- no perfil deste solo foi correlacionada com o conteúdo de Fe-ditionito (Fed) e Fe-ditionito menos Fe-oxalato (Fed, Feo). Não houve efeito do calcário e do FG na produção de grãos de milho, mostrando que as plantas não puderam se beneficiar das melhorias no solo. Foi observado apreciável movimento de S para o subsolo em amostras de um Latossolo Vermelho distrófico muito argiloso, mesmo em médio prazo (após 3,5 anos), apesar de o solo apresentar alta capacidade de adsorção de sulfato. Nesta área, o FG teve efeitos positivos no rendimento das culturas de cereais, devido ao fornecimento de Ca2+ e S-SO4 2- . A aplicação de FG e as mudanças no uso da terra alteraram tanto a composição quantitativa (avaliada pela técnica de fracionamento químico) quanto qualitativa (avaliada por meio da espectroscopia de raios-X próxima à borda de absorção - XANES) dos grupos funcionais de S em um solo subtropical da região úmida sob PD. Em comparação com o PD, os solos sob floresta apresentaram maior conteúdo de C orgânico, N e S total. As perdas de S devido ao cultivo foram superiores às perdas de C e N, e o uso de fertilizantes sulfatados parece ser vital para a recuperação do S do solo. A dinâmica de decomposição dos materiais vegetais foi principalmente regida pela razão C/S. A mineralização de enxofre foi impulsionada pela forma de S nos materiais iniciais, e não pela concentração S no tecido, conforme revelado por XANES. A incorporação de resíduos vegetais e biocarvão levou ao aumento nos ésteres de sulfato na fase inicial de incubação, fração posteriormente mineralizada, apresentando declínio no final da avaliação. Estas descobertas incentivam mais investigações do biocarvão como fonte de S, envolvendo carvões produzidos a partir de diferentes matérias-primas e temperaturas de pirólise.

Orientador: Carolina Fernandes / Banca: Rafael Gonçalves Peluco / Banca: Marcos Guimarães de Andrade Landell / Banca: Carlos Eduardo Angeli Furlani / Banca: Dilermando Perecin / Resumo: Aspectos relacionados à compactação do solo têm sido considerados como limitantes para o aumento da produtividade na cultura da canade- açúcar. Diante disso, o setor vem buscando alternativas para o preparo do solo por meio de sistemas que sejam capazes de melhorar a produtividade dos canaviais e, consequentemente, sua competitividade no mercado. Dentro desse contexto, este trabalho foi realizado com o objetivo de avaliar a qualidade física do solo, por meio da avaliação da sua resistência à penetração, suas alterações e persistência no tempo, em decorrência de seu preparo com subsolagem na linha de plantio e em área total, e das possíveis interferências dos manejos na produtividade da cana-de-açúcar. O experimento foi conduzido no estado de São Paulo, em uma área localizada no município de Guariba, em um solo classificado como Latossolo Vermelho, e outra localizada no município de Monte Alto, em um solo classificado como Argissolo Amarelo. As áreas experimentais foram compostas por 20 parcelas cada e os tratamentos foram constituídos pelo preparo de solo com subsolagem na linha de plantio e outro com subsolagem em área total. As amostragens foram realizadas nas camadas de 0,00-0,10 m, 0,10-0,20 m e 0,20-0,40 m na linha de plantio e na entrelinha. A produção de colmos (t ha-1) foi determinada em cada uma das parcelas. A análise de variância foi realizada no delineamento, em parcelas grandes pareadas; e a comparação das médias das variáveis foi realizada utilizando-se o teste ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Soil compaction has been considered a limiting factor to the increasing of productivity in sugarcane crop. Therefore, the sector has been seeking alternatives for soil tillage through systems that are capable of improving sugarcane productivity and, consequently, its competitiveness in the market. In this context, this study was carried out with the aim of evaluating the physical soil quality through the evaluation of its resistance against penetration, its changes and perseveration in time, as a result of soil tillage with subsoiling in the planting line and in total area, and the possible interferences of managements during the productivity of sugarcane. The experiment was carried out in Guariba, SP, in a soil classified as Oxisol, and another one in Monte Alto, SP, in a soil classified as Ultisol. The experimental areas were composed of 20 plots each and the treatments were composed of soil tillage in the planting line and another one in total area. The samples were performed in the layers of 0.00-0.10 m, 0.10-0.20 m and 0.20-0.40 m in the planting line and in the interline. The productivity (t ha-1) was determined in each of the plots. The analysis of variance was performed in the design of paired large plots and the comparison of the means of the variables was performed using the Tukey test, at a significant level of the probability of 5% (p <0.05). The T test was performed to verify the effects of the treatments in the soil resistance against penetration, evaluated thro... (Complete abstract click electronic access below) / Doutor

