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• 1331. [Article] Effects of 2-chloroethylphosphonic acid (Ethrel) and selected environmental factors on growth of quackgrass (Agropyron repens L. (Beauv.)) and field bindweed (Convolvulus arvensis L.)

  The primary purposes of these studies were to investigate: (1) the effects of air temperature, soil moisture, and supplemental light on sprouting ability of quackgrass (Agropyron repens L. (Beauv. )) rhizome ...

  Citation × Citation Citation Abstract Copy Title: Effects of 2-chloroethylphosphonic acid (Ethrel) and selected environmental factors on growth of quackgrass (Agropyron repens L. (Beauv.)) and field bindweed (Convolvulus arvensis L.) Author: Akhavein, Ali Asghar, 1931- The primary purposes of these studies were to investigate: (1) the effects of air temperature, soil moisture, and supplemental light on sprouting ability of quackgrass (Agropyron repens L. (Beauv. )) rhizome buds; (2) the influence of 2-chloroethylphosphonic acid (Ethrel) on growth, morphology, and regenerative capacity of quackgrass and field bindweed (Convolvulus arvensis L.); and (3) the efficacy of Ethrel in enhancing the phytotoxicity of a mixture of 3-aminos- triazole and ammonium thiocyanate (amitrol-T) and 2, 2 -dichloro propionic acid (dalapon) on the regenerative capacity of quackgrass rhizomes. The studies were carried out in a greenhouse or growth chambers. The percent sprouting of the single-node quackgrass rhizome buds was decreased if the plants were subjected to 70°F day and 60°F night air temperatures, a reduced level of light intensity, or severe soil moisture stress. Ethrel applied to mature quackgrass plants effectively induced the rhizome buds to grow and develop into either rhizome branches or into leafless, rhizome-like aerial shoots. The aerial shoots did not develop normal leaves for two to four weeks. Later, as the effect of Ethrel diminished, normal leaves developed on the upper parts of the new shoots. Higher rates of Ethrel (4 to 6 lb/A) were more effective in evoking growth of the rhizome buds than the lower rates, but the resulting shoots remained leafless for a longer time. A high level of soil-applied nutrients also induced growth of quackgrass rhizome buds. In this regard, the effect of Ethrel and high soil nutrient level was simply additive not synergistic. Ethrel applied to intact quackgrass plants or to its excised rhizome buds did not increase or decrease the percent sprouting of the single-node rhizome buds. But the excised rhizome buds from quackgrass plants growing at a high level of soil nutrients had a higher percent sprouting. Over a six-week period, Ethrel (6 lb/A) application doubled the fresh and the dry weight of the leaves plus the newly formed shoots, moderately reduced the dry weight but not the fresh weight of the rhizomes, and inhibited root growth of the treated quackgrass plants in comparison to the untreated plants. Pre-treating quackgrass plants with Ethrel did not enhance the effectiveness of amitrol-T, applied subsequently, as measured by the average weight of regrowth produced by the replanted rhizome segments. But Ethrel in combination with amitrol-T completely inhibited the rhizome segments of 60% to 80% of the plants from producing any regrowth. When amitrol-T alone was used, the rhizome segments of 30% to 50% of the plants failed to have any regrowth. The rhizome pieces from quackgrass plants treated with Ethrel and dalapon produced more regrowth dry weight than the rhizome segments obtained from similar plants treated with dalapon alone. The reason for this antagonistic relation between Ethrel and dalapon was not investigated. Mature field bindweed plants sprayed with Ethrel sustained severe to complete defoliation. Many of the existing stems also died. The rootstocks of these plants, especially those treated with 1.0 lb Ethrel/A, were stimulated to initiate numerous visible shoot-buds. The initiated buds close to the soil surface emerged and developed into aerial shoots with minute leaves and short internodes. The rootstocks of field bindweed plants were segmented and replanted to measure their regrowth potential. The segmented rootstocks from Ethrel (1.0 lb/A) treated plants produced three times as many shoots and five times as much regrowth dry weight than the untreated plants. The effects of low rates of Ethrel (1/4 to 1.0 lb/A) on shoot and root growth of young field bindweed were similar to those of mechanical defoliation or mowing. Title: Effects of 2-chloroethylphosphonic acid (Ethrel) and selected environmental factors on growth of quackgrass (Agropyron repens L. (Beauv.)) and field bindweed (Convolvulus arvensis L.) Author: Akhavein, Ali Asghar, 1931- The primary purposes of these studies were to investigate: (1) the effects of air temperature, soil moisture, and supplemental light on sprouting ability of quackgrass (Agropyron repens L. (Beauv. )) rhizome buds; (2) the influence of 2-chloroethylphosphonic acid (Ethrel) on growth, morphology, and regenerative capacity of quackgrass and field bindweed (Convolvulus arvensis L.); and (3) the efficacy of Ethrel in enhancing the phytotoxicity of a mixture of 3-aminos- triazole and ammonium thiocyanate (amitrol-T) and 2, 2 -dichloro propionic acid (dalapon) on the regenerative capacity of quackgrass rhizomes. The studies were carried out in a greenhouse or growth chambers. The percent sprouting of the single-node quackgrass rhizome buds was decreased if the plants were subjected to 70°F day and 60°F night air temperatures, a reduced level of light intensity, or severe soil moisture stress. Ethrel applied to mature quackgrass plants effectively induced the rhizome buds to grow and develop into either rhizome branches or into leafless, rhizome-like aerial shoots. The aerial shoots did not develop normal leaves for two to four weeks. Later, as the effect of Ethrel diminished, normal leaves developed on the upper parts of the new shoots. Higher rates of Ethrel (4 to 6 lb/A) were more effective in evoking growth of the rhizome buds than the lower rates, but the resulting shoots remained leafless for a longer time. A high level of soil-applied nutrients also induced growth of quackgrass rhizome buds. In this regard, the effect of Ethrel and high soil nutrient level was simply additive not synergistic. Ethrel applied to intact quackgrass plants or to its excised rhizome buds did not increase or decrease the percent sprouting of the single-node rhizome buds. But the excised rhizome buds from quackgrass plants growing at a high level of soil nutrients had a higher percent sprouting. Over a six-week period, Ethrel (6 lb/A) application doubled the fresh and the dry weight of the leaves plus the newly formed shoots, moderately reduced the dry weight but not the fresh weight of the rhizomes, and inhibited root growth of the treated quackgrass plants in comparison to the untreated plants. Pre-treating quackgrass plants with Ethrel did not enhance the effectiveness of amitrol-T, applied subsequently, as measured by the average weight of regrowth produced by the replanted rhizome segments. But Ethrel in combination with amitrol-T completely inhibited the rhizome segments of 60% to 80% of the plants from producing any regrowth. When amitrol-T alone was used, the rhizome segments of 30% to 50% of the plants failed to have any regrowth. The rhizome pieces from quackgrass plants treated with Ethrel and dalapon produced more regrowth dry weight than the rhizome segments obtained from similar plants treated with dalapon alone. The reason for this antagonistic relation between Ethrel and dalapon was not investigated. Mature field bindweed plants sprayed with Ethrel sustained severe to complete defoliation. Many of the existing stems also died. The rootstocks of these plants, especially those treated with 1.0 lb Ethrel/A, were stimulated to initiate numerous visible shoot-buds. The initiated buds close to the soil surface emerged and developed into aerial shoots with minute leaves and short internodes. The rootstocks of field bindweed plants were segmented and replanted to measure their regrowth potential. The segmented rootstocks from Ethrel (1.0 lb/A) treated plants produced three times as many shoots and five times as much regrowth dry weight than the untreated plants. The effects of low rates of Ethrel (1/4 to 1.0 lb/A) on shoot and root growth of young field bindweed were similar to those of mechanical defoliation or mowing. Close

