Recent Submissions

  • Applied Range Ecology Of Reindeer (Rangifer Tarandus Tarandus) On The Seward Peninsula, Alaska

    Finstad, Gregory Lawrence; Kielland, Knut; Harris, Norman (2008)
    Linking variation of the environment to animal production is key to successful range management. Ecological site descriptions (ESDs) are landscape units used by land managers for the grazing management of domestic reindeer ( Rangifer tarandus tarandus) on the Seward Peninsula, Alaska. This study investigated the appropriateness of using ESDs for the grazing management of reindeer and explored the use of alternate units to link landscape variation to animal production. ESD composition of reindeer ranges varied across the Seward Peninsula, but there was no relationship to either animal production, estimated by June calf weight and cow/calf ratios, or reindeer serum and tissue mineral concentrations. I have shown that reindeer do not graze uniformly across ESDs, but are selective, both temporally and spatially, in what they consume. Reindeer diet selection and animal production appear to be driven by temporal variation in the nutritional characteristics of individual forage species. Biomass production and seasonal nutritional characteristics of forage species were used develop a computerized mapping program for reindeer producers to identify high quality grazing areas. Production among herds was related with identified forage sources of protein in the diet. Reindeer in herds with smaller June calves consumed more catkins, stems and leaf buds of shrubs in May, presumably to compensate for lower protein reserves. Diets of reindeer and June calf weight were significantly predicted by the delta15N ‰ differential between antler core (AC) and antler periosteum (AP). Although animal production was related to landscape stratification at the species level, data showed that weather patterns affected forage nutrient concentration and foraging accessibility at a landscape level. Body weight and growth of female calves and the proportion of yearlings lactating the next summer were positively correlated with spring temperature and negatively correlated with winter severity and summer temperature. Land managers are using ESDs to monitor and assess the impact of grazing, but I have shown that landscape variation described at a multitude of scales other than ESD are linked to grazing patterns and animal production. I concluded that these alternative landscape units be integrated into reindeer range management currently being practiced on the Seward Peninsula.
  • Mechanisms Involved In The Cold Tolerant Trichoderma Atroviride Biocontrol

    Cheng, Mingyuan; McBeath, Jenifer H. (2004)
    Trichoderma atroviride is a cold tolerant fungus that parasitizes a wide range of plant pathogenic fungi. The mechanisms involved in biocontrol by T. atroviride are only partially understood. This research evaluated the effect of four different groups of plant pathogenic fungi (Botrytis cinerea, Phytophthora capsici, Rhizoctonia solani and Sclerotinia sclerotiorum) on enzyme expression at 22�C and 7�C. The enzymes expressed (proteinase and endo-beta-1,3-glucanase) were purified and characterized, and three 73 kDa N-acetyl-beta- D-glucosaminidase genes from three different T. atroviride biotypes were sequenced. The R-1,6-glucanase profiles and the regulation of N-acetyl-beta-D-glucosaminidases by plant pathogenic fungi were also studied. I document the production of N-acetyl-beta-D-glucosaminidase, exochitinase, endochitinase, beta-1,3-glucanase, beta-1,6-glucanase and proteinase by T. atroviride at room temperature. The timing of enzyme expression was pathogen dependent. A high concentration of glucose repressed the expression of glucanases, but had no effect on the expression of N-acetyl-beta-D-glucosaminidase. At 7�C, T. atroviride produced the same enzymes as at room temperature except beta-1,6-glucanase. The total activities of the chitinases increased over a 30 day incubation period while the expression of glucanases and proteinase depended on the inducer. A new 18.8 kDa serine proteinase and a new 77 kDa endo-beta-1,3-glucanase were purified to electrophoretical homogeneity. These two purified enzymes showed strong antifungal activity by inhibiting conidial germination of Botrytis cinerea. Three 73 kDa N-acetyl-beta-D-glucosaminidase genes were sequenced from T. atroviride biotypes 861, 453 and 603. Gene sequences of the enzyme from the T. atroviride biotypes are different from the published gene sequence of T. harzianum . This indicates that the N-acetyl-beta-D-glucosaminidase sequence can be used to differentiate the species and isolates of Trichoderma. The expression of beta-1,6-glucanase is complex and at least three different sizes of beta-1,6-glucanase were detected from T. atroviride. The expression of beta-1,6-glucanase varied with carbon source and pH. Mycelia of plant pathogen regulated the expression of N-acetyl-beta-D-glucosaminidase. Two different sizes of N-acetyl-beta-D-glucosaminidase were detected when T. atroviride was grown with S. sclerotiorum and its filtrates. Only one N-acetyl-beta- D-glucosaminidase was detected with other pathogens, autoclaved mycelia or glucose. The expression of a 73 kDa N-acetyl-beta-D-glucosaminidase was contact-dependent and regulated by an extracellular factor.
  • Nutritional quality of large round bale silage as affected by compaction, color of wrap, or preservative in Southcentral Alaska

