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• 261. [Article] Pollen fidelity of Apis mellifera L. during pollination of Limnanthes alba Hartw. ex Benth. ssp. alba, Limnanthaceae

  Limnanthes alba, commonly known as meadowfoam is a popular commercial crop because its seed oil is composed of long carbon chains that provide it with high oxidative stability and consequently make it ...

  Citation × Citation Citation Abstract Copy Title: Pollen fidelity of Apis mellifera L. during pollination of Limnanthes alba Hartw. ex Benth. ssp. alba, Limnanthaceae Author: Watkins, Ann J. Limnanthes alba, commonly known as meadowfoam is a popular commercial crop because its seed oil is composed of long carbon chains that provide it with high oxidative stability and consequently make it a desirable ingredient in cosmetic products. As a commercial pollinator, the western honey bee, Apis mellifera, may be utilized to pollinate monocultures such as L. alba. The pollen fidelity of a pollinator with regard to its intended crop determines the efficiency and overall benefit of the pollinator’s presence in the field. This research examines pollen fidelity of A. mellifera with regard to L. alba in a commercial setting. The average L. alba proportion of total trapped pollen was determined to be 88.5%. The high fidelity of A. mellifera to L. alba suggests that it was beneficial to have a supplemental pollinator present, but to definitively determine that a comparative study would need to be performed. Title: Pollen fidelity of Apis mellifera L. during pollination of Limnanthes alba Hartw. ex Benth. ssp. alba, Limnanthaceae Author: Watkins, Ann J. Limnanthes alba, commonly known as meadowfoam is a popular commercial crop because its seed oil is composed of long carbon chains that provide it with high oxidative stability and consequently make it a desirable ingredient in cosmetic products. As a commercial pollinator, the western honey bee, Apis mellifera, may be utilized to pollinate monocultures such as L. alba. The pollen fidelity of a pollinator with regard to its intended crop determines the efficiency and overall benefit of the pollinator’s presence in the field. This research examines pollen fidelity of A. mellifera with regard to L. alba in a commercial setting. The average L. alba proportion of total trapped pollen was determined to be 88.5%. The high fidelity of A. mellifera to L. alba suggests that it was beneficial to have a supplemental pollinator present, but to definitively determine that a comparative study would need to be performed. Close

• 262. [Article] Winter wheat in continuous cropping systems (high precipitation zone)

  Revised November 2006.Reviewed July 2012. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Winter wheat in continuous cropping systems (high precipitation zone) Author: Wysocki, Donald John, 1952-, Lutcher, L. K. (Lawrence K.), Horneck, Donald Arthur, Hart, John M. (John Mervyn), 1947-, Petrie, S. E., Oregon State University. Extension Service, Corp, Mary K. Revised November 2006.Reviewed July 2012. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Winter wheat in continuous cropping systems (high precipitation zone) Author: Wysocki, Donald John, 1952-, Lutcher, L. K. (Lawrence K.), Horneck, Donald Arthur, Hart, John M. (John Mervyn), 1947-, Petrie, S. E., Oregon State University. Extension Service, Corp, Mary K. Revised November 2006.Reviewed July 2012. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 263. [Article] Effect of certain blood enzymes and cellular constituents on growth in different genetic groups of sheep

  In the present study, five breeds of ewes and their lambs were utilized. The breeds used were: Border Cheviot, Dorset Horn, Columbia, Suffolk and Willamette. In all, 31 ewes and 42 lambs were involved. The ...

