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2661. [Article] Weed, water, and nutrient management practices for organic blackberry during establishment
The study was conducted in an organic trailing blackberry (Rubus L. subgenus Rubus, Watson) planting established at the North Willamette Research and Extension Center in Aurora, OR on 26 May 2010. Three ...Citation Citation
- Title:
- Weed, water, and nutrient management practices for organic blackberry during establishment
- Author:
- Harkins, Renee H.
The study was conducted in an organic trailing blackberry (Rubus L. subgenus Rubus, Watson) planting established at the North Willamette Research and Extension Center in Aurora, OR on 26 May 2010. Three weed management systems were compared for 'Marion' and 'Black Diamond': 1) non-weeded; 2) hand-hoed two to three times per year (hand weed); and 3) black landscape fabric mulch (weed mat). The planting was certified organic in May 2012, the first fruiting year. Aboveground weed dry weight (DW) increased from 2010 through 2012 in the non-weeded plots. Findings suggest that nitrogen (N) was the major nutrient affecting blackberry cane growth and fruit development. Other nutrients were considered sufficient as evidenced by soil and plant tissue testing, with the exception of calcium (Ca) and boron, which were at the low end of the sufficiency range in some soil and tissue samples. Soil nutrients fluctuated a small amount by distance and location relative to the emitter and sampling depth. However overall nutrient concentrations were adequate for good blackberry growth. Given some of the observed nutrient trends, soil sampling should be completed in-row, under the drip emitters where fertilizer is applied, at a 0.15 cm depth, to ensure proper long-term soil management. Total aboveground plant biomass increased from 0.3 and 2.0 t·ha⁻¹ in the non-fruiting years (2010 and 2011, respectively) to 3.4 t·ha⁻¹ in the fruiting year (2012). Primocane number and plant DW were not affected by cultivar or weed management in 2010. In 2011, 'Black Diamond' had shorter primocanes and less biomass and macro- and micro-nutrient accumulation than 'Marion'. Plants grown without weed control produced fewer but longer primocanes with less biomass and lower nutrient content. In 2012, floricane biomass removed at pruning was greater for ‘Marion’ plants and was least for plants in non-weeded plots, and greatest for plants in weed mat plots. Floricanes had greater macro- and micronutrient concentrations than the primocanes, but less than when the floricane leaves were sampled in July, indicating nutrient loss to the fruit and possibly remobilization of some nutrients during cane senescence. Ultimately, floricanes were also a sink for nutrients, reducing primocane biomass in 2012. During the first harvest year (2012), the cultivars did not differ in the DW yield, however, 'Black Diamond' had a greater fresh yield than 'Marion' (6.0 kg·plant⁻¹ and 5.2 kg·plant⁻¹, respectively). The proportion of above-ground DW biomass allocated to fruit in weed controlled plots averaged 40% in 'Marion' and 56% in 'Black Diamond', suggesting a greater yield efficiency of 'Black Diamond' plants. Non-weeded plots produced approx. half the fresh yield (3.65 kg·plant-1), 39% of the fruit DW biomass as weed mat plots, and the treatment had fruit with lower moisture content, higher percent soluble solids, and lower Ca concentrations, than the other treatments. Net gain of N averaged 41 kg·ha⁻¹ with weed control compared to 25 kg·ha⁻¹ without weed control. Both cultivars accumulated large quantities of N, potassium, and Ca for growth and yield. Nutrient gains may have exceeded fertilizer nutrients available in the fruit production year. Overall, cultivar and weed management strategies had inconsistent effects on tissue and soil nutrient status during the study, with the exception of N. 'Black Diamond' and 'Marion' performed similarly across all three weed management strategies and appeared well suited to organic production for high-value processed markets. Weed mat appeared best suited for organic systems, reducing labor required for weed control, enhancing nutrient uptake by plants, and producing the greatest amount of plant growth and yield. Weed management strategies affected nutrient accumulation and loss, indicating fertilization may need to be adjusted depending on the strategy used.
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Response from nitrogen and chloride fertilization was measured in field experiments on winter wheat (Triticum aestivum L. Em. Thell. var. 'Stephens' and 'Yamhill') grown in western Oregon in an environment ...
