• Bromegrass in Alaska. V. Heading and Seed Production as Influence by Time and Rate of Nitrogen Fertilization, Sod Disturbance, and Aftermath Management

      Klebesadel, Leslie J. (School of Agriculture and Land Resources Management, Agricultural and Forestry Experiment Station, 1996-06)
      This report summarizes five primarily exploratory experiment conducted at the University of Alaska's Matanuska Research Farm (61.6'N) near Palmer in southcentral Alaska. The problem addresses was the rapid decline in Polar bromegrass seed yields with each year of production.
    • Effects of Nitrogen, Lime, and Boron on Candle Rape Grown in the Trapper Creek and Pt. MacKenzie Areas of Southcentral Alaska

      Laughlin, Winston M.; Smith, Glenn R.; Peters, Mary Ann (School of Agriculture and Land Resources Management, Agricultural and Forestry Experiment Station, 1987-10)
      When growers in the Susitna Valley and later in the Pt. MacKenzie area of southcentral Alaska inquired as to the feasibility of growing rapeseed, we decided to determine the crops suitability and performance by conducting a field experiment. Bolton (1980) had attempted to predict the feasibility of producing rapeseed in Alaska's interior, but no research had been done in southcentral Alaska. We conducted one study from 1979 through 1981 on Rabideux silt loam (pH 5.1) near Trapper Creek and another from 1982 through 1984 on Kashwitna silt loam (pH 5.4) on the University of Alaska' s research tract in the Pt. MacKenzie area. The first area had been cleared prior to 197 8. This area was rototilled and roots removed in September 1978. The second area was on a tract cleared during the winter of 1981. After clearing, rotary plowing was done twice on the area. During the summer of 1981, roots were removed , and a field cultivator was used twice to loosen and bring roots to the surface.
    • Effects of Potassium, Sulfur, Nitrogen Rate, And Nitrogen Source on Bromegrass Forage Yield and Composition

      Laughlin, Winston M.; Smith, Glenn R.; Peters, Mary Ann (School of Agriculture and Land Resources Management, Agricultural and Forestry Experiment Station, 1987-09)
      Production of adequate , high-quality forage is essential for Alaska's livestock industry. Smooth bromegrass (Bromus inermis) is the dominant and most dependable perennial forage crop in the Matanuska Valley and other areas of Alaska. Four areas of Knik silt loam on the University of Alaska's Matanuska Research Farm near Palmer were seeded to bromegrass and were used over a period of 18 years to determine the need of high-yielding bromegrass for applications of potassium (K) and sulfur (S). A bromegrass field on the Woods estate two miles south of Palmer was selected in 1976 for a study comparing three rates of two nitrogen (N) sources with and without S. The soil type was Bodenburg silt loam.
    • Post-fire variability in Siberian alder in Interior Alaska: distribution patterns, nitrogen fixation rates, and ecosystem consequences

      Houseman, Brian Richard; Ruess, Roger; Hollingsworth, Teresa; Verbyla, Dave (2017-12)
      The circumpolar boreal forest is responsible for a considerable proportion of global carbon sequestration and is an ecosystem with limited nitrogen (N) pools. Boreal forest fires are predicted to increase in severity, size, and frequency resulting in increased losses of N from this system due to volatilization. Siberian alder (Alnus viridis ssp. fruticosa) N-fixation is a significant source of N-input within the interior Alaskan boreal forest and likely plays a pivotal, though poorly understood, role in offsetting losses of N due to fire. This study disentangles the effects of fire severity, post-fire age, and environmental variables on Siberian alder N-input across the upland boreal forest and quantifies the landscape-level implications of Siberian alder N-input on N pool balance. Stand types of an early- and intermediate-age burn scar were determined by relevé plot sampling, hierarchical clustering, and indicator species analysis. Alder growth traits (density, nodule biomass, nodule N-fixation, and other traits) were sampled across all stand types, burn scars, and a fire severity gradient. Pre- and post-fire landscape-level N-fixation inputs were quantified within the early-age burn scar by scaling-up Siberian alder growth traits to the stand-level and then mapping the total area of pre- and post-fire stand types. Results show that fire severity shares a complex relationship with Siberian alder N-input in black spruce stands, wherein moderate fire severity has a negligible effect on Siberian alder N-input, moderate to high fire severity increases Siberian alder N-input, and high fire severity reduces Siberian alder N-input. Fire likely limited alder vegetative propagation in post-fire black spruce trajectory stands but enhanced propagation in post-fire deciduous trajectory stands that experienced moderate severity. Following the 2004 Boundary Fire, Siberian alder N-input showed an overall increase across the landscape, mostly within post-fire deciduous stand types. Future increases of fire severity and subsequent conversions of stand type from black spruce to deciduous dominance have the potential to increase total short-term N-input on the landscape, but a majority of those gains will be concentrated within a small proportion of the post-fire landscape (i.e. deciduous trajectory stand types). In the boreal forest, the temporal and spatial pattern of ecosystem processes that rely on N fixation inputs is dependent on the recruitment and growth of Siberian alder, which is in turn dependent on a complex relationship between fire severity, stand type, and post-fire age.
    • Rates and Methods of Application of Nitrogen and Phosphorus for Commercial Field Production of Head Lettuce in Southcentral Alaska

      Walworth, James L.; Carling, Donald E.; Gavlak, Raymond G. (School of Agriculture and Land Resources Management, Agricultural and Forestry Experiment Station, 1994-04)
      Head lettuce (Lactuca sativa L.) is one of the major agricultural crops grown in Alaska. In 1992, its wholesale value was approximately $314,000, second only to potatoes among Alaska’s commercially field grown vegetables (Brown et al., 1992). The quality of head lettuce is as important as yield, as lettuce heads that do not meet minimum size and weight standards are unmarketable. Head size and weight are strongly influenced by management practices, dictating a high level of management for successful commercial production. Among manageable cultural variables, rate of fertilizer application and the method of fertilizer placement are two of the most critical. Despite the value of the head lettuce crop to Alaska vegetable growers and the importance of fertilization as a management practice, little research has been published on rates of application and method of applying nitrogen and phosphorus to commercially grown head lettuce.