The work was focused on the research of soil organic matter content and quality of selected forest soils. In the theoretical part of the thesis there were described in detail terms important to understand the given topic. In the practical part soil probes were excavated and soil samples were taken from individual horizons. The probing was carried out in two stands with a different representation of trees (forest type 0P, district Hodějov, Forest Management Třeboň, ownership of the Czech Republic, right to manage Forests of the Czech Republic, etc.). In the first case, it was a vegetation of deciduous trees (vegetation 356D12), in the second one with a vegetation of coniferous trees (356E11). In the laboratory of the Department of Agroecosystems of the Faculty of Agriculture of the University of South Bohemia in České Budějovice soil samples were modified and further examined in terms of the quantity and quality of soil organic matter. A new method, proposed by the collections of authors Kopecký, Kolář, Borová-Batt (2016), was used to compare the quality of the primary soil organic matter in individual samples by determining the velocity constant of the oxidation of the primary soil organic matter. The humus content was then determined and the degree of humification was calculated. The results show that the monitored parameters differ considerably in individual soil horizons. Significant differences were also observed when comparing soils of coniferous and deciduous stands. A considerable difference can be seen, for example, in the organic carbon content at the top horizons. For example, at the Ahe horizon, the total organic carbon content was found to be 39.71 % for coniferous soil, while in the leafy soil the carbon content at the same horizon was only 7.06 %. The highest value of the velocity constant to oxidation of the primary soil organic matter, which indicates its highest quality, was recorded at the Ep horizon (9-20 cm depth) of the deciduous soil probe.

This dissertation aims primarily at determining the energy yield that can be produced, if certain species of energy crops are grown (under various regimes of fertilizing and sowing) by the Faculty of Agriculture, the University of South Bohemia, on a university's trial parcel. Zea mays L. is one of the energy crops chosen for the experiment; it is grown on a large area in the Czech Republic nowadays. Perennial crops of Phalaris arundinacea L., Elymus elongatus subsp. ponticus cv. Szarvasi-1 andMiscanthus × giganteus were also chosen for this experiment. Based on the collected data, a risk of erosion provoked by the above-mentioned crops has been determined by using USLE method. The crop stands and the soil have been analysed too. This analysis has focused on the organic matter evaluation, by using a brand new method. Last but not least, occurrence of Carabidae beetles has been studied and evaluated within the research; they are considered bio indicators of the environmental conditions. Our experiment has shown that Zea mays L. is the most high-yielding species. On the other hand, Phalaris arundinacea L. has not produced positive results; the most high-yielding variation of it only made a half yield of Zea mays L. In contrast to Zea mays L., grass species of Phalaris arundinacea L. andElymus elongatus have had an extraordinary anti-erosion capacity. Studying the amount of primary organic matter in the soil, we have found almost double amount of it in Miscanthus × giganteus andZea mays L. crop stands, compared to another two species. Monitoring oxidation reaction kinetics of the primary organic matter, we could count the oxidation speed constant of k. There have been dramatic differences between the individual soil samples. However, the data file is too complicated to draw the general conclusion from. On the other hand, evaluating the data gathered by studying Carabidae beetles and the environmental values of the crops stands, we have found out the crop stands are not too valuable from the environmental point of view. We have found out the perennial species have got an extraordinary anti-erosion capacity. We recommend Miscanthus × giganteus and Elymus elongatus, in particular, as an alternative to corn, especially to regions highly endangered by erosion.

