Limits to Ice Thickness in Iowa During the Late Wisconsinan

Minimum and maximum limits to Des Moines Lobe ice thickness in Iowa during the Late Wisconsinan glaciation are calculated. These limits are based on minimum and maximum ice thickness calculations for the Des Moines Lobe in eastern North Dakota using crustal depression indicated by Lake Agassiz strandlines. Minimum and maximum basal shear stresses for the Des Moines Lobe are calculated by projecting a flow line from the terminus of the Des Moines Lobe back up-ice to the study site in northeastern North Dakota. Ice thickness in Iowa is then calculated with a method that uses the basal shear stress values. The ice thickness limits calculated in this study assume that 1) post-glacial rebound in North Dakota is complete, 2) restrained rebound in eastern North Dakota did not exceed 73 %, 3) basal shear stress controlled ice thickness in the marginal portions of the Laurentide Ice Sheet, and 4) the pore water pressure in the basal till of the reconstructed ice sheet was very close to the glaciostatic pressure. Ice thickness is calculated at between 131 and 484 m at the Iowa-Minnesota border. The results of this study are then compared to results from other Des Moines Lobe ice thickness studies

The Influence of Long-Term Anthropogenically-Induced Compaction on Select Properties of Soils in the Midwestern United States

Soil compaction by heavy equipment has become one of the most important problems in modern large-scale plant production, but one area that has not received much attention is the effect of soil compaction on prairie soils over time periods in excess of about 10 years. This study addresses this issue by comparing properties in compacted to noncompacted soils in an abandoned farmyard and along a preserved stretch of the Mormon Trail. Properties compared include soil morphology, bulk density, carbon, C/N ratio, and ap­parent electrical conductivity (ECa). Bulk density, organic carbon, and ECa values were consistently different in the compacted versus noncompacted soils. Darker soil colors were consistently found at greater depths and roots were more abundant in the noncompacted soils. Some changes in C/N ratios were observed and a zone of platy structure was found in the abandoned farmyard

Isostatic rebound in the Lake Agassiz Basin since the late Wisconsinan

This study addressed three main questions: I) how thick was the ice that covered the southern Lake Agassiz basin during the Wisconsinan and how much that ice depressed the crust, 2) how much rebound has occurred since deglaciation and whether or not rebound is complete, and 3) what were the effects of this rebound on the basin. The most direct method of measuring rebound in the Lake Agassiz basin is from strandlines left by glacial Lake Agassiz. The oldest complete strandline, the Herman, presumably rebounded, with the northern end rebounding more because the ice was thicker there and had melted from that end later. The difference in elevation of this strandline represents absolute minimum rebound, 54.5 meters. Up to 73% of rebound was restrained; the initial depression may have been as much as 200 meters. However, restrained rebound may have been regarded as ice was replaced by Lake Agassiz water and sediments. The average depth of Lake Agassiz at Grand Forks, ND, was as much as 100 meters, and the average thickness of sediments as much as 46 meters. These masses would cause crustal depression of 38 meters and 40 meters, respectively. The sediments are still in place in the Lake Agassiz Basin, causing 40 meters of depression. When added to the 54.5meters of minimum depression, a total of 94.5 meters of depression is indicated. Minimum ice thickness would have been approximately 280 meters. Using a slope profile method, former ice thickness in the Grand Forks, ND area was about 390 meters, with approximately 424 meters at the international border. Basal shear stress methods indicate ice thicknesses between 313 and 986 m. Maximum ice thickness indicated by the strandlines is 1040 meters. Ice thickness must have exceeded the minimum. Several beach and scarp remnants are as much as 30 meters above the Herman strandline. On the other hand, the water and sediments of Lake Agassiz slowed rebound. Ice thickness, therefore, most likely was between 435 and 986 meters, causing a depression of 140 to 330 m. Results of the rebound include decreased river gradients, changing river courses, and more frequent and intense flooding in the Lake Agassiz basin. Rebound definitely continues north of Lake Winnipeg, and may still be occurring in the southern Lake Agassiz basin, although the strandlines indicate that rebound in the southern Lake Agassiz basin is complete. In either case, the potential for increased flooding exists

