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• 21. [Article] Enhancement of the weed competitive ability of lowland rice (Oryza sativa L.) cultivars

  Most of the presently grown cultivars of rice (Oryza sativa L.) have poor competitive ability against weeds if compared with traditional cultivars. Therefore, effective weed control is an important but ...

  Citation × Citation Citation Abstract Copy Title: Enhancement of the weed competitive ability of lowland rice (Oryza sativa L.) cultivars Author: Ranasinghe, Lakshman L. Most of the presently grown cultivars of rice (Oryza sativa L.) have poor competitive ability against weeds if compared with traditional cultivars. Therefore, effective weed control is an important but often costly and difficult management practice in rice crop production. If weed competitive ability of rice cultivars could be improved by changing the plant morphology and some agronomic practices, crop losses and the cost of weed control in rice production would be reduced. Three field experiments were conducted to identify weed competitive morphological traits of rice and to evaluate the effect of delaying starter fertilizer application on weed competition in rice. The nature of rice-barnyardgrass competition varies greatly with rice cultivar morphology. In an addition series experiment, the semi-dwarf, erect leaved, high yielding cultivar BG 350, which possesses much of the plant characteristics required for a high yield was affected much more than the cultivar BG 94-2, which has a tall stature, high leaf area index and good seedling vigor. In the varietal testing experiment, as predicted by the sensitivity analysis, cultivars with rapid height growth, high leaf area growth and plant dry weight increase during seedling stage, height and leaf area at maturity were associated with high competitive ability. The weed competitive ability of tested cultivars varied from relatively high in cultivars PPL and BG 94-2, moderate in BW 267-3 to poor in BG 1611 and BG 350. The delay of starter fertilizer application by 14 days in cultivar BG 350 improved its competitive ability against barnyardgrass (BYG). Under BYG competition, a 14-day delay of starter fertilizer application reduced the percent crop loss by weed competition 6.64 and 22.99% under the normal planting density in the Maha and Yala cultivation seasons, respectively. The crop-weed competition model INTERCOM simulated yield losses for the tested cultivars followed the trends observed in field experiments. However the simulated values were always higher than the observed values. Title: Enhancement of the weed competitive ability of lowland rice (Oryza sativa L.) cultivars Author: Ranasinghe, Lakshman L. Most of the presently grown cultivars of rice (Oryza sativa L.) have poor competitive ability against weeds if compared with traditional cultivars. Therefore, effective weed control is an important but often costly and difficult management practice in rice crop production. If weed competitive ability of rice cultivars could be improved by changing the plant morphology and some agronomic practices, crop losses and the cost of weed control in rice production would be reduced. Three field experiments were conducted to identify weed competitive morphological traits of rice and to evaluate the effect of delaying starter fertilizer application on weed competition in rice. The nature of rice-barnyardgrass competition varies greatly with rice cultivar morphology. In an addition series experiment, the semi-dwarf, erect leaved, high yielding cultivar BG 350, which possesses much of the plant characteristics required for a high yield was affected much more than the cultivar BG 94-2, which has a tall stature, high leaf area index and good seedling vigor. In the varietal testing experiment, as predicted by the sensitivity analysis, cultivars with rapid height growth, high leaf area growth and plant dry weight increase during seedling stage, height and leaf area at maturity were associated with high competitive ability. The weed competitive ability of tested cultivars varied from relatively high in cultivars PPL and BG 94-2, moderate in BW 267-3 to poor in BG 1611 and BG 350. The delay of starter fertilizer application by 14 days in cultivar BG 350 improved its competitive ability against barnyardgrass (BYG). Under BYG competition, a 14-day delay of starter fertilizer application reduced the percent crop loss by weed competition 6.64 and 22.99% under the normal planting density in the Maha and Yala cultivation seasons, respectively. The crop-weed competition model INTERCOM simulated yield losses for the tested cultivars followed the trends observed in field experiments. However the simulated values were always higher than the observed values. Close

• 22. [Article] The agronomic, economic and social effects of the availability of new weed control treatments to small corn farmers in the North Atlantic Zone of Costa Rica

  The North Atlantic zone of Costa Rica is an alluvial plain, whose fairly good soils and warm, extremely wet climate generate serious weed problems in cultivated crops and pastureland. Basic foods - corn, ...

