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• 661. [Article] Developing a Real-Time PCR Assay for Detection and Quantification of Pratylenchus neglectus in Soil

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by The American ...

  Citation × Citation Citation Abstract Copy Title: Developing a Real-Time PCR Assay for Detection and Quantification of Pratylenchus neglectus in Soil Author: Smiley, Richard W., Okubara, Patricia A., Reardon, Catherine L., Yan, Guiping, Skantar, Andrea M. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by The American Phytopathological Society and can be found at: https://www.apsnet.org/publications/Pages/default.aspx. Title: Developing a Real-Time PCR Assay for Detection and Quantification of Pratylenchus neglectus in Soil Author: Smiley, Richard W., Okubara, Patricia A., Reardon, Catherine L., Yan, Guiping, Skantar, Andrea M. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by The American Phytopathological Society and can be found at: https://www.apsnet.org/publications/Pages/default.aspx. Close

• 662. [Article] Effect of Brassicaceae seed meals with different glucosinolate profiles on Rhizoctonia root rot in wheat

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier ...

  Citation × Citation Citation Abstract Copy Title: Effect of Brassicaceae seed meals with different glucosinolate profiles on Rhizoctonia root rot in wheat Author: Mazzola, Mark, Handiseni, Maxwell, Zemetra, Robert, Brown, Jack To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.elsevier.com/. Title: Effect of Brassicaceae seed meals with different glucosinolate profiles on Rhizoctonia root rot in wheat Author: Mazzola, Mark, Handiseni, Maxwell, Zemetra, Robert, Brown, Jack To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.elsevier.com/. Close

• 663. [Article] The effect of seeding time on the heading and yield of wheat in the Willamette Valley

  Wheat is an important cereal crop in the Willamette Valley of Oregon and the stiff-strawed, high yielding winter varieties are the predominate types grown although spring varieties are not uncommon. Because ...

  Citation × Citation Citation Abstract Copy Title: The effect of seeding time on the heading and yield of wheat in the Willamette Valley Author: al-Falahi, Tariq Salih Wheat is an important cereal crop in the Willamette Valley of Oregon and the stiff-strawed, high yielding winter varieties are the predominate types grown although spring varieties are not uncommon. Because of the mild, often open winters; present in the Willamette, it is not unusual to be able to seed wheat almost every month from early fall until late spring. The purpose of these studies was to determine the cold requirement and critical heading period of some important winter wheat varieties. The cold requirement and critical heading period was measured by determining the extent that each of the winter varieties would develop heads from various planting dates from late fall until early summer. Results were obtained on the percentage of heading for each variety in the 1961-62 trial and for heading and yields in bushels per acre in the 1962-63 trial. The critical seeding date was determined for each variety and a comparison was made between the two years. The new winter wheat variety, Gaines, had the highest average yield from all dates of seeding for the winter varieties and Gaines likewise had the highest yield from the latest date of seeding in the spring. There was more variation in the critical heading periods in 1961-62 than in 1962-63. Redmond showed the greatest variation between the two years. The critical period for yield was earlier than the critical period for heading. The results also showed lack of agreement between the winter hardiness of the winter varieties and the critical heading period. Title: The effect of seeding time on the heading and yield of wheat in the Willamette Valley Author: al-Falahi, Tariq Salih Wheat is an important cereal crop in the Willamette Valley of Oregon and the stiff-strawed, high yielding winter varieties are the predominate types grown although spring varieties are not uncommon. Because of the mild, often open winters; present in the Willamette, it is not unusual to be able to seed wheat almost every month from early fall until late spring. The purpose of these studies was to determine the cold requirement and critical heading period of some important winter wheat varieties. The cold requirement and critical heading period was measured by determining the extent that each of the winter varieties would develop heads from various planting dates from late fall until early summer. Results were obtained on the percentage of heading for each variety in the 1961-62 trial and for heading and yields in bushels per acre in the 1962-63 trial. The critical seeding date was determined for each variety and a comparison was made between the two years. The new winter wheat variety, Gaines, had the highest average yield from all dates of seeding for the winter varieties and Gaines likewise had the highest yield from the latest date of seeding in the spring. There was more variation in the critical heading periods in 1961-62 than in 1962-63. Redmond showed the greatest variation between the two years. The critical period for yield was earlier than the critical period for heading. The results also showed lack of agreement between the winter hardiness of the winter varieties and the critical heading period. Close