Citation Citation
- Title:
- Response of winter wheat (Triticum aestivum L. Em. Thell) to nitrogen and chloride fertilization in the presence of take-all root rot (Gaeumannomyces graminis var. tritici Walker)
- Author:
- Maatougui, Mohamed El Hadi
Response from nitrogen and chloride fertilization was measured in field experiments on winter wheat (Triticum aestivum L. Em. Thell. var. 'Stephens' and 'Yamhill') grown in western Oregon in an environment with a range of susceptibility to take-all root rot (Gaumannomyces graminis var. tritici Walker). Cropping sequences and expected disease severity considered in the study were: first year wheat after clover (low risk of severe take-all root rot: Nixon I experiment), second year wheat with high disease infection in the previous crop (high risk of severe take-all root rot: Keyt II experiment), second year wheat with low disease infection in the previous crop (moderate risk of severe take-all root rot: Nixon II and Coon experiment), third year wheat (high risk of severe take-all root rot: Jones experiment), fifth year wheat (high risk of severe take-all root rot: Keyt II experiment), and eighteenth year wheat (take-all decline established: the pathogen is present in the soil but does not cause damage, Evers experiment). Nitrogen treatments were applied at 0, 67, 134, and 202 kg/ha in all experiments where wheat followed wheat and at 0, 45, 90, and 134 kg/ha in the experiment where wheat followed clover. Chloride treatments were applied at 0, 45, and 90 kg/ha in all experiments and a rate of 134 kg C1/ha was also used on the Jones experiment. Nitrogen was predominantly supplied from urea while ammonium chloride supplied chloride and ammonium sulfate supplied the crop requirement for sulfur (about 20 kg/ha). Fertilizers were top-dressed in split application with chloride and sulfur containing fertilizers applied first (February) and urea applied later (March) in all experiments but those conducted in the Nixon farm where a single fertilizer was applied in March. Crop response was measured through the effects of N and c1 treatments on dry matter production, plant nitrogen content, plant nitrogen uptake and plant percent nitrogen recovery, as well as grain yield, yield components, grain nitrogen content, grain protein content, grain nitrogen uptake, and grain percent nitrogen recovery. The results of the study strongly indicated that take-all root rot was only a problem in the Jones, Keyt I, and Keyt II experiments and was most severe in third year wheat (Jones experiment). This also was the only experiment with significant (p = 0.05) response from rates of 202 kg N/ha. Nitrogen fertilization was the main factor that greatly influenced the levels of the variables studied while chloride fertilization generally did not have a significant (p = 0.05) influence. 134 kg N/ha was generally the rate accounting for the best levels of each variable studied in all experiments except in the Jones experiment as precised earlier. Crop response was also affected by a relatively long 'dry' period (April 20th to June 20th), particularly in the experiment where take-all root rot was a problem. Levels of the variables studied accounted for by the optimum rates of N were consistently higher in the experiments where take-all root rot was not a problem than where it was a problem by the following amounts: dry matter yields-17%, plant nitrogen contents-18%, plant nitrogen uptake levels-30%, plant nitrogen recoveries-28%, grain yields-22%, grain nitrogen contents-only 4%, grain protein contents-only 2%, grain nitrogen uptake levels-26%, grain nitrogen recoveries-18%, and spikes/m²-24%.
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2663. [Article] Soil moisture storage, distribution, and use by winter wheat in a 250-350 mm precipitation zone of eastern Oregon
The semi-arid dryland wheat-producing areas of the Pacific Northwest are characterized by cool, moist winters and dry, hot summers. The amount of annual precipitation is generally quite variable and inadequate ...Citation Citation
- Title:
- Soil moisture storage, distribution, and use by winter wheat in a 250-350 mm precipitation zone of eastern Oregon
- Author:
- Henderson, Robert L.
The semi-arid dryland wheat-producing areas of the Pacific Northwest are characterized by cool, moist winters and dry, hot summers. The amount of annual precipitation is generally quite variable and inadequate for annual cropping. Where soil depth is adequate, the predominant loessal soils generally supply sufficient moisture for small grain production through the practice of summer fallowing. Though inefficient in moisture storage, fallowing reduces the risk of crop failure by storing a portion of the precipitation received during the 14-month fallow period for later use during a 10-month winter-grain growing season. Nitrogen fertilizer rates must be balanced with available moisture supply for maximum yields and desired protein contents. In order to develop predictive moisture availability equations, five fallow-crop precipitation patterns characteristic of the 250-350 mm precipitation zone of eastern Oregon were simulated in the field on a commercial dryland farm near Moro, Oregon, beginning in 1977; two 24-month fallow-crop cycles were completed during a three-year period. Moisture measurements made to a minimum depth of 270 cm at different times during both the fallow and crop periods have provided useful agronomic information. The soil moisture content continued to decline through upward movement from the beginning of the fallow period to the period of winter precipitation; vertical movement depended on the tension gradient. The greatest efficiency in moisture storage occurred during the first winter storage period when the fallow soil was generally dry; cumulative storage efficiency was highest on the plots which had received the least precipitation. The greatest rate of measured moisture loss occurred immediately after the fallow winter storage period. Soil moisture continued to decline during the remainder of the fallow period, especially in the 0-90 cm soil profile, but at a much lower rate due primarily to the development of a soil mulch through spring tillage. On the average, there would have been no moisture storage advantage to fallowing when the level of net storage in the spring of the fallow period was 194 mm or greater in the 0-270 cm soil profile (r² = 0.94). After the crop winter storage period, comparison of precipitation treatments that eventually would have equal amounts of cumulative precipitation indicated that a greater amount of stored moisture was stored in the plots which had the wetter fallow period, and in these plots more moisture was stored in the 90-180 cm soil profile than in plots with a drier fallow period. The plots with the wetter fallow also showed more soil moisture removal by the crop than plots with a drier fallow. A significant increase in grain yield, water-use-efficiency, and soil moisture extraction occurred as nitrogen fertilizer rates increased from zero; increases in soil moisture extraction due to fertilizer were most pronounced in the 90-180 cm soil profile. Linear regression analyses showed the relationship between the maximum grain yield (kg/ha) in each main plot, and the sum (mm) of the precipitation (P) and moisture depletion from the 0-180 cm soil profile (SM) between early spring of the crop period and harvest to be defined by the following equation: Y = 21.1 (SM + P - 62); r ² = 0.80 Soil moisture held between 1/3 and 15 bars tension was not uniformly depleted to the 15-bar level throughout the root zone, but rather the amount extracted tended to decrease with increasing soil depth. Extractable moisture, defined as the difference between the highest measured volumetric soil moisture content in early spring of the crop period and the soil moisture content at harvest, more accurately reflects the amount of soil moisture utilized through evapotranspiration than does the amount of moisture held between 1/3 and 15 bars tension. Linear regression equations were developed to estimate the amount of extractable soil moisture in the 0-90, 90- 180, and 180-270 cm soil depths from soil moisture measurements in early spring of the crop year. Estimates of extractable moisture, together with an estimate of anticipated crop season precipitation, can be used to predict the potential grain yield, which in turn is necessary to calculate the optimum amount of nitrogen fertilizer.
