This dissertation analyzes the impact of climate, and atmospheric carbon dioxide (CO2) on crop yields and grain transportation. The analysis of crop yields endeavors to advance the literature by statistically estimating the effects of atmospheric carbon dioxide (CO2) on observed crop yields. This is done using an econometric model estimated over pooled historical data for 1950-2009 and data from the free air CO2 enrichment experiments. The main findings are: 1) yields of soybeans, cotton, and wheat directly respond to the elevated CO2, while yields of corn and sorghum do not; 2) the effect of crop technological progress on mean yields is non-linear; 3) ignoring atmospheric CO2 in an econometric model of crop yield likely leads to overestimates of the pure effects of climate change and technological progress on crop yields; and 4) average climate conditions and climate variability contribute in a statistically significant way to average crop yields and their variability. To examine climate change impacts on grain transportation flows, this study employs two modeling systems, a U.S. agricultural sector model and an international grain transportation model, with linked inputs/outputs. The main findings are that under climate change: 1) the excess supply of corn and soybeans generally increases in Northern U.S. regions, while it declines in Central and Southern regions; 2) the Corn Belt, the largest producer of corn in the U.S., is anticipated to ship less corn; 3) the importance of lower Mississippi River ports, the largest current destination for U.S. grain exports, diminishes under the climate change cases, whereas the role of Pacific Northwest ports, Great Lakes ports, and Atlantic ports is projected to increase; 4) the demand for grain shipment via rail and truck rises, while demand for barge transport drops.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 4 uppsatser.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 6 uppsatser.

Licentiatavhandling (sammanfattning) Uppsala : Sveriges lantbruksuniversitet. / Härtill 3 uppsatser.

Orientador: Jairo Osvaldo Cazetta / Banca: Silvelena Vanzolini Segato / Banca: Edson Lazarini / Banca: Domingos Fornasieri Filho / Banca: Rogério Farinelli / Resumo: O extrato pirolenhoso (EP) é um subproduto oriundo da condensação de compostos da fumaça produzida durante o processo de produção de carvão vegetal. O EP tem em sua composição compostos bioativos que podem influenciar na germinação e no vigor de sementes. Dessa forma, o objetivo do trabalho foi avaliar a influência de diferentes concentrações de EP na cultura do milho, em sementes, no desenvolvimento inicial das plantas e no campo. Foram utilizadas 5 concentrações de EP aplicadas nas sementes: 0, 25, 50, 75 e 100% em solução (10 mL kg-1 de sementes), avaliando sua influência na germinação e no vigor através dos testes de germinação, primeira contagem de germinação, índice de velocidade de emergência, comprimento de plântulas, massa seca de plântulas, em laboratório, com 5 repetições em delineamento inteiramente casualizado (DIC) e, o teste de emergência em campo, com 4 repetições em delineamento em blocos casualizados (DBC). O desenvolvimento inicial das plantas de milho foi avaliado em casa de vegetação, com cultivo em vasos contendo 7 dm3 de solo, com duas plantas por vaso, utilizando-se 5 concentrações de EP aplicadas nas sementes: 0, 25, 50, 75 e 100%; via solo: 0, 0,5, 1,0, 1,5 e 2,0% (v v-1) e foliar: sem aplicações, 0,15 (aos 10, 20 e 30 dias após a emergência - DAE) e 0,2% (aos 40 DAE), 0,3 e 0,4%, 0,45 e 0,6% e 0,6 e 0,8% (v v-1), sendo utilizadas 5 repetições em DIC, verificando a influência do EP aos 55 DAE. Em campo, foram realizados dois experimentos, nas safras 2007/2008 e 2008/2009, sendo utilizadas 5 concentrações de EP aplicadas nas sementes: 0, 25, 50, 75 e 100%; via solo: 0, 2, 4, 6 e 8 L ha-1 e foliar: sem aplicações, 0,6 (10, 20 e 30 DAE) e 0,8 L ha-1 (40 DAE), 1,2 e 1,6 L ha-1, 1,8 e 2.4 L ha-1 e 2,4 e 3,2 L ha-1, avaliando sua influência nas características agronômicas, nos componentes da produção... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The pyroligneous acid (PA) is a byproduct comes from the condensation of smoke compounds produced during the process of charcoal production. The PA contains bioactive compounds that may influence of germination and seed vigor. Thus, the objective this research was to evaluate the influence of different concentrations of PA in seeds, in the initial corn development and field. Were used five concentrations of EP applied to seeds: 0, 25, 50, 75 and 100% solution (10 mL kg-1 seed), evaluating their influence on germination and vigor by germination, speed of emergence index, first germination count, dry matter weight, seedling length tests in the laboratory, with five replications in a complete randomized design (CRD), and field seedling emergence test with four replications in randomized block design (RBD). The initial development of corn plants was evaluated in a greenhouse, with cultivation in pots containing 7 dm3 of soil, two plants per pot, using five concentrations of PA applied to seeds: 0, 25, 50, 75 and 100 %, in soil: 0, 0.5, 1.0, 1.5 and 2.0% (v v-1) and leaves: no applications, 0.15 (10, 20 and 30 days after emergence - DAE) and 0.2% (40 DAE), 0.3 and 0.4%, 0.45% and 0.6 and 0.6 and 0.8% (v v-1), using five replications in CRD, verifying the influence of PA 55 DAE. In the field, two experiments were conducted in 2007/2008 and 2008/2009 seasons, using five concentrations of PA applied to seeds: 0, 25, 50, 75 and 100%, in soil: 0, 2, 4, 6 and 8 L ha-1 and leaves: no applications, 0.6 (10, 20 and 30 DAE) and 0.8 L ha-1 (40 DAE), 1.2 and 1.6 L ha-1, 1,8 and 2.4 L ha-1 and 2.4 and 3.2 L ha-1 to evaluate its influence on agronomic traits, yield components and corn yield, with four replications in RBD, for the first season. In the second, were used four concentrations of PA applied to seeds: 0, 25, 50 and 100%, in soil: 0, 2, 4 and 8 L ha-1 and leaves: no applications... (Complete abstract click electronic access below) / Doutor

Made available in DSpace on 2014-06-11T19:30:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-17Bitstream added on 2014-06-13T19:19:12Z : No. of bitstreams: 1 marques_rr_dr_botfca.pdf: 1561857 bytes, checksum: f962228d29c966c9acd2c4e111c35a0d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Estudos relacionados ao cultivo de amendoim no sistema de semeadura direta são escassos, principalmente relacionados com aplicação superficial de calcário e gesso. A aveia branca é uma das alternativas para o cultivo de inverno no Brasil, por produzir grãos para alimentação humana, forragem e adubo verde, diversificando a atividade agrícola, no entanto são inexistentes na literatura informações a respeito da calagem e gessagem superficiais nesta cultura. Em função do exposto, o presente trabalho teve por objetivo avaliar o comportamento das culturas de amendoim e aveia branca cultivadas no sistema semeadura direta, em área com aplicação superficial de calcário e gesso, bem como as conseqüências no movimento de bases no perfil do solo, na concentração de cátions solúveis na parte aérea, na nutrição e produtividade das culturas. O experimento foi conduzido nos anos agrícolas de 2004/2005 e 2005/2006 na Fazenda Experimental Lageado da Faculdade de Ciências Agronômicas – Campus de Botucatu, num Latossolo Vermelho distrófico. Foi utilizado o delineamento experimental em blocos casualizados com parcelas subdivididas e quatro repetições. As parcelas foram constituídas pela aplicação de quatro níveis de calcário dolomítico com PRNT = 71,2. As doses de calcário foram definidas de acordo com a análise química do solo na profundidade 0-0,2m para elevar a saturação por bases a 70% (2.000 kg ha- 1), metade da dose recomendada (1.000 kg ha-1), o dobro da dose recomendada (4.000 kg ha-1) e uma testemunha (sem aplicação). As subparcelas foram constituídas pela ausência e presença da aplicação de 2.100 kg ha-1 de gesso agrícola. Como cultura de verão foi utilizado o cultivar de amendoim (IAC 886) nos dois anos de condução do experimento em toda a área experimental e como cultura de inverno foi utilizado o cultivar de aveia branca (IAC 7) nos dois anos... / There have been few studies about peanut crop in no-tillage system mainly about superficial liming and gypsum application. White oat is an alternative for winter cropping in Brazil to be used as human food, forage and green manure; nevertheless, there is no information about superficial liming and gypsum application for this crop. Therefore, the objective of this work was to evaluate peanut and white oat yield as affected by superficial liming and gypsum application in no-tillage system as well as base movement in soil profile, concentration of water-soluble cations in the shoot of plants