• 664. [Article] Sweet corn (Zea mays L.) production in a white clover (Trifolium repens L.) living mulch : the establishment year

  Oregon sweet corn growers face high fertilizer, fuel and weed control costs; soil compaction, erosion, organic matter and nutrient depletion; and difficult equipment operations in muddy fields. An alternative ...

  Citation × Citation Citation Abstract Copy Title: Sweet corn (Zea mays L.) production in a white clover (Trifolium repens L.) living mulch : the establishment year Author: Cooper, Alan S. Oregon sweet corn growers face high fertilizer, fuel and weed control costs; soil compaction, erosion, organic matter and nutrient depletion; and difficult equipment operations in muddy fields. An alternative production system might ease some of these problems. Testing was begun to evaluate a living-mulch cropping system for sweet corn (Zea mays L. 'Golden Jubliee') production in Western Oregon. Several establishment-year management options for growing sweet corn with white clover (Trifolium repens L. 'New Zealand') were tested at three Willamette Valley, Oregon locations. Production practices tested were: fall, spring, or summer clover seeding; weed control prior to clover planting with (a) EPTC (S-ethyl dipropylthiocarbamate), (b) vernolate (S-propyl dipropylthiocarbamate) or (c) no control; and clover suppression with (a) atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)- s-triazine), (b) PP333 H2RS,3RS)-1-(4-chloropheny1)-4,4- dimethyl-2-1,2,4-triazol-l-y1-)pentan-3-01), (c) mowing, or (d) no suppression. Combinations of these practices were compared with conventional corn production. Fall clover planting resulted in the most ground cover and fewest weeds by summer. Plots where preplant herbicides were applied had fewer grasses but more broadleaf weeds compared to plots not receiving a preplant herbicide application. There was no identified change in corn yield resulting from the level of weed infestation. Where clover was most vigorous, suppression was necessary to avoid corn yield reductions. Atrazine proved most effective in reducing clover growth and allowing corn yields comparable to conventional practices. Yield reductions due to management system occurred at one location, and only where the clover received no suppression treatment. As the clover becomes better established, more severe suppression will probably be necessary to avoid corn yield reductions. Casual observations indicated increasing populations of rodents. Some form of control may be required. Overall results indicate that the system has potential to reduce erosion and suppress weeds and it may be an alternative to conventional sweet corn production in the area tested. Title: Sweet corn (Zea mays L.) production in a white clover (Trifolium repens L.) living mulch : the establishment year Author: Cooper, Alan S. Oregon sweet corn growers face high fertilizer, fuel and weed control costs; soil compaction, erosion, organic matter and nutrient depletion; and difficult equipment operations in muddy fields. An alternative production system might ease some of these problems. Testing was begun to evaluate a living-mulch cropping system for sweet corn (Zea mays L. 'Golden Jubliee') production in Western Oregon. Several establishment-year management options for growing sweet corn with white clover (Trifolium repens L. 'New Zealand') were tested at three Willamette Valley, Oregon locations. Production practices tested were: fall, spring, or summer clover seeding; weed control prior to clover planting with (a) EPTC (S-ethyl dipropylthiocarbamate), (b) vernolate (S-propyl dipropylthiocarbamate) or (c) no control; and clover suppression with (a) atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)- s-triazine), (b) PP333 H2RS,3RS)-1-(4-chloropheny1)-4,4- dimethyl-2-1,2,4-triazol-l-y1-)pentan-3-01), (c) mowing, or (d) no suppression. Combinations of these practices were compared with conventional corn production. Fall clover planting resulted in the most ground cover and fewest weeds by summer. Plots where preplant herbicides were applied had fewer grasses but more broadleaf weeds compared to plots not receiving a preplant herbicide application. There was no identified change in corn yield resulting from the level of weed infestation. Where clover was most vigorous, suppression was necessary to avoid corn yield reductions. Atrazine proved most effective in reducing clover growth and allowing corn yields comparable to conventional practices. Yield reductions due to management system occurred at one location, and only where the clover received no suppression treatment. As the clover becomes better established, more severe suppression will probably be necessary to avoid corn yield reductions. Casual observations indicated increasing populations of rodents. Some form of control may be required. Overall results indicate that the system has potential to reduce erosion and suppress weeds and it may be an alternative to conventional sweet corn production in the area tested. Close