Made available in DSpace on 2016-04-01T17:54:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-05-30. Added 1 bitstream(s) on 2016-04-01T18:00:16Z : No. of bitstreams: 1 000563940.pdf: 1802779 bytes, checksum: bdeb041776e02ff589caa819ea3d5177 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Em todo processo, é presumível a condição da geração de resíduos, sendo cada vez mais premente a busca de alternativas para destinação correta destes resíduos. Neste sentido, foi realizado um experimento com a compostagem de diferentes resíduos sólidos industriais provenientes do processo de extração do princípio ativo de plantas medicinais. O experimento constitui-se na mistura, em proporções diferentes dos resíduos: a) Resíduo orgânico - gerado a partir do esmagamento da planta de jambú (Spilanthes oleracea), após a extração do princípio ativo, b) lodo físico-químico, gerado a partir do processo de tratamento de água e c) lodo biológico, oriundo do esgoto da empresa. Este trabalho teve como objetivos gerar uma alternativa, ambientalmente correta, para o reaproveitamento do lodo físico-químico e verificar o efeito agronômico dos compostos resultantes na produção da alface. O processo de compostagem deu-se no período de 120 dias. A temperatura das pilhas foi medida diariamente, em três diferentes profundidades. Ao final, o composto foi pesado e avaliou-se, em média, o rendimento. Na segunda fase do experimento, buscando avaliar o efeito agrônomico dos compostos sobre a produção da alface (Lactuca sativa L.), os materiais compostos foram dispostos em vasos, em casa de vegetação, formando um delineamento inteiramente casualizado (DIC), com fatorial 4 x 4, sendo o fator 1 formado por 4 tratamentos: composto 1 (C1 - 0% lodo - 100% jambú), composto 2 (C2 - 7% lodo - 93% jambú), composto 3 (C3 - 13% lodo - 87% jambú), composto 4 (C4 - 26% lodo - 74% jambú) e o fator 2 formado por 4 diferentes doses de compostos: (0, 45, 90 e 135 t ha-¹ ) e quatro repetições, totalizando 64 unidades experimentais. Nas avaliações realizadas após 45 dias do transplantio da alface, o tratamento C1 dose três (90 t ha-¹) apresentou os melhores resultados de rendimentos. Nos demais tratamentos, ocorreram um decréscimo... / It is assumed that there is generation condition in every production process. Alternative ways for the correct destination of the residues has become essential. Therefore, an experiment on different industrial solid residues compound from medicinal plants active principle extration has been performed. The experiment was based on the mixture of the residues in different proportions: a) organic residue generated from jambu (Spilanthes oleracea) smashing after active principle extraction, b) physiochemic mud generated from water treatment process and c) biologic mud originated from the company sewage. This work aimed at generating an environmentally correct alternative for phisiochemic mud reutilization and verify the agronomic effects of the resulting compounds in lettuce production. The compounding process lasted 120 days. Piles temperature was measured in three different depths. At the end, the compound was weighed and the average yield was evaluated. In the second phase of the experiment we aimed at evaluating the compound agronomic effects on lettuce (Lactuca sativa L.) production. The compounded materials were placed ins vases in greenhouses in an entirely randomized order, with factorial 4 x 4. Factor 1 was formed by 4 treatments: compound 1 (C1 - 0% mud - 100% jambu), compound 2 (C2 - 7% mud - 93% jambu), compound 3 (C3 - 13% mud - 87% jambu), compound 4 (C4 - 26% mud - 74% jambu). Factor 2 was formed by 4 differente compound dosages: (0,45, 90 e 135 t ha-¹) and hour repetitions, totaling 64 experomental unities. Treatment C1, dosage 3 (90 t ha-¹) presented the best results in the evaluation 45 days after lettuce transplantation. In the remaining treatments there was alinear decrease in lettuce production. However, C4 that 26% mud in its composition was superior than those with 0 dosage of organic matter. Compound can be considered an environmentally correct alternative for these residues with the possibility of agronomic utilization.