• 1332. [Article] Height-diameter and volume equations, growth intercept and needle length site quality indicators, and yield equations for young ponderosa pine plantations in Neuquén, Patagonia, Argentina

  Ponderosa pine (Pinus ponderosa Dougl. ex Laws.) is the most widely planted species in the Patagonian Andes region of Argentina for economic development. However, information on site quality and yield ...

  Citation × Citation Citation Abstract Copy Title: Height-diameter and volume equations, growth intercept and needle length site quality indicators, and yield equations for young ponderosa pine plantations in Neuquén, Patagonia, Argentina Author: Gonda, Hector Eduardo Ponderosa pine (Pinus ponderosa Dougl. ex Laws.) is the most widely planted species in the Patagonian Andes region of Argentina for economic development. However, information on site quality and yield is so limited that potential forest investors and managers do not have a reliable basis on which to make sound decisions. To ameliorate this problem I completed five silvicultural studies in Neuquen, the northernmost province where ponderosa pine is planted. Data were collected in 127 stands throughout Neuquen. 1) Four height(H)-diameter(D) equations were tested and [math equation] was selected to predict individual tree H at the stand level. 2) Nineteen volume (V) equations were fitted with V = β₀+ β₁ D²H + β₂D + ε and V = β₀ + β₁D + β₂D² + ε selected to predict total inside-bark tree V when H data are and are not available respectively. The effect of crown ratio was not significant when added to D and H. A comparison demonstrated that trees of the same D and H appeared to have more volume in Neuquen than in western United States. 3) The ability of 13-growth intercepts to predict stand top height and crop height was examined between ages 12 and 20 years. A growth intercept index (GII) was developed to determine site quality based on the length of the five internodes starting at or above breast height. 4) The ability of needle length, measured around the bud on the terminal leader (TNL) and on the tip of first order lateral branches (LNL), to predict top height at age 20 was tested. A preliminary needle length index to determine site quality based on LNL was developed. 5) Yield equations based on stand age, GII, trees/ha (or basal area), and longitude, were developed. These equations predict higher volumes for Neuquén stands than those attained by highly productive California ponderosa pine plantations of the same age, dominant height, and trees/ha. Neuquén stands support very high stocking and they exhibit negligible mortality despite their very high basal areas and relative densities by North American standards. Title: Height-diameter and volume equations, growth intercept and needle length site quality indicators, and yield equations for young ponderosa pine plantations in Neuquén, Patagonia, Argentina Author: Gonda, Hector Eduardo Ponderosa pine (Pinus ponderosa Dougl. ex Laws.) is the most widely planted species in the Patagonian Andes region of Argentina for economic development. However, information on site quality and yield is so limited that potential forest investors and managers do not have a reliable basis on which to make sound decisions. To ameliorate this problem I completed five silvicultural studies in Neuquen, the northernmost province where ponderosa pine is planted. Data were collected in 127 stands throughout Neuquen. 1) Four height(H)-diameter(D) equations were tested and [math equation] was selected to predict individual tree H at the stand level. 2) Nineteen volume (V) equations were fitted with V = β₀+ β₁ D²H + β₂D + ε and V = β₀ + β₁D + β₂D² + ε selected to predict total inside-bark tree V when H data are and are not available respectively. The effect of crown ratio was not significant when added to D and H. A comparison demonstrated that trees of the same D and H appeared to have more volume in Neuquen than in western United States. 3) The ability of 13-growth intercepts to predict stand top height and crop height was examined between ages 12 and 20 years. A growth intercept index (GII) was developed to determine site quality based on the length of the five internodes starting at or above breast height. 4) The ability of needle length, measured around the bud on the terminal leader (TNL) and on the tip of first order lateral branches (LNL), to predict top height at age 20 was tested. A preliminary needle length index to determine site quality based on LNL was developed. 5) Yield equations based on stand age, GII, trees/ha (or basal area), and longitude, were developed. These equations predict higher volumes for Neuquén stands than those attained by highly productive California ponderosa pine plantations of the same age, dominant height, and trees/ha. Neuquén stands support very high stocking and they exhibit negligible mortality despite their very high basal areas and relative densities by North American standards. Close

• 1333. [Article] The link between nitrogen cycling and soil microbial community composition in forest soils of western Oregon

  The objectives of this thesis were to examine the links between soil microbial community composition and function using the nitrogen (N) cycle as a model for these interactions and to assess the impact ...