• 665. [Article] Influence of grazing and nitrogen fertilization on winter growth, seed and straw production of Lolium multiflorum Lam

  The influence of grazing closing dates and form and amount of nitrogen fertilizer on Gulf annual and Oregon annual ryegrass was studied at locations in the Willamette Valley of Oregon. Closing dates were ...

  Citation × Citation Citation Abstract Copy Title: Influence of grazing and nitrogen fertilization on winter growth, seed and straw production of Lolium multiflorum Lam Author: Herron, Gordon Richard The influence of grazing closing dates and form and amount of nitrogen fertilizer on Gulf annual and Oregon annual ryegrass was studied at locations in the Willamette Valley of Oregon. Closing dates were established as mid-April, and May 1 together with ungrazed plots for comparison. Fertility consisted of a single 207.2 kgN/ha application February 1 of sulfur coated urea (SCU-30, a recent development of TVA); 207.2 kgN/ha in the form of ammonium sulfate applied in split applications during the trial; and a single application May 1 of 140 kgN/ha in the form of ammonium sulfate. Considerable total seed yield and seed size reductions were caused by late grazing of both varieties but little effect was induced by fertility variables. Crop residue in the form of straw was considerably reduced by later closing dates in both varieties. Later applications of nitrogen regardless of form tended to increase amounts of straw, The number of fertile tillers per unit area was significantly increased by later closing dates on Oregon annual ryegrass but significantly decreased in the Gulf annual variety. Another factor affected by later closing dates was the number of spikelets per spike which was significantly decreased in both varieties. The number of spikelets per spike was significantly increased by application of sulfur-coated urea. The largest amount of forage produced for grazing was achieved from treatments of SCU-30 applied at beginning of grazing February 1. The least amount of vegetative growth was harvested from plots that received no nitrogen during grazing. Intermittent clipping in the same quadrats gave more yield than a final single clipping. It was evident from this research that the loss of seed yield due to grazing would be justified by the production of high quality forage. Also the addition of nitrogen fertilizer in late winter would increase available forage in quantities to offset the fertilizer cost. Title: Influence of grazing and nitrogen fertilization on winter growth, seed and straw production of Lolium multiflorum Lam Author: Herron, Gordon Richard The influence of grazing closing dates and form and amount of nitrogen fertilizer on Gulf annual and Oregon annual ryegrass was studied at locations in the Willamette Valley of Oregon. Closing dates were established as mid-April, and May 1 together with ungrazed plots for comparison. Fertility consisted of a single 207.2 kgN/ha application February 1 of sulfur coated urea (SCU-30, a recent development of TVA); 207.2 kgN/ha in the form of ammonium sulfate applied in split applications during the trial; and a single application May 1 of 140 kgN/ha in the form of ammonium sulfate. Considerable total seed yield and seed size reductions were caused by late grazing of both varieties but little effect was induced by fertility variables. Crop residue in the form of straw was considerably reduced by later closing dates in both varieties. Later applications of nitrogen regardless of form tended to increase amounts of straw, The number of fertile tillers per unit area was significantly increased by later closing dates on Oregon annual ryegrass but significantly decreased in the Gulf annual variety. Another factor affected by later closing dates was the number of spikelets per spike which was significantly decreased in both varieties. The number of spikelets per spike was significantly increased by application of sulfur-coated urea. The largest amount of forage produced for grazing was achieved from treatments of SCU-30 applied at beginning of grazing February 1. The least amount of vegetative growth was harvested from plots that received no nitrogen during grazing. Intermittent clipping in the same quadrats gave more yield than a final single clipping. It was evident from this research that the loss of seed yield due to grazing would be justified by the production of high quality forage. Also the addition of nitrogen fertilizer in late winter would increase available forage in quantities to offset the fertilizer cost. Close