Submitted by CASSIANO FORNER null (forner@wln.com.br) on 2016-04-05T01:11:21Z No. of bitstreams: 1 Forner_2016.pdf: 1210475 bytes, checksum: 3679481a5b70ba553b219d69908042c0 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-04-08T14:48:31Z (GMT) No. of bitstreams: 1 forner_c_dr_bot.pdf: 1210475 bytes, checksum: 3679481a5b70ba553b219d69908042c0 (MD5) / Made available in DSpace on 2016-04-08T14:48:31Z (GMT). No. of bitstreams: 1 forner_c_dr_bot.pdf: 1210475 bytes, checksum: 3679481a5b70ba553b219d69908042c0 (MD5) Previous issue date: 2016-01-21 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os resíduos orgânicos e agentes de biocontrole podem constituir em alternativas no controle dos fitopatógenos habitantes do solo. O trabalho teve por objetivo estudar o controle de Fusarium spp. com resíduos orgânicos e agentes de biocontrole. Inicialmente foi avaliado o efeito de hidrolisado e emulsão de peixe, nas concentrações de 0, 10, 20, 30, 40 e 50% do volume de água para atingir a capacidade de campo do solo; e de alga, casca de camarão, concha de marisco e caroço de abacate moídos, nas concentrações de 0, 1, 2, 3, 4 e 5% v/v, na germinação de microconídios de Fusarium oxysporum f. sp. lactucae, em casa de vegetação. Enquanto a emulsão e o hidrolisado de peixe reduziram a germinação de microconídios do patógeno, os demais resíduos não apresentaram efeito. Também foi avaliado o efeito de resíduos de alga, concha de marisco, casca de caranguejo e repolho triturado fresco, nas concentrações de 0, 1, 2 e 4% v/v, sobre a germinação de microconídios de Fusarium circinatum em condições controladas, e associado ou não, a Trichoderma harzianum, no controle da fusariose (F. circinatum) em plantas de Pinus radiata mantidas em casa de vegetação. Nenhum resíduo reduziu a germinação de microconídios de F. circinatum ou a doença em casa de vegetação. No terceiro estudo foi avaliado o efeito de hidrolisado de peixe nas concentrações de 0, 5, 10, 15 e 20% do volume de água necessário para atingir a capacidade de campo, a partir do solo seco, associados ou não a T. harzianum (Iblf 006) e Bacillus subtilis + Bacillus licheniformis no controle de F. oxysporum f. sp. lycopersici (raça 3) em tomateiro, em casa de vegetação. O hidrolisado de peixe e os agentes de biocontrole não controlaram a doença. / The organic residues and biocontrol agent might be alternative in the control of soilborne plant pathogens. This work aimed to study the control of Fusarium species with organic residues and biocontrol agents. First, the effect of fish hydrolyzed and fish emulsion was evaluated, at concentrations of 0, 10, 20, 30, 40 and 50% of volume of water required to reach the water retention capacity of the soil; and the seaweed, shrimp shells, clamshell and grounded avocado seeds at concentration of 0, 1, 2, 3, 4 and 5% v/v in the microconidia germination of Fusarium oxysporum f. sp. lactucae in greenhouse. Fish emulsion and fish hydrolyzed reduced the microconidia germination and none of the other residues presented effect. Also, it was evaluated the effect of seaweed, clamshell, crab shell and fresh triturated cabbage, at concentrations of 0, 1, 2 and 4% v/v, in the germination of Fusarium circinatum microconidia under controlled conditions and associated or not with Trichoderma harzianum in Pinus radiata to control the disease caused by F. circinatum in greenhouse. Neither residue reduced the F. circinatum microconidia germination or the disease in greenhouse. In the third study the effect of fish hydrolyzed was evaluated at concentration of 0, 5, 10, 15 and 20% of volume of water to required to reach the water retention capacity of the soil, from dry soil, associated or not with T. harzianum (Iblf 006) and Bacillus subtilis + Bacillus licheniformis in the control of F. oxysporum f. sp. lycopersici (race 3) in tomato plants in the greenhouse. Neither residue or biocontrol agents controlled the disease. / CNPq: 140309/2012-8 / CAPES: 99999.005706/2014-09