  Citation × Citation Citation Abstract Copy Title: The agronomic, economic and social effects of the availability of new weed control treatments to small corn farmers in the North Atlantic Zone of Costa Rica Author: McCarty, Thomas Vere The North Atlantic zone of Costa Rica is an alluvial plain, whose fairly good soils and warm, extremely wet climate generate serious weed problems in cultivated crops and pastureland. Basic foods - corn, beans, rice and yuca - are important small farm crops. New land is still being opened for small farming, encouraged by a government-sponsored homesteading program. Research was initiated in 1976 by the International Plant Protection Center, in cooperation with CATIE, to determine whether the weed control practices currently used by small farmers could be improved. Agronomic results indicate that tilling the soil gives no advantage over the farmers present no-tillage methods. Pre-plant treatments with the herbicides glyphosate and paraquat have been shown to save labor in corn crops. There is little evidence that the new treatments raise corn yields. A survey of small farmers was conducted in the region in 1977 and 1978. A random sample of 21 farmers were selected for interviews. The information included a general description of each farm family and the complete farm operation and detailed descriptions of cultural practices in corn and beans crop, with special emphasis on weed control. Social and economic information was also obtained. Small farms in the sample are in various stages of development. The first step is usually to brush out the native timberland and fence off areas for a few cattle to graze. Then parcels are cleared for annual crops, especially corn, which is the most dependable cash crop. The farmer rotates parcels for annual crops, weedy fallow and pasture. He constantly attempts to build up his beef herd. Development of perennial plots is limited by the quantities demanded for home and local use. Nearly half the labor, and half the cash resources, expended in corn production are for weed control. The farmers typically cut the weeds with machete and leave the vegetation as mulch before planting, weed the crop with machete or with very light applications of 2,4-D, and cut the weeds once more with machete before doubling the ears and harvesting. Some temporary local shortages of labor occur in the peak periods, when harvesting for one season overlaps with soil preparation and planting for the next, although general underemployment prevails in the long slack periods. Weed conditions influence greatly the quantities of labor used for weed control. Rottboellia exaltata is the most noxious weed in corn cropping. The quantitative information from the survey was tabulated in partial budgets or detailed accounting sheets of variable costs and revenues, for corn parcels on each sample farm. Analysis of variance and regression models were used to test hypothetical relationships among the variables. These results were then compared with estimated capabilities and costs of the experimental weed control treatments for the corn crop on each sample farm. Reported wage rates and calculated returns to family labor were used to estimate the values of family labor. It was found that a minority of the small corn farmers - those who currently use relatively high quantities of cash resources - might be able to reduce costs with the new treatments, without losing revenue. Their increases in cash income would not always exceed the losses in gainful employment suffered by the farmworkers. For the majority of small farmers in the region - those who raise corn with family labor as the main resource - the new treatments do not appear to offer any economic advantages. The treatments are expensive, they offer little promise for raising yields, and their labor-saving effects do not fall squarely in the peak labor periods. It is suggested, therefore, that recommendation of the new treatments should be subject to the farmers' financial conditions and to their actual objectives in growing corn. The use of soil samples and research in the control of pasture weeds are also suggested for further research by the IPPC. Finally, it is suggested that assistance in the development of extra-local banana markets for small farmers might be of great value. Title: The agronomic, economic and social effects of the availability of new weed control treatments to small corn farmers in the North Atlantic Zone of Costa Rica Author: McCarty, Thomas Vere The North Atlantic zone of Costa Rica is an alluvial plain, whose fairly good soils and warm, extremely wet climate generate serious weed problems in cultivated crops and pastureland. Basic foods - corn, beans, rice and yuca - are important small farm crops. New land is still being opened for small farming, encouraged by a government-sponsored homesteading program. Research was initiated in 1976 by the International Plant Protection Center, in cooperation with CATIE, to determine whether the weed control practices currently used by small farmers could be improved. Agronomic results indicate that tilling the soil gives no advantage over the farmers present no-tillage methods. Pre-plant treatments with the herbicides glyphosate and paraquat have been shown to save labor in corn crops. There is little evidence that the new treatments raise corn yields. A survey of small farmers was conducted in the region in 1977 and 1978. A random sample of 21 farmers were selected for interviews. The information included a general description of each farm family and the complete farm operation and detailed descriptions of cultural practices in corn and beans crop, with special emphasis on weed control. Social and economic information was also obtained. Small farms in the sample are in various stages of development. The first step is usually to brush out the native timberland and fence off areas for a few cattle to graze. Then parcels are cleared for annual crops, especially corn, which is the most dependable cash crop. The farmer rotates parcels for annual crops, weedy fallow and pasture. He constantly attempts to build up his beef herd. Development of perennial plots is limited by the quantities demanded for home and local use. Nearly half the labor, and half the cash resources, expended in corn production are for weed control. The farmers typically cut the weeds with machete and leave the vegetation as mulch before planting, weed the crop with machete or with very light applications of 2,4-D, and cut the weeds once more with machete before doubling the ears and harvesting. Some temporary local shortages of labor occur in the peak periods, when harvesting for one season overlaps with soil preparation and planting for the next, although general underemployment prevails in the long slack periods. Weed conditions influence greatly the quantities of labor used for weed control. Rottboellia exaltata is the most noxious weed in corn cropping. The quantitative information from the survey was tabulated in partial budgets or detailed accounting sheets of variable costs and revenues, for corn parcels on each sample farm. Analysis of variance and regression models were used to test hypothetical relationships among the variables. These results were then compared with estimated capabilities and costs of the experimental weed control treatments for the corn crop on each sample farm. Reported wage rates and calculated returns to family labor were used to estimate the values of family labor. It was found that a minority of the small corn farmers - those who currently use relatively high quantities of cash resources - might be able to reduce costs with the new treatments, without losing revenue. Their increases in cash income would not always exceed the losses in gainful employment suffered by the farmworkers. For the majority of small farmers in the region - those who raise corn with family labor as the main resource - the new treatments do not appear to offer any economic advantages. The treatments are expensive, they offer little promise for raising yields, and their labor-saving effects do not fall squarely in the peak labor periods. It is suggested, therefore, that recommendation of the new treatments should be subject to the farmers' financial conditions and to their actual objectives in growing corn. The use of soil samples and research in the control of pasture weeds are also suggested for further research by the IPPC. Finally, it is suggested that assistance in the development of extra-local banana markets for small farmers might be of great value. Close

• 23. [Article] Effect of seed protein content on plant growth of barley and wheat

  The purpose of this study was to evaluate the effect of seed protein content on plant growth of barley (Hordeum vulgare L. ) and wheat (Triticum aestivum L. ). The effects of nitrogen application on chemical ...