• 666. [Article] Influence of nitrogen fertilization management on the bread making quality of different wheat genotypes

  Breadmaking quality is an important criterion in breeding and development of hard wheat (Triticum aestivum L.) cultivars. Improvements in N management are needed to produce superior quality grain and satisfy ...

  Citation × Citation Citation Abstract Copy Title: Influence of nitrogen fertilization management on the bread making quality of different wheat genotypes Author: Derényi, Marina Castro Breadmaking quality is an important criterion in breeding and development of hard wheat (Triticum aestivum L.) cultivars. Improvements in N management are needed to produce superior quality grain and satisfy market demands for protein content. Field experiments with three hard red and two hard white spring wheat cultivars were conducted in 1998 and 1999 at Corvallis and Pendleton, Oregon. Nitrogen rates were varied from 0 to 250 kg N ha⁻¹, applied all at planting, or split between planting and stem elongation. Resulting grain was evaluated for protein content, protein quality, dough handling, and bread-making quality. Grain protein content of the five cultivars increased with increasing levels of applied nitrogen. There was a concurrent improvement in bread-making quality, as indicated by increasing protein quality, loaf volume, loaf crumb score. Use of split nitrogen applications contributed to increased grain protein content at both the intermediate and high N rates. At the higher N rates, a split application had no apparent influence on protein quality. However, at intermediate N rates, a split application contributed to improvements in protein quality and loaf volume. Nitrogen use efficiency and wheat end-use quality can be improved by using split applications of nitrogen during the crop cycle. Title: Influence of nitrogen fertilization management on the bread making quality of different wheat genotypes Author: Derényi, Marina Castro Breadmaking quality is an important criterion in breeding and development of hard wheat (Triticum aestivum L.) cultivars. Improvements in N management are needed to produce superior quality grain and satisfy market demands for protein content. Field experiments with three hard red and two hard white spring wheat cultivars were conducted in 1998 and 1999 at Corvallis and Pendleton, Oregon. Nitrogen rates were varied from 0 to 250 kg N ha⁻¹, applied all at planting, or split between planting and stem elongation. Resulting grain was evaluated for protein content, protein quality, dough handling, and bread-making quality. Grain protein content of the five cultivars increased with increasing levels of applied nitrogen. There was a concurrent improvement in bread-making quality, as indicated by increasing protein quality, loaf volume, loaf crumb score. Use of split nitrogen applications contributed to increased grain protein content at both the intermediate and high N rates. At the higher N rates, a split application had no apparent influence on protein quality. However, at intermediate N rates, a split application contributed to improvements in protein quality and loaf volume. Nitrogen use efficiency and wheat end-use quality can be improved by using split applications of nitrogen during the crop cycle. Close

• 667. [Article] Identification and development of cultural practices for upland rice production systems for savanna soils of Colombia

  A great potential for increasing upland rice production exists in the savanna soils of Colombia. These vast areas are currently underutilized. However, they have good soil structure, flat topography, coupled ...

