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Quantitative and qualitative Soil Organic Matter (SOM) properties were observed in the soil samples of a medium-term field experiment (Cambisol ? Studena, Czech Republic) and an exact field experi?ment (Chernozem ? Gross Enzersdorf, Austria) in the year 2005 considering different soil tillage systems (conventional and minimum tillage). Except the standard parameters, soil organic matter content and quality in particulate water stable aggregates size fractions was additional determinated for Cambisol. Cambisol showed more favourable values of both quantitative and qualitative SOM parameters in minimum tillage system compared to those in conventional tillage system. SOM quality in the water stable aggregates fractions was better in minimum tillage compared to conventional tillage. Cambisol also showed that SOM in aggregates fractions is much more quality compared to SOM in the original soil samples. Chernozem showed higher values of both quantitative and qualitative SOM parameters in conventional tillage compared to those in minimum tillage but the differences are not high. It can be said that Chernozem organic matter reaction to tillage technology changes is slower and of minor rate in comparison with that of Cambisol organic matter. The results of quantitative and qualitative parameters do not conform to the generally recognised values for the Chernozem soil type.

Soil organic matter (SOM) decomposition and formation is an important climate feedback, with the potential to amplify or offset climate forcing. To understand the fate of soil carbon (C) stores and fluxes (i.e., soil respiration) under future climate it is necessary to investigate responses across spatial and temporal scales, from the ecosystem to the molecular level, from diurnal to decadal trends. Moreover, it is important to question the assumptions and paradigms that underlie apparently paradoxical evidence to reveal the true nature of soil-climate feedbacks. My dissertation includes research into the response of soil respiration in Pacific Northwest prairies to warming and wetting along a natural regional climate gradient (Chapter II), and then delves deeper into the mechanisms underlying SOM decomposition and formation, examining the temperature sensitivity of SOM decomposition of prairie soils that were experimentally warmed for ~2 yr, and a forest soil in which litter-inputs were manipulation for 20 yr (Chapter III), and finally testing soil C cycling dynamics, including mineral-associated C pools, decomposition dynamics, and the molecular nature of SOM itself, under litter-manipulation in order to understand the controls on SOM formation and mineralization (Chapter IV). This dissertation includes previously published and unpublished coauthored material; see the individual chapters for a list of co-authors, and description of contributions.

The aim of the theses was to describe soil organic matter changes in model landscape Stropnice subcatchments that have different biotopes and agricultural and forest management.Particular aims were: 1) to determine the link between landuse, soil environment changes and catchment matter losses. 2)to experimentally prove the water regime impact on carbon and other substances losses during and between vegetation seasons.

To this day are terminological inaccuracies in subject publications, which direct us to wrong deductions. Therefore I devote oneself to literature search about soil organic matter, in my theses. Separately is split primary organic matter, levels of it´s lability and stable humus. I clarify the term stability and the difference in humus and primary soil organic matter. In this theses were effected analyses acid cambi soil in region Czech Budejovice and acid cambi soil in range of Bohemian Forest ? Kubova Huť. Was quantificated content HK, FK, Cox, humification degree SH, mineralized carbon Cminer, speed constant of biochemical oxidation C, fraction of labile organic substance Ccws, Chws, a CPM. I had compared this data with data, which we keep at one´s disposal from analyses effected twelve years ago. By comparing the real quality of humus in samples A (Kubova Huť) and B (České Budějovice) it stands to reason, that the B sample is superior in quality than sample A. Practice and media very often consider as ?humus? total content of Cox. If this thought should be the true, I would have to consider sample A (with content 9,3% Cox) as a soil with high level of humus and I would expect record returns in it. This conclusion would be real absurd. We can not talk about humus according to Cox content only. It is also necessary to take the primary claims (that the content Chws is an indicator of soil fertility) of some big men in field of pedology (for example Haynes) with a grain of salt. This applies only if soil micro ? edaphon is not decimated somehow. I came to the conclusions, that the final result of the analyses, effected by my thesis supervisor (Kolář) twelve years ago, on practically identical soil samples, are almost exactly the same with my results.

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.

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.