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2664. [Article] Effect of organic production system and harvest date on the quality of blackberry fruit for fresh and processed markets
Blackberry (Rubus sp.) fruit are a good source of phenolic compounds and anthocyanins, and are consumed in fresh and processed forms. Though organic products become more popular, limited information is ...Citation Citation
- Title:
- Effect of organic production system and harvest date on the quality of blackberry fruit for fresh and processed markets
- Author:
- Liu, Mingyang
Blackberry (Rubus sp.) fruit are a good source of phenolic compounds and anthocyanins, and are consumed in fresh and processed forms. Though organic products become more popular, limited information is available about how different organic production methods affect the post-harvest quality of blackberry fruit. The objective of this project was to investigate the effects of different organic production systems and harvest times on the physicochemical and nutraceutical properties of four cultivars of blackberry fruit during refrigerated and frozen storage. Trailing blackberry 'Obsidian' and semi-erect blackberry 'Triple Crown' were studied under refrigerated storage while two trailing blackberry 'Marion' and 'Black Diamond' were studied under frozen storage. 'Obsidian' and 'Triple Crown' were grown organically and treated with three different organic fertilizers: processed poultry litter, soy meal, and a blend of fish emulsion and hydrolysate. Each fertilizer was applied at the same rate of 56 kg nitrogen/ha in 2012 and 2013. Samples were hand-picked three times per season at 1 wk intervals, packed immediately into clamshell containers, and stored at 4.0 ± 0.2 ºC and 90 ± 5% relative humidity for up to 12 d. Physicochemical properties, including decay, leakage, pH, titratable acidity (TA), weight loss, firmness, and moisture content, and antioxidant content and capacities, including total phenolic content (TPC), total monomeric anthocyanins (TMA), radical scavenging activity (RSA), oxygen radical absorbance capacity (ORAC), and ferric reducing ability of plasma (FRAP), were measured prior to and during refrigerated storage. Harvest date and storage time showed more effect on the physicochemical properties than that of fertilizer type. During storage, late-harvest fruit of both cultivars had the least decay in 2012 while early-harvest fruit exhibited the least decay in 2013. Fruit leakage in both cultivars increased during storage, reaching 54.3% and 62.5% in 'Obsidian' and 62.3% and 73.0% in 'Triple Crown' in 2012 and 2013, respectively. Fruit pH increased while titratable acidity decreased during storage in both cultivars. Firmness of 'Obsidian' fruit was significantly higher in 2012 than in 2013. Overall, fruit firmness decreased during storage. 'Obsidian' fruit had a 2.52% weight loss while that of 'Triple Crown' fruit had a 3.15% weight loss after 10 d of storage. The type of fertilizer only affected fruit weight loss in 'Obsidian'. 'Obsidian' also had as much as 37% higher ORAC values than 'Triple Crown' at harvest. Late-harvest fruit from plants fertilized with fish emulsion showed 29% higher ORAC values than fruit harvested from plants in the other fertilizer treatments. Generally, 'Obsidian' blackberry showed greater variability in antioxidant properties than 'Triple Crown'. 'Marion' and 'Black Diamond' were also grown organically but, in this case with three different weed management strategies: non-weeding, hand weeding, and weed mat. Fruit were machine-harvested three times at 1 wk intervals in 2012, sorted by hand to exclude molded and damaged samples, frozen in a forced-air freezer at -25 ºC, and stored at the freezer for up to 9 mo. Physicochemical properties, including pH, TA, and total soluble solids (TSS), and antioxidant content, including TPC and TMA were measured prior to and during frozen storage. Antioxidant capacities, including RSA, ORAC, and FRAP were also measured prior to frozen storage. Although weed management had no significant effect on the physicochemical properties of the fruit, it had numerous effects on TPC, TMA, RSA, ORAC and FRAP. Late-harvest 'Marion' fruit had the highest ORAC and FRAP values compared to 'Black Diamond' fruit and 'Marion' fruit from the earlier two harvests. Fruit from the hand-weeded treatments had up to 30% higher antioxidant content and capacity during the first second harvests than fruit from the non-weeded and weed mat treatments. This study provided important information about the effects of organic production systems on post-harvest quality of blackberry fruit during refrigerated and frozen storage. Such information will be helpful for providing guidelines to the organic berry industry (growers, packers and processors) for making decisions on the selection of organic fertilizers and weed management practices, the timing of fruit harvest, and the maximum amount of time in which the fruit should be refrigerated or frozen without a significant loss in quality.