  Citation × Citation Citation Abstract Copy Title: Effect of seed protein content on plant growth of barley and wheat Author: Lopez, Arturo The purpose of this study was to evaluate the effect of seed protein content on plant growth of barley (Hordeum vulgare L. ) and wheat (Triticum aestivum L. ). The effects of nitrogen application on chemical and morphological characteristics of the seed were also studied. Seeds of 'Casbon' winter barley and 'Nugaines' winter wheat with different protein content were obtained by field applications of various amounts of nitrogen at seeding time (fall) and tillering time (spring). The increase in protein content from high nitrogen rates was accompanied by a decrease in seed size and yield. The protein increase occurred primarily in the endosperm. Neither protein content nor size of the embryo was affected by rates of nitrogen application. The effect of seed protein content on plant growth was evaluated in terms of inhibition and respiration, speed of germination and subsequent seedling growth, root and shoot elongation at 15, 20 and 25C, and dry matter production when grown in low and high nitrogen soils in the green house. A positive relationship was found between seed protein content and plant performance. The rates of water absorption and oxygen consumption of germinating barley and wheat seed increased as a result of high protein content. High protein seed had a faster speed of germination and developed into larger seedlings with a higher dry matter content when grown in nitrogen-deficient soil. In nitrogen-enriched soil, seed protein content had little effect on seedling growth. The beneficial effects of seed protein content are more clearly expressed under stress conditions and are more evident when plant growth depends on the nutrients available from the seed. During initiation of germination, temperature influences the expression of the protein effect. After the seedling has formed and is capable of photosynthesis, the nitrogen availability in the soil influences the effect of seed protein content on plant growth. The relationship between seed protein content and plant growth can be an important factor in crop production because the increase in protein can be controlled by field application of nitrogen. However, since the high rates of nitrogen necessary to produce high seed protein levels are not consistent with the optimum nitrogen rates for yield, growers would probably be reluctant to apply such high rates unless some type of incentive were given them to do so. For seed production, it could still be important to strive for high protein levels in spite of some loss in yield if improved performance from high protein seeds proves to be of economic value. The results of this study indicate that producing and planting seeds rich in protein may be an effective method of achieving faster stand establishment of cereal crops. Additional research will determine the effects of high protein on yield. Title: Effect of seed protein content on plant growth of barley and wheat Author: Lopez, Arturo The purpose of this study was to evaluate the effect of seed protein content on plant growth of barley (Hordeum vulgare L. ) and wheat (Triticum aestivum L. ). The effects of nitrogen application on chemical and morphological characteristics of the seed were also studied. Seeds of 'Casbon' winter barley and 'Nugaines' winter wheat with different protein content were obtained by field applications of various amounts of nitrogen at seeding time (fall) and tillering time (spring). The increase in protein content from high nitrogen rates was accompanied by a decrease in seed size and yield. The protein increase occurred primarily in the endosperm. Neither protein content nor size of the embryo was affected by rates of nitrogen application. The effect of seed protein content on plant growth was evaluated in terms of inhibition and respiration, speed of germination and subsequent seedling growth, root and shoot elongation at 15, 20 and 25C, and dry matter production when grown in low and high nitrogen soils in the green house. A positive relationship was found between seed protein content and plant performance. The rates of water absorption and oxygen consumption of germinating barley and wheat seed increased as a result of high protein content. High protein seed had a faster speed of germination and developed into larger seedlings with a higher dry matter content when grown in nitrogen-deficient soil. In nitrogen-enriched soil, seed protein content had little effect on seedling growth. The beneficial effects of seed protein content are more clearly expressed under stress conditions and are more evident when plant growth depends on the nutrients available from the seed. During initiation of germination, temperature influences the expression of the protein effect. After the seedling has formed and is capable of photosynthesis, the nitrogen availability in the soil influences the effect of seed protein content on plant growth. The relationship between seed protein content and plant growth can be an important factor in crop production because the increase in protein can be controlled by field application of nitrogen. However, since the high rates of nitrogen necessary to produce high seed protein levels are not consistent with the optimum nitrogen rates for yield, growers would probably be reluctant to apply such high rates unless some type of incentive were given them to do so. For seed production, it could still be important to strive for high protein levels in spite of some loss in yield if improved performance from high protein seeds proves to be of economic value. The results of this study indicate that producing and planting seeds rich in protein may be an effective method of achieving faster stand establishment of cereal crops. Additional research will determine the effects of high protein on yield. Close

• 24. [Article] Biodiesel in Oregon: an agricultural perspective

  Biodiesel is a renewable, non-toxic, and biodegradable diesel fuel made from agricultural feedstocks. With a vibrant agricultural industry, Oregon is positioned to play an important role in the future ...

