• Characteristics and Fertility Status of Soils and Minesoils in Selected Areas of Usibelli Coal Mine, Healy, Alaska

      Ping, Chien-Lu; Kaija, Kevin J. (School of Agriculture and Land Resources Management, Agricultural and Forestry Experiment Station, 1989-12)
      Alaska has been proven to contain not only bountiful oil and gas reserves. but also vast coal fields occurring from the southcentral coastline to the Interior and the Arctic zone to the north. Because of concerns for stable sources of energy, particularly by the energy-short, industrial nations of the Orient, more exploration and stripmining for coal can be expected in the near future. Therefore, it is important to know the consequences of large-area soil disturbances tn the subarctic and bow the effects of man's reclamation efforts and natural processes combine in reestablishing vegetative community. The culmination or synthesis of these processes is soil development and is of great importance in successful stripmine reclamation. The Usibelli Coal Mine Company in the Healy coal field, located in Interior Alaska. commenced stripmining in 1943. Its operation has been continuous, moving from area to area, for the last 40 years. Stripmining requires the excavation of overburden and subsequent redeposition, therefore the Healy operation has exposed minespoils from different strata on various topography. In 1972, the Usibelli Coal Mine company initiated a reclamation program and, over the ensuing l0 years, has seeded and fertilized over 2000 acres. Nevertheless, there remain barren areas and areas undergoing natural revegetation. Additionally, experimental trials in seeding and fertilization were started in 1980. Large areas of intact native plant communities adjoin the mined areas. The company property provides opportunities to study the processes of soil formation under different sets of conditions. The objectives of this study were to (1) characterize the soils on the mine lease area for baseline data, (2) to characterize the mine soils with various history, (3) to study the process of soil formation under different sets of conditions, and (4) to evaluate the nutrient levels of both soil and minesoils to form a basis for establishing soil-handling requirements to promote reclamation practices.
    • The effects of permafrost degradation on soil carbon dynamics in Alaska's boreal region

      O'Donnell, Jonathan A. (2010-12)
      High-latitude regions store large quantities of organic carbon (C) in permafrost soils and peatlands, accounting for nearly half of the global belowground C pool. Projected climate warming over the next century will likely drive widespread thawing of near-surface permafrost and mobilization of soil C from deep soil horizons. However, the processes controlling soil C accumulation and loss following permafrost thaw are not well understood. To improve our understanding of these processes, I examined the effects of permafrost thaw on soil C dynamics in forested upland and peatland ecosystems of Alaska's boreal region. In upland forests, soil C accumulation and loss was governed by the complex interaction of wildfire and permafrost. Fluctuations in active layer depth across stand age and fire cycles determined the proportion of soil C in frozen or unfrozen soil, and in turn, the vulnerability of soil C to decomposition. Under present-day climate conditions, the presence of near-surface permafrost aids C stabilization through the upward movement of the permafrost table with post-fire ecosystem recovery. However, sensitivity analyses suggest that projected increases in air temperature and fire severity will accelerate permafrost thaw and soil C loss from deep mineral horizons. In the lowlands, permafrost thaw and collapse-scar bog formation resulted in the dramatic redistribution of soil water, modifying soil thermal and C dynamics. Water impoundment in collapse-scar bogs enhanced soil C accumulation in shallow peat horizons, while allowing for high rates of soil C loss from deep inundated peat horizons. Accumulation rates at the surface were not sufficient to balance deep C losses, resulting in a net loss of 26 g C m⁻² y⁻¹ from the entire peat column during the 3000 years following thaw. Findings from these studies highlight the vulnerability of soil C in Alaska's boreal region to future climate warming and permafrost thaw. As a result, permafrost thaw and soil C release from boreal soils to the atmosphere should function as a positive feedback to the climate system.
    • A farmers guide to evaluate soil health using physical, chemical, and biological indicators on an agricultural field in Alaska

      Cole, Cory J.; Zhang, Mingchu; Matney, Casey; Karlsson, Meriam (2018-12)
      Farmers across Alaska face many challenges. These challenges include climate extremes, wind and water erosion, weed pressure, crop pests, and nutrient-poor soils. Cover crops, crop rotation, crop residue, and tillage management are common conservation practices used to address soil related resource concerns. Research in the continental United States has shown that these soil conservation practices improve soil health. Resource managers are trying to determine the usefulness of soil health indicators to assess conservation practices in Alaska. The objective of this project was to provide Alaskan farmers, conservation planners, and land managers with a background on soil health, soil health indicators, soil health assessments, and the use of conservation practices to improve soil health. Establishing linkages between soil conservation practices and soil health indicators will allow individuals to focus conservation efforts on improving soil conditions, evaluate soil management practices and techniques over time to determine trends, make qualitative comparisons of soil health among management systems, and provide tested measures of soil health (indicators) that will allow farmers and land managers to make more informed resource decisions. Numerous studies were conducted across Alaska to gauge the success of cover cropping, crop rotation, and reduced tillage (no-till). Improvements in physical, chemical, and biological indicators were documented. After one year of study, most cover crops resulted in lower bulk density at the soil surface compared to conventional tillage. Among the cover crop treatments, the perennial forage grass Timothy (Phleum pratense var. Engmo) ranked highest in soil organic matter, soil water content, and improvement to the soil structure. Preliminary data from this project has been gathered to develop an Alaska specific Soil Health Assessment Card and supplementary User Guide.
    • Lime Requirement Indices of Alaskan Soils