  Citation × Citation Citation Abstract Copy Title: Identification and development of cultural practices for upland rice production systems for savanna soils of Colombia Author: Leal-M, Dario A great potential for increasing upland rice production exists in the savanna soils of Colombia. These vast areas are currently underutilized. However, they have good soil structure, flat topography, coupled with sufficient and well distributed rainfall, making savanna soils ideal for upland rice cropping system. The major constraints to upland rice production in these soils are their low fertility and lack of appropriate technology for their management. The basic concept is to alleviate or overcome soil constraints by planting rice cultivars to Al toxicity and low native fertility, and obtaining reasonable, but not necessarily the maximum yield obtained with lowland or paddy rice. Upland rice production systems were evaluated in representative savanna soils of CRI La Libertad, Llanos Orientales, Colombia, during the rainy seasons of 1983 and 1984. Cultivars such as Perola, Tox 1011-4-2, IAC 47, IAC 165, IRAT 101 and Makalioka 34 showed a high yield potential and good level of resistance against the prevalent pests and diseases. They also have thick and deep roots which make them suitable for upland rice culture in savanna soils. They are tolerant to Al toxicity, and have good level of adaptation to acid-soil conditions. A second component of a successful rice production technology was the determination of appropiate rates of P an Ca. Based on plant tissue analyses and in grain yield, a fertilization rate of 150 Kg Ca/ha using dolomite, and 60 Kg P₂0₅/ha as concentrate superphosphate, appears to be adequate for acceptable yield levels on savanna soils. An additional component of the management system is to drill plant adapted rice cultivars in rows 15 cm apart, with a rate of seeding of 60 Kg/ha. Significantly higher yield was obtained with these cultural practices. Through the integration of these management practices a productive upland rice production technology can be developed and the incorporation of savanna soils to food production is feasible. Title: Identification and development of cultural practices for upland rice production systems for savanna soils of Colombia Author: Leal-M, Dario A great potential for increasing upland rice production exists in the savanna soils of Colombia. These vast areas are currently underutilized. However, they have good soil structure, flat topography, coupled with sufficient and well distributed rainfall, making savanna soils ideal for upland rice cropping system. The major constraints to upland rice production in these soils are their low fertility and lack of appropriate technology for their management. The basic concept is to alleviate or overcome soil constraints by planting rice cultivars to Al toxicity and low native fertility, and obtaining reasonable, but not necessarily the maximum yield obtained with lowland or paddy rice. Upland rice production systems were evaluated in representative savanna soils of CRI La Libertad, Llanos Orientales, Colombia, during the rainy seasons of 1983 and 1984. Cultivars such as Perola, Tox 1011-4-2, IAC 47, IAC 165, IRAT 101 and Makalioka 34 showed a high yield potential and good level of resistance against the prevalent pests and diseases. They also have thick and deep roots which make them suitable for upland rice culture in savanna soils. They are tolerant to Al toxicity, and have good level of adaptation to acid-soil conditions. A second component of a successful rice production technology was the determination of appropiate rates of P an Ca. Based on plant tissue analyses and in grain yield, a fertilization rate of 150 Kg Ca/ha using dolomite, and 60 Kg P₂0₅/ha as concentrate superphosphate, appears to be adequate for acceptable yield levels on savanna soils. An additional component of the management system is to drill plant adapted rice cultivars in rows 15 cm apart, with a rate of seeding of 60 Kg/ha. Significantly higher yield was obtained with these cultural practices. Through the integration of these management practices a productive upland rice production technology can be developed and the incorporation of savanna soils to food production is feasible. Close

• 668. [Article] The volcanic stratigraphy of the Mickey Hot Springs area, Harney County, Oregon

  Steens Mountain is a major horst block near the northern terminus of the Basin and Range geomorphic province of southeastern Oregon. A section of Miocene volcanic rocks totaling 5000 feet in thickness ...