  Citation × Citation Citation Abstract Copy Title: Biodiesel in Oregon: an agricultural perspective Author: Lahmann, Emily Loren Biodiesel is a renewable, non-toxic, and biodegradable diesel fuel made from agricultural feedstocks. With a vibrant agricultural industry, Oregon is positioned to play an important role in the future of this energy source. Limiting factors to widespread biodiesel production include low value of biodiesel feedstock crops, lack of infrastructure, lagging consumer demand, and high production costs. These factors are slowing the growth of the biodiesel industry in Oregon. This project identified opportunities and limitations for a partnership between agriculture and biodiesel in the Willamette Valley and the state of Oregon more broadly. In-depth interviews and a survey of farmer attitudes toward, familiarity with, and experience with biodiesel were conducted. Findings from this survey indicate that a majority of farmers are aware of the role agriculture can play in the future of biodiesel, agree that they have an opportunity to help reduce our nation’s dependence on foreign oil, believe that biodiesel will be an important national market for Oregon agricultural products in the next ten years, and are interested in the ability of biodiesel to provide a profitable crop. The opportunities are obvious; farmers are positively predisposed to biodiesel and wait for openings to become full participants in Oregon’s biodiesel future. Title: Biodiesel in Oregon: an agricultural perspective Author: Lahmann, Emily Loren Biodiesel is a renewable, non-toxic, and biodegradable diesel fuel made from agricultural feedstocks. With a vibrant agricultural industry, Oregon is positioned to play an important role in the future of this energy source. Limiting factors to widespread biodiesel production include low value of biodiesel feedstock crops, lack of infrastructure, lagging consumer demand, and high production costs. These factors are slowing the growth of the biodiesel industry in Oregon. This project identified opportunities and limitations for a partnership between agriculture and biodiesel in the Willamette Valley and the state of Oregon more broadly. In-depth interviews and a survey of farmer attitudes toward, familiarity with, and experience with biodiesel were conducted. Findings from this survey indicate that a majority of farmers are aware of the role agriculture can play in the future of biodiesel, agree that they have an opportunity to help reduce our nation’s dependence on foreign oil, believe that biodiesel will be an important national market for Oregon agricultural products in the next ten years, and are interested in the ability of biodiesel to provide a profitable crop. The opportunities are obvious; farmers are positively predisposed to biodiesel and wait for openings to become full participants in Oregon’s biodiesel future. Close

• 25. [Article] Quantifying the fertilizer value of algal meal : an evaluation of an integrated dairy-anaerobic digester-algae production facility

  Algae have shown great potential as a source for renewable fuels. However, current production schemes have not been able to prove a sustainable energy return on investment due in part to the high costs ...

  Citation × Citation Citation Abstract Copy Title: Quantifying the fertilizer value of algal meal : an evaluation of an integrated dairy-anaerobic digester-algae production facility Author: Andrews, Shannon B. Algae have shown great potential as a source for renewable fuels. However, current production schemes have not been able to prove a sustainable energy return on investment due in part to the high costs of nutrient addition and the energy required for drying the biomass. Integrated algae-dairy production systems have been posited as a potential solution for algal production barriers as well as a way to capture environmentally problematic nutrients excreted by animals in concentrated animal feeding operations. As the organic food industry grows, so will the need for organic nitrogen (N) fertilizers. Algal meal, the high protein co-product of algal biodiesel production, could help meet this need. This work has two objectives: 1) to quantify the fertilizer value of algal meal relative to an organic N fertilizer, feather meal, and a conventional standard, urea; 2) to show that utilizing the fertilizer value of algal meal at $800 Mg⁻¹ will allow an integrated dairy-anaerobic digester-algae production facility to be an economically viable manure management system. A laboratory incubation was carried out to characterize carbon (C) and N mineralization of two different algal meal products. The N mineralization rate, C respiration rate, and impact on pH and soluble salts were the same for feather meal and one of the algal meals. A field trial was conducted to assess the overall crop productivity of corn grown with algal meal fertilizer, feather meal, and urea. There was no significant difference in corn ear yield or ear N uptake among any of the algal meal treatment rates (101 kg N ha⁻¹, 146 kg N ha⁻¹, 190 kg N ha⁻¹) and the high rate of feather meal or urea (190 kg N ha⁻¹) application. These results indicate that algal meal is an effective N fertilizer that should be valued relative to feather meal on a price per unit of nutrient basis. Considering environmental benefits and current policy incentives, assigning a fertilizer value of algal meal of $800 Mg⁻¹ for a 7-3-1 product adds enough income to make an integrated dairy-anaerobic digester-algae system an economically viable, sustainable farm-energy production system. Title: Quantifying the fertilizer value of algal meal : an evaluation of an integrated dairy-anaerobic digester-algae production facility Author: Andrews, Shannon B. Algae have shown great potential as a source for renewable fuels. However, current production schemes have not been able to prove a sustainable energy return on investment due in part to the high costs of nutrient addition and the energy required for drying the biomass. Integrated algae-dairy production systems have been posited as a potential solution for algal production barriers as well as a way to capture environmentally problematic nutrients excreted by animals in concentrated animal feeding operations. As the organic food industry grows, so will the need for organic nitrogen (N) fertilizers. Algal meal, the high protein co-product of algal biodiesel production, could help meet this need. This work has two objectives: 1) to quantify the fertilizer value of algal meal relative to an organic N fertilizer, feather meal, and a conventional standard, urea; 2) to show that utilizing the fertilizer value of algal meal at $800 Mg⁻¹ will allow an integrated dairy-anaerobic digester-algae production facility to be an economically viable manure management system. A laboratory incubation was carried out to characterize carbon (C) and N mineralization of two different algal meal products. The N mineralization rate, C respiration rate, and impact on pH and soluble salts were the same for feather meal and one of the algal meals. A field trial was conducted to assess the overall crop productivity of corn grown with algal meal fertilizer, feather meal, and urea. There was no significant difference in corn ear yield or ear N uptake among any of the algal meal treatment rates (101 kg N ha⁻¹, 146 kg N ha⁻¹, 190 kg N ha⁻¹) and the high rate of feather meal or urea (190 kg N ha⁻¹) application. These results indicate that algal meal is an effective N fertilizer that should be valued relative to feather meal on a price per unit of nutrient basis. Considering environmental benefits and current policy incentives, assigning a fertilizer value of algal meal of $800 Mg⁻¹ for a 7-3-1 product adds enough income to make an integrated dairy-anaerobic digester-algae system an economically viable, sustainable farm-energy production system. Close