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2665. [Article] Experimental analysis of subsurface heating and irrigation on the temperature and water content of soils
Multiple use of waste heat from power plants may become an important consideration in the development, siting, and certification of these plants. A multiple use system of components that can beneficially ...Citation Citation
- Title:
- Experimental analysis of subsurface heating and irrigation on the temperature and water content of soils
- Author:
- Sepaskhah, Ali Reza
Multiple use of waste heat from power plants may become an important consideration in the development, siting, and certification of these plants. A multiple use system of components that can beneficially utilize waste heat may include home heating and cooling, greenhouses, animal enclosures, open basins for single cell protein production and fish farming, and open field soil warming. A subsurface irrigation-soil warming system utilizing waste heat was analyzed in this study. Thermal power plant condenser cooling water pumped through buried porous pipes was considered as a heat and water source for soil heating and subsurface irrigation. Energy is transferred from the heat source to the surrounding soil, warming it above its natural temperature. In addition, water seeping from the porous pipe prevents drying around the heat source and supplies the plant roots throughout the soil profile while avoiding the large evaporation losses at the soil surface associated with surface irrigation methods. Experiments were conducted in the laboratory to study this system. Soil was packed in containers 48 cm deep, 40 cm wide, and 4 cm thick. A heat source consisting of a copper covered electrical resistance wire was placed against one side of the box at a depth of 32 cm. A water source consisting of a porous tube was placed 2 cm above the heat source. The contained soil slab thus represented a subsurface soil warming and irrigation system with heat and water sources at depths of 32 and 30 cm respectively and a 77 cm spacing. A series of experiments was conducted with heat source temperatures of 29, 36, and 44 C, and surface heat load cycles with maxima of 0, 13, 52, and 117 watts. These experiments were repeated for Quincy, Cloquato, and Chehalis soils. The box filled with soil was saturated with water and then drained. Experiments were initiated by energizing the heat source. Temperature distributions throughout the soil profile and rates of energy dissipation were measured. Water application rates required to maintain a constant soil water content were obtained. In each experiment, water was applied at such a rate that the water content at a point near the heat source, monitored with a gamma ray attenuation system, remained constant. Apparent thermal conductivities of Quincy, Cloquato, and Chehalis soils as a function of water content were measured at 25 and 45 C by the heat probe method. The soil apparent thermal conductivity was also computed from a theoretical model based on its mineral composition, porosity, water content, and the thermal conductivity of the individual components. This model takes into account the vapor flow contribution to the apparent thermal conductivity in wet soils. Its magnitude depends on the available air-filled pore space, total porosity, and the free energy of the retained water. Predicted and experimental values of thermal conductivities showed good agreement. Soil temperature distributions were calculated using theoretical models presented in the literature. Predicted and measured isotherms showed good agreement. Energy dissipation rates as a function of soil thermal conductivity, temperature differences between heat source and soil surface, and depth and spacing of heat source were obtained. They were in agreement with those calculated from theoretical considerations. The total land area required to dissipate the waste energy from a 1000 MWe power plant operating with 34 percent efficiency was calculated for each of the three soils used in the experiments. It was found that 2841, 3714, and 4390 hectare would be required for Quincy, Cloquato, and Chehalis soils respectively. Quincy soil would require the smallest land area for this purpose because of its higher thermal conductivity. Economical and technical considerations for the installation of subsurface heating and irrigation systems require flat land close to the electrical power plant. Large areas of flat land are not always present. Subsurface irrigation replenished water lost by surface evaporation. Water use rates were obtained as a function of temperature differences between heat source and soil surface, soil type, and a range of surface heat loads. The water application rates ranged from 1.50 mm/day for Chehalis soil with a heat source temperature of 29 C in combination with the lowest surface heat load to 6.0 mm/day for Quincy soil with a heat source temperature of 44 C in combination with the highest surface heat load. These rates were adequate to prevent drying around the heat sources and supply the water needs of an actively growing crop. The effective use of this system depends on the development of suitable tubing to conduct and discharge water which could be used without clogging of the pores through which water seeps into the ground. The proposed soil warming and irrigation system does not appear to be an attractive alternative power plant cooling system. The system holds promise however as an economically attractive management system for the production of high value crops.