  Citation × Citation Citation Abstract Copy Title: The link between nitrogen cycling and soil microbial community composition in forest soils of western Oregon Author: Boyle, Stephanie A. The objectives of this thesis were to examine the links between soil microbial community composition and function using the nitrogen (N) cycle as a model for these interactions and to assess the impact of environmental factors such as microclimate, vegetation type, and nutrient availability on microbial diversity and N transformations in forest soils. The first study consisted of a reciprocal transfer experiment where soil cores were transferred between high-elevation forest and adjacent meadow environments. It focused on bacterial denitrifying communities by measuring denitrification enzyme activity and community composition as determined by terminal restriction fragment length polymorphism (T-RFLP) profiles targeting the gene for nitrous oxide reductase (nosZ). Results from this experiment showed that while transferring meadow soils into forests increased denitrification rate, denitrifying community composition did not appear to change after two years. The second study examined N cycling and microbial community composition in soils from 20-year-old experimental tree plantations with pure stands of Douglas fir (Pseudotsuga menziesii) and red alder (Alnus rubra) in a high- and a low-productivity forest. 15N isotope dilution was combined with antibiotics to assess the roles of bacteria and fungi in N mineralization and nitrification. Data showed that nitrification was a major sink for NH4+ in all soil types and bacteria were the primary nitrifiers. Increased ammonification following antibiotic additions suggested that organic N may be important for the growth of heterotrophic bacteria and fungi. Results of nitrification potential assays showed that most nitrification was acetylene insensitive (autotrophic). Community composition of ammonia-oxidizing bacteria and archaea were assessed by targeting bacterial and archaeal ammonia-monooxygenase (amoA) genes. The composition and population size of ammonia-oxidizing bacteria differed between Douglas fir and red alder and tended to group with Nitrosospira clusters 2 and 4. Archaeal amoA was only amplified from the high-productivity site and grouped with other archaeal clones from soil and estuary sediments. Environmental factors affected rates of N cycling within two years, but community compositional changes responded more slowly, e.g., nitrifying communities differed between 20-year-old tree stands. This suggests that if environmental changes persist they may lead to changes in microbial community composition. Title: The link between nitrogen cycling and soil microbial community composition in forest soils of western Oregon Author: Boyle, Stephanie A. The objectives of this thesis were to examine the links between soil microbial community composition and function using the nitrogen (N) cycle as a model for these interactions and to assess the impact of environmental factors such as microclimate, vegetation type, and nutrient availability on microbial diversity and N transformations in forest soils. The first study consisted of a reciprocal transfer experiment where soil cores were transferred between high-elevation forest and adjacent meadow environments. It focused on bacterial denitrifying communities by measuring denitrification enzyme activity and community composition as determined by terminal restriction fragment length polymorphism (T-RFLP) profiles targeting the gene for nitrous oxide reductase (nosZ). Results from this experiment showed that while transferring meadow soils into forests increased denitrification rate, denitrifying community composition did not appear to change after two years. The second study examined N cycling and microbial community composition in soils from 20-year-old experimental tree plantations with pure stands of Douglas fir (Pseudotsuga menziesii) and red alder (Alnus rubra) in a high- and a low-productivity forest. 15N isotope dilution was combined with antibiotics to assess the roles of bacteria and fungi in N mineralization and nitrification. Data showed that nitrification was a major sink for NH4+ in all soil types and bacteria were the primary nitrifiers. Increased ammonification following antibiotic additions suggested that organic N may be important for the growth of heterotrophic bacteria and fungi. Results of nitrification potential assays showed that most nitrification was acetylene insensitive (autotrophic). Community composition of ammonia-oxidizing bacteria and archaea were assessed by targeting bacterial and archaeal ammonia-monooxygenase (amoA) genes. The composition and population size of ammonia-oxidizing bacteria differed between Douglas fir and red alder and tended to group with Nitrosospira clusters 2 and 4. Archaeal amoA was only amplified from the high-productivity site and grouped with other archaeal clones from soil and estuary sediments. Environmental factors affected rates of N cycling within two years, but community compositional changes responded more slowly, e.g., nitrifying communities differed between 20-year-old tree stands. This suggests that if environmental changes persist they may lead to changes in microbial community composition. Close

• 1334. [Article] Owyhee Russet: A Variety with High Yields of U.S. No. 1 Tubers, Excellent Processing Quality, and Moderate Resistance to Fusarium Dry Rot (Fusarium solani var. coeruleum)

  This is the publisher’s final pdf. The published article is copyrighted by Springer for the Potato Association of America and can be found at: http://www.springerlink.com/content/1099-209x/. To the best ...

  Citation × Citation Citation Abstract Copy Title: Owyhee Russet: A Variety with High Yields of U.S. No. 1 Tubers, Excellent Processing Quality, and Moderate Resistance to Fusarium Dry Rot (Fusarium solani var. coeruleum) Author: Pavek, J. J., Feibert, E., Charlton, B. A., Brandt, T. L., Shock, C. C., Yilma, S., James, S. R., Novy, R. G., Stark, J. C., Brown, C. R., Karaagac, E., Whitworth, J. L., Leroux, L., Knowles, N. R., Culp, D., Vales, M. I., Mosley, A. R., Olsen, N., Corsini, D. L., Pavek, M. J., Hane, D. C. This is the publisher’s final pdf. The published article is copyrighted by Springer for the Potato Association of America and can be found at: http://www.springerlink.com/content/1099-209x/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Title: Owyhee Russet: A Variety with High Yields of U.S. No. 1 Tubers, Excellent Processing Quality, and Moderate Resistance to Fusarium Dry Rot (Fusarium solani var. coeruleum) Author: Pavek, J. J., Feibert, E., Charlton, B. A., Brandt, T. L., Shock, C. C., Yilma, S., James, S. R., Novy, R. G., Stark, J. C., Brown, C. R., Karaagac, E., Whitworth, J. L., Leroux, L., Knowles, N. R., Culp, D., Vales, M. I., Mosley, A. R., Olsen, N., Corsini, D. L., Pavek, M. J., Hane, D. C. This is the publisher’s final pdf. The published article is copyrighted by Springer for the Potato Association of America and can be found at: http://www.springerlink.com/content/1099-209x/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Close

• 1335. [Article] Development and application of SSR markers for measuring gene flow in Douglas-fir

  Gene flow is a major evolutionary force and an important factor in the breeding and conservation of forest trees. I studied the applicability of SSR markers for measuring pollen-mediated gene flow (i.e., ...