This thesis examines the growth response and inter-relationships between shoots and roots of plants grown in compact soil. In the field, two topsoil and two subsoil conditions were created with five vegetable crops sequentially grown. Between 6 and 12% of the root system grew in the compact subsoil, which had a soil strength of 3.1 c.f. 1.9 MPa in the loosened subsoil. Both the root length density (Lv) and the specific root length were lower in the compact subsoil (80% and 30%, respectively). This had no effect on shoot growth when water and nutrients were well supplied. Compensatory root growth in the lose soil above the compact subsoil occurred in broccoli plants. As a result plants grown in soil with or without a compact subsoil had a similar total root length but with altered root distribution. When the water and nitrogen supplied to the soil was reduced, the lower subsoil Lv in the compact subsoil did not restrict water or N acquisition. This was possibly due to a large increase in the specific uptake per unit length of root, by the fewer roots in the compact subsoil. Compared to the subsoil treatments, only small changes in topsoil physical properties occurred when tillage was ceased. From the field trials the proportion and time of root growth into compact soil appeared important in determining the plant response. In a series of split-root experiments (horizontal and vertical arrangements of compact and loose soil) compensatory root growth in the loose soil only occurred when the root system was exposed to horizontally compact soil When compensatory root growth did not occur shoot growth was reduced. This resulted in there being a close relationship between total root length and leaf area. Further test results support a direct effect of mechanical impedance on shoot growth with a rapid (within 10 minutes) and large (50%) reduction in leaf elongation occurring when roots were mechanically impeded. In the field only plants whose roots were totally exposed to compact soil had reduced shoot growth with very compact subsoil having no effect. / Doctor of Philosophy (PhD)

xv, 270 leaves : photos., tables, graphs ; 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 Agronomy, 1979

Studies were conducted in 2004, 2005, and 2006 in south Texas to evaluate fall, winter, and spring weed control for commercial rice production, study tillage intensity and herbicide rate interactions for rice production, and determine the tolerance of red rice ecotypes from Texas rice fields using selected herbicides at varying rates. A single application of any herbicide or combination of herbicides was not adequate for weed control throughout the fall, winter, and spring. Fall applications of clomazone plus flumioxazin provided consistent weed control. Addition of flumioxazin to glyphosate provided excellent winter annual grass control with winter application. A residual herbicide, coupled with the proper contact herbicide is the key to extending control. In 2006, all tillage by herbicide treatments in all studies provided ≥ 90% control of all weed species. The conventional tillage treatment with low herbicide input provided the highest rice grain yield in 2005 and 2006, though they were not significantly different from the spring stale seedbed program with medium or high herbicide input in 2006. In 2006, fall stale seedbed treatments were among the lowest in yield. A stale seedbed program may be useful, but with substantial weed pressure, increasing the intensity of herbicide applications is necessary to overcome the absence of tillage. All rice ecotypes were adequately controlled by glyphosate and only one ecotype was found to be tolerant to 2x rates of both imazethapyr and imazamox. All ecotypes were adequately controlled by 2x rates of more than two of the four herbicides which included imazethapy, imazamox, glufosinate, and glyphosate. Ecotypes from the 3.2 group, genetically similar to the ecotype TX4, appear to be the most likely to exhibit tolerance to a given herbicide. Tolerance to glufosinate was found in 70% of the group 3.2 ecotypes. Sixty percent of ecotypes from group 3.1, genetically similar to Oryza rufipogon were not adequately controlled by glufosinate.

Dark tobacco (Nicotiana tabacum L.) has historically been produced usingconventional tillage practices. Soil is cultivated multiple times throughout a growing season leading to an increased incidence of soil erosion. No-till systems have been growing in popularity with the advent of new technology that has enabled the practice to be performed effectively and efficiently. With the recent expansion of no-till practices throughout the agricultural community, many crops have had success in producing comparable yields while reducing input costs and saving soil resources. For this experiment, a traditional tobacco transplanter was modified for use in a no-till environment. All modifications were fabricated without using specialty tools and made possible to be removed if desired or necessary. Frame extensions were designed and built to accommodate row cleaners and coulters. Tillage shanks were also added to aid in optimal furrow formation. Double-disc opening shoes replaced the original round point shoes and the curved edges of the rear drive wheels were removed, creating a flat surface to increase soil contact. Experimental no-till plots in fescue sod and soybean chaff residues were conducted alongside conventional tillage plots at the Western Kentucky University Agricultural Research and Education Complex in summer 2011. Five treatments, one conventionally tilled (Conv) and four no-till, were replicated three times within a randomized complete block design and used to determine the efficacy of transplanter modifications (consistency of depth, furrow closure, observed plant damage), survival of the transplants, and the amount of residue displacement. The four no-till treatments utilized different combinations including: coulter, row cleaner and shank (CRS), row cleaner and shank (RS), coulter and shank (CS), and shank only (S). These treatments demonstrated the functionality of each combination in comparison to conventional treatments. No treatment performed equally well in both residue locations. Plots in fescue residue utilizing a combination of coulter, row cleaner, shank (CRS), exhibited the lowest amount of root exposure, highest survival rate, and comparable cured weight when compared to conventionally tilled treatments. In soybean residue plots, the treatment operating with row cleaners and shanks (RS) had equivalent amounts of furrow closure to conventionally tilled plots. Pairing specific modification combinations with previous crop residue can provide furrow closure, transplant survival, and cured yield equivalent to conventionally tilled dark tobacco.