and plant nutrition. The experiment was carried out in the growing seasons of 2004/2005 and 2005/2006 in Botucatu, São Paulo State, Brazil, on a dystrophic Red Latosol. The experimental design was the completely randomized block with subdivided plots and four replications. The main plots consisted of four dolomite limestone levels with neutralization power of 71.2. Limestone levels were determined by soil chemical analysis in the 0-0.20m depth; the aim was to apply the recommended dose to raise base saturation up to 70% (2000 kg ha-1), half of the recommended dose (1.000 kg ha-1) and twice the recommended dose (4000 kg ha-1) besides the control, with no application. Subplots consisted of areas with and without gypsum application (2000 kg ha-1). Peanut (cultivar IAC 886) and white oat (IAC 7) consisted of the summer and winter crops cultivated in two growing seasons, respectively. The results of the present research showed that superficial liming affected soil acidity and increased Ca and Mg levels in the soil profile along with gypsum application, which contributed for the effects to be observed in deeper layers. Then, it was found that superficial liming showed residual effects and allowed fine lime particles to move down in the soil profile... (Complete abstract click electronic access below)

Master of Science / Department of Horticulture and Natural Resources / Charles J. Barden / Windbreaks were originally promoted across the Great Plains region of the U.S to reduce wind erosion in general. A review paper published nearly 30 years ago showed yield increases for a variety of crops associated with windbreaks. However, with the widespread use of no-till systems in all farming and advanced crop genetics, the question is “Do windbreaks still provide a yield benefit?” This study compared multiple years of data from protected and unprotected fields across Kansas and few sites in Nebraska looking at relative crop yield differences of five crops: soybeans, wheat, corn, sorghum and sunflowers. Georeferenced data already existed, generated by automated combine yield monitors, and stored on farmer's computers. There were three sets of data collected for each field. The first level is general field level information, using aerial photography and on-site observations to measure the characteristics of the windbreak (length, height and density). The second was from the yield monitor; this data was analyzed with ArcGIS 10.3.1 to visualize windbreak interaction with crop yield. Multiple means comparisons (protected versus unprotected) through two sample T-tests were conducted to determine if the yield in protected areas of fields was significantly different from the yield in unprotected areas. The third data-layer is climate data that was factored into yield analysis to compare wet, normal and dry growing seasons through a Chi-Square 2x2 test analysis. Optical density of windbreaks from leaf-on/off ground-based photos was assessed using SigmaScan Pro 5.0 software as possibly an important factor influencing the windbreak effect. Finally, the yield loss was estimated from the windbreak footprint to see if yield increases are enough to compensate for the area taken out of crop production. Results showed that soybeans (81 crop/years) had the most positive response to windbreak effect with a yield increase 46% of the time, with a 16% average yield increase. Sorghum (31 crop/years) had the highest average yield increase with 25%. Narrow windbreaks (1 to 2 tree rows with an average of 52 ft. width) and those on the north edge of fields resulted in yield increases which compensated for the footprint of the windbreak more often than wider windbreaks on the south edges of fields. Significant yield increases were less than the decreases in the protected area. There was no evidence to show the windbreak effect on yield had any association with critical month precipitation for any crop or orientation group. According to the results obtained, modern hybrids and varieties are possibly less responsive to yield increases due to windbreak effect than older crop varieties. Future studies should collect more data from fields with different windbreak widths distributed more widely across the region to confirm these results. Overall, this project updated our knowledge of windbreak/crop yield interactions and may possibly influence their future role as a conservation practice in the Great Plains.