• 26. [Article] Broadening the horizons of inland fish-farming in the African economy

  Research Paper

  Citation × Citation Citation Abstract Copy Title: Broadening the horizons of inland fish-farming in the African economy Author: Tazoacha, Francis Research Paper Title: Broadening the horizons of inland fish-farming in the African economy Author: Tazoacha, Francis Research Paper Close

• 27. [Article] The influence of air and soil temperatures on the growth and development of Easter lily, Lilium longiflorum, during different growth phases

  Greenhouse-grown, September-harvested Lilium longiflorum cv. 'Nellie white' bulbs were used to determine temperature requirements during 5 pre-bloom and 1 post-bloom phases of development each of 1 month's ...

  Citation × Citation Citation Abstract Copy Title: The influence of air and soil temperatures on the growth and development of Easter lily, Lilium longiflorum, during different growth phases Author: Wang, Yin-Tung Greenhouse-grown, September-harvested Lilium longiflorum cv. 'Nellie white' bulbs were used to determine temperature requirements during 5 pre-bloom and 1 post-bloom phases of development each of 1 month's duration. Plantes were subjected to 3 air temperatures(24°day/ 18°C night, 18°/13° and 13°/10°) in combination with soil temperatures at 30°, 24°, and equal to or lower than ambient air temperature during each growth phase and evaluated by growth analysis at the termination of each phase. This study has substantiated that top growth needs high air temperature and daughter scale initiation and filling require high soil temperature. An air and soil temperature of 24°C was required for rapid flowering, leaf unfolding and stem elongation but at the expense of reserves in mother scales. Air temperature approaching 18°/13° during the month prior to anthesis favored maintenance of mother scales. Growth of daughter scales during the pre-bloom period was directly related to soil temperature rather than air temperature with 30° soil temperature being no better than 24°. Soil temperature had no effect on flower bud expansion after buds-visible stage, air temperature being the determining factor thereafter. Growth of the flower bud, leaf unfolding rate or stem elongation were of equal value in monitoring crop growth rate and status. Soil temperatures approaching 24°C. favored scale primordia initiation, regardless of air temperature. Daughter meristem diameter, as well as the rate of scale primordia initiation decreased progressively from daughter bulb appearance toward anthesis of the mother axis. High soil temperatures also reduced daughter bulb apex diameter during early growth phases. Since prevailing air and soil temperatures in the commercial lily growing sites are below those required for maximum growth and development of above- and below-ground organs during the pre-bloom period, it is concluded that air temperatures alone are adequate in monitoring field crop status and predicting ultimate yield potential during this period. Title: The influence of air and soil temperatures on the growth and development of Easter lily, Lilium longiflorum, during different growth phases Author: Wang, Yin-Tung Greenhouse-grown, September-harvested Lilium longiflorum cv. 'Nellie white' bulbs were used to determine temperature requirements during 5 pre-bloom and 1 post-bloom phases of development each of 1 month's duration. Plantes were subjected to 3 air temperatures(24°day/ 18°C night, 18°/13° and 13°/10°) in combination with soil temperatures at 30°, 24°, and equal to or lower than ambient air temperature during each growth phase and evaluated by growth analysis at the termination of each phase. This study has substantiated that top growth needs high air temperature and daughter scale initiation and filling require high soil temperature. An air and soil temperature of 24°C was required for rapid flowering, leaf unfolding and stem elongation but at the expense of reserves in mother scales. Air temperature approaching 18°/13° during the month prior to anthesis favored maintenance of mother scales. Growth of daughter scales during the pre-bloom period was directly related to soil temperature rather than air temperature with 30° soil temperature being no better than 24°. Soil temperature had no effect on flower bud expansion after buds-visible stage, air temperature being the determining factor thereafter. Growth of the flower bud, leaf unfolding rate or stem elongation were of equal value in monitoring crop growth rate and status. Soil temperatures approaching 24°C. favored scale primordia initiation, regardless of air temperature. Daughter meristem diameter, as well as the rate of scale primordia initiation decreased progressively from daughter bulb appearance toward anthesis of the mother axis. High soil temperatures also reduced daughter bulb apex diameter during early growth phases. Since prevailing air and soil temperatures in the commercial lily growing sites are below those required for maximum growth and development of above- and below-ground organs during the pre-bloom period, it is concluded that air temperatures alone are adequate in monitoring field crop status and predicting ultimate yield potential during this period. Close

• 28. [Article] Effect of cereal companion crops on the establishment of red fescue (Festuca rubra L.) for seed production

  Some perennial grass seed crops such as red fescue (Festuca rubra L.) do not produce a profitable seed crop during the first growing season. The present establishment method in Oregon for red fescue seed crops ...