The age of vines as a controlling factor of soil erosion processes in Mediterranean vineyards

Vineyards incur the highest soil and water losses among all Mediterranean agricultural fields. The state-of-the-art shows that soil erosion in vineyards has been primarily surveyed with topographical methods, soil erosion plots and rainfall simulations, but these techniques do not typically assess temporal changes in soil erosion. When vines are planted they are about 30 cm high × 1 cm diameter without leaves, the root system varies from 2 to over 40 cmdepth, and sometimes the lack of care used during transplanting can result in a field with highly erodible bare soils. This means that the time since vine plantation plays a key role in soil erosion rates, but very little attention has been paid to this by the scientific community. Thus, the main goal of this research was to estimate soil losses and assess soil erosion processes in two paired vineyard plantations of different ages. To achieve this goal, the improved stock unearthing method (ISUM) was applied to vineyards on colluvial parent materials with similar soil properties, topographical characteristics and landmanagements in the Les Alcusses Valley, southwestern Valencia province, Spain. Our findings suggested that the old vineyards showed lower erosion rates (−1.61 Mg ha−1 yr−1) than those that were recently planted (−8.16 Mg ha−1 yr−1). This is because of the damage that the plantation of the vines causes to soil. Tillage after planting (4 times per year) resulted in changes in the inter-rowand rowmorphology, promoting the development of a ridge underneath the vines that disconnected the inter-rows and reduced soil losseswith time. After the second year and until the 25th year after plantation, soil erosionwas approximately 1Mg ha−1 y−1,whichmeans thatmost of the erosion took place during the first two years after the plantation. Soil conservation strategies should be applied immediately after the plantationworks to allow sustainable grape production. That is when soil erosion most needs to be controlled

Geodiversity and geoheritage: Detecting scientific and geographic biases and gaps through a bibliometric study

Many scientists have recognized that there is diversity in nature, including biodiversity, geodiversity, and pedodiversity. Studies in biodiversity date back as far as the 1700s, but geodiversity and pedodiversity studies are much more recent, dating to the late 1970s to early 1980s. Given that we are now approaching 40 years of geodiversity and geoheritage work, this study was undertaken to determine areas that have been well addressed and where current gaps are. This was accomplished by reviewing the publications in the journal 'Geoheritage', the Scopus and Google Scholar databases, and established geoparks according to UNESCO records. It was found that geodiversity studies typically do not include the findings or utilize the techniques of biodiversity and pedodiversity research, despite the fact that common definitions of geodiversity include soils. Including the findings and techniques of bio- and pedodiversity would expand geodiversitywork. Likewise, geoheritage preservation sites are not geographically balanced, with European countries, Brazil, Australia, and China creating the large majority. The European and East Asian countries, especially China, have dominated in the establishment of geoparks. The most pressing need in future studies is more balanced geographic distribution, as the current strong slant towards a limited portion of the world cannot adequately capture (on the research front) and preserve (on the geoparks front) global geodiversity. Finally, there is a need investigate whether the spatial patterns of biodiversity are idiosyncratic or are also a characteristic of abiotic resources, permitting the standardization of diversity research methods. This review contends that there are intriguing similarities in biodiversity, geodiversity, and pedodiversity patterns that should be explored, something that would benefit all of these research areas

The Impact of White Pine (Pinus strobus) on a Mollisol After Seven Decades of Soil Development

Selected chemical, physical, and macro and micromorphological properties in two pedons of a Clarion soil (Fine-loamy, mixed, superactive, mesic Typic Hapludolls) formed in till parent material, one planted to white pines (Pinus strobus) for the past 75 years and the other to grass, were compared. The most obvious difference between the two was the increased biological activity under pines; the variety and quantity of excrements suggested the activity of soil microfauna and variability of species resulted in finer and better aggregation of biological origin (crumbs and granules), numerous excrements in voids, and higher total porosity under pines. The matrix was lighter colored in the upper horizons under pines. The soil under pines seemed to be drier and to have more expressed water oscillations in the middle part of profile. There was some evidence of higher groundmass activity in the soil under pines and the groundmass b-fabric was slightly better expressed. The soil under the pines exhibited evidence of stronger weathering (weathered biotite at a shallower depth, more iron-rich fine fraction, common amorphous iron impregnation and frequent amorphous iron coatings related to grains or pores together with abundant iron nodules) than the soil under grass. Analytical and micromorphology methods showed only slight changes in the Clarion soil under pines. That means 75 years, at least under the prevailing climate, is too short a period for the formation of pronounced morphological and physico-chemical differences