The contribution of energy from biomass sources is projected to increase in Britain to assist in meeting renewable energy targets and reducing anthropogenic CO2 emissions. With increasing concerns over the sustainability of food crop-based biofuels, purpose-grown lignocellulosic biomass crops such as Miscanthus and short rotation coppice (SRC) willow have been promoted as more sustainable feedstocks for the production of heat and electricity as well as for the future production of liquid biofuels. With the introduction of the Energy Crops Scheme, land-use change (LUC) for lignocellulosic biomass crop production has become increasingly common in Britain in recent decades. However, there is limited understanding of the impact this has on soil organic carbon (SOC) stocks and limited predictability concerning the overall trajectory, magnitude and rate of SOC changes under a range of different conditions. Using a chronosequence of 93 biomass crop plantations in England and Wales, mainly of 1 to 14 years age, empirical models were developed to determine the short term trajectory of SOC stocks following LUC from arable and grassland to SRC willow and Miscanthus production. SOC stocks were calculated for each site using a fixed sampling depth of 30 cm and estimated changes were inferred by comparing with typical pre-change SOC stocks. These results indicate that only LUC from arable crops to SRC willow demonstrated an overall increase in SOC stocks, by an estimated 15.3 ± 2.2 t C ha-1 (± 95% confidence intervals) after 14 years and 68.8 ± 49.4 t C ha-1 after 22 years. LUC from arable crops to Miscanthus and from both arable crops and grassland to SRC willow and Miscanthus demonstrated no overall net effect on SOC stocks. Soil texture and climate data were measured for each site and multivariable models were created to assess the influence of different environmental conditions on SOC trajectory. In most cases the addition of these explanatory variables improved the model fit, and the models provide some preliminary estimates of more region-specific changes in SOC following LUC. Since LUC to biomass crops often causes a loss of SOC, at least in the short term, the potential for pyrogenic carbon (PyC) to ameliorate this effect was investigated. Studies indicate that PyC can interact with and stabilise native SOC, a process termed negative priming, although the potential for PyC to reduce LUC-induced losses of SOC by negative priming has not yet been assessed. Although negative priming has been observed in many studies, most of these are long term incubation experiments which do not account for the impact of environmental weathering of PyC on interactions with native SOC. Here the aim was to assess the impact of environmentally weathered PyC on native SOC mineralisation at different points in LUC from arable crops to SRC willow. Soil was sampled to a 5 cm depth from multiple recently established SRC willow plantations approximately 2 years after amendment with PyC. Cumulative CO2 flux was measured weekly from incubated soil and soil-surface CO2 flux was also measured in the field. The results demonstrate a PyC-induced increase in CO2 flux for the surface 5 cm of soil. However, no net effect on soil-surface CO2 flux was observed in the field. Although the mechanisms for these contrasting effects remain unclear, they do not suggest that PyC can reduce LUC-induced SOC losses through negative priming.