  Citation × Citation Citation Abstract Copy Title: The volcanic stratigraphy of the Mickey Hot Springs area, Harney County, Oregon Author: Hook, Richard Steens Mountain is a major horst block near the northern terminus of the Basin and Range geomorphic province of southeastern Oregon. A section of Miocene volcanic rocks totaling 5000 feet in thickness are exposed in a fault escarpment on the eastern side of Steens Nountain. These include: the Pike Creek Formation, consisting of rhyolite and dacite flows and tuffs about 1000 feet in thickness, including one rhyolite ignimbrite locally 900 feet thick; the Andesite Series (also known as Steens Mountain Volcanics), a sequence of andesite and basaltic andesite flows totaling about 1500 feet in thickness; Steens Basalt, a series of 15 million year old high-alumina olivine basalt flows totaling about 3000 feet in thickness, which crop out extensively in southeastern Oregon. Steens Basalt also crops out in the Mickey Hot Springs area, 16 miles east of Steens Mountain, where it is overlain by a thin, continuous ignimbrite and a younger basalt, here informally named Mickey basalt. The basalts of Steens Mountain were compared to those o the Mickey Rot Springs area. Correlation is established on the basis of a paleomagnetic reversal observed in the two areas, and supported by petrologic observations and chemical analysis. A large circular fault basin north of Mickey Hot Springs is suggestive of a collapsed caldera structure. The great thickness of a rhyolite ignimbrite in the Pike Creek formation may have been deposited in a rhyolite-flood eruption associated with a caldera collapse, creating a structure such as the one north of Mickey Hot Springs. Title: The volcanic stratigraphy of the Mickey Hot Springs area, Harney County, Oregon Author: Hook, Richard Steens Mountain is a major horst block near the northern terminus of the Basin and Range geomorphic province of southeastern Oregon. A section of Miocene volcanic rocks totaling 5000 feet in thickness are exposed in a fault escarpment on the eastern side of Steens Nountain. These include: the Pike Creek Formation, consisting of rhyolite and dacite flows and tuffs about 1000 feet in thickness, including one rhyolite ignimbrite locally 900 feet thick; the Andesite Series (also known as Steens Mountain Volcanics), a sequence of andesite and basaltic andesite flows totaling about 1500 feet in thickness; Steens Basalt, a series of 15 million year old high-alumina olivine basalt flows totaling about 3000 feet in thickness, which crop out extensively in southeastern Oregon. Steens Basalt also crops out in the Mickey Hot Springs area, 16 miles east of Steens Mountain, where it is overlain by a thin, continuous ignimbrite and a younger basalt, here informally named Mickey basalt. The basalts of Steens Mountain were compared to those o the Mickey Rot Springs area. Correlation is established on the basis of a paleomagnetic reversal observed in the two areas, and supported by petrologic observations and chemical analysis. A large circular fault basin north of Mickey Hot Springs is suggestive of a collapsed caldera structure. The great thickness of a rhyolite ignimbrite in the Pike Creek formation may have been deposited in a rhyolite-flood eruption associated with a caldera collapse, creating a structure such as the one north of Mickey Hot Springs. Close

• 669. [Article] Identification of restoration potential on southwestern Oregon rangelands

  The objectives of this research were to 1) evaluate the establishment and peak standing crop of Berber Orchardgrass (Dactylis glomerata var. "Berber"), Palestine Orchardgrass (Dactylis glomerata var. "Palestine"), ...