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2666. [Article] Three essays on the economics of malaria
Malaria is the world’s most important parasitic infectious disease, and is a major cause of mortality and morbidity in many developing countries. In this dissertation I study the interaction of malaria ...Citation Citation
- Title:
- Three essays on the economics of malaria
- Author:
- Datta, Saurabh Charles
Malaria is the world’s most important parasitic infectious disease, and is a major cause of mortality and morbidity in many developing countries. In this dissertation I study the interaction of malaria and economic development at both the macro- and micro-economic levels. In the first essay I examine the economic impact of malaria on income per capita using cross-country time-series data for 100 malaria prone countries between the years 1985 and 2001. I try to explain the so-called “malaria gap,” which refers a general difference (gap) in parameter estimates found between macro- and micro-economic studies of the impact of malaria on economic well-being. By using more detailed data and controlling for a larger number of economic determinants of malaria than previous macro-economic studies, I am able to resolve most of the “malaria gap” associated with earlier studies in the literature. I show that the impact of malaria on economic well-being is statistically significant but fairly small, which coincides with the findings of certain recent micro-level studies. Policy implications of these empirical findings are discussed. In the second essay I turn my focus to the fact that malaria itself is an endogenous variable over which households and government have some control. I start with simple plots of data that show that malaria has a negative correlation with national income per capita, whether looking across countries at a point in time, or looking at a single country over time. Some countries have moved steadily over time from an equilibrium characterized by low income and high malaria, to a new equilibrium with a relatively high income and low rate of malaria. I develop and estimate a simultaneous equations model to explain these relationships. I distinguish three potential causal chains: the ability for decreases in malaria to increase income, the ability for increases in income to reduce malaria (reverse causality), and external factors that may lead to both higher income and lower malaria (incidental association). I find that changes in income have a much stronger effect on malaria incidence than the other way around. While a 1% rise in the number of malaria cases per million decreases income per capita by less than 0.01%, a 1% rise in income per capita decreases the number of malaria cases per million by more than 1.1%. If income were just 1% higher, 603,189 cases of malaria could be averted annually in the 100 countries of the sample. In the third essay I take a completely different approach in that I use micro-economic household survey data to examine how farming households in poor, malaria-prone areas respond to an outbreak of malaria. I focus on their choice of cropping pattern, since they may shift away from labor-intensive, high-risk yet high-return crops towards those with lower risk and effort yet much lower returns. Households may also move away from formal jobs with long time commitments towards daily labor type activities in which they only work when healthy. These hypotheses are tested using detailed data for 919 households of the Kagera region in Tanzania over the 1991-94 period. To specify an appropriate econometric model, I first develop a theoretical model that captures the micro-economic processes that I highlight above. The econometric results are generally consistent with the ideas in the theoretical model. Outbreaks of malaria and other natural disasters, such as pest attacks and drought, prompt households to move away from chemical-input- and labor-intensive crops (e.g., sugarcane, tobacco, cotton) towards subsistence (e.g., cassava and sweet potato) and tree crops (e.g., coffee and banana). At the same time, they are found to be depending more on casual labor employment and remittance income, while cutting down expenditures on purchased agricultural inputs and net asset creation.
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2667. [Article] Pesticides and produce : risk perceptions of extension clientele
While there is growing public concern over the safety of the food supply, few studies have contrasted varying perceptions of pesticide risk. This study assessed and contrasted perceptions of three groups ...Citation Citation
- Title:
- Pesticides and produce : risk perceptions of extension clientele
- Author:
- Love, Margaret L.
While there is growing public concern over the safety of the food supply, few studies have contrasted varying perceptions of pesticide risk. This study assessed and contrasted perceptions of three groups of Oregon State University Extension Service clientele (home food preservers, Master Gardener volunteers, commercial growers) and factors influencing these perceptions. The impact of the pesticide risk perceptions on purchasing decisions and pesticide application practices was assessed. Two questionnaires were developed: one for home food preservers/Master Gardener volunteers and one for commercial growers. One hundred twenty-seven questionnaires were completed by a convenience sample of home food preservers (85% adjusted return rate) and 155 questionnaires were completed by randomly selected Oregon State University Master Gardener volunteers (81% adjusted return rate). A shortened version of the questionnaire was completed by 124 participants at the annual meeting of Willamette Valley Processed Vegetable Growers. Home preservers were 84% female (mean age=49 ± 14 years), volunteers were 50% female/50% male (mean age=56 ±14 years), and commercial growers were 95% male (mean age=42 ± 11 years). Three different measures of pesticide risk perceptions were used to test six hypotheses: Respondents rated 1) "eating foods produced using pesticides" as high, low, or no risk, and agreed/disagreed (on Likert scales) whether 2) "chemical residues remaining on produce are a major health concern," and 3) "children are at a greater risk for illness from pesticides than adults." Produce selection decisions, pesticide application practices, life stages, gender, media awareness, and knowledge of agricultural production techniques and practices were also assessed to determine their relationship with risk perceptions. Perceptions of risk varied among the three groups. Fifty-five percent of preservers rated "eating foods produced using pesticides" as a "high" risk compared to 34% of volunteers and 2% of growers. Thirty-four percent of preservers strongly agreed that "chemical residues remaining on produce are a major health concern" compared to 25% of volunteers and 7% of growers. Forty-six percent of preservers strongly agreed that "children are at a greater risk of illness from pesticides than adults" compared to 42% of volunteers. Fifty-two percent of growers strongly/ somewhat agreed that children are at no greater risk. Gender was significantly associated with respondents' perceptions. Eighty-nine percent of preservers rating the risk of "eating food produced using pesticides" as "high" were female as were 65% of volunteers. Female volunteers moderately agreed that "chemical residues remaining on produce are a major health concern" compared to males who tended to neither agree nor disagree. The presence of children living in the home was significantly related to the volunteers' perceptions that chemicals are a major health concern and that children are at greater risk. Preservers and growers' results indicated there were no significant differences. Awareness of pesticide reports in the media was measured by recall of four media events. Media awareness was significantly associated with preservers' perceptions that eating foods produced with pesticides was "high" risk and that children are at a greater risk for illness because of pesticide residues. There was no media association for either volunteers or growers. Influence of risk perceptions on produce purchase decisions was measured with a series of questions about past, present, and future purchases. Results indicated that volunteers' pesticide risk perceptions were significantly related to more produce selection decisions than were home food preservers. The risk perception measure that "chemical residues remaining on produce are a major health concern" was most significantly associated with purchase decisions for both preservers and volunteers. For preservers and volunteers there were significant relationships between all three measures of pesticide risk perceptions and three of the twelve purchase decisions tested. Those who perceived a higher risk were 1) more willing to pay a higher price for certified residue free produce, 2) more concerned about pesticide residues when buying imported produce, and 3) intended to purchase produce grown without synthetic pesticides even if it costs more. Knowledge of agricultural practices was measured by a set of five questions. Mean scores ranged from 0.9 ± 0.9 for preservers to 1.6 ± 1.0 for volunteers out of a possible 5.0. Volunteers' with higher scores were significantly more likely to agree that chemicals are a major health concern and that children are at a greater risk of illness from pesticide residues. No significant associations were seen for preservers. Pesticide application practices were significantly related to pesticide risk perceptions. Preservers and volunteers who generally perceived the risks as "high" reported not using pesticides. Preservers reporting changes in application practices moderately agreed chemical residues are a major health concern while volunteers' reporting changes in application practices strongly agreed that children are at higher risk than adults. Growers tended to disagree that pesticides are a major health concern and they were less concerned that children are at a greater risk from pesticides. The study concluded that the home food preservers and Master Gardener volunteers perceived the risks associated with pesticides and produce as much higher than commercial vegetable growers. This difference in perceptions is reflected in some of their produce selection decisions and pesticide application practices. Children living at home, gender, media awareness, and knowledge of agricultural practices were associated with the pesticide risk perceptions of these Extension clientele. Results suggest that educational programming to increase knowledge about pesticide usage in agricultural production is warranted. There is also a need to foster better communications among groups with differing points of views about pesticide residue risks.