Submitted by JÉSSYCA DELLINHARES LOPES MARTINS null (dellinhares@hotmail.com) on 2017-04-14T13:16:41Z No. of bitstreams: 1 Tese jessyca.pdf: 2737738 bytes, checksum: 4a9e9501939a9f6435d392bb370132b7 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-04-18T14:34:35Z (GMT) No. of bitstreams: 1 martins_jdl_dr_bot.pdf: 2737738 bytes, checksum: 4a9e9501939a9f6435d392bb370132b7 (MD5) / Made available in DSpace on 2017-04-18T14:34:35Z (GMT). No. of bitstreams: 1 martins_jdl_dr_bot.pdf: 2737738 bytes, checksum: 4a9e9501939a9f6435d392bb370132b7 (MD5) Previous issue date: 2017-03-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Dentre os nutrientes que mais limitam a produtividade da cultura da batata (Solanum tuberosum L.) está o fósforo (P). Esta cultura tem respondido à adubação fosfatada com incrementos na produtividade até altas doses, principalmente em solos com baixo teor de P disponível, que é uma característica dos solos tropicais brasileiros, os quais são naturalmente deficientes em P. A fim de melhorar a eficiência de aplicação do adubo fosfatado, é possível utilizar fertilizantes contendo substâncias húmicas (SH) ou aplicá-las diretamente no solo. No entanto, o efeito da aplicação de SH pode depender dentre outros fatores, da textura do solo, que interfere na retenção do P. Portanto, o objetivo do presente estudo foi avaliar o efeito da aplicação de SH e doses de fertilizante fosfatado sobre a nutrição, acúmulo de matéria seca (MS), crescimento radicular, absorção e exportação de nutrientes e produtividade de tubérculos da cultura da batata, em solos de diferentes texturas. Esta pesquisa foi desenvolvida através da condução de quatro experimentos, dois em casa de vegetação e dois em campo. Dois dos experimentos foram realizados em solo de textura arenosa (um de casa de vegetação e um de campo) e os dois demais em solo de textura argilosa. Em todos os experimentos, o delineamento experimental utilizado foi em blocos ao acaso, no esquema fatorial 4 x 3. Os tratamentos consistiram de quatro doses de P (10, 50, 100 e 200 mg dm-3 de P nos experimentos de casa de vegetação; 0, 100, 200 e 400 kg ha-1 de P2O5 nos de campo) e três doses da SH (0, 1,25 e 7,5 mL vaso-1 de P nos experimentos de casa de vegetação; 0, 50 e 300 L ha-1 nos de campo). A aplicação de SH afetou ligeiramente o crescimento radicular da batateira somente no solo arenoso. No solo de textura arenosa, a aplicação da SH, especialmente na dose de 50 L ha-1 (equivalente a 1,25 mL vaso-1) no sulco de plantio, aumentou a produção de matéria seca na planta, a absorção e exportação de nutrientes e melhorou o desempenho produtivo da batateira, porém, somente na ausência ou com o fornecimento de dose reduzida do adubo fosfatado. Contudo, não aumentou a eficiência da adubação fosfatada. No solo de textura argilosa, a aplicação de substância húmica aumentou a produtividade de tubérculos da classe especial, porém não interferiu na nutrição e produtividade total da cultura da batata, independentemente da dose de fertilizante fosfatado aplicado. A associação da dose mais elevada de SH e de P não teve efeito ou reduziu a produção de MS, teor e acúmulo de nutrientes e a produtividade de tubérculos da batata. Em ambos os solos, a adubação fosfatada aumentou de forma similar a absorção de nutrientes pelas plantas, exportação de nutrientes pelos tubérculos, número de tubérculos por planta, peso médio de tubérculos e a produtividade de tubérculos da barateira. / Phosphorus (P) is among the nutrients that most limits the potato crop yield (Solanum tuberosum L.). This crop has responded to phosphate fertilization with increases in productivity up to high rates, especially in soils with low available P content, which is a characteristic of the Brazilian tropical soils, which are naturally deficient in P. In order to improve the efficiency of application of the phosphate fertilizer, it is possible to use fertilizers containing humic substances (HS) or to apply them directly to the soil. However, the effect of HS application may depend, among other factors, on soil texture, which interferes with the retention of P. Therefore, the objective of this study was to evaluate the effect of the application of SH and rates of phosphorus fertilizer on nutrition, dry matter accumulation (DM), root growth, nutrient uptake and removal and yield of tubers from the potato in different textures soils. This research was developed through the conduction of four experiments, two in greenhouse and two in the field. Two of the experiments were carried out on sandy soils (one from a greenhouse and one from the field) and the other two from a clayey soil. The treatments consisted of four rates of P (10, 50, 100, and 200 mg dm-3 of P in the greenhouse experiments, and 0, 100, 200, and 400 kg ha-1 of P2O5 in the field experiments) and three rates of the HS (0, 1.25, and 7.5 mL pot-1 in the greenhouse experiments; 0, 50 and 300 L ha-1 in the field experiments). The application of HS only slightly affected the potato root growth and only when it was cultivated in the sandy soil. In sand soil, HS application, especially at the rate of 50 L ha-1 (equivalent to 1.25 mL pot-1) in planting furrow, had increased dry matter (DM) yield, nutrient uptake and removal, and improved productive performance of the potato, but only in the absence or the supply of reduced rate of the phosphate fertilizer. However, it did not increase the efficiency of phosphate fertilization. In clay soil, the HS increased tuber yield special class, but did not affect the total tuber yield and nutrition of the potato, regardless of phosphate fertilizer rate applied. The association of the highest rates of HS and P had no effect or reduced the production of DM, concentration and uptake of nutrients, and tuber yield of potato. In both soils, phosphate fertilization increased similarly the nutrient uptake by plants, nutrient removal by tubers, number of tubers per plant, mean weight of tubers, and tuber yield of potato.