Browsing by Subject "soils"
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Item Field Research in Soil Science(Regents of the University of Minnesota, 1993) Department of Soil Science, University of MinnesotaItem Field Research in Soil Science(Regents of the University of Minnesota, 1992) Department of Soil Science, University of MinnesotaItem Field Research in Soil Science(Regents of the University of Minnesota, 1994) Department of Soil Science, University of MinnesotaItem Field Research in Soil Science(Regents of the University of Minnesota, 1997) Department of Soils, University of MinnesotaItem Field Research in Soil Science(Regents of the University of Minnesota, 1996) Department of Soil Science, University of MinnesotaItem Field Research in Soil Science(Regents of the University of Minnesota, 1994) Department of Soil Science, University of MinnesotaItem Inoculation of alfalfa on lime-deficient sandy soils(University of Minnesota. Minnesota Agricultural Experiment Station, 1927-03) Alway, Frederick J.; Nesom, George H.Item Magnetic minerals in soils and paleosols as recorders of paleoclimate(2017-06) Maxbauer, DanielIt is a fundamental challenge for geologists to create quantitative estimates of rainfall and temperature in past climates. Yet, records of past climates are integral for understanding the complexities of earth system dynamics. The research presented in this dissertation begins to establish a framework for reconstructing paleoclimates using the magnetic properties of fossilized soils. Magnetic minerals are ubiquitous in soils, and their composition, grain size, and concentration is often directly related to the ambient climatic conditions that were present during soil formation. Using rock magnetic methods, it is possible to sensitively characterize the magnetic mineral assemblages in natural materials - including soils and paleosols. The fundamentals of rock magnetism and many of the common methods used in rock magnetic applications are presented in chapter 2 and chapter 3, respectively. Chapter 4 reviews the physical, chemical, and biological factors that affect magnetic mineral assemblages in soils, the magnetic methods we use to characterize them, and the known relationships between magnetic minerals in soils and climate. A critical component to developing replicable tools for reconstructing paleoclimate is developing analytical and statistical tools that are accessible to the greater community. Chapter 5 introduces a new model, MAX UnMix, that was developed as an open-source, online tool for rock magnetic data processing that is designed to be user-friendly and accessible. Two case studies, on both fossil (Chapter 7) and modern (Chapter 6) soils, are presented and discuss many issues related to applying magnetic paleoprecipitation proxies in deep time. Chapter 7 discusses difficulties in disentangling the effects of pedogenesis, diagenesis, and recent surficial weathering in Paleocene-Eocene (56-55 Ma) paleosols. Chapter 6 explores the relative influence of soil forming factors (vegetation vs. climate) on controlling the pedogenic formation of magnetic minerals in soils developing across the forest-to-prairie ecotone in NW Minnesota. The body of research presented in this dissertation provides many challenges to future workers, while at the same time highlighting that rock magnetism should be a useful tool for researchers interested in deep time paleoclimates moving forward.Item Maximum Application Rates for Land Treatment of Septage(Water Resources Research Center, University of Minnesota, 1983-05) Anderson, James L.; Clanton, C.J.; Hansel, M.J.; Machmeier, R.E.During 1980, septage was applied in rates of 1120 and 1500 kg of nitrogen per hectare to three different soil textures in an attempt to determine maximum loading rates. These rates resulted in increased concentrations of nitrates in the soil water for a Hubbard loamy Sanci, Waukegan silt loam and Lester clay loam, indicating that the application rates exceeded the maximum rate that the soils could treat. The first year's results indicate that soil type, application rates and soil depth resulted in no significant difference in total Kjeldahl nitrogen, ammonia, fecal streptococcus and fecal coliforms in the soil water samples. Nitrate concentrations, however, were significantly different between the soils, application rates and soil depths. For the Hubbard loamy sand, rainfall had a larger effect on nitrate concentrations and movement within the soil profile than for the Waukegan silt loam or Lester clay 1oam. 0n the Waukegan silt loam and Lester clay loam there was relatively little change in the nitrate concentration in the soil profile during the period when septage was applied twice a week. After the design loading had been applied to the soil and no further applications made, a sharp increase in nitrate concentrations was observed in the soil profile. This probably resulted from changing the anaerobic surface layer to an aerobic condition resulting in nitrification and subsequent movement of nitrates through the profile following a rainfall event. With no additional septage application, the second year's data indicate a significant difference in nitrate-N between soils, application rates, and depths. Generally, the nitrate concentrations in the Hubbard loamy sand and Waukegan silt loam were less than the first year, but the concentrations in the Lester clay loam were higher than the first year. This indicates that nitrification and nitrate movement in the Lester clay loam are slower than the other two soils. Application resulted in a significant increase in the concentration of soil water calcium, magnesium, sodium and potassium during the first year of the study. However, there was no increase in the phosphorus content of the soil water.Item Publications and Faculty of the Department of Soil Science 1888 to 1970(Regents of the University of Minnesota, 1973) Department of Soil Science, University of MinnesotaItem A REPORT ON FIELD RESEARCH IN SOIL SCIENCE(Regents of the University of Minnesota, 1976) Department of Soils, University of MinnesotaItem A Report on Field Research in Soil Science(Regents of the University of Minnesota, 1989) Department of Soil Science, University of MinnesotaItem A Report on Field Research in Soil Science(Regents of the University of Minnesota, 1986) Department of Soil Science, University of MinnesotaItem A Report on Field Research in Soil Science(Regents of the University of Minnesota, 1985) Department of Soil Science, University of MinnesotaItem A Report on Field Research in Soil Science(Regents of the University of Minnesota, 1988) Department of Soil Science, University of MinnesotaItem A Report on Field Research in Soil Science(Regents of the University of Minnesota, 1981) Department of Soil Science, University of MinnesotaItem A Report on Field Research in Soil Science(Regents of the University of Minnesota, 1983) Department of Soil Science, University of MinnesotaItem A Report on Field Research in Soil Science(Regents of the University of Minnesota, 1990) Department of Soil Science, University of MinnesotaItem A Report on Field Research in Soil Science(Regents of the University of Minnesota, 1980) Department of Soil Sciences, University of MinnesotaItem A Report on Field Research in Soil Science(Regents of the University of Minnesota, 1982) Department of Soil Science, University of Minnesota
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