Made available in DSpace on 2014-06-11T19:31:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-04-22Bitstream added on 2014-06-13T19:41:57Z : No. of bitstreams: 1 bassan_cfd_dr_botfca.pdf: 763512 bytes, checksum: d8464f6ac6e486c2b19bc8c3b3b6f5aa (MD5) / Universidade Estadual Paulista (UNESP) / Certain cultures present especification in the assimilation of some ions, that are or not in available ways in the soil. The minerals have fundamental paper in the presence of those elements that, a lot of times, they are together originating from of the processes of meteorization of the rocks with the decomposition of the organic matter. This work had for objective to study the extraction and/or solubilization of some present chemical elements in the studied minerals and in a red latosoil, for the action of some organic acids produced starting from the decomposition of the matter ligno-cellulousic, through the microbial action, hoping to contribute in some way in the understanding of the mechanisms of fertility of the soil and, consequently, in the mineral nutrition of plants. The used minerals were: manganite [MnO(OH)], hematite (Fe2O3), pirolusite (MnO2), caolinite [Al2Si2O5(OH)4], goethite (HFeO2), bentonite [Na3(Al,Mg)2 2(Si4O10)(OH)2.H2O] e magnetite(Fe3O4), that commonly happen in areas humid intertropicals and a red latosoil, of sandy texture that, it represents more that 20% of the area of the State of Saint Paulo. The minerals and LV were triturated and drizzled in 0,05mm mesh, separately. After having examined with relationship your structure for Difratometric of Ray-X (XRD), 1g of those minerals and LV were conditioned, separately, in glass flasks. Some samples were only treated with distilled water and other with solution 0,02 mol.L-1 of the following acids: acetic, butyric, citric, carbolic, lactic, malic, oxalic, propionic and tannic, separately, for 53 days, with weekly agitations and conditions aerobics. After the digestion of the samples, they were certain the litio concentrations, sodium, potassium, magnesium, calcium, barium, vanadium, cromium, molibdenium, manganese, iron, cobalt, nickel, copper, zinc, cadmium, mercury, boron, aluminum, silicio, tin, lead, match... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:31:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-12-14Bitstream added on 2014-06-13T20:22:31Z : No. of bitstreams: 1 silva_fam_dr_botfca.pdf: 1972009 bytes, checksum: 0dcccdfed704fff416f6b751d389c3ff (MD5) / A compostagem é uma alternativa reconhecidamente viável para o aproveitamento racional de resíduos. Todavia, ainda são necessárias pesquisas mais aprofundadas para a melhoria da eficiência deste processo, o que levaria à produção de compostos de maior qualidade, assim como o fornecimento de nutrientes como condicionadores de solo. Sendo assim, este trabalho teve como objetivos avaliar a qualidade de compostos produzidos a partir de combinações de resíduos do processamento de plantas medicinais com esterco bovino e verificar o potencial agronômico dos materiais resultantes na produção da alface. Em uma primeira etapa foram utilizados quatro resíduos do processamento de plantas medicinais: 1) Unha-de-gato (Uncaria tomentosa); 2) Cascara Sagrada (Rhamnus Purshianus); 3) Ipê roxo (Tabebuia impetiginosa) e 4) Boldo (Phaemus boldus), a partir dos quais produziram-se quatro compostos de composição distinta. A amostragem para determinação de parâmetros de maturação (pH, condutividade elétrica, teores de amônio e nitrato, fracionamento da matéria orgânica, macronutrientes, carbono total. relação C/N e testes de germinação) foi feita aos 0, 30, 60, 90 e 120 dias de compostagem. A temperatura, entretanto, foi medida diariamente apenas até aos 90 dias. Na segunda etapa, buscando avaliar o potencial agronômico dos compostos sobre a produção da alface (Lactuca sativa), cultivar crespa Verônica, bem como o efeito residual dos materiais compostados instalaram-se experimentos em vasos com dois cultivos consecutivos. Nestes experimentos, constaram os seguintes tratamentos: composto 1 (C1) (Unha-de-gato), composto 2 (C2) (Cascara Sagrada), composto 3 (C3) (Ipê roxo), composto (4) (C4) mistura dos materiais nas doses 30, 60, 90 e 120t/ha. O delineamento experimental utilizado foi o DIC em esquema fatorial (4 compostos x 4 doses) com 4 repetições e um tratamento testemunha... / Composting is a recognized viable alternative to make good use of residues. However, more accurate studies are required to improve the efficiency of the composting process, producing composts with better quality, supplying nutrients to soil and acting as a soil conditioning. This work aimed to evaluate composts quality produced by combination of residues obtained from medicinal