    Lussier, Charlotte L. (2007-05)
    Large round bale silage (LRBS), fermented hay, baled at 45-65% moisture content might be a better product than air-dried hay for farmers and ranchers in Southcentral Alaska. Variable weather and sometimes unfavorable conditions for drying hay to the required 18% moisture content makes high quality hay production unpredictable. Our study was designed to determine what practices might produce the highest nutritional quality LRBS. Treatments included using black and white plastic bale wrap, two different baler compaction levels, and application of a buffered propionic acid preservative. The study used four different forage fields over a two year period. Three fields were harvested on each cutting date. We measured dry matter (DM), neutral detergent fiber, acid detergent fiber, lignin, acid detergent insoluble nitrogen, crude protein, and digestible energy. Fermentation analysis measured levels of lactic, acetic, propionic and butyric acids, ammonia and pH on LRBS. The denser bales, bales wrapped in black plastic, and those treated with preservative produced highest quality forage. Dense bales had lower DM, lower pH, and also had the highest lactic acid. Ammonia levels declined when moisture content decreased.
  • Size-fractionation and characterization of cryoturbated soil organic matter in Arctic tundra, Alaska

    Xu, Chunhao (2005-12)
    Recent studies indicated a second layer of organic matter often accumulates in the lower active layer and upper permafrost in arctic tundra soils due to cryoturbation. The objective of this study is to characterize cryoturbated organic matter by the combination of physical size-fractionation approaches with modern analytical techniques. The results of elemental composition (C, N), stable isotope (¹³C, ¹⁵N), radiocarbon age (¹⁴C), and molecular fingerprints (Py-GC/MS) analysis indicated cryoturbated organic matters are little humified and highly bioavailable. SOM (soil organic matter) associated with fine sand size particles was considered to be the organic carbon pool most sensitive to the changing climate. Clay minerals stabilize less humifed organic matter than those in temperate and tropical soils. The bioavailable soluble organics extracted from cryoturbated organic matter were found to have significant long-term accumulated effects on carbon cycling. The similar molecular compositions between cryoturbated and surface organic matter suggest vegetation covers haven't changed since the early Holocene. Furthermore, the quality of SOM in moist acidic tundra is higher than that of wet nonacidic tundra. With the deepening active layer followed by thawing permafrost, cryoturbated organic matter could reenter the biogeochemical cycles in the Arctic, resulting in a positive feedback to climate change.
  • Soil properties and forest stand characteristics along a toposequence of the Smith Lake area near Fairbanks, Alaska

    Zhu, Lijie (2004-12)
    Forests, soils and their relationships were studied along a toposequence over an elevation range from 161 meters to 213 meters near Smith Lake on the University of Alaska Fairbanks campus, Fairbanks, Alaska. Forest cover type and understory species composition change along the slope from top to bottom and are related to temperature and moisture. Aspen occurs on the ridge top. Paper birch grows best on the shoulder. White spruce, which has the greatest commercial value, is the only species present on all slope positions; it grows best on shoulder and back slopes. Black spruce dominates on the wet and cold top slope that has a thick organic layer. Organic horizon depth increases, whereas rooting depth decreases, along the toposequence from the shoulder slope to the top slope. Soil textures are mainly silt loam and fine sandy loam with slightly acidic reactions in the surface mineral horizons to calcareous reactions in subsoils. Organic carbon is concentrated in the surface organic horizons and the surface mineral horizons and decreases drastically in the subsurface horizons. This thesis was an exploratory effort; although soil properties along the Smith Lake toposequence cannot be used as quantitative predictors of forest productivity, the qualitative results provide a basis for matching species to site.
  • An investigation of soil-plant and plant-animal mineral nutrition landscapes of agricultural areas in the Fairbanks and Delta Junction regions of Interior Alaska

    Andrews, Robin N. (2004-05)
    I attempted to identify biologically limiting minerals and assess mineral variability by collecting soil and plant samples in June, July, and August from 14 bromegrass fields and adjacent woodlands, in the Fairbanks and Delta Junction regions. Soil extractable P, K, Ca, Mg, Al, B, Cd, Co, Cr, Cu, Fe, Mn, Pb, Zn, NO⁻³ and NH⁴ as well as pH and organic matter content were measured at three depths. Bromus inermis, Calamagrostis canadensis, Epilobium angustifolium and Salix alaxensis were analyzed for N, P, K, S, Ca, Mg, Al, B, Cd, Cu, Fe, Mn, and Zn. Plant sample variability was assessed by species, date, and location. Mineral content of plants and soils among locations was highly variable with proximate sites showing little similarity. Local differences seemed more important than regional variation in determining soil and plant mineral abundances. Plant mineral content was highly affected by species, date, and location. With the exception of magnesium, plant mineral content was generally not correlated with extractable soil minerals. In most cases, organic matter content and pH were generally not correlated with plant mineral content. Plants, in these regions, may be limited by sulfur, magnesium, and boron availability. High levels of manganese and cadmium in some plant species and low levels of copper and possibly zinc in late season forages may negatively affect herbivores.
  • Foxtail barley (Hordeum jubatum) control with propoxycarbazone-sodium and fluazifop-p-butyl in three Alaska Native grass species