  Citation × Citation Citation Abstract Copy Title: Effect of certain blood enzymes and cellular constituents on growth in different genetic groups of sheep Author: Hutto, Daniel C. In the present study, five breeds of ewes and their lambs were utilized. The breeds used were: Border Cheviot, Dorset Horn, Columbia, Suffolk and Willamette. In all, 31 ewes and 42 lambs were involved. The blood constituents which were determined for the ewes and lambs were: acid and alkaline phosphatase, hematocrit, hemoglobin and red and white blood cell numbers. Blood samples were taken and analyzed for each ewe and lamb, at two-week intervals, from the ninth or tenth day of lactation until approximately 94 days subsequent to lambing. At 100 days of age the lambs were scored for conformation and condition. Then the lambs were slaughtered and a sample of each carcass was cooked and submitted to a taste panel to obtain scores for tenderness and preference. Acid phosphatase levels of activity were approximately three times higher for lambs than for ewes at 10 days following lambing, and two times higher than the level for ewes for the entire testing period. Highly significant breed and period differences were observed for acid phosphatase levels in lambs. No breed differences for this enzyme were noted in ewes. Alkaline phosphatase levels of activity were higher in lambs than in ewes throughout the testing period. The average alkaline phosphatase value for lambs was 8.07 units compared to 2.96 units for the ewes. The average alkaline phosphatase value of lambs was highest at 10 days (11.00 units) and lowest at 80 days (6.36 units). Alkaline phosphatase levels were affected statistically (P<.01) by breed, sex and period, and ewe values were affected (P<.01) by breed, period and type of birth. Hematocrit values were only slightly higher in lambs than in ewes. At the first testing period the ewe values slightly exceeded the lamb values, but from the second period until the end of the test the lamb values were higher than the ewe values. Highly significant (P<.01) differences were found in ewes according to breed and period, whereas, lamb hematocrit values differed according to age of dam and period (P<.01). Hemoglobin levels followed a pattern similar to that found for hematocrit in lambs and ewes. Hemoglobin values for lambs and ewes reached the highest level at 24 days subsequent to lambing. Hemoglobin levels differed significantly (P<.01) in ewes according to breed and period, and in lambs according to period (P<.01) and sex (P<.05). Average red blood cell counts were higher for ewes (9,690,000) than for lambs (8,920,000) at 10 days subsequent to lambing, but by 94 days the average ewe red blood count was 8,440,000 compared to 10,680,000 for lambs. No breed differences could be found in red blood cell numbers for ewes or lambs. However, period and birth type differences were observed in lambs. White blood cell numbers were slightly more than one thousand lower for lambs than for ewes at 10 days following lambing. The lamb values were still lower than the ewe values at 24 days, but by 38 days the lamb values exceeded the ewe values. White blood cell numbers differed significantly (P<.01) for ewes according to breed and according to breed, birth type and period for lambs. A slight sex difference in white blood cell numbers was observed in lambs. The Columbia lambs had the lowest conformation and condition scores of any of the breeds. The Border Cheviots and the Willamettes had the highest scores for conformation and condition, respectively. However, the Columbias had the highest preference and tenderness scores of any of the breeds, while the Border Cheviots had the lowest preference and tenderness scores of any of the breeds. The breeds ranked in the following order for average weight gains of lambs: Willamettes, Suffolks, Columbias, Dorest Horns and Border Cheviots. Body weight of lambs differed significantly (P<.01) according to breed, birth type and period and (P<.05) according to sex. None of the variables studied seemed to be highly related to growth rate in lambs. Title: Effect of certain blood enzymes and cellular constituents on growth in different genetic groups of sheep Author: Hutto, Daniel C. In the present study, five breeds of ewes and their lambs were utilized. The breeds used were: Border Cheviot, Dorset Horn, Columbia, Suffolk and Willamette. In all, 31 ewes and 42 lambs were involved. The blood constituents which were determined for the ewes and lambs were: acid and alkaline phosphatase, hematocrit, hemoglobin and red and white blood cell numbers. Blood samples were taken and analyzed for each ewe and lamb, at two-week intervals, from the ninth or tenth day of lactation until approximately 94 days subsequent to lambing. At 100 days of age the lambs were scored for conformation and condition. Then the lambs were slaughtered and a sample of each carcass was cooked and submitted to a taste panel to obtain scores for tenderness and preference. Acid phosphatase levels of activity were approximately three times higher for lambs than for ewes at 10 days following lambing, and two times higher than the level for ewes for the entire testing period. Highly significant breed and period differences were observed for acid phosphatase levels in lambs. No breed differences for this enzyme were noted in ewes. Alkaline phosphatase levels of activity were higher in lambs than in ewes throughout the testing period. The average alkaline phosphatase value for lambs was 8.07 units compared to 2.96 units for the ewes. The average alkaline phosphatase value of lambs was highest at 10 days (11.00 units) and lowest at 80 days (6.36 units). Alkaline phosphatase levels were affected statistically (P<.01) by breed, sex and period, and ewe values were affected (P<.01) by breed, period and type of birth. Hematocrit values were only slightly higher in lambs than in ewes. At the first testing period the ewe values slightly exceeded the lamb values, but from the second period until the end of the test the lamb values were higher than the ewe values. Highly significant (P<.01) differences were found in ewes according to breed and period, whereas, lamb hematocrit values differed according to age of dam and period (P<.01). Hemoglobin levels followed a pattern similar to that found for hematocrit in lambs and ewes. Hemoglobin values for lambs and ewes reached the highest level at 24 days subsequent to lambing. Hemoglobin levels differed significantly (P<.01) in ewes according to breed and period, and in lambs according to period (P<.01) and sex (P<.05). Average red blood cell counts were higher for ewes (9,690,000) than for lambs (8,920,000) at 10 days subsequent to lambing, but by 94 days the average ewe red blood count was 8,440,000 compared to 10,680,000 for lambs. No breed differences could be found in red blood cell numbers for ewes or lambs. However, period and birth type differences were observed in lambs. White blood cell numbers were slightly more than one thousand lower for lambs than for ewes at 10 days following lambing. The lamb values were still lower than the ewe values at 24 days, but by 38 days the lamb values exceeded the ewe values. White blood cell numbers differed significantly (P<.01) for ewes according to breed and according to breed, birth type and period for lambs. A slight sex difference in white blood cell numbers was observed in lambs. The Columbia lambs had the lowest conformation and condition scores of any of the breeds. The Border Cheviots and the Willamettes had the highest scores for conformation and condition, respectively. However, the Columbias had the highest preference and tenderness scores of any of the breeds, while the Border Cheviots had the lowest preference and tenderness scores of any of the breeds. The breeds ranked in the following order for average weight gains of lambs: Willamettes, Suffolks, Columbias, Dorest Horns and Border Cheviots. Body weight of lambs differed significantly (P<.01) according to breed, birth type and period and (P<.05) according to sex. None of the variables studied seemed to be highly related to growth rate in lambs. Close