plants industrial processing and bovine manure, verifying the agronomic potential of these obtained composts in lettuce production. In a first step, it was used four residues from medicinal plants industrial processing: 1) Unha-de-gato (Uncaria tomentosa); 2) Cascara Sagrada (Rhamnus Purshianus); 3) Ipê roxo (Tabebuia impetiginosa) e 4) Boldo (Phaemus boldus), which produced four organic composts with distinct composition. The sampling to determine maturation parameters (pH, electric conductivity, ammonium and nitrate, organic matter fractionation, macronutrients, total carbon, C/N relation and germination tests) was made at zero, 30, 60, 90 and 120 days after composting beggining. Temperature was daily verified until 90 days. In a second step, aiming to evaluate the agronomic potential of the composts in lettuce (Lactuca sativa) production,as well the residual effect of these composts in soil. In these cultivation, it was followed the treatments: compost 1 (C1) (Unha-de-gato), compost 2 (C2) (Cascara Sagrada), compost 3 (C3) (Ipê roxo), compost (4) (Boldo) and compost 5 (C5) (mix of residues) in doses of 30, 60, 90 e 120 t ha-1. The experiment was laid out in a complete randomized design, ordered in factorial arrangement (4 composts x 4 doses) with 4 replication and a without N mineral...(Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:33:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-04-26Bitstream added on 2014-06-13T18:45:42Z : No. of bitstreams: 1 cojunior_c_dr_jabo.pdf: 771211 bytes, checksum: 2514fabf2a9a11bd79af83b4e42be6db (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho foi analisar a composição química do solo (M.O, CTC e H+Al), em cinco camadas (0-20, 20-40, 40-60, 60-80 e 80-100 cm), com 18 cultivares da cana-de-açúcar. O experimento foi realizado na Fazenda de Ensino e Pesquisa da FCAV/UNESP, localizada no Município de Jaboticabal, Estado de São Paulo. O experimento foi instalado em um Latossolo-Vermelho Escuro, eutrófico, A moderado, textura muito argilosa – EUTRUSTOX. Nas camadas (0-20, 20-40, 40-60, 60-80 e 80-100 cm) foram coletadas 03 subamostras dos solos que, depois foram submetidas à análise química para fins de fertilidade, as quais foram realizadas pelo Laboratório de Análise de Solo do Departamento de Solos e Adubos da FCAV. Foram realizados três experimento com delineamento experimental em blocos casualizados com 6 cultivares e 3 epocas, em esquema fatorial 6x3, com 3 repetições para cada cultivar. Os tratamentos principais foram composto por 6 cultivares precoces, 6 cultivares médias e 6 cultivares tardias e o secundário as 3 épocas analisadas (12, 15 e 17 meses). Nas cultivares precoces os valores de CTC no solo acompanharam todos os resultados da matéria orgânica, apresentando redução dos valores ao longo das épocas analisadas. Relação inversa foi obtida pela acidez potencial. Nas cultivares médios, o solo com a cultivar IACSP94-4004 se destacou, apresentando os maiores teores de matéria orgânica e menor teor de acidez potencial, além de obter elevados valores de CTC na camada superficial do solo. Enquanto que para as cultivares tardias os valores de CTC no solo acompanharam todos os resultados da matéria orgânica, apresentando redução dos valores ao longo das épocas analisadas. A acidez potencial aos 17 meses apresentou maiores valores em toda camadas analisadas / The aim of this study was to analyze the chemical composition of soil (organic matter, CEC and H + Al) in five layers (0-20, 20-40, 40-60, 60-80 and 80-100 cm) with 18 cultivars of cane sugar. The experiment was conducted at the Teaching and Research Farm, FCAV / UNESP, located in Jaboticabal, São Paulo. The experiment was installed in a dystrophic, dark red, well-nourished, moderate, clayey - EUTRUSTOX. Layers (0-20, 20-40, 40-60, 60-80 and 80-100 cm) were collected 03 subsamples of the soils that were later subjected to chemical analysis for fertility, which were performed by the Laboratory of Soil Analysis, Department of Soils and Fertilizers of FCAV. We conducted three experiments with randomized complete block design with six cultivars and three epochs in 6x3 factorial design with three replications for each cultivar. The main treatments consisted of 6 early cultivars, six medium and six cultivars late cultivars and the three secondary sampling seasons (12, 15 and 17 months). In the early cultivars in the soil CEC values followed all the results of organic matter, a reduction of the values along the studied periods. Inverse relationship was obtained by the potential acidity. Cultivars, the average soil with cv IACSP94-4004 stood out, with higher organic matter content and lower acidity potential, and achieve high CEC values in the topsoil. While for the late cultivars in the soil CEC values followed all the results of organic matter, a reduction of the values along the studied periods. The potential acidity at 17 months was highest in all layers analyzed