  Citation × Citation Citation Abstract Copy Title: Development and application of SSR markers for measuring gene flow in Douglas-fir Author: Slavov, Gancho Trifonov Gene flow is a major evolutionary force and an important factor in the breeding and conservation of forest trees. I studied the applicability of SSR markers for measuring pollen-mediated gene flow (i.e., pollen flow) in Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco). I developed SSR markers, tested alternative approaches for measuring pollen flow using SSR markers, then measured pollen contamination and characterized within-block mating patterns in one block of a seed orchard complex. Useful markers were developed from 4.1% of the SSR sequences screened. The 22 markers obtained are among the most informative genetic markers available for Douglas-fir. The observed heterozygosity and the number of alleles per marker averaged 0.855 (SE=0.020) and 23 (SE=1.6), respectively. Mistyping (i.e., false identification of genotypes) results in overestimating pollen flow. Requiring multiple mismatches for paternity exclusion, while assuring that the probability of detecting immigrant genotypes is high, results in accurate estimates of pollen flow. I developed and made available the Pollen Flow (PFL) computer program, which performs paternity exclusion and measures pollen flow based on multiple fatheroffspring mismatches. Pollen contamination was consistently high in all three years in which seed crops were sampled from the orchard block (mean = 35.3%). Levels of pollen contamination varied substantially among clones, and were significantly higher in clones with early female receptivity (mean = 55.5%) than in those with intermediate (mean = 36.4%) or late (mean = 28.3%) female receptivity. Seeds resulting from self-fertilization were rare (mean = 1.8%). Differences in the relative paternal contributions of the clones in the block were greater than ten-fold, and there was preferential mating among parents with similar floral phenology. Information from analyses of SSR data can be used to minimize pollen contamination and improve within-orchard mating patterns. Furthermore, SSRs can be used to advance knowledge of gene flow in natural populations. The availability of large sets of highly variable SSRs makes it possible to perform landscape-scale studies of gene flow and better understand the interactions between gene flow and adaptation. These studies will ultimately provide a basis for decisions in breeding and conservation programs. Title: Development and application of SSR markers for measuring gene flow in Douglas-fir Author: Slavov, Gancho Trifonov Gene flow is a major evolutionary force and an important factor in the breeding and conservation of forest trees. I studied the applicability of SSR markers for measuring pollen-mediated gene flow (i.e., pollen flow) in Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco). I developed SSR markers, tested alternative approaches for measuring pollen flow using SSR markers, then measured pollen contamination and characterized within-block mating patterns in one block of a seed orchard complex. Useful markers were developed from 4.1% of the SSR sequences screened. The 22 markers obtained are among the most informative genetic markers available for Douglas-fir. The observed heterozygosity and the number of alleles per marker averaged 0.855 (SE=0.020) and 23 (SE=1.6), respectively. Mistyping (i.e., false identification of genotypes) results in overestimating pollen flow. Requiring multiple mismatches for paternity exclusion, while assuring that the probability of detecting immigrant genotypes is high, results in accurate estimates of pollen flow. I developed and made available the Pollen Flow (PFL) computer program, which performs paternity exclusion and measures pollen flow based on multiple fatheroffspring mismatches. Pollen contamination was consistently high in all three years in which seed crops were sampled from the orchard block (mean = 35.3%). Levels of pollen contamination varied substantially among clones, and were significantly higher in clones with early female receptivity (mean = 55.5%) than in those with intermediate (mean = 36.4%) or late (mean = 28.3%) female receptivity. Seeds resulting from self-fertilization were rare (mean = 1.8%). Differences in the relative paternal contributions of the clones in the block were greater than ten-fold, and there was preferential mating among parents with similar floral phenology. Information from analyses of SSR data can be used to minimize pollen contamination and improve within-orchard mating patterns. Furthermore, SSRs can be used to advance knowledge of gene flow in natural populations. The availability of large sets of highly variable SSRs makes it possible to perform landscape-scale studies of gene flow and better understand the interactions between gene flow and adaptation. These studies will ultimately provide a basis for decisions in breeding and conservation programs. Close

• 1336. [Article] The utilization of school-owned property in the vocational agriculture curriculum

  There is a lack of available information concerning availability, usability and utilization of school-owned land in western Oregon, southwestern Washington and northwestern California. It would be helpful ...

  Citation × Citation Citation Abstract Copy Title: The utilization of school-owned property in the vocational agriculture curriculum Author: Atwood, Melvin Boyd There is a lack of available information concerning availability, usability and utilization of school-owned land in western Oregon, southwestern Washington and northwestern California. It would be helpful to know if land is available for agricultural use, how it is used, and ways that it can be used to give experience and background to students who wish to go into agricultural occupations. A survey was made of this area by sending questionnaires to high schools currently offering vocational agriculture in the school curriculum. Eighty-five percent of high schools receiving questionnaires returned them. Ten schools in western Oregon were personally visited and a check list type of questionnaire was used to obtain specific information. Those schools visited were using school-owned land for maximum instructional purposes first, work experience programs second, and money-making projects third. Most of the schools with large acreages of school land have a farm manager or the man with the most priority in the vocational agriculture department has released time to manage the school farm. Production on the individual school farm is determined by the type of soil, availability of help to plant and harvest crops, and the type of equipment owned. Trials are limited to small acreage except where fertilizer or spray programs are used. Two schools of the interviewed sample have land available for work experience programs. Schools using school land for money-making projects do this through the Future Farmers of America chapter. None of the sample schools visited have individuals using school land for their own monetary gain. Students in agricultural education who lack space or equipment for projects, use school-owned land for training and work experience. Nine of the schools visited work with the local implement dealer in securing equipment to operate school farms. Most instructors agreed that school farms should be used in the vocational agriculture department for instructional purposes. The school land should be close to school and used as part of the classroom instructional program. Work experience programs are ideal methods of teaching basic skills to non-farm students and should be a part of every high schools T vocational agriculture program. School farms should be used where the instructor is experienced, and the school has a farm manager to over see daily tasks, relieving the instructor to devote his time to instructional purposes. All instructors visited in the interview sample felt that the school should pay all bills and receive profit, if any, and that the school farm should become a part of the total instructional program in vocational agriculture. Departments using school land for Future Farmers of America chapter farms felt pressure from the community to pay for seed, fertilizer, and chemicals before harvest. Title: The utilization of school-owned property in the vocational agriculture curriculum Author: Atwood, Melvin Boyd There is a lack of available information concerning availability, usability and utilization of school-owned land in western Oregon, southwestern Washington and northwestern California. It would be helpful to know if land is available for agricultural use, how it is used, and ways that it can be used to give experience and background to students who wish to go into agricultural occupations. A survey was made of this area by sending questionnaires to high schools currently offering vocational agriculture in the school curriculum. Eighty-five percent of high schools receiving questionnaires returned them. Ten schools in western Oregon were personally visited and a check list type of questionnaire was used to obtain specific information. Those schools visited were using school-owned land for maximum instructional purposes first, work experience programs second, and money-making projects third. Most of the schools with large acreages of school land have a farm manager or the man with the most priority in the vocational agriculture department has released time to manage the school farm. Production on the individual school farm is determined by the type of soil, availability of help to plant and harvest crops, and the type of equipment owned. Trials are limited to small acreage except where fertilizer or spray programs are used. Two schools of the interviewed sample have land available for work experience programs. Schools using school land for money-making projects do this through the Future Farmers of America chapter. None of the sample schools visited have individuals using school land for their own monetary gain. Students in agricultural education who lack space or equipment for projects, use school-owned land for training and work experience. Nine of the schools visited work with the local implement dealer in securing equipment to operate school farms. Most instructors agreed that school farms should be used in the vocational agriculture department for instructional purposes. The school land should be close to school and used as part of the classroom instructional program. Work experience programs are ideal methods of teaching basic skills to non-farm students and should be a part of every high schools T vocational agriculture program. School farms should be used where the instructor is experienced, and the school has a farm manager to over see daily tasks, relieving the instructor to devote his time to instructional purposes. All instructors visited in the interview sample felt that the school should pay all bills and receive profit, if any, and that the school farm should become a part of the total instructional program in vocational agriculture. Departments using school land for Future Farmers of America chapter farms felt pressure from the community to pay for seed, fertilizer, and chemicals before harvest. Close