    Jackson, Brian Earl (2007-08)
    Foxtail barley is one of the most detrimental weeds for the Alaska native grass seed industry. Its control is essential for improving seed production and stand longevity so producers can meet statewide seed demands. The objective of this study was to determine suitable chemical controls of foxtail barley for three different native grass species: 'Nortran' tufted hairgrass (Deschampsia caespitosa L.), 'Gruening' alpine bluegrass (Poa alpina L.), and 'Wainwright' slender wheatgrass (Elymus trachycalus L.) formerly (Agropyron pauciflorum L.). Field and greenhouse experiments were performed to identify selectivity between two herbicide compounds and the crops studied. Foxtail barley was extremely sensitive to both compounds at the 1X rate whereas 'Nortran' tufted hairgrass was tolerant of propoxycarbazone. 'Gruening' alpine bluegrass and 'Wainwright' slender wheatgrass were not tolerant of either compound at the full rate but showed greater tolerance of propoxycarbazone at the 1/2X rate. Propoxycarbazone is a potential tool for foxtail barley control in all three native grass species used for seed production in Alaska.
  • Nitrogen fertilization of smooth bromegrass in Interior and Southcentral Alaska

    Howard, Natalie D. (2007-12)
    Although forage crops occupy the majority of agricultural land in Alaska, best fertilizer management practices to maximize forage yield and quality in Alaska are not well established. The objective of this study was to determine optimum time and rate of nitrogen (N) fertilizer applications to produce high yields of high quality forage in interior and Southcentral Alaska from smooth bromegrass (Bromus inermus). Nine N fertilization treatments, differing in rate and time of application, were applied at four sites. Forage samples were harvested twice per season in 1999 and 2000 to obtain yield and quality values. Nitrogen applied at 225 kg ha⁻¹ produced greater yields than N applied at 125 kg ha⁻¹, but there were no significant differences between single and split applications. Yield and crude protein content of the control were significantly lower than plots receiving N treatment. Midseason application of N increased crude protein percentages in second cuts at most sites. Acid and neutral detergent fiber were not affected by N treatment. N fertilizer use appeared to be more efficient for split applications, but no significant differences were found. This study showed potential for the production of high yielding, good quality grass forages in Alaska under a variety of N fertilizer strategies.
  • Clay mineralogy and soil formation in moist acidic tundra and moist nonacidic tundra of northern Sagwon HLS, Alaska

    Borden, Patrick William (2006-05)
    Clay mineralogy, physical and chemical characteristics were studied in three sites of moist acidic tundra (MAT) and three sites in moist nonacidic tundra (MNT) in the Northern Sagwon Hills, Alaska. The major similarities found in physical characteristics between MAT and MNT were color, field texture and consistence. Dissimilarities were in the depth, boundary and thickness of the horizons as well as soil structure. The major similarities found in chemical characteristics across MAT and MNT were in % carbon and nitrogen, ammonium phosphorus, iron and aluminum contents. The major dissimilarities were in pH, cation exchange capacity, nitrate and base saturation. Upper horizon pH in MAT was lower than MNT while deeper horizons had similar pH's. The mean average annual soil temperature was around -5°C in both MAT and MNT. The most common clay minerals found were illite, vermiculite and kaolinite. Kaolinite was determined to be detrital, not neoformed. Vermiculite from weathered illite was determined to be the most significant weathering product. The study also determined that the proportion of vermiculite to illite was higher in MAT and the illite to vermiculite proportion was higher in MNT. This finding showed that soil acidity does affect weathering reactions despite the low soil temperature.
  • High tunnel production of lettuce (Lactuca sativa) and snap beans (Phaseolus vulgaris l.) in a High Latitude location

    Rader, Heidi B.; Karlsson, Meriam; Zhang, Mingchu; Smeenk, Jeffrey (University of Alaska Fairbanks, 2006-12)
    Fairbanks, Alaska (lat. 64°49’N) has a short, variable growing season which necessitates alternative growing techniques for reliable vegetable production. Air and soil temperatures, relative humidity, light penetration, and management requirements were evaluated for a double bay high tunnel [15.8 m wide × 3.7 m high × 14.6 m long]. Mean air temperature was 0.5 °C and soil 1.2 °C higher in the high tunnel than the adjacent field, but differences varied with ventilation and heating practices. Yield and growth characteristics of lettuce (Lactuca sativa: ‘Paris Island cos’ and ‘Two Star’) and snap beans (Phaseolus vulgaris L.: ‘Concesa’ and ‘Provider’) were evaluated. Lettuce was frost hardy in the open field, prone to bolting in the high tunnel, and in general did not benefit from the high tunnel environment, except in quality due to cleanliness. ‘Concesa’ produced significantly more in the high tunnel compared with the field (P < 0.005). ‘Provider’, produced more in the high tunnel in 2006 compared to the field, but differences were not statistically significant over two seasons. The perceived benefits of high tunnel production included protection from frost, wind, pest, and rain, improved yields depending on crop and cultivar, and decreased weed emergence and moisture accumulation.