• 264. [Article] Factors affecting establishment, survival, and production of birdsfoot trefoil (Lotus corniculatus L.) and alfalfa (Medicago sativa L.)

  Field, greenhouse, growth chamber and laboratory experiments evaluated factors affecting establishment, survival and production of birdsfoot trefoil (Lotus corniculatus L.) and alfalfa (Medicago sativa ...

  Citation × Citation Citation Abstract Copy Title: Factors affecting establishment, survival, and production of birdsfoot trefoil (Lotus corniculatus L.) and alfalfa (Medicago sativa L.) Author: Cooper, Clee Scott Field, greenhouse, growth chamber and laboratory experiments evaluated factors affecting establishment, survival and production of birdsfoot trefoil (Lotus corniculatus L.) and alfalfa (Medicago sativa L.) Field studies investigated the effects of a barley companion crop, seedling year harvest management and nitrogen and phosphorus fertilization upon stands, survival and subsequent production of legumes. Seedings were made in each of two years. Stands of legumes were not affected by fertilization or harvest management, but decreased with increasing levels of companion crop competition. Death of seedlings occurred early in the establishment period and the degree of loss was similar for both species. Additional losses of plants did not occur during the establishment year. Losses of birdsfoot trefoil plants established with a companion crop occurred during the first winter following seeding. Stand reduction in the seeding year persisted for the duration of the experiment. Companion crops inhibited the growth of surviving seedlings. Growth inhibition was less when barley was clipped periodically than when it was matured to grain. In the absence of a companion crop, growth of seedlings was inhibited more by frequent clipping of thin weed stands than by allowing weeds to mature. Yields of weeds were inversely proportional to density of barley plants. Wild oats was more detrimental to seedling growth and was less readily controlled by clipping than redroot pigweed or pigeon grass. The percentage of solar radiation intercepted by barley varied from 89 in early morning or late evening to 22 at noon. Light intensity was reduced more by barley in early season and less by barley in late season than by wild oats. Yields of mixtures in the year after seeding were reduced as a result of establishment with a companion crop and to a greater degree and for a longer period of time when barley had been allowed to mature. Yield reductions of legumes were compensated for by increased grass yields. Grass grown with birdsfoot trefoil yielded significantly more in early season and significantly less in late season than grass grown with alfalfa. Greenhouse studies evaluated the influenee of soil temperature and phosphorus fertilization upon growth and phosphorus uptake of birdsfoot trefoil and alfalfa. Root growth of both species increased with increasing soil temperatures. Weight of alfalfa roots was twice that of birdsfoot trefoil at all temperatures. Top growth of birdsfoot trefoil increaeed to a greater degree than that of alfalfa with increasing temperature. The greater top growth of birdsfoot trefoil resulted in reduced root-shoot ratios. Birdsfoot trefoil produced less dry matter per cm.² of leaf area than alfalfa. Root growth of both species increased with increasing applications of P fertilizer. Phosphorus appeared to be more important to growth at low than at high temperatures. Phosphorus and nitrogen uptake by both species increased with increasing soil temperature. Growth chamber studies evaluated the influence of low light intensities and seedling age upon growth of seedlings and distribution of accumulated dry matter. Seedlings gained weight at light intensities of 200 to 800 f.c. With decreasing light intensity, stem elongation occurred at the expense of roots. A smaller percentage of accumulated dry matter went into roots of two-week than in older seedlings. Roots of two-week old seedlings of alfalfa lost weight at 200 f.c. Laboratory studies evaluated oxygen uptake of germinating birdsfoot trefoil and alfalfa seeds. Average oxygen uptake by both species on a per unit weight basis was similar. Alfalfa, due to its greater size, had a greater oxygen uptake on a