  Citation × Citation Citation Abstract Copy Title: Identification of restoration potential on southwestern Oregon rangelands Author: Barrington, Mack R. The objectives of this research were to 1) evaluate the establishment and peak standing crop of Berber Orchardgrass (Dactylis glomerata var. "Berber"), Palestine Orchardgrass (Dactylis glomerata var. "Palestine"), and Sheep Fescue (Festuca ovina var. "Covar") ; 2) to assess establishment and production changes resulting from environmental gradients (elevation, slope, aspect, soil texture, precipitation, and resident annual community) across the foothill landscape; 3) develop a mathematical model that predicts site potential for restoration; and 4) evaluate the utility of Geographic Information Systems for creation and analysis of spatial data which identify site production potential. Sixteen sites were chosen which reflect the general character of the foothill rangelands in southwestern Oregon. A Randomized Complete Block design was used to select treatment arrangement on each site. Seeded treatments received both chemical (Glyphosate, Hoelon, and 2,4-D) and mechanical (residue removal) disturbance. Test species were seeded into three replications at each site. Each replication also included a non-treatment control. Standing crop data for test species and resident exotics were collected after three growing seasons. Berber orchardgrass did not establish at most sites and where establishment did take place production was less than 132 kgDM/ha. Palestine orchardgrass established on on a majority of the study sites and produced most aboveground phytomass at mid-elevations where coarser soil textures and deeper soil depths were common. Sheep fescue was the most successful of the three test species and did best on low elevation high clay sites. There was significantly (P=0.001) more phytomass produced by annual exotics on seeded plots than on undisturbed controls at most sites. Both Palestine orchardgrass and sheep fescue treatments significantly suppressed the annual exotics when compared to the Berber treatments. Generally, "Covar" sheep fescue can establish and successfully compete with exotics on heavier textured soils at low elevations. "Palestine orchardgrass is adapted to mid-elevation coarser soils. Title: Identification of restoration potential on southwestern Oregon rangelands Author: Barrington, Mack R. The objectives of this research were to 1) evaluate the establishment and peak standing crop of Berber Orchardgrass (Dactylis glomerata var. "Berber"), Palestine Orchardgrass (Dactylis glomerata var. "Palestine"), and Sheep Fescue (Festuca ovina var. "Covar") ; 2) to assess establishment and production changes resulting from environmental gradients (elevation, slope, aspect, soil texture, precipitation, and resident annual community) across the foothill landscape; 3) develop a mathematical model that predicts site potential for restoration; and 4) evaluate the utility of Geographic Information Systems for creation and analysis of spatial data which identify site production potential. Sixteen sites were chosen which reflect the general character of the foothill rangelands in southwestern Oregon. A Randomized Complete Block design was used to select treatment arrangement on each site. Seeded treatments received both chemical (Glyphosate, Hoelon, and 2,4-D) and mechanical (residue removal) disturbance. Test species were seeded into three replications at each site. Each replication also included a non-treatment control. Standing crop data for test species and resident exotics were collected after three growing seasons. Berber orchardgrass did not establish at most sites and where establishment did take place production was less than 132 kgDM/ha. Palestine orchardgrass established on on a majority of the study sites and produced most aboveground phytomass at mid-elevations where coarser soil textures and deeper soil depths were common. Sheep fescue was the most successful of the three test species and did best on low elevation high clay sites. There was significantly (P=0.001) more phytomass produced by annual exotics on seeded plots than on undisturbed controls at most sites. Both Palestine orchardgrass and sheep fescue treatments significantly suppressed the annual exotics when compared to the Berber treatments. Generally, "Covar" sheep fescue can establish and successfully compete with exotics on heavier textured soils at low elevations. "Palestine orchardgrass is adapted to mid-elevation coarser soils. Close

• 670. [Article] Stand density in young red alder plantations : production, photosynthate partitioning, nitrogen fixation, and an optimal initial spacing model

  Dimension analysis, acetylene reduction and canopy structure measurements were used to evaluate the relationship between density and dry weight production, nitrogen (N₂) fixation and photosynthate partitioning ...