  Citation × Citation Citation Abstract Copy Title: Effect of cereal companion crops on the establishment of red fescue (Festuca rubra L.) for seed production Author: Chastain, Thomas G. Some perennial grass seed crops such as red fescue (Festuca rubra L.) do not produce a profitable seed crop during the first growing season. The present establishment method in Oregon for red fescue seed crops generally entails spring planting which does not satisfy vernalization requirements for seed production in the year of planting. This establishment procedure relies on the amortization of establishment costs over the seed producing life of the stand. In Europe, perennial grass seed crops are often established with annual companion crops such as winter rape, flax, peas and cereals. Companion crops provide income in the year of establishment, thereby increasing the profitability of the seed production venture over the life of the stand. However, the companion crop competes with the grass seed crop for light, soil moisture and nutrients which often causes unsatisfactory establishment. The primary objective of this study was to determine the feasibility of establishing red fescue with cereal companion crops in Oregon's Willamette Valley. The second objective was to examine the influence of cereal companion crops, cultivars and row spacings on the growth and environment of red fescue. This was investigated to identify companion cropping methods that would be the least competitive with the establishing seed crop. The third objective was to evaluate the effect of companion cropping on subsequent red fescue seed production and income relationships over a two-year period. Two experiments were initiated in October 1982 and October 1983 at the Oregon State University Hyslop Crop Science Field Laboratory. 'Pennlawn' red fescue was established with two winter wheat cultivars, 'Hill 81' and 'Yamhill1, and two winter barley cultivars, 'Hesk' and 'Scio', as companion crops. Cereal companion crops were drilled in 15-, 30-, 45-, and 60-cm row spacings, perpendicular to red fescue rows. Red fescue was also established without a companion crop as a control. Companion crop tiller height, tillers m⁻² and leaf area tiller⁻¹ were measured to determine their influence on red fescue growth and development during establishment. The effect of cereal companion crops on red fescue environment was investigated by measuring photosynthetic photon flux density (PPFD) incident on red fescue plants and by determining soil moisture levels. Red fescue tiller height, leaf area, dry matter production, and tillers m⁻² were examined to evaluate the effect of companion crops on red fescue growth. Companion crop grain yields were obtained to calculate additional revenues from establishment with companion crops. First-year red fescue seed yield and yield components were measured to determine the seed production capability of red fescue established with cereal companion crops. Finally, a partial budgeting technique was employed to evaluate the economic feasibility of companion cropping in Oregon. Cereal companion crops markedly reduced PPFD incident on red fescue plants. This greatly decreased red fescue tiller m⁻², dry matter m⁻², individual tiller weight, and increased the height of tillers. Leaf area tiller⁻¹ was generally unaffected by companion crops. Increasing companion crop row spacing resulted in more red fescue tillers m⁻², dry matter m⁻² and reduced etiolation of tillers because of higher PPFD availability. Soil moisture content was not decreased by establishment with cereal companion crops. Although companion crops adversely affected red fescue growth during the establishment year, first-year seed yield was not significantly reduced. Red fescue seed yields ranged from 490 kg ha⁻¹ when planted with Hill 81 wheat to 654 kg ha⁻¹ with Scio barley. The seed yield of red fescue planted without a companion crop was 589 kg ha⁻¹. Establishment with Yamhill wheat in 15-cm rows increased net income over a two-year period by $416 ha⁻¹ over monocultural red fescue. Establishment with Hesk barley proved to be the least successful in terms of income. Establishment with companion crops was shown to be most profitable when cereal market prices were high and red fescue prices low. The results of this research clearly indicate the potential for increased profits by establishment of red fescue seed crops with cereal companion crops. Title: Effect of cereal companion crops on the establishment of red fescue (Festuca rubra L.) for seed production Author: Chastain, Thomas G. Some perennial grass seed crops such as red fescue (Festuca rubra L.) do not produce a profitable seed crop during the first growing season. The present establishment method in Oregon for red fescue seed crops generally entails spring planting which does not satisfy vernalization requirements for seed production in the year of planting. This establishment procedure relies on the amortization of establishment costs over the seed producing life of the stand. In Europe, perennial grass seed crops are often established with annual companion crops such as winter rape, flax, peas and cereals. Companion crops provide income in the year of establishment, thereby increasing the profitability of the seed production venture over the life of the stand. However, the companion crop competes with the grass seed crop for light, soil moisture and nutrients which often causes unsatisfactory establishment. The primary objective of this study was to determine the feasibility of establishing red fescue with cereal companion crops in Oregon's Willamette Valley. The second objective was to examine the influence of cereal companion crops, cultivars and row spacings on the growth and environment of red fescue. This was investigated to identify companion cropping methods that would be the least competitive with the establishing seed crop. The third objective was to evaluate the effect of companion cropping on subsequent red fescue seed production and income relationships over a two-year period. Two experiments were initiated in October 1982 and October 1983 at the Oregon State University Hyslop Crop Science Field Laboratory. 'Pennlawn' red fescue was established with two winter wheat cultivars, 'Hill 81' and 'Yamhill1, and two winter barley cultivars, 'Hesk' and 'Scio', as companion crops. Cereal companion crops were drilled in 15-, 30-, 45-, and 60-cm row spacings, perpendicular to red fescue rows. Red fescue was also established without a companion crop as a control. Companion crop tiller height, tillers m⁻² and leaf area tiller⁻¹ were measured to determine their influence on red fescue growth and development during establishment. The effect of cereal companion crops on red fescue environment was investigated by measuring photosynthetic photon flux density (PPFD) incident on red fescue plants and by determining soil moisture levels. Red fescue tiller height, leaf area, dry matter production, and tillers m⁻² were examined to evaluate the effect of companion crops on red fescue growth. Companion crop grain yields were obtained to calculate additional revenues from establishment with companion crops. First-year red fescue seed yield and yield components were measured to determine the seed production capability of red fescue established with cereal companion crops. Finally, a partial budgeting technique was employed to evaluate the economic feasibility of companion cropping in Oregon. Cereal companion crops markedly reduced PPFD incident on red fescue plants. This greatly decreased red fescue tiller m⁻², dry matter m⁻², individual tiller weight, and increased the height of tillers. Leaf area tiller⁻¹ was generally unaffected by companion crops. Increasing companion crop row spacing resulted in more red fescue tillers m⁻², dry matter m⁻² and reduced etiolation of tillers because of higher PPFD availability. Soil moisture content was not decreased by establishment with cereal companion crops. Although companion crops adversely affected red fescue growth during the establishment year, first-year seed yield was not significantly reduced. Red fescue seed yields ranged from 490 kg ha⁻¹ when planted with Hill 81 wheat to 654 kg ha⁻¹ with Scio barley. The seed yield of red fescue planted without a companion crop was 589 kg ha⁻¹. Establishment with Yamhill wheat in 15-cm rows increased net income over a two-year period by $416 ha⁻¹ over monocultural red fescue. Establishment with Hesk barley proved to be the least successful in terms of income. Establishment with companion crops was shown to be most profitable when cereal market prices were high and red fescue prices low. The results of this research clearly indicate the potential for increased profits by establishment of red fescue seed crops with cereal companion crops. Close