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This research is concerned with the current debate among Oregonians on how to improve the standard of living and accelerate economic development in Oregon. The main question is what economic activities ...
Citation Citation
- Title:
- Strategic investments in agricultural industries and Oregon's economic development
- Author:
- Koong, Dennis T
This research is concerned with the current debate among Oregonians on how to improve the standard of living and accelerate economic development in Oregon. The main question is what economic activities make Oregon, and regions within Oregon grow? To find out where Oregon's economic strength and weaknesses lie, first we have to understand the income and employment contributions of different industries in Oregon. Second, decisions for improving Oregon's economic growth may be guided by investment in the production of goods for which Oregon is competitive relative to other goods in domestic and international regions. Third, we can investigate and hypothesize about reasons for strengths and weaknesses of Oregon's industries relative to other industries locally, nationally, and internationally. To provide a guideline for Oregon economic development, this study first classifies Oregon's economic activities into eight major economic sectors: agriculture, lumber and wood, high-tech, other manufacturing, non-financial private services, financial services, other private services, and government services. In 1995, it is estimated that these sectors generated about $72 billion in gross state product (GSP) for Oregon's economy, employed over 1.4 million people and provided total payroll of about $36.5 billion. Oregon's aggregate service sector, which includes both nongovernment private services and government services, generated about 76% of Oregon's gross state product (64% and 12% respectively), received about 76% of Oregon's payroll (58% and 18% respectively), and employed about 80% of Oregon's total employment (64% and 16% respectively). The wood sector contributed about 7% to Oregon's GSP, received 6% of Oregon's payroll, and employed about 5% of Oregon's employment. The agriculture sector generated about 7% of Oregon's GSP, received about 4% of Oregon's payroll, and accounted for about 5% of Oregon's employment. The high-tech industries contributed about 5% of Oregon's GSP, received 7% of Oregon's payroll, and employed about 4% of employment. Oregon exported about $ 9.43 billion in 1995. High-tech equipment exports were about 46% of Oregon's total exports. The agriculture sector accounted for 26%, of exports, the wood sector exported 15%, and other manufacturing products 13%. While Oregon's recent growth has accured mostly through aggregate service activities, the trade oriented sectors including agriculture, wood, and high-tech injected nearly nine and half billion dollars of foreign revenue into the state's economy in 1995. Second, this research utilizes state-level statistics along with "revealed comparative advantage" methodology and computes competitiveness indexes. These are calculated for individual industries in Oregon relative to the Pacific Northwest and the United States economies to illustrate the strengths and weaknesses of the Oregon economy. The comparison of Oregon's efficiency in the agricultural sector relative to the PNW and U.S. indicates that, in the last seven years, Oregon's comparative advantage in agricultural farm production (crops) has increased but its comparative advantage in food processing has been declining since 1992. In fact, in 1994 and 1995 Oregon exhibited a comparative disadvantage in food products relative to both the PNW and the United States economies. One hypothesis advanced in this study is that such decline may be due to the Oregon's higher labor costs relative to other states in the PNW and U.S. The possibility that Oregon pays higher wages to workers in food production relative to the PNW and U.S., combined with the notion that food production in Oregon is more labor-intensive relative to the PNW and U.S. may account for the fact that Oregon's comparative advantage in food processing has declined in recent years. With regard to the wood sector, Oregon has a comparative advantage in lumber and wood products relative to both the PNW and U.S. economies In the furniture and fixtures category Oregon holds a clear comparative advantage against the PNW region, however it has a distinct disadvantage compared to the United States economy. In the paper products, Oregon holds a comparative advantage relative to the U.S., however, Oregon is at a comparative disadvantage relative to the PNW (except for 1991 and 1992 when Oregon had a slight comparative advantage). During the 1989-1995 time period, Oregon has been more competitive relative to the PNW region in industrial machinery and computer equipment. However, the degree of advantage has declined from 157% in 1989, to 105% in 1995. Relative to U.S., Oregon improved its comparative advantage in the production of same goods from -16% comparative disadvantage in 1989, to being +25% more efficient in 1995. Similarly, Oregon held its comparative advantage in the production of electric equipment and measuring instruments relative to PNW during 1989-1995 time period. Relative to U.S., Oregon improved its efficiency in the production of electric equipment from -37% inefficiency in 1989, to +5% of comparative advantage in 1995. Oregon's comparative advantage in measuring instrument varied between 11% and 26% over 1989-1995 time period. With regard to recent arguments advanced against high-tech industries, the results of this study indicate that Oregon is becoming more efficient (regionally as well as nationally) in manufacture of high-tech products, this may be partially be due to economies of scale associated with this sector. With regards to food processing industries, it may be that costs associated with labor, materials, capital investment, and other inputs are high relative to other regions. Hence, we cannot be competitive in those industries. Alternatively, one may argue that labor productivity in Oregon's food industry is lower than other regions. If this is the case, increasing training and education programs to increase labor productivity, in addition to changing infrastructure, could improve efficiency in food industries and thereby improve Oregon's economic development.