• 1337. [Article] A model for rating agricultural suitability of land parcels in western Oregon

  A model was developed that allows potential users to identify the agricultural suitability of parcels of land in western Oregon. Literature was reviewed regarding five possible benefits to be derived from ...

  Citation × Citation Citation Abstract Copy Title: A model for rating agricultural suitability of land parcels in western Oregon Author: Rogers, William Reinhold A model was developed that allows potential users to identify the agricultural suitability of parcels of land in western Oregon. Literature was reviewed regarding five possible benefits to be derived from public policies designed to preserve productive agricultural land. They are (1) the provision of sufficient cropland to supply the food needs of an expanding national and world population; (2) the maintenance of healthy local economies in predominantly agricultural areas; (3) the increased efficiency that results from more orderly urban development; (4) the reduction of resource misallocations resulting fromthe conversion of the better agricultural lands to other uses; (5) the provision of open space in rapidly urbanizing areas. Systems currently being used to identify productive agricultural land were also reviewed. Among these were the land capability classification system, the "prime" and "unique" farmlands criteria, and various numerical indices such as the corn suitability rating. A comprehensive compilation was made of all factors having potentially significant effects on agricultural land use. Similar factors were grouped together and a model was developed incorporating the most important of these factors. Specific criteria were developed for evaluating the effects of the factors. The workability of the model was determined by applying it in several test areas and through numerous consultations. The model itself was developed in the form of a branching flow chart. After an initial question regarding commitment to other uses has been answered, the procedure involves the determination of two separate scores, one for soil productivity that ranges from 0-52 points and one for compatibility that ranges from 0- 48 points. The overall rating of agricultural suitability ranges from 0-100 points and is obtained by adding the two separate scores. Information needed to calculate the two scores is readily available. The determination of the soil productivity score requires use of crop yield data as well as irrigation and drainage information for soil map units. The determination of the compatibility score requires information about surrounding land uses and the location of the nearest urban growth boundary. To validate the model 43 parcels of land in six counties in western Oregon (Benton, Clackamas, Jackson, Lane, Marion and Tillamook) were selected as representative of six predetermined situations regarding soil productivity and extent of urban growth pressure. These situations were: (1) highly productive soils with little growth pressure; (2) highly productive soils with heavy growth pressure; (3) moderately productive soils with little growth pressure; (4) moderately productive soils with heavy growth pressure; (5) soils with relatively low productivity and little growth pressure; (6) soils with relatively low productivity and heavy growth pressure. The t test using pooled variances (Sp²) was used to determine whether differences between the means of the six situations were significant. The resulting analysis showed that when applying the model, those parcels with highly productive soils and little growth pressure had significantly higher total scores than all other parcels. Likewise, the parcels with soils of relatively low productivity and heavy growth pressure had the lowest scores. The other parcels fell somewhere in between. The model has several potential applications in Oregon. It can be used as a tool in evaluating the effects of changes in agricultural management, in evaluating the effects of land use decisions on surrounding agricultural lands, or in evaluating proposals for lot splits. It could also be used as part of the general long-range planning process. Other applications may be discovered by potential users as the need arises. Title: A model for rating agricultural suitability of land parcels in western Oregon Author: Rogers, William Reinhold A model was developed that allows potential users to identify the agricultural suitability of parcels of land in western Oregon. Literature was reviewed regarding five possible benefits to be derived from public policies designed to preserve productive agricultural land. They are (1) the provision of sufficient cropland to supply the food needs of an expanding national and world population; (2) the maintenance of healthy local economies in predominantly agricultural areas; (3) the increased efficiency that results from more orderly urban development; (4) the reduction of resource misallocations resulting fromthe conversion of the better agricultural lands to other uses; (5) the provision of open space in rapidly urbanizing areas. Systems currently being used to identify productive agricultural land were also reviewed. Among these were the land capability classification system, the "prime" and "unique" farmlands criteria, and various numerical indices such as the corn suitability rating. A comprehensive compilation was made of all factors having potentially significant effects on agricultural land use. Similar factors were grouped together and a model was developed incorporating the most important of these factors. Specific criteria were developed for evaluating the effects of the factors. The workability of the model was determined by applying it in several test areas and through numerous consultations. The model itself was developed in the form of a branching flow chart. After an initial question regarding commitment to other uses has been answered, the procedure involves the determination of two separate scores, one for soil productivity that ranges from 0-52 points and one for compatibility that ranges from 0- 48 points. The overall rating of agricultural suitability ranges from 0-100 points and is obtained by adding the two separate scores. Information needed to calculate the two scores is readily available. The determination of the soil productivity score requires use of crop yield data as well as irrigation and drainage information for soil map units. The determination of the compatibility score requires information about surrounding land uses and the location of the nearest urban growth boundary. To validate the model 43 parcels of land in six counties in western Oregon (Benton, Clackamas, Jackson, Lane, Marion and Tillamook) were selected as representative of six predetermined situations regarding soil productivity and extent of urban growth pressure. These situations were: (1) highly productive soils with little growth pressure; (2) highly productive soils with heavy growth pressure; (3) moderately productive soils with little growth pressure; (4) moderately productive soils with heavy growth pressure; (5) soils with relatively low productivity and little growth pressure; (6) soils with relatively low productivity and heavy growth pressure. The t test using pooled variances (Sp²) was used to determine whether differences between the means of the six situations were significant. The resulting analysis showed that when applying the model, those parcels with highly productive soils and little growth pressure had significantly higher total scores than all other parcels. Likewise, the parcels with soils of relatively low productivity and heavy growth pressure had the lowest scores. The other parcels fell somewhere in between. The model has several potential applications in Oregon. It can be used as a tool in evaluating the effects of changes in agricultural management, in evaluating the effects of land use decisions on surrounding agricultural lands, or in evaluating proposals for lot splits. It could also be used as part of the general long-range planning process. Other applications may be discovered by potential users as the need arises. Close