• 29. [Article] Biological considerations for a new approach to regulating genetically modified crops in the United States

  The debate over GM crops is one of the most controversial issues of recent decades. The debate has many dimensions, including environmental impacts, benefits and risks to human health, intellectual property ...

  Citation × Citation Citation Abstract Copy Title: Biological considerations for a new approach to regulating genetically modified crops in the United States Author: McDonough, Ashley The debate over GM crops is one of the most controversial issues of recent decades. The debate has many dimensions, including environmental impacts, benefits and risks to human health, intellectual property rights, adequacy of biosafety regulations, and fundamental ethical acceptability. The potential benefits of GM crops are numerous, including improved nutritional value, decreased production costs, resistance to pests, and reduced pesticide use. However, there are also substantial and complex health, environmental, and social risks, including effects on gene flow and biodiversity, creation of new toxins or allergens in food, consolidation of seed companies, and restricted access to genetic information and methods. Current US regulations are imposed only on crops produced through recombinant DNA methods, though all of these risks apply to crops modified through conventional biotechnologies as well. I argue that this current regulatory system impedes progress by presenting large obstacles to even low risk GM crops with medical and economic benefits. I suggest that a better approach would be a tiered system that takes into account the specific biological properties of the modified traits, the biology of the crops in which they are produced, and the environments in which they are grown. Title: Biological considerations for a new approach to regulating genetically modified crops in the United States Author: McDonough, Ashley The debate over GM crops is one of the most controversial issues of recent decades. The debate has many dimensions, including environmental impacts, benefits and risks to human health, intellectual property rights, adequacy of biosafety regulations, and fundamental ethical acceptability. The potential benefits of GM crops are numerous, including improved nutritional value, decreased production costs, resistance to pests, and reduced pesticide use. However, there are also substantial and complex health, environmental, and social risks, including effects on gene flow and biodiversity, creation of new toxins or allergens in food, consolidation of seed companies, and restricted access to genetic information and methods. Current US regulations are imposed only on crops produced through recombinant DNA methods, though all of these risks apply to crops modified through conventional biotechnologies as well. I argue that this current regulatory system impedes progress by presenting large obstacles to even low risk GM crops with medical and economic benefits. I suggest that a better approach would be a tiered system that takes into account the specific biological properties of the modified traits, the biology of the crops in which they are produced, and the environments in which they are grown. Close

• 30. [Article] The effect of soil acidity and lime placement on root growth and yield of winter wheat and alfalfa

  The application of lime to an acid Nekia soil significantly increased the yield of winter wheat and alfalfa in a field experiment. Crop yields maximized when the lime was partially mixed into the surface four ...