per plant basis than did birdsfoot trefoil. Title: Factors affecting establishment, survival, and production of birdsfoot trefoil (Lotus corniculatus L.) and alfalfa (Medicago sativa L.) Author: Cooper, Clee Scott Field, greenhouse, growth chamber and laboratory experiments evaluated factors affecting establishment, survival and production of birdsfoot trefoil (Lotus corniculatus L.) and alfalfa (Medicago sativa L.) Field studies investigated the effects of a barley companion crop, seedling year harvest management and nitrogen and phosphorus fertilization upon stands, survival and subsequent production of legumes. Seedings were made in each of two years. Stands of legumes were not affected by fertilization or harvest management, but decreased with increasing levels of companion crop competition. Death of seedlings occurred early in the establishment period and the degree of loss was similar for both species. Additional losses of plants did not occur during the establishment year. Losses of birdsfoot trefoil plants established with a companion crop occurred during the first winter following seeding. Stand reduction in the seeding year persisted for the duration of the experiment. Companion crops inhibited the growth of surviving seedlings. Growth inhibition was less when barley was clipped periodically than when it was matured to grain. In the absence of a companion crop, growth of seedlings was inhibited more by frequent clipping of thin weed stands than by allowing weeds to mature. Yields of weeds were inversely proportional to density of barley plants. Wild oats was more detrimental to seedling growth and was less readily controlled by clipping than redroot pigweed or pigeon grass. The percentage of solar radiation intercepted by barley varied from 89 in early morning or late evening to 22 at noon. Light intensity was reduced more by barley in early season and less by barley in late season than by wild oats. Yields of mixtures in the year after seeding were reduced as a result of establishment with a companion crop and to a greater degree and for a longer period of time when barley had been allowed to mature. Yield reductions of legumes were compensated for by increased grass yields. Grass grown with birdsfoot trefoil yielded significantly more in early season and significantly less in late season than grass grown with alfalfa. Greenhouse studies evaluated the influenee of soil temperature and phosphorus fertilization upon growth and phosphorus uptake of birdsfoot trefoil and alfalfa. Root growth of both species increased with increasing soil temperatures. Weight of alfalfa roots was twice that of birdsfoot trefoil at all temperatures. Top growth of birdsfoot trefoil increaeed to a greater degree than that of alfalfa with increasing temperature. The greater top growth of birdsfoot trefoil resulted in reduced root-shoot ratios. Birdsfoot trefoil produced less dry matter per cm.² of leaf area than alfalfa. Root growth of both species increased with increasing applications of P fertilizer. Phosphorus appeared to be more important to growth at low than at high temperatures. Phosphorus and nitrogen uptake by both species increased with increasing soil temperature. Growth chamber studies evaluated the influence of low light intensities and seedling age upon growth of seedlings and distribution of accumulated dry matter. Seedlings gained weight at light intensities of 200 to 800 f.c. With decreasing light intensity, stem elongation occurred at the expense of roots. A smaller percentage of accumulated dry matter went into roots of two-week than in older seedlings. Roots of two-week old seedlings of alfalfa lost weight at 200 f.c. Laboratory studies evaluated oxygen uptake of germinating birdsfoot trefoil and alfalfa seeds. Average oxygen uptake by both species on a per unit weight basis was similar. Alfalfa, due to its greater size, had a greater oxygen uptake on a per plant basis than did birdsfoot trefoil. Close

• 265. [Article] Influence of cropping and sulfur fertilization on sulfur transformations in soil

  A 2-year field study was conducted on the effects of two sulfur fertilizers (calcium sulfate or elemental S, 0 or 50 kg S ha⁻¹ yr⁻¹) on the distribution of sulfur fractions (inorganic sulfate, C-bonded, ester ...