• 1338. [Article] Agricultural erosion and sediment in the western Willamette Valley as indicated by redistribution of Cesium-137

  Modern agricultural erosion was studied using ¹³⁷Cs from fallout as an indicator of erosion/deposition. The study area was a 285 ha agricultural watershed in the hilly western margin of the Willamette ...

  Citation × Citation Citation Abstract Copy Title: Agricultural erosion and sediment in the western Willamette Valley as indicated by redistribution of Cesium-137 Author: Brown, R. B. (Randall Barber) Modern agricultural erosion was studied using ¹³⁷Cs from fallout as an indicator of erosion/deposition. The study area was a 285 ha agricultural watershed in the hilly western margin of the Willamette Valley, a high winter rainfall zone in which fall-planted crops are commonly grown. Objectives of the study were (i) to identify, based on areal concentration and depth distribution of ¹³⁷Cs activity, those parts of the landscape that had been most severely eroded over the period of fallout (since early 1954), (ii) to identify, based likewise on ¹³⁷Cs signature, those parts of the landscape that had been subject to net deposition over the same period, and (iii) to quantify erosion rates over the fallout period. Along each of eight transects representing a variety of elevations, slope aspects, and slope gradients, sample sites were selected in ridgetop, steep sideslope, and concave footslope areas. Also sampled were a single convex ridge shoulder, a high ridgetop, two fencerow-controlled alluvial fans, two sites on a floodplain, and two sites in a farm pond built in 1971. Replicate soil cores were collected within a small (< 2 m²) area at each of the 32 sampling sites. Cores were cut into depth increments of 7.5, 10, or 15 cm increments. Corresponding increments from replicates at each site were lumped. Samples were analyzed at Oak Ridge National Laboratory for ¹³⁷Cs activity. Patterns of depth distributions of ¹³⁷Cs activity suggested strongly that ¹³⁷Cs had been retained in surface soils on the watershed and therefore was a good tracer in erosion/sediment studies. Cesium-137 signatures of sideslope sites and those of ridgetop sites were, on the average, indistinguishable from each other. Depositional sites, in contrast with both sideslopes and ridgetops, tended to have overthickened ¹³⁷Cs profiles and high total contents of ¹³⁷Cs. Average total ¹³⁷Cs activity in depositional sites was about 12 pCi/ cm². In sideslopes and ridgetops it was about 8 pCi/cm². Concave footslope positions are important zones of sediment storage. Two of eight footslopes sampled had ¹³⁷Cs signatures that did not reflect deposition, suggesting the existence of a dynamic deposition/re-entrainment environment in footslopes. The two alluvial fans sampled had strongly depositional ¹³⁷Cs signatures, but contained much less total sediment than did upstream footslopes. The two floodplain sites had not experienced net detectable deposition over the fallout period, which was indicative of a diffuse, thin spreading of sediment in the wide floodplain zone. Sites in the eight year old pond were marginally to strongly depositional. Two different approaches, "volumetric" and "gravimetric," were used to estimate post-1954 erosion rates in two nested watersheds, 6 and 13 ha in size. The "volumetric" approach involved calculation of the volume and mass of sediment currently residing in depositional zones, based on areal extent of the zone and depth of occurrence of ¹³⁷Cs in the zone. Erosion rate estimates by this technique ranged from 3 to 14 MT/ha/yr (1 to 6 T/a/yr). The "gravimetric" approach involved algebraic manipulation of measured areal concentrations of ¹³⁷Cs activity in depositional and non-depositional zones, to obtain estimates of the amount of depletion of fallout ¹³⁷Cs that had occurred in upland zones. Conversion of the ¹³⁷Cs loss to sediment loss yielded soil loss estimates ranging from 6 to 27 MT/ha/yr (3 to 12 T/a/yr). Imprecision in these estimates is great. But the estimates do indicate strongly that modern erosion rates, while not spectacular, have been great enough to warrant the use of appropriate conservation measures in hilly croplands of the region. Title: Agricultural erosion and sediment in the western Willamette Valley as indicated by redistribution of Cesium-137 Author: Brown, R. B. (Randall Barber) Modern agricultural erosion was studied using ¹³⁷Cs from fallout as an indicator of erosion/deposition. The study area was a 285 ha agricultural watershed in the hilly western margin of the Willamette Valley, a high winter rainfall zone in which fall-planted crops are commonly grown. Objectives of the study were (i) to identify, based on areal concentration and depth distribution of ¹³⁷Cs activity, those parts of the landscape that had been most severely eroded over the period of fallout (since early 1954), (ii) to identify, based likewise on ¹³⁷Cs signature, those parts of the landscape that had been subject to net deposition over the same period, and (iii) to quantify erosion rates over the fallout period. Along each of eight transects representing a variety of elevations, slope aspects, and slope gradients, sample sites were selected in ridgetop, steep sideslope, and concave footslope areas. Also sampled were a single convex ridge shoulder, a high ridgetop, two fencerow-controlled alluvial fans, two sites on a floodplain, and two sites in a farm pond built in 1971. Replicate soil cores were collected within a small (< 2 m²) area at each of the 32 sampling sites. Cores were cut into depth increments of 7.5, 10, or 15 cm increments. Corresponding increments from replicates at each site were lumped. Samples were analyzed at Oak Ridge National Laboratory for ¹³⁷Cs activity. Patterns of depth distributions of ¹³⁷Cs activity suggested strongly that ¹³⁷Cs had been retained in surface soils on the watershed and therefore was a good tracer in erosion/sediment studies. Cesium-137 signatures of sideslope sites and those of ridgetop sites were, on the average, indistinguishable from each other. Depositional sites, in contrast with both sideslopes and ridgetops, tended to have overthickened ¹³⁷Cs profiles and high total contents of ¹³⁷Cs. Average total ¹³⁷Cs activity in depositional sites was about 12 pCi/ cm². In sideslopes and ridgetops it was about 8 pCi/cm². Concave footslope positions are important zones of sediment storage. Two of eight footslopes sampled had ¹³⁷Cs signatures that did not reflect deposition, suggesting the existence of a dynamic deposition/re-entrainment environment in footslopes. The two alluvial fans sampled had strongly depositional ¹³⁷Cs signatures, but contained much less total sediment than did upstream footslopes. The two floodplain sites had not experienced net detectable deposition over the fallout period, which was indicative of a diffuse, thin spreading of sediment in the wide floodplain zone. Sites in the eight year old pond were marginally to strongly depositional. Two different approaches, "volumetric" and "gravimetric," were used to estimate post-1954 erosion rates in two nested watersheds, 6 and 13 ha in size. The "volumetric" approach involved calculation of the volume and mass of sediment currently residing in depositional zones, based on areal extent of the zone and depth of occurrence of ¹³⁷Cs in the zone. Erosion rate estimates by this technique ranged from 3 to 14 MT/ha/yr (1 to 6 T/a/yr). The "gravimetric" approach involved algebraic manipulation of measured areal concentrations of ¹³⁷Cs activity in depositional and non-depositional zones, to obtain estimates of the amount of depletion of fallout ¹³⁷Cs that had occurred in upland zones. Conversion of the ¹³⁷Cs loss to sediment loss yielded soil loss estimates ranging from 6 to 27 MT/ha/yr (3 to 12 T/a/yr). Imprecision in these estimates is great. But the estimates do indicate strongly that modern erosion rates, while not spectacular, have been great enough to warrant the use of appropriate conservation measures in hilly croplands of the region. Close