      Loynachan, T. E. (School of Agriculture and Land Resources Management, Agricultural and Forestry Experiment Station, 1979)
      Perhaps the most significant single measurement of a soil's ability to adequately support plant growth is a pH determination. If soils are too acid, reduced nutrient availability of all the macronutrients will result. Conversely with several of the micronutrients, low soil pH can increase solubilities, even to the point of causing plant toxicity. Aluminum, an element regarded as nonessential for plant growth, has been shown by numerous workers to produce toxic plant effects at low soil pH (1). High soil pH likewise is undesirable for plant growth and can result in reduced availability of several micronutrients such as boron, zinc, iron, and manganese. Phosphate fixation can occur when excessive calcium is present. Therefore, the majority of agronomic plants do best when grown in neutral to slightly acid soils in the 6 to 7 pH range
    • Soils and Vegetation of the Trans-Alaska Pipeline Route: A 1999 Survey

      McKendrick, Jay D. (School of Agriculture and Land Resources Management, Agricultural and Forestry Experiment Station, 2002-01)
      This report presents the results of a survey of soil s and vegetation along the Trans Alaska Pipeline System (TAPS) right-o f-way (ROW) from Prudhoe Bay to Valdez, Alaska. This survey, conducted in the summer of 1999, was designed to secure an overall perspective of the soil fertility and general vegetation conditions in the ROW and in the undisturbed habitat immediately adjacent to the ROW. Researchers examined 52 sites along the 800-mile ROW, which crosses three vegetation zones: tundra, alpine, and boreal (includes coastal forest). Soil samples were collected for laboratory analysis of plant nutrients, vascular plant species were inventoried, and photographs were taken at each site. This information can be used to assess the impacts of TAPS on vegetation and the success or failure of revegetation efforts performed during pipeline construction in the 1970s and to make recommendations for revegetation of future disturbed areas in regions similar to the TAPS ROW. The Federal Agreement and Grant of Right-of-Way for the Trans-Alaska Pipeline System requires that seeding and planting of disturbed areas be conducted as soon as practicable and, if necessary, repeated until vegetation was successful. As a res ult , a reasdisturbed during pipe line construction were revegetated by seeding grasses and fertilizing soil s and by planting willow cuttings and transplants from natural sources and greenhouse production. Seeding and fertilizing were the most extensively used applications along the route. Transpl anted trees and shrubs were used where the pipeline crossed public roads, in order to shield the view of the open ROW from the highway. Native and non-native grasses were seeded. As a res ult, some weeds were introduced and grasses were established, some of which have persisted.
    • A study of soil topo-sequences in the Steese and White Mountains of Alaska

      Geisler, Eric S.; Ping, Chien-Lu; Juday, Glen; Swanson, David (2018-08)
      The Steese Mountains of Alaska present a complex landscape on which to study soil formation and characteristics in relation to topographic position. The White and Steese Mountains of Alaska are located approximately 70 to 220 km northeast of Fairbanks. Ten toposequences with 3 or 4 sites each were described in the field, sampled, and analyzed in the laboratory in order to determine the relationship between soil morphology and soil-forming factors. Permafrost is discontinuous within the study area and vegetation ranges from tundra on summits to boreal stands of resin birch, quaking aspen, black spruce and white spruce along the lower elevations. There have been many wildfires over time that may have altered the soils and affected the vegetation successional patterns. The processes through which various soil patterns have formed and the unique characteristics of the soils are described here based on field data obtained from both burned and unburned sites. The analysis includes biophysical settings, parent material, texture and nutrient concentrations. Organic horizons were common on most of the transects and play a key role in the depth of the active layer where they exist. Nutrient concentrations are also closely tied to the presence and depth of the organic horizons. Some patterns described in other areas of the boreal region were not observed in this study. There were some soil properties that are not readily described under the current taxonomy protocols which are suggested to be added in a future revision of Soil Taxonomy.