  Citation × Citation Citation Abstract Copy Title: Influence of cropping and sulfur fertilization on sulfur transformations in soil Author: Castellano, Steven D. A 2-year field study was conducted on the effects of two sulfur fertilizers (calcium sulfate or elemental S, 0 or 50 kg S ha⁻¹ yr⁻¹) on the distribution of sulfur fractions (inorganic sulfate, C-bonded, ester sulfate, and residual S), arylsulfatase enzyme activity, and microbial biomass carbon (C) and sulfur (S) over time in an Aquultic Argixeroll in cropped (winter rape, Brassica napus) and uncropped treatments. Despite high rainfall, winter SO₄⁻² levels in the 0 to 15 cm depth ranged from 7 to 13 mg SO₄⁻²-S kg⁻¹ soil in calcium sulfate treated plots, compared to control plots which ranged from 2 to 7 mg SO₄⁻²-S kg⁻¹ soil. However, in the months from March to May, SO₄⁻² levels (0 to 15 cm depth) decreased to < 4 and < 6 mg SO₄⁻²-S kg⁻¹ soil (years 1 and 2, respectively) and were not significantly different among treatments. From March to May of 1988 biomass S increased from 2 to nearly 6 mg S kg⁻¹ soil, which provided evidence that S immobilization is occurring in the spring. Overall, there was a significant (P< 0.01) effect of the sulfur fertilizer on SO₄⁻² levels in the surface soil, but the effect of cropping was not significant. Results of this study indicate that residual S varied seasonally, and is not a completely inert S fraction. Cropping increased biological activity, as cropped plots had significantly greater arylsulfatase activities and microbial biomass C than uncropped plots. Conversely, distributions of organic S fractions were unaffected by the presence of plants during the two-year period. Subsoil SO₄⁻² appeared to be both a source and a sink for S in surface soil. After 2 years, extractable SO₄⁻² in the 60-90 cm depth was significantly affected by cropping and S fertilization, with uncropped calcium sulfate treated plots having the greatest accumulation of SO₄⁻² which increased from 17 to 27 mg SO₄⁻²-S kg⁻¹ soil over the course of the study. During the unusually dry, warm period in the fall of 1987, total S levels in the surface soil increased, even in uncropped control plots, suggesting the possibility of upward movement of SO₄⁻² from the subsoil. At the end of the study (July, 1988), the SO₄⁻² rich subsoil zone below the 60 cm depth showed significant differences in extractable SO₄⁻² due to cropping and S fertilization. Results from this study raise a concern about using extractable SO₄⁻² as an S soil test. First, SO₄⁻² levels varied widely over time, even in the control which ranged from 2 to 14 mg SO₄⁻²-S kg⁻¹ soil. Secondly, S fertilizer applications increased SO₄⁻² levels in the calcium sulfate treated plots, but elemental S treatments remained similar to the controls. Because seed yield responses to elemental S were observed each year, it is apparent that extractable SO₄⁻² does not predict plant availability of S from elemental S applications. Critical levels have been established at 2-3 mg SO₄⁻²-S kg⁻¹ soil, thus depending on what time of year a soil sample is taken different conclusions would be reached as to whether this soil would be responsive to S fertilization. Title: Influence of cropping and sulfur fertilization on sulfur transformations in soil Author: Castellano, Steven D. A 2-year field study was conducted on the effects of two sulfur fertilizers (calcium sulfate or elemental S, 0 or 50 kg S ha⁻¹ yr⁻¹) on the distribution of sulfur fractions (inorganic sulfate, C-bonded, ester sulfate, and residual S), arylsulfatase enzyme activity, and microbial biomass carbon (C) and sulfur (S) over time in an Aquultic Argixeroll in cropped (winter rape, Brassica napus) and uncropped treatments. Despite high rainfall, winter SO₄⁻² levels in the 0 to 15 cm depth ranged from 7 to 13 mg SO₄⁻²-S kg⁻¹ soil in calcium sulfate treated plots, compared to control plots which ranged from 2 to 7 mg SO₄⁻²-S kg⁻¹ soil. However, in the months from March to May, SO₄⁻² levels (0 to 15 cm depth) decreased to < 4 and < 6 mg SO₄⁻²-S kg⁻¹ soil (years 1 and 2, respectively) and were not significantly different among treatments. From March to May of 1988 biomass S increased from 2 to nearly 6 mg S kg⁻¹ soil, which provided evidence that S immobilization is occurring in the spring. Overall, there was a significant (P< 0.01) effect of the sulfur fertilizer on SO₄⁻² levels in the surface soil, but the effect of cropping was not significant. Results of this study indicate that residual S varied seasonally, and is not a completely inert S fraction. Cropping increased biological activity, as cropped plots had significantly greater arylsulfatase activities and microbial biomass C than uncropped plots. Conversely, distributions of organic S fractions were unaffected by the presence of plants during the two-year period. Subsoil SO₄⁻² appeared to be both a source and a sink for S in surface soil. After 2 years, extractable SO₄⁻² in the 60-90 cm depth was significantly affected by cropping and S fertilization, with uncropped calcium sulfate treated plots having the greatest accumulation of SO₄⁻² which increased from 17 to 27 mg SO₄⁻²-S kg⁻¹ soil over the course of the study. During the unusually dry, warm period in the fall of 1987, total S levels in the surface soil increased, even in uncropped control plots, suggesting the possibility of upward movement of SO₄⁻² from the subsoil. At the end of the study (July, 1988), the SO₄⁻² rich subsoil zone below the 60 cm depth showed significant differences in extractable SO₄⁻² due to cropping and S fertilization. Results from this study raise a concern about using extractable SO₄⁻² as an S soil test. First, SO₄⁻² levels varied widely over time, even in the control which ranged from 2 to 14 mg SO₄⁻²-S kg⁻¹ soil. Secondly, S fertilizer applications increased SO₄⁻² levels in the calcium sulfate treated plots, but elemental S treatments remained similar to the controls. Because seed yield responses to elemental S were observed each year, it is apparent that extractable SO₄⁻² does not predict plant availability of S from elemental S applications. Critical levels have been established at 2-3 mg SO₄⁻²-S kg⁻¹ soil, thus depending on what time of year a soil sample is taken different conclusions would be reached as to whether this soil would be responsive to S fertilization. Close