• 1339. [Article] Floral and vegetative development in Dactylis glomerata as influenced by different temperature levels and durations

  Growth chamber and field experiments were conducted to investigate the effects of different temperature levels and durations on floral induction and vegetative growth in orchardgrass. Propagules of two ...

  Citation × Citation Citation Abstract Copy Title: Floral and vegetative development in Dactylis glomerata as influenced by different temperature levels and durations Author: Von Amsberg, Hans Joachim Growth chamber and field experiments were conducted to investigate the effects of different temperature levels and durations on floral induction and vegetative growth in orchardgrass. Propagules of two clones, XLI-8 (clone R) and MID-5 (clone 0), from the synthetic variety Pennlate, were used in all experiments. Clone R plants were less dependent than clone 0 plants on extended low temperature exposure for floral induction. Temperature regimes in the growth chambers, where daily maxima were above 65°F for the durations of exposure used in these experiments, did not induce clone 0 propagules. However, clone R plants were induced to some degree with all temperature regimes except where the maximum temperature reached over 90°F for 10 hours each day. The longer the exposure periods of inductive regimes, the higher the percentage of plants initiating an inflorescence and the larger the number of tillers induced. Clone R plants were usually induced in a shorter time than was true for clone 0. A positive linear relationship between floral induction and exposure time through the longest duration of 10 weeks suggests that the optimum duration of exposure under growth chamber conditions was not reached. Constant 38°F and alternating 38°-60°F induced the highest percentage of plants of both clones. Cyclic daily temperatures of 15 hours at 38°F and 5 hours at 60°F temperatures gave the highest number of inflorescences per plant for clone 0. This effect appeared to be due in part to the more favorable conditions for tillering with alternating temperatures, which resulted in more potentially inducible tillers. Alternating temperatures of 38°-60°F did not show a similar advantage over 38°F constant in number of inflorescence per plant for clone R, but did increase the number of tillers per plant. Cyclic temperatures with high temperature maxima usually favored tiller development, both in the controlled environment chamber and after they had been transferred to the greenhouse. Constant 38°F temperatures were less promotive to tillering and reduced leaf development on the main tiller. Leaf development was accelerated by high temperatures with response related to the duration of high temperature received in each cyclic regime. Field results indicated that the earlier the plant were transplanted to the field, the larger were the number of inflorescences. Differences in the number of floral primordia were more pronounced for clone 0 than they were for clone R plants. Earlier planting dates for either clone resulted in earlier inflorescence exsertion. Inflorescence exsertion started about a week earlier for clone 0 than for clone R. Clone 0 plants were superior to clone R plants in number of reproductive primordia, as well as in the total number of tillers developed in the field for early dates of planting. These differences were smaller or nonexistent with the later planting dates. Title: Floral and vegetative development in Dactylis glomerata as influenced by different temperature levels and durations Author: Von Amsberg, Hans Joachim Growth chamber and field experiments were conducted to investigate the effects of different temperature levels and durations on floral induction and vegetative growth in orchardgrass. Propagules of two clones, XLI-8 (clone R) and MID-5 (clone 0), from the synthetic variety Pennlate, were used in all experiments. Clone R plants were less dependent than clone 0 plants on extended low temperature exposure for floral induction. Temperature regimes in the growth chambers, where daily maxima were above 65°F for the durations of exposure used in these experiments, did not induce clone 0 propagules. However, clone R plants were induced to some degree with all temperature regimes except where the maximum temperature reached over 90°F for 10 hours each day. The longer the exposure periods of inductive regimes, the higher the percentage of plants initiating an inflorescence and the larger the number of tillers induced. Clone R plants were usually induced in a shorter time than was true for clone 0. A positive linear relationship between floral induction and exposure time through the longest duration of 10 weeks suggests that the optimum duration of exposure under growth chamber conditions was not reached. Constant 38°F and alternating 38°-60°F induced the highest percentage of plants of both clones. Cyclic daily temperatures of 15 hours at 38°F and 5 hours at 60°F temperatures gave the highest number of inflorescences per plant for clone 0. This effect appeared to be due in part to the more favorable conditions for tillering with alternating temperatures, which resulted in more potentially inducible tillers. Alternating temperatures of 38°-60°F did not show a similar advantage over 38°F constant in number of inflorescence per plant for clone R, but did increase the number of tillers per plant. Cyclic temperatures with high temperature maxima usually favored tiller development, both in the controlled environment chamber and after they had been transferred to the greenhouse. Constant 38°F temperatures were less promotive to tillering and reduced leaf development on the main tiller. Leaf development was accelerated by high temperatures with response related to the duration of high temperature received in each cyclic regime. Field results indicated that the earlier the plant were transplanted to the field, the larger were the number of inflorescences. Differences in the number of floral primordia were more pronounced for clone 0 than they were for clone R plants. Earlier planting dates for either clone resulted in earlier inflorescence exsertion. Inflorescence exsertion started about a week earlier for clone 0 than for clone R. Clone 0 plants were superior to clone R plants in number of reproductive primordia, as well as in the total number of tillers developed in the field for early dates of planting. These differences were smaller or nonexistent with the later planting dates. Close