Thesis (M.Sc. Agriculture (Horticulture)) -- University of Limpopo, 2017 / Phytonematicides, mainly due to their allelopathic nature, might be highly phytotoxic to crops protected against nematode damage. Phytotoxicity issues are compounded by the fact that the efficacy of plant extracts on nematode suppression depended much on their concentration and duration of exposure to the nematodes. Phytotoxicity could result in low crop yield and/or even in the eventual death of the protected crops. Concentrations that were suppressive to nematode numbers, but phytotoxic to the tested crop would not be useful when applied as a post-planting phytonematicides. The Mean Concentration Stimulation Point (MCSP) values were developed from the Curve fitting Allelochemical Response Dosage (CARD)computer based model to ensure that a non-phytotoxic concentration was applied for each crop. The objective of this study was to determine whether a series of Nemarioc-AL and Nemafric-BL phytonematicide concentrations would provide the MCSP for beetroot (Beta vulgaris) under greenhouse, microplot and field conditions. The greenhouse treatments included 0, 2, 4, 8, 16 and 32% for each phytonematicide. The microplot treatments were 0, 0.8, 1.6, 3.2, 6.4 and 12.8% concentrations, whereas in the field trial treatments were 0, 2.4, 4.8, 9.6, 19.2 and 38.4%. Under each condition, treatments of Nemarioc-AL and Nemafric-BL phytonematicides were, in separate experiments arranged in a randomised complete block design, with the greenhouse, microplot and field trials having 15, 10 and 9 replications, respectively. In the greenhouse, seedlings were raised in 20cm diameter plastic pots, containing pasteurised river sand and commercial seedling growing medium Hygromix® at 3:1 (v/v) ratio. Each seeding was inoculated with 5000 eggs and second-stage juveniles (J2) of Meloidogyne incognita. Seedlings were irrigated with chlorine free tapwater every other day using 250 ml/plant, with irrigation substituted by the treatment once weekly. On the microplot, the procedures were as in the greenhouse except that they growing mixture comprised pasteurised soil collected from the site. In the field, seedlings were directly transplanted into the soil. At 56 days after inoculation, in the greenhouse trial, the effects of Nemarioc-AL and Nemafric-BL phytonematicides were highly significant (P ≤ 0.01) on root galls, contributing 77 and 72% in total treatment variation (TTV) of root galls, respectively. Relative to untreated control, the respective products reduced root galls by 28-72% and 43-67%. Nemarioc-AL and Nemafric-BL phytonematicides had MCSP values on beetroot of 18.1 and 6.4%, respectively, with overall sensitivity values of 0 and 1, respectively.There was no treatment effect on nematode since there was absence of nematode in untreated control.Under microplottrials,Nemafric-BL phytonematicide had significant (P≤ 0.05) effects on fresh root mass, dry root mass and root galls, contributing 20, 19 and 57% in TTV of the three variables, with relative increases for fresh root mass and dry root mass of 65-159% and 63-143%, respectively, whereas root galls were reduced by 82-100%. Nemafric-BL phytonematicide had MCSP value on beetroot of 10.2%, with overall sensitivity value of 4 units. There was no treatment effect on nematode since there was absence of nematode in untreated control. In microplots, Nemarioc-AL phytonematicide did not have significant effects on all plant variables. Under field conditions, the treatments did not have significant effects on plant variables. In conclusion, results of the current study suggested that under greenhouse and microplot conditions the MCSP values of the phytonematicides ranged from 6.4 to 18.1%, with a wide range of overall sensitivities of phytonematicides to the test of beetroot cultivar / National Research Foundation (NRF) and Land Bank Chair of Agriculture - University of Limpopo and the Agricultural Research Council Universities Collaboration Centre

MSCAGR ( Soil Science) / Department of Soil Science / See the attached abstract below