Le priming effect (PE) est la sur-minéralisation de la matière organique du sol (MOS) après un apport de matière organique fraiche. Ce phénomène serait généré par deux mécanismes distincts, la décomposition stœchiométrique et le « nutrient mining », ayant leur propre dynamique, leurs propres acteurs, leurs propres déterminants et leur propre stock de MO ciblés. Le premier serait plutôt lié à la séquestration de MO dans les sols et l’autre à sa déstabilisation. Comprendre comment piloter l’équilibre entre ces processus à travers les pratiques agricoles, permettrait d’améliorer durablement la fertilité des sols cultivés en milieu tropical dans un contexte de changement climatique. Pour identifier les déterminants, les acteurs et les effets du climat et des pratiques agricoles sur les différents processus générateurs de PE, nous avons combiné la caractérisation physicochimique des sols, la caractérisation des communautés microbiennes et le suivi de la minéralisation des MO par les techniques isotopiques. Ainsi, nous avons pu identifier différentes populations bactériennes et fongiques, associées à chacun des processus, que nous avons classées dans des guildes fonctionnelles. La taille de ces guildes déterminait l’équilibre entre les processus, et était corrélée à la qualité de la MO présente dans le sol. Plus précisément, nous avons montré que le PE stœchiométrique était favorisé dans les sols enrichis en matière organique peu évoluée et en nutriments N et P, entretenant donc une forte communauté de décomposeurs. Ces décomposeurs devaient ainsi limiter l’accès des mineurs à la nouvelle matière organique fraichement apportée et limiter le PE par « nutrient mining ». Sur parcelles agricoles, nos résultats suggéraient que le non labour, l’association légumineuses-céréales, et l’apport de compost favorisaient ces décomposeurs responsables du priming effect stœchiométrique et donc potentiellement la stabilisation durable de la matière organique dans les sols. / The priming effect (PE) is the supplementary mineralization of soil organic matter (MOS) after the addition of fresh organic matter. This phenomenon would be generated by two distinct mechanisms, stoichiometric decomposition and "nutrient mining", having their own dynamics, their own actors, their own determinants and their own MO stock targeted. The first would be related to the sequestration of MO in the soil and the other to its destabilization. Understanding how to manage the balance between these processes through agricultural practices, would allow to improve the fertility of soil cultivated in a tropical environment in a context of climate change.To identify the determinants, actors and effects of climate and agricultural practices on the various processes generating PE, we have combined soil physicochemical characterization, characterization of microbial communities and monitoring of mineralization of MO by isotopic techniques. Thus, we were able to identify different bacterial and fungal populations, associated with processes, which we classified in the functional guilds. The size of these guilds determined the balance between the processes, and was correlated with the quality of the MO present in the soil. Specifically, we showed that stoichiometric PE was favored in soils enriched with high quality organic matter and nutrients, N and P, thus maintaining a strong community of decomposers. These decomposers also limit the access of miners to the provided new organic matter hence limiting PE by "nutrient extraction". On agricultural plots, our results suggest that non-tillage, legume-cereal rotations and compost amendments favor these decomposers responsible for the stoichiometric priming effect and thus potentially the long-term stabilization of organic matter in soils.