• 266. [Article] Nitrogen available to winter wheat as influenced by previous crop in a moist xeric environment

  Rotating wheat with other crops is a common practice in the Willamette Valley of western Oregon. Depending upon previous crop and soil type, current N fertilizer recommendations for wheat in the Willamette ...

  Citation × Citation Citation Abstract Copy Title: Nitrogen available to winter wheat as influenced by previous crop in a moist xeric environment Author: Qureshi, Maqsood Hassan Rotating wheat with other crops is a common practice in the Willamette Valley of western Oregon. Depending upon previous crop and soil type, current N fertilizer recommendations for wheat in the Willamette Valley vary widely. Excessive fertilizer poses environmental risk, whereas lower N inputs than required by the crop represent economic losses to growers. Growers and their advisors face the challenge to minimize the environmental risk, and at the same time to maintain or increase economic returns. Questions are often raised concerning the efficient use of N fertilizer and accurately predicting the amount of N needed by wheat following different crops. The first study measured growth, N uptake and N use efficiency (NUE) of winter wheat grown after either a legume or oat for three years. In all three growing seasons, winter wheat showed higher biomass, N uptake and NUE when grown after a legume than after oat. The contribution of legume was evident before the wheat was fertilized in spring, indicating that legume N had mineralized in fall or winter. Contribution of soil N to wheat suggested that fertilizer N can be reduced by 44 kg N ha⁻¹ if a legume is grown previously. Nitrogen use efficiency estimated 50 to 70 days after N application by isotopic method (24 to 94%) was comparable with that estimated simply by difference (21 to 94%) at the same time. The second study predicted gross mineralization rates using analytical models. Comparable N mineralization was predicted by a model assuming remineralization and a model assuming no remineralization, suggesting that remineralization was negligible. In the spring, mineralization-immobilization turnover was at a lower pace than expected in both rotations. In two growing seasons, gross mineralization rates were higher where the previous crop was legume (0.37 to 0.74 kg⁻¹ ha⁻¹ day⁻¹) as compared to where oat was grown previously (0.14 to 0.6 kg⁻¹ ha⁻¹ day). Negative net mineralization indicated that fertilizer N was immobilized in the oat-wheat rotation. The third study evaluated calibration and digestion techniques used to determine elemental concentration in grasses. Use of a dry ashed standard to calibrate the ICP spectrometer generated highly variable calibration curves and was not a viable calibration method. Good agreement was found between chemical and microwave digested standards. Dry ashing resulted in considerable S and Mn losses, whereas, perchloric acid digestion and microwave digestion showed similar results. Our study suggests that if routine analysis are to be performed for macro nutrients or involve trace level work, the best method is microwave digestion with chemical standard calibration of ICP spectrometer. Title: Nitrogen available to winter wheat as influenced by previous crop in a moist xeric environment Author: Qureshi, Maqsood Hassan Rotating wheat with other crops is a common practice in the Willamette Valley of western Oregon. Depending upon previous crop and soil type, current N fertilizer recommendations for wheat in the Willamette Valley vary widely. Excessive fertilizer poses environmental risk, whereas lower N inputs than required by the crop represent economic losses to growers. Growers and their advisors face the challenge to minimize the environmental risk, and at the same time to maintain or increase economic returns. Questions are often raised concerning the efficient use of N fertilizer and accurately predicting the amount of N needed by wheat following different crops. The first study measured growth, N uptake and N use efficiency (NUE) of winter wheat grown after either a legume or oat for three years. In all three growing seasons, winter wheat showed higher biomass, N uptake and NUE when grown after a legume than after oat. The contribution of legume was evident before the wheat was fertilized in spring, indicating that legume N had mineralized in fall or winter. Contribution of soil N to wheat suggested that fertilizer N can be reduced by 44 kg N ha⁻¹ if a legume is grown previously. Nitrogen use efficiency estimated 50 to 70 days after N application by isotopic method (24 to 94%) was comparable with that estimated simply by difference (21 to 94%) at the same time. The second study predicted gross mineralization rates using analytical models. Comparable N mineralization was predicted by a model assuming remineralization and a model assuming no remineralization, suggesting that remineralization was negligible. In the spring, mineralization-immobilization turnover was at a lower pace than expected in both rotations. In two growing seasons, gross mineralization rates were higher where the previous crop was legume (0.37 to 0.74 kg⁻¹ ha⁻¹ day⁻¹) as compared to where oat was grown previously (0.14 to 0.6 kg⁻¹ ha⁻¹ day). Negative net mineralization indicated that fertilizer N was immobilized in the oat-wheat rotation. The third study evaluated calibration and digestion techniques used to determine elemental concentration in grasses. Use of a dry ashed standard to calibrate the ICP spectrometer generated highly variable calibration curves and was not a viable calibration method. Good agreement was found between chemical and microwave digested standards. Dry ashing resulted in considerable S and Mn losses, whereas, perchloric acid digestion and microwave digestion showed similar results. Our study suggests that if routine analysis are to be performed for macro nutrients or involve trace level work, the best method is microwave digestion with chemical standard calibration of ICP spectrometer. Close