  Citation × Citation Citation Abstract Copy Title: The effect of soil acidity and lime placement on root growth and yield of winter wheat and alfalfa Author: Kauffman, Marvin Dean The application of lime to an acid Nekia soil significantly increased the yield of winter wheat and alfalfa in a field experiment. Crop yields maximized when the lime was partially mixed into the surface four inches of the soil. Thorough mixing of the lime into the surface six inches of soil did not increase crop yields over partial mixing of lime, and on some plots the yields were reduced by the more thorough mixing treatment. The reduction in yield on the thoroughly mixed plots occurred with the lower rates of lime application. Deterioration of soil structure due to rototilling was also a factor in the reduction of yield in the plots where the lime was thoroughly mixed. The yields of wheat decreased over a three-year period following the application of one ton of lime per acre. It was felt that part of this decrease in yield was caused by a more thorough mixing of the lime into the soil with annual seedbed preparation on the partially mixed plots, and by a decrease of Ca and increase of Al in the soil solution as the quantity of free lime in the soil decreased. The importance of the soil solution pH and Al and Ca concentrations in the soil solution is also demonstrated by the fact that the R 2 values for the relationship between the soil test pH and wheat yields, were highest for the 1 N KC1 pH values the first two years, and highest for the water pH value the third year. Third-year wheat yields were also decreased by an infestation of the root fungus, Ophiobolus Graninus, with the adverse effect on the yield decreasing as the lime rates increased. High levels of soil acidity adversely affected the survival of the alfalfa seedlings and the rhizobia which inoculate the alfalfa. The concentration of nitrogen in the plants and the quantity of nitrogen harvested in the plants, increased as the rate of lime applied increased. The wheat and alfalfa roots which grew in the unlimed soil exhibited Al-toxicity symptoms. The Al-toxic roots were thicker than the healthy roots, and there was very little lateral root development on the Al-affected roots. The application of the intermediate and high rates of lime to the acid Nekia soil eliminated the Al-toxicity symptoms and promoted the growth of fine fibrous root systems. The distribution of the alfalfa roots in the samples taken from the field experiment, corresponded with the distribution of the lime in the soil. The field experimental data showed that the yields of wheat and alfalfa were closely correlated to the weight of the root samples. Growth chamber experiments using winter wheat as an indicator crop and acid Nekia and Dayton soils were also conducted. Maximum yields of dry matter were harvested when 30 per cent of the total soil volume was limed, and the dry matter yield decreased as the low rate of lime was mixed into larger volumes of soil. The wheat roots grew in the limed portion of soil, whereas root growth was restricted in the unlimed soil. Plant analysis data showed that the concentrations of plant nutrients were similar for all lime treatments. Plant water potential data indicated that water stress induced by Al-toxicity of wheat roots contributed to the lower yields of wheat grown in soil receiving zero and one ton of lime per acre. Title: The effect of soil acidity and lime placement on root growth and yield of winter wheat and alfalfa Author: Kauffman, Marvin Dean The application of lime to an acid Nekia soil significantly increased the yield of winter wheat and alfalfa in a field experiment. Crop yields maximized when the lime was partially mixed into the surface four inches of the soil. Thorough mixing of the lime into the surface six inches of soil did not increase crop yields over partial mixing of lime, and on some plots the yields were reduced by the more thorough mixing treatment. The reduction in yield on the thoroughly mixed plots occurred with the lower rates of lime application. Deterioration of soil structure due to rototilling was also a factor in the reduction of yield in the plots where the lime was thoroughly mixed. The yields of wheat decreased over a three-year period following the application of one ton of lime per acre. It was felt that part of this decrease in yield was caused by a more thorough mixing of the lime into the soil with annual seedbed preparation on the partially mixed plots, and by a decrease of Ca and increase of Al in the soil solution as the quantity of free lime in the soil decreased. The importance of the soil solution pH and Al and Ca concentrations in the soil solution is also demonstrated by the fact that the R 2 values for the relationship between the soil test pH and wheat yields, were highest for the 1 N KC1 pH values the first two years, and highest for the water pH value the third year. Third-year wheat yields were also decreased by an infestation of the root fungus, Ophiobolus Graninus, with the adverse effect on the yield decreasing as the lime rates increased. High levels of soil acidity adversely affected the survival of the alfalfa seedlings and the rhizobia which inoculate the alfalfa. The concentration of nitrogen in the plants and the quantity of nitrogen harvested in the plants, increased as the rate of lime applied increased. The wheat and alfalfa roots which grew in the unlimed soil exhibited Al-toxicity symptoms. The Al-toxic roots were thicker than the healthy roots, and there was very little lateral root development on the Al-affected roots. The application of the intermediate and high rates of lime to the acid Nekia soil eliminated the Al-toxicity symptoms and promoted the growth of fine fibrous root systems. The distribution of the alfalfa roots in the samples taken from the field experiment, corresponded with the distribution of the lime in the soil. The field experimental data showed that the yields of wheat and alfalfa were closely correlated to the weight of the root samples. Growth chamber experiments using winter wheat as an indicator crop and acid Nekia and Dayton soils were also conducted. Maximum yields of dry matter were harvested when 30 per cent of the total soil volume was limed, and the dry matter yield decreased as the low rate of lime was mixed into larger volumes of soil. The wheat roots grew in the limed portion of soil, whereas root growth was restricted in the unlimed soil. Plant analysis data showed that the concentrations of plant nutrients were similar for all lime treatments. Plant water potential data indicated that water stress induced by Al-toxicity of wheat roots contributed to the lower yields of wheat grown in soil receiving zero and one ton of lime per acre. Close