  Citation × Citation Citation Abstract Copy Title: Stand density in young red alder plantations : production, photosynthate partitioning, nitrogen fixation, and an optimal initial spacing model Author: Bormann, Bernard T. Dimension analysis, acetylene reduction and canopy structure measurements were used to evaluate the relationship between density and dry weight production, nitrogen (N₂) fixation and photosynthate partitioning (as indicated by dimension analysis) in 5-year-old red alder (Alnus rubra Bong.) plantations established at three initial spacings. Density strongly affected most dry weight components and N₂ fixation. Low density stands (9 x 9 ft initial spacing) had the highest values per tree for all measured weight, volume, and surface area components and N₂ fixation. Mid-density stands (4 x 6 ft initial spacing) had the highest per unit area values for leaf weight, canopy volume, branch weight and surface area, root and stump weight, net branch production, aboveground net production and N₂ fixation. The highest density stands (2 x 4 ft initial spacing) had the highest values per unit area of the variables:wood volume, bole and total aboveground dry weight and net bole production. Nodule weight per unit area was approximately equal in the mid- and high-density stands averaging 146 kg/ha. Correlation coefficients for dimension analysis were high (eg. leaf wt.: r =0.952; branch wt.: r =0.963; bole wt.: r =0.995; root wt.: r =0.971; nodule wt.: r =0.931). Stand density, as an independent variable, improved the correlation coefficient for many of these equations, indicating that density strongly affected photosynthate partitioning. The high correlation between per tree N₂ fixation and leaf weight (r =0.892) supports the hypothesis of Gordon and Wheeler (1978). Leaf weight and N₂ fixation per unit area (averaging 2.15 metric tons/ha and 70 kgha⁻¹yr⁻¹, respectively), however, were not highly correlated suggesting that less photosynthate was allocated to nodules in high density stands. Component net production to total aboveground net production ratios changed with density also suggesting that density strongly affects photosynthate allocation patterns. Crown structure related well to observed allocation patterns: a higher proportion of leaves close to the ground corresponded to higher N₂ fixation rates per tree. An optimal spacing model is proposed that may eventually aid in economic evaluation of alder plantation designs and rotations. The model predicts optimal spacings for wood products (pulpwood, sawlogs) and uses variables that are physiologically tied to competition-linked processes (live-crown-ratio, crown volume and leaf density). Estimated spacing for sawlogs is similar to that predicted in the literature but projected pulpwood spacing appears too close. Assumed live-crown-ratio seems to have the greatest effect on projected spacing but crown shape and leaf density are also important. It may be possible to modify the model to produce estimates of alder yield under management. Thus, it could aid in an economic evaluation of alder investment opportunities. Additional research, especially on live-crown-ratios, is needed before this model can be widely used. Title: Stand density in young red alder plantations : production, photosynthate partitioning, nitrogen fixation, and an optimal initial spacing model Author: Bormann, Bernard T. Dimension analysis, acetylene reduction and canopy structure measurements were used to evaluate the relationship between density and dry weight production, nitrogen (N₂) fixation and photosynthate partitioning (as indicated by dimension analysis) in 5-year-old red alder (Alnus rubra Bong.) plantations established at three initial spacings. Density strongly affected most dry weight components and N₂ fixation. Low density stands (9 x 9 ft initial spacing) had the highest values per tree for all measured weight, volume, and surface area components and N₂ fixation. Mid-density stands (4 x 6 ft initial spacing) had the highest per unit area values for leaf weight, canopy volume, branch weight and surface area, root and stump weight, net branch production, aboveground net production and N₂ fixation. The highest density stands (2 x 4 ft initial spacing) had the highest values per unit area of the variables:wood volume, bole and total aboveground dry weight and net bole production. Nodule weight per unit area was approximately equal in the mid- and high-density stands averaging 146 kg/ha. Correlation coefficients for dimension analysis were high (eg. leaf wt.: r =0.952; branch wt.: r =0.963; bole wt.: r =0.995; root wt.: r =0.971; nodule wt.: r =0.931). Stand density, as an independent variable, improved the correlation coefficient for many of these equations, indicating that density strongly affected photosynthate partitioning. The high correlation between per tree N₂ fixation and leaf weight (r =0.892) supports the hypothesis of Gordon and Wheeler (1978). Leaf weight and N₂ fixation per unit area (averaging 2.15 metric tons/ha and 70 kgha⁻¹yr⁻¹, respectively), however, were not highly correlated suggesting that less photosynthate was allocated to nodules in high density stands. Component net production to total aboveground net production ratios changed with density also suggesting that density strongly affects photosynthate allocation patterns. Crown structure related well to observed allocation patterns: a higher proportion of leaves close to the ground corresponded to higher N₂ fixation rates per tree. An optimal spacing model is proposed that may eventually aid in economic evaluation of alder plantation designs and rotations. The model predicts optimal spacings for wood products (pulpwood, sawlogs) and uses variables that are physiologically tied to competition-linked processes (live-crown-ratio, crown volume and leaf density). Estimated spacing for sawlogs is similar to that predicted in the literature but projected pulpwood spacing appears too close. Assumed live-crown-ratio seems to have the greatest effect on projected spacing but crown shape and leaf density are also important. It may be possible to modify the model to produce estimates of alder yield under management. Thus, it could aid in an economic evaluation of alder investment opportunities. Additional research, especially on live-crown-ratios, is needed before this model can be widely used. Close