Islands of biogeodiversity in arid lands on a polygons map study: Detecting scale invariance patterns from natural resources maps

Abstract Many maps (geology, hydrology, soil, vegetation, etc.) are created to inventory natural resources. Each of these resources is mapped using a unique set of criteria, including scales and taxonomies. Past research indicates that comparing results of related maps (e.g., soil and geology maps) may aid in identifying mapping deficiencies. Therefore, this study was undertaken in Almeria Province, Spain to (i) compare the underlying map structures of soil and vegetation maps and (ii) investigate if a vegetation map can provide useful soil information that was not shown on a soil map. Soil and vegetation maps were imported into ArcGIS 10.1 for spatial analysis, and results then exported to Microsoft Excel worksheets for statistical analyses to evaluate fits to linear and power law regression models. Vegetative units were grouped according to the driving forces that determined their presence or absence: (i) climatophilous (ii) lithologic-climate; and (iii) edaphophylous. The rank abundance plots for both the soil and vegetation maps conformed to Willis or Hollow Curves, meaning the underlying structures of both maps were the same. Edaphophylous map units, which represent 58.5% of the vegetation units in the study area, did not show a good correlation with the soil map. Further investigation revealed that 87% of the edaphohygrophilous units were found in ramblas, ephemeral riverbeds that are not typically classified and mapped as soils in modern systems, even though they meet the definition of soil given by the most commonly used and most modern soil taxonomic systems. Furthermore, these edaphophylous map units tend to be islands of biodiversity that are threatened by anthropogenic activity in the region. Therefore, this study revealed areas that need to be revisited and studied pedologically. The vegetation mapped in these areas and the soils that support it are key components of the earth's critical zone that must be studied, understood, and preserved

Straw uses trade-off only after soil organic carbon steady-state

Soil organic matter (SOM) is the key for a healthy soil and a relevant property to achieve the sustainability on soil management. However, soils are still net exporters of organic matter. One example is the use of wheat straw residue for industrial and energy applications, which has gained attention in the last years. The offfarm use of this abundant and low cost resource should follow sustainability criteria to avoid soil degradation and SOM losses. Straw residue incorporation is recognized as a recommended management practice to control erosion and mitigate CO2 emissions by increasing SOM. The goal of this work was: i) to evaluate the steady-state carbon (C) level in relation to C input and estimate the minimum residue input needed to maintain this SOC level in a durum wheat-based cropping system in long-term experiment; and ii) estimate the potential availability of durum wheat straws for alternative use. Results showed that a C steady-state can be achieved after 3.4 years with an annual organic C input of 4.5 Mgha-1. Only after reaching a steady-state, straws can be used for trade-off, leaving 1.03 Mgha-1y-1 of C input remain in the soil

The importance of soil education to connectivity as a dimension of soil security

The connectivity concept within soil security posits that people need to have a connection to soil in order to properly value it. Showing how soil is important in everyday life can create connections to soil, because people care about things they see as impacting their quality of life. Education can demonstrate these connections and may take place in either formal or informal settings and over a wide range of age groups. Creating an effective educational environment is critical, which involves understanding the specific group being addressed, including their existing knowledge of and interest in soil. Soil scientists increasingly teach to student groups that need to know about soils within their chosen careers but are not necessarily training to be soil specialists. Within this formal setting, education that demonstrates the various functions that soils provide in support of human wellbeing may be important to connectivity because it clearly demonstrates the impact of soils on peoples’ lives. In less formal settings, it will be important to identify concepts that will resonate with the public or stakeholders, such as terroir, soil health, or soil security, and to effectively reach these groups with a message built around these concepts. Social marketing, social media, storytelling, soil apps, and soil games are all approaches that have promise to deliver the desired message, therefore creating connections between people and soil