Master of Science / Department of Agronomy / Antonio R. Asebedo / Johanna A. Dille / Field experiments were conducted in 2016 and 2017 across nine locations in Kansas to develop and evaluate a procedure for variable-rate applications (VRA) of soil-applied herbicides in corn and grain sorghum based on soil properties. Soil electrical conductivity (EC) and soil organic matter (SOM) data were collected at each location using a Veris MSP3. Soil EC was correlated to soil texture and herbicide algorithms were developed for two different tank-mixes for corn and for grain sorghum. Three algorithms were evaluated in the field for each tank-mix based only on SOM (alg-SOM), SOM and soil texture (alg-SOMtex), or a flat rate based on the average soil properties for the entire field. Rates for each tank-mix were based on the maximum usage rate (MUR) allowed. When soil variability across a field was adequate, VRA based on algorithms were effective at five of the nine locations. Across these five locations, alg-SOM resulted in the same or better weed control at 8 weeks after treatment (WAT) compared to the flat rate and reduced herbicide use by 12% for both tank-mixes in grain sorghum. Using alg-SOMtex reduced herbicide use by 24% in grain sorghum, but had less weed control at several locations compared to the flat rate. VRA was practical at Morganville, KS in 2017. Both alg-SOM and alg-SOMtex increased the amount of herbicide applied compared to the flat rate, but alg-SOMtex resulted in greater Palmer amaranth control (92%) compared to the flat rate (71%). Separate greenhouse and field experiments were conducted in 2017 to evaluate the activity of soil-applied herbicides on controlling HPPD-inhibitor resistant Palmer amaranth populations. A dose-response greenhouse experiment of soil-applied mesotrione and isoxaflutole was performed using resistant (Stafford County) and susceptible (Riley County) Palmer amaranth populations. Reduced susceptibility was observed with resistant-to-susceptible ratios being 7.2 for mesotrione and 4.1 for isoxaflutole. Field experiments were conducted at two locations in KS with one field having HPPD-resistant (Barton County) and the other HPPD-susceptible (Reno County) Palmer amaranth populations. Treatments were three HPPD-inhibiting herbicides [mesotrione (¼X, ½X, and 1X = 210 g ha-1), isoxaflutole (½X and 1X = 105 g ha-1), and bicyclopyrone (1X = 50 g ha-1 and 2X in formulated tank-mix with bromoxynil at 700 and 1400 g ha-1)] in comparison to other soil-applied herbicides commonly used for Palmer amaranth control. HPPD-inhibitor treatments were applied alone and tank-mixed with atrazine (2240 g ha-1). Overall, control of Palmer amaranth was reduced for HPPD-resistant compared to -susceptible populations. All treatments of mesotrione and isoxaflutole at 4 WAT resulted in 81 to 99% control in Reno County, but only 55 to 89% control in Barton County. For mesotrione and isoxaflutole treatments across both sites, Palmer amaranth control at 4 WAT was greater when 1X was applied (89%) compared to 0.5X (81%). Tank-mixing atrazine with mesotrione and isoxaflutole increased Palmer amaranth control from 82 to 88%. Soil-applied HPPD-inhibitors were most effective when applied at field usage rate in combination with atrazine for both populations. When using soil-applied HPPD-inhibitors, management recommendations should be the same regardless of Palmer amaranth population.

abstract: The focus of this thesis is to study dissolved organic carbon composition and reactivity along the Colorado and Green Rivers. Dissolved organic carbon (DOC) in large-scale, managed rivers is relatively poorly studied as most literature has focused on pristine unmanaged rivers. The Colorado River System is the 7th largest in the North America; there are seventeen large dams along the Colorado and Green River. DOC in rivers and in the lakes formed by dams (reservoirs) undergo photo-chemical and bio-degradation. DOC concentration and composition in these systems were investigated using bulk concentration, optical properties, and fluorescence spectroscopy. The riverine DOC concentration decreased from upstream to downstream but there was no change in the specific ultraviolet absorbance at 254 nm (SUVA254). Total fluorescence also decreased along the river. In general, the fluorescence index (FI) increased slightly, the humification index (HIX) decreased, and the freshness index (β/α) increased from upstream to downstream. Photo-oxidation and biodegradation experiments were used to determine if the observed changes in DOC composition along the river could be driven by these biogeochemical alteration processes. In two-week natural sunlight photo-oxidation experiments the DOC concentration did not change, while the SUVA254 and TF decreased. In addition, the FI and ‘freshness’ increased and HIX decreased during photo-oxidation. Photo-oxidation can explain the upstream to downstream trends for TF, FI, HIX, and freshness observed in river water. Serial photo-oxidation and biodegradation experiments were performed on water collected from three sites along the Colorado River. Bulk DOC concentration in all samples decreased during the biodegradation portion of the study, but DOC bioavailability was lower in samples that were photo-oxidized prior to the bioavailability study. The upstream to downstream trends in DOC concentration and composition along the river can be explained by a combination of photo-chemical and microbial degradation. The bulk DOC concentration change is primarily driven by microbial degradation, while the changes in the composition of the fluorescent DOC are driven by photo-oxidation. / Dissertation/Thesis / Masters Thesis Chemistry 2015