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Body size explains much of the interspecific variation in the physiology, behavior, and morphology of birds, such as metabolic rate, diet selection, intake rate, gut size, and bill size. Based on mass-specific ...
Citation Citation
- Title:
- The role of body size in the foraging strategies and management of avian herbivores : a comparison of dusky Canada geese (Branta canadensis occidentalis) and cackling geese (B. hutchinsii minima) wintering in the Willamette Valley of Oregon
- Author:
- Mini, Anne E.
Body size explains much of the interspecific variation in the physiology, behavior, and morphology of birds, such as metabolic rate, diet selection, intake rate, gut size, and bill size. Based on mass-specific metabolic requirements and relative energetic costs of activities, being a certain body size has both advantages and disadvantages. In particular, avian herbivores such as geese possess a relatively simple digestive system, consume foods with low digestibility and poor nutrient content, and have increased energetic demands compared to other bird taxa; therefore, any effects of body size on foraging strategies should be readily apparent in this foraging guild. The influence of body size on the behavior and management of Canada Geese (Branta canadensis) and Cackling Geese (B. hutchinsii) as avian herbivores has not been well studied. My dissertation explores the role of body size in comparative foraging behavior, habitat selection, and winter conservation planning for two congeneric geese, the Dusky Canada Goose (B. c. occidentalis; hereafter Duskys) and the Cackling Goose (B. h. minima; hereafter Cacklers). These two taxa share the same over-winter foraging environment (grass seed fields) in the same restricted geographic area (the Willamette Valley) during winter. Duskys and Cacklers differ by more than a factor of two in body size and have different relative bill sizes and social organization. Because of smaller body size, Cacklers have greater relative energy demands and less fasting endurance compared to Duskys; however, Cacklers have comparatively low energetic costs for flight and transport. Duskys, however, have higher total energy requirements than Cacklers. Additionally, Cacklers form large, high-density flocks and have a total over-wintering population size in the study area of about 200,000. Duskys occur in relatively small family groups and have a total over-wintering population size of about 13,000. My study demonstrated that interspecific differences in body size between Cacklers and Duskys was associated with differences in foraging behavior, movements, and habitat selection. Cacklers foraged a greater percentage of time (30%) in all habitats and across the entire winter compared to Duskys. Cacklers had higher peck rates (up to 100 pecks min⁻¹ greater) than Duskys in all foraging habitats expect pasture. The pecking rate of Cacklers was greatest in fields of young grass (200 pecks min⁻¹), which may indicate that Cacklers had relatively high intake rates in this foraging habitat. Based on differences in foraging behavior among habitats, Cacklers may have the foraging strategy of energy intake maximizers, whereas the foraging strategy of Duskys is more towards time-energy expenditure minimizers, at least for part of the winter. Cacklers moved across the landscape very differently from Duskys, exhibiting less site fidelity and greater commuting distances to foraging areas. Cacklers showed a preference for young grass during all periods of the winter, reaffirming that Cacklers are specialized grazers on short green forage, whereas Duskys preferred young grass and pasture. Fields of young grass were the preferred foraging habitat of Cacklers, had less standing crop biomass, and may have enabled higher foraging efficiencies, which may have led to higher intake rates. The ability of the landscape to support wintering geese changed across the winter because total available plant biomass fluctuated with the rate of grass regrowth. The estimated carrying capacity of the landscape for geese decline by almost one-half during mid-winter (mid-December to mid-February) compared to early winter or late winter periods. Although Cacklers have lower individual energy requirements compared to Duskys, due to a much larger target population size, Cacklers required 89% more foraging habitat than Duskys. Forage requirements encountered a bottleneck during mid-winter, when grass regrowth rates were low and day length was short. Commensurate with this pattern of forage availability, goose body condition declined during the mid-winter period. To support Pacific Flyway target populations for geese, approximately 18,000 ha of total grazing habitat in young and mature grass is needed in the Willamette Valley to support a total over-wintering population composed of 340,000 geese belonging to four subspecies. The role of body size in influencing the foraging behavior and decisions of over-wintering geese has important implications for conservation planning of goose populations. Small-bodied Cacklers are selective in field choice, yet more likely to redistribute across the landscape. Disturbances (e.g., hunting, hazing, or predation) will have a disproportionate effect on the movements of smaller-bodied geese compared to larger geese. These characteristics of Cacklers will make conservation planning to retain geese on public land more difficult. Coordinated management with private landowners and farming practices that maximize preferred goose foraging habitat on public lands may attract geese to utilize protected areas and minimize conflicts with agriculture in the Willamette Valley. Availability of resources during critical periods in winter is an important factor affecting the distribution of geese, but may affect small and large bodied geese differently. Management could be targeted during these critical time periods. By considering the role of body size in the context of life history characteristics, foraging behavior and habitat selection, appropriate management strategies can be developed and implemented to reduce the effects of agricultural depredation by geese, while promoting the future conservation of wintering geese in the Willamette Valley.