• 267. [Article] Expansion of scouringrush (Equisetum spp. L.) : crop interference and control options in winter wheat (Triticum aestivum L.) and chemical fallow cropping cropping systems

  Scouringrushes (Equisetum hyemale L.; E. xferrissii Clute; E. laevigatum L.) are ancient perennial seedless vascular plants historically associated with wetlands, low-lying roadsides or field margins with ...

  Citation × Citation Citation Abstract Copy Title: Expansion of scouringrush (Equisetum spp. L.) : crop interference and control options in winter wheat (Triticum aestivum L.) and chemical fallow cropping cropping systems Author: Kerbs, Blake D. Scouringrushes (Equisetum hyemale L.; E. xferrissii Clute; E. laevigatum L.) are ancient perennial seedless vascular plants historically associated with wetlands, low-lying roadsides or field margins with more plant available water. There has been little research conducted on scouringrush species in the context of agricultural production because traditional farming practices confined them to field margins and roadside depressions. An increasing amount of dryland winter wheat (Triticum aestivum L.) hectares in the inland Pacific Northwest have replaced summer tilled-fallow rotations with chemical fallow. Where chemical fallow rotations have become the standard practice, scouringrush has expanded out of its historical habitat into production fields and established at high enough densities to cause concern from growers. Research was conducted to identify control options that fit chemical fallow cropping systems, evaluate the magnitude of crop interference by scouringrush, and address how soil pH affects scouringrush growth and establishment, as soil acidification is another agronomic issue caused by intensive wheat production in the Pacific Northwest. Field studies located in Reardan, WA, and near The Dalles, OR, were established in commercial wheat production fields that evaluated 10 herbicide treatments for efficacy on scouringrush. An additional factor in the trials was to determine if pre-herbicide mowing affected herbicide efficacy. At both locations pre-herbicide mowing had no effect on efficacy and only chlorsulfuron plus MCPA-ester controlled scouringrush though the subsequent winter wheat rotation. A third herbicide trial determined that triclopyr or increased rates of chlorsulfuron plus 2,4-D and dicamba or asulam were able to effectively control scouringrush seven and 10 months after treatment at a non-crop site in eastern Oregon. Under field conditions wheat yield reductions were correlated with increasing scouringrush density, but in a controlled study scouringrush density had no effect on winter wheat development or grain yield. Disagreement between these results is hypothesized to be a function of nutrient deficiencies within production fields. Results from three greenhouse studies showed that scouringrush biomass production increased as soil pH increased from ≈4.6 to ≈8.0 and that scouringrush was able to establish and survive in soil pH conditions that are unsuitable for winter wheat production. Title: Expansion of scouringrush (Equisetum spp. L.) : crop interference and control options in winter wheat (Triticum aestivum L.) and chemical fallow cropping cropping systems Author: Kerbs, Blake D. Scouringrushes (Equisetum hyemale L.; E. xferrissii Clute; E. laevigatum L.) are ancient perennial seedless vascular plants historically associated with wetlands, low-lying roadsides or field margins with more plant available water. There has been little research conducted on scouringrush species in the context of agricultural production because traditional farming practices confined them to field margins and roadside depressions. An increasing amount of dryland winter wheat (Triticum aestivum L.) hectares in the inland Pacific Northwest have replaced summer tilled-fallow rotations with chemical fallow. Where chemical fallow rotations have become the standard practice, scouringrush has expanded out of its historical habitat into production fields and established at high enough densities to cause concern from growers. Research was conducted to identify control options that fit chemical fallow cropping systems, evaluate the magnitude of crop interference by scouringrush, and address how soil pH affects scouringrush growth and establishment, as soil acidification is another agronomic issue caused by intensive wheat production in the Pacific Northwest. Field studies located in Reardan, WA, and near The Dalles, OR, were established in commercial wheat production fields that evaluated 10 herbicide treatments for efficacy on scouringrush. An additional factor in the trials was to determine if pre-herbicide mowing affected herbicide efficacy. At both locations pre-herbicide mowing had no effect on efficacy and only chlorsulfuron plus MCPA-ester controlled scouringrush though the subsequent winter wheat rotation. A third herbicide trial determined that triclopyr or increased rates of chlorsulfuron plus 2,4-D and dicamba or asulam were able to effectively control scouringrush seven and 10 months after treatment at a non-crop site in eastern Oregon. Under field conditions wheat yield reductions were correlated with increasing scouringrush density, but in a controlled study scouringrush density had no effect on winter wheat development or grain yield. Disagreement between these results is hypothesized to be a function of nutrient deficiencies within production fields. Results from three greenhouse studies showed that scouringrush biomass production increased as soil pH increased from ≈4.6 to ≈8.0 and that scouringrush was able to establish and survive in soil pH conditions that are unsuitable for winter wheat production. 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• 268. [Article] Assessing the effects of ocean diffusivity and climate sensitivity on the rate of global climate change