• 1340. [Article] Effect of seed source on growth and performance of potato (Solanum tuberosum L.)

  Twenty Russet Burbank seed lots were collected from four states and one Canadian Province in 1988 and planted in replicated trails at Powell Butte and Hermiston, Oregon as part of a two year study to quantify ...

  Citation × Citation Citation Abstract Copy Title: Effect of seed source on growth and performance of potato (Solanum tuberosum L.) Author: Whitworth, Jonathan L. Twenty Russet Burbank seed lots were collected from four states and one Canadian Province in 1988 and planted in replicated trails at Powell Butte and Hermiston, Oregon as part of a two year study to quantify clonal differences in the cultivar. Samples of each seed lot were concurrently increased and stored under identical conditions at Powell Butte to preclude physiological age differences in seed used for similar plantings in 1989. Non-genetic influences were further reduced in the second year (1989) planting by subjecting seed to a combination of eye-indexing and ELISA testing to eliminate virus infected tubers. It was postulated that any differences in yield and performance observed in 1989 would be primarily genetically related. Significant differences (p = 0.05) were noted in U.S. No. 1 yields at both locations and in total yields at Powell Butte in 1988. Similar plantings in 1989 using standardized seed from the 1988 Powell Butte increase showed significant differences in U.S. No. 1 yields only at Hermiston. However, differences significant at the p = 0.10 level were observed for both total and U.S. No. 1 yields, tuber size distribution, and tuber specific gravity during both years at Hermiston. The range in yields decreased with the use of standardized seed at Powell Butte as expected but increased at Hermiston. Reasons for these seemingly contradictory responses are unclear. If substantial differences in maturity existed among the seed lots/clones, the long growing season at Hermiston would have accentuated yield differences. The 1989 Hermiston season was 20 days longer than in 1988 and could have broadened yield ranges in 1989. It is possible that non-genetic factors such as physiological age and viral infection might have partially masked maturity effects at Hermiston in 1988. The Powell Butte growing season is too short to show strong yield benefits from delayed maturity. Consistent differences in seed lot performance in the absence of non-genetic influences such as seed tuber physiological age and viral content would suggest that useful clonal differences exist. Four seed lots in these studies consistently produced high yields at Powell Butte and three at Hermiston during both years while one produced high yields at both locations. Further, large yield differences were still evident at Hermiston in 1989 in trials planted with virus-tested, identically aged seed. These results suggest that line selection from these seed lots could produce high yielding Russet Burbank clones with good tuber conformation. Additional field trials are needed to fully characterize the nature and importance of these potential clonal differences. Title: Effect of seed source on growth and performance of potato (Solanum tuberosum L.) Author: Whitworth, Jonathan L. Twenty Russet Burbank seed lots were collected from four states and one Canadian Province in 1988 and planted in replicated trails at Powell Butte and Hermiston, Oregon as part of a two year study to quantify clonal differences in the cultivar. Samples of each seed lot were concurrently increased and stored under identical conditions at Powell Butte to preclude physiological age differences in seed used for similar plantings in 1989. Non-genetic influences were further reduced in the second year (1989) planting by subjecting seed to a combination of eye-indexing and ELISA testing to eliminate virus infected tubers. It was postulated that any differences in yield and performance observed in 1989 would be primarily genetically related. Significant differences (p = 0.05) were noted in U.S. No. 1 yields at both locations and in total yields at Powell Butte in 1988. Similar plantings in 1989 using standardized seed from the 1988 Powell Butte increase showed significant differences in U.S. No. 1 yields only at Hermiston. However, differences significant at the p = 0.10 level were observed for both total and U.S. No. 1 yields, tuber size distribution, and tuber specific gravity during both years at Hermiston. The range in yields decreased with the use of standardized seed at Powell Butte as expected but increased at Hermiston. Reasons for these seemingly contradictory responses are unclear. If substantial differences in maturity existed among the seed lots/clones, the long growing season at Hermiston would have accentuated yield differences. The 1989 Hermiston season was 20 days longer than in 1988 and could have broadened yield ranges in 1989. It is possible that non-genetic factors such as physiological age and viral infection might have partially masked maturity effects at Hermiston in 1988. The Powell Butte growing season is too short to show strong yield benefits from delayed maturity. Consistent differences in seed lot performance in the absence of non-genetic influences such as seed tuber physiological age and viral content would suggest that useful clonal differences exist. Four seed lots in these studies consistently produced high yields at Powell Butte and three at Hermiston during both years while one produced high yields at both locations. Further, large yield differences were still evident at Hermiston in 1989 in trials planted with virus-tested, identically aged seed. These results suggest that line selection from these seed lots could produce high yielding Russet Burbank clones with good tuber conformation. Additional field trials are needed to fully characterize the nature and importance of these potential clonal differences. Close