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2670. [Article] Three essays on the effectiveness of Oregon's land-use planning system : economic analysis with quasi-experimental methods
Oregon's land use planning system is often recognized as having been successful in its goals of limiting urban sprawl and protecting resource lands from development. However, it is difficult to quantify ...Citation Citation
- Title:
- Three essays on the effectiveness of Oregon's land-use planning system : economic analysis with quasi-experimental methods
- Author:
- Dempsey, Judith
Oregon's land use planning system is often recognized as having been successful in its goals of limiting urban sprawl and protecting resource lands from development. However, it is difficult to quantify the impact of these regulations, because we cannot observe what would have happened in the absence of land use planning. The three essays in this dissertation explore the effects of Oregon's land use planning regulations on development patterns in the state, and also examine how the land use regulations are administered at the local level. The first essay in this dissertation asks if Oregon’s land use regulations have successfully restricted sprawl outside of urban areas. Urban containment policies, including Urban Growth Boundaries (UGBs), are a common tool used by city planners to promote compact development. We analyze how well UGBs do in containing development using fine-scale GIS data on cities in Oregon. Earlier studies on UGBs yield mixed results, with some authors finding no effects of UGBs on housing market variables and urbanization rates and others finding significant effects. A challenge in measuring these effects is that the location of the UGB is unlikely to be an exogenous determinant of a land parcel's value for development. The panel structure of our dataset allows us to estimate the UGB's effect on the probability of development using a difference-in-difference estimator. This estimator controls for time-invariant unobservable variables and common temporal effects among parcels, thereby mitigating the potential for biased estimates due to the endogeneity of the UGB's location. We also pursue a novel approach to controlling for time-varying factors inspired by regression discontinuity design. We find that UGBs are effective in containing development in many of the Oregon cities we examine, although there are some cities in which development rates are the same inside and outside of the UGB. Our results show that we would greatly overstate the effects of the UGBs were we to evaluate cross-sectional differences in development rates, as is common in previous studies. Besides the creation of UGBs, another goal of Oregon's land use regulations is to encourage citizen involvement in the planning process. The second essay in this dissertation examines the use of voter annexation as a form of citizen involvement. More specifically, this paper addresses the following two questions. First, does voter annexation cause changes in city demographics and characteristics? Second, assuming that a city votes for amendments and annexations to the UGB and city limits, what factors impact the outcome of the vote? We analyze the first question using the method of propensity score matching, which has not previously been used to explore this topic. This allows us to account for the endogeneity that stems from the fact that cities with certain characteristics may be more likely to use voter annexation in the first place. The second question, which is only evaluated for cities that employ voter annexation, is analyzed with the use of the logit model. Oregon's land use regulations must be approved at the state level, but are administered locally. Therefore, unlike past studies, we are able to isolate specific differences in the way the program is administered, and are not evaluating the stringency of the program itself. Previous studies have found that voter-approved annexation causes developers to provide more public goods and increase the scale of development, thereby shifting community demographics. Once a land use decision is on the ballot, it is also noted that cities that are whiter, wealthier, and more liberal are more likely to pass referenda that promote preservation and restrict development. For the first question, we compare specific demographic indicators between the two groups of cities. Contrary to the results of previous studies, we find no effect of voter annexation on these indicators. Our results for the second question indicate that the characteristics of the voting process itself impact the outcome more than community characteristics, which also differs from the results of previous analyses. The third essay in this dissertation is an extension of the first essay, and focuses on the impact of Oregon's land use regulations on the protection of land in riparian corridors and land that has been designated for exclusive farm use (EFU). Riparian corridors are protected with the use of Oregon Goal 5, which focuses on development of natural resource lands inside of UGBs, while EFU land is protected with the use of Oregon Goal 3, which focuses on protection of agricultural land at the county level. The LCT dataset that was used in the first essay is also used in this essay. EFU land by definition has no probability of development in the initial period. Land located in riparian corridors may also face different initial levels of protection than other land. We deal with this endogeneity, and also account for location inside or outside of a UGB, with the use of the difference -in-difference-in-differences estimator. This is an approach that has not been used to explore the effect of Oregon's land use regulations on these land categories. Most of the past studies that have examined the impact of land use planning on development of agricultural land in Oregon have relied on analysis of general trends and indicators, and have concluded that land use regulations have been successful in protecting this land. Previous research on riparian zone protection has focused on protection of aquatic wildlife, and for the most part has not examined the protection of riparian corridors inside of UGBs. The limited studies that have studied the effect of these regulations in UGBs have determined them to be effective in slowing, but not stopping, development in these areas. Overall, we find that Oregon's land use regulations have been successful in protecting both county level agricultural land and riparian corridors located inside of UGBs from development. It is less clear whether these regulations have protected riparian corridors located inside of UGBs from other anthropogenic uses.