  This is the publisher’s final pdf. The published article is copyrighted by Co-Action Publishing and can be found at: http://co-action.net/.

  Citation × Citation Citation Abstract Copy Title: Assessing the effects of ocean diffusivity and climate sensitivity on the rate of global climate change Author: Kothavala, Zavareh, Matthews, H. Damon, Ross, Andrew, Schmittner, Andreas This is the publisher’s final pdf. The published article is copyrighted by Co-Action Publishing and can be found at: http://co-action.net/. Title: Assessing the effects of ocean diffusivity and climate sensitivity on the rate of global climate change Author: Kothavala, Zavareh, Matthews, H. Damon, Ross, Andrew, Schmittner, Andreas This is the publisher’s final pdf. The published article is copyrighted by Co-Action Publishing and can be found at: http://co-action.net/. Close

• 269. [Article] A value-based individual transferable quota scheme - a preliminary examination of its suitability as a fisheries management technique

  Research Paper

  Citation × Citation Citation Abstract Copy Title: A value-based individual transferable quota scheme - a preliminary examination of its suitability as a fisheries management technique Author: Willmann, Rolf Research Paper Title: A value-based individual transferable quota scheme - a preliminary examination of its suitability as a fisheries management technique Author: Willmann, Rolf Research Paper Close

• 270. [Article] Value Chain Analysis of the Sea Cucumber Fishing Industry in Sri Lanka

  Suggested Bibliographic Reference: Challenging New Frontiers in the Global Seafood Sector: Proceedings of the Eighteenth Biennial Conference of the International Institute of Fisheries Economics and Trade, ...

  Citation × Citation Citation Abstract Copy Title: Value Chain Analysis of the Sea Cucumber Fishing Industry in Sri Lanka Author: Dayarathne, Kelum, Dissanayake, Chamari Year: 2016 Suggested Bibliographic Reference: Challenging New Frontiers in the Global Seafood Sector: Proceedings of the Eighteenth Biennial Conference of the International Institute of Fisheries Economics and Trade, July 11-15, 2016. Compiled by Stefani J. Evers and Ann L. Shriver. International Institute of Fisheries Economics and Trade (IIFET), Corvallis, 2016. Title: Value Chain Analysis of the Sea Cucumber Fishing Industry in Sri Lanka Author: Dayarathne, Kelum, Dissanayake, Chamari Year: 2016 Suggested Bibliographic Reference: Challenging New Frontiers in the Global Seafood Sector: Proceedings of the Eighteenth Biennial Conference of the International Institute of Fisheries Economics and Trade, July 11-15, 2016. Compiled by Stefani J. Evers and Ann L. Shriver. International Institute of Fisheries Economics and Trade (IIFET), Corvallis, 2016. Close