Browsing by Author "Qian, Yaling, committee member"
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Item Open Access Alfalfa reference crop evapotranspiration in Colorado and its use for irrigation scheduling(Colorado State University. Libraries, 2015) Aljrbi, Abdulkariem Mukhtar, author; Davis, Jessica G., advisor; Andales, Allan A., advisor; Qian, Yaling, committee member; Hansen, Neil, committee memberThe goal of irrigation scheduling is efficient use of water such that water is applied to the field for optimal crop production. Previous studies have optimized irrigation scheduling using different models to manage sprinkler irrigation. This research evaluated approaches for obtaining alfalfa reference evapotranspiration (ETr) and its use in a new irrigation scheduling model for a furrow irrigation system. The objectives of this research were to: 1) Compare seasonal trends of daily ETr from the American Society of Civil Engineers Standardized Penman-Monteith (ASCE-SPM) equation and the Penman-Kimberly (PK) equation along a climatic gradient in Colorado, 2) Verify the agreement between calculated ETr from the ASCE-SPM equation and measured ETr from a lysimeter during the 2010 season for the Arkansas Valley of Colorado and correct the lysimeter ETr for alfalfa overgrowth, and 3) Test the ASCE-SPM ETr along with a locally adapted Kcr curve for corn in an irrigation scheduling spreadsheet tool for simulating the daily soil water deficit of furrow irrigated corn in northeast Colorado. The two reference ET equations were compared using R2, Root-Mean-Square Error (RMSE), Relative Error (RE), and index of agreement (d). The R2 values ranged from 0.93 to 0.99; d ranged from 0.98 to 0.99, RMSE ranged from 0.29 to 0.75 mm/d, and RE ranged from -6.35 to 1.91 %. In a comparison of the ASCE-SPM and PK equations at the Fort Collins and Rogers Mesa sites in 2011, differences were observed between the energy balance and aerodynamic terms of each equation. The energy budget calculated by the ASCE-SPM was generally 28% lower than the energy budget calculated by the PK equation at both locations for 2011. On the other hand, the aerodynamic term calculated by the ASCE-SPM equation was from 27 - 28 % higher than the aerodynamic term calculated from PK during most of 2011 at both locations. The second objective of this research compared alfalfa ET measured with a lysimeter in the center of a 4.06 ha furrow irrigated field at the Colorado State University Arkansas Valley Research Center in Rocky Ford, CO to the calculated values from the ASCE-SPM equation in periods of reference conditions in 2010. Four days were selected when alfalfa in the lysimeter was 50 - 55 cm tall, unstressed, completely covering the ground, but with its canopy extending beyond the outer walls of the lysimeter. On these dates, hourly lysimeter ETr was 0.08 to 0.11 mm/h higher than ASCE-SPM ETr. The theoretical surface area of the lysimeter was 9.181 m², while the observed effective canopy area was up to 12.461 m² due to overgrowth. Surface area corrections for the overgrowth increased the index of agreement (d) between hourly lysimeter ETr and ASCE-SPM ETr from the 0.96 - 0.98 range to the 0.99 - 1.0 range. These results showed that it is important to use the correct effective canopy area when computing ETr from a weighing lysimeter. The CIS model for calculating water deficit under a furrow irrigation system with the addition of some data from field measurements such as soil moisture content, gross irrigation, climate data, and plant height and leaf area index generated good results. The water deficit under corn was simulated at the Limited Irrigation Research Farm (LIRF) located near Greeley, Colorado during the years 2010, 2011 and 2012. Daily corn crop ET (ETc) calculated from daily ASCE-SPM ETr and a locally-derived crop coefficient curve (Kcr) were used by the CIS for daily soil water deficit calculations via water balance. This data was used to test a furrow irrigation system via the CIS model and to simulate the field irrigation by predicting the time and the amount of water for the next irrigation. The results showed good agreement between calculated and measured deficits where index of agreement (d) ranged from 0.5 to 0.99 for most years of this study, specifically when measurements of soil water content (SWC) were inserted bi-weekly or monthly. The RMSE did not exceed 2.54 mm when using SWC once per season in 2011, while bi-weekly measurements recorded d to be 0.96 in 2010, 0.99 in 2011 and 0.70 in 2012. Also, the CIS showed that irrigation water usage could be reduced by 30 to 50% through use of CIS.Item Open Access Benefits of using variable frequency drives on greenhouse exhaust systems(Colorado State University. Libraries, 2012) Schreiner, Matthew, author; Newman, Steven, advisor; Qian, Yaling, committee member; Tisserat, Ned, committee memberGreenhouses provide many benefits to a plant producer by allowing for a tightly controlled environment best suited for the crop. Since sunlight is allowed almost free access to the inside of a greenhouse, removing heat buildup becomes a large obstacle to deal with. Energy needed to meet a typical cooling requirement can be costly and lowering overhead will be helpful to a sustainable greenhouse business. Variable frequency drive (VFD) technology has the potential to not only save electricity and reduce monthly operating costs, but can offer the grower climactic and water use benefits as well. Two greenhouses were compared for this study, one having a typical On/Off style fan system and the other has a VFD system installed. The parameters looked at were short cycling, total energy use, temperature, crop growth, and water use. The results of the research indicate that VFDs do offer significant reduction in electricity usage, showing only half of what the On/Off fans used. A reduction in water use was also seen with slightly greater crop growth in the VFD greenhouse. VFDs on exhaust fans show benefits that any greenhouse grower would like to have in their operation.Item Open Access Chemical equilibrium modeling of phosphorus removal and recovery processes for advanced wastewater treatment(Colorado State University. Libraries, 2018) Liu, Jinna, author; Carlson, Kenneth, advisor; Sharvelle, Sybil, committee member; Qian, Yaling, committee memberPhosphorus (P) is a fundamental element to all life. However, unmanaged phosphorus can create negative effects in the environment. Wastewater is a significant source of phosphorus and every day, thousands of wastewater treatment and recovery facilities treat billions of gallons of nutrient rich wastewater. During the treatment process, a large amount of sludge is produced and needs to be treated and disposed. The main process for sludge treatment is anaerobic digestion after which the solids are dewatered. However, the dewatered sludge liquor or centrate contains very high levels of nutrients (nitrogen and phosphorus) that needs to be removed from this water stream before being returned to the secondary treatment process. This recycle stream adds additional nutrients to the plant which affects treatment efficiencies and increases operating costs. Additionally, when the phosphorus, magnesium and ammonia are released in the digester, they combine and can create struvite, a mineral that can cause significant damage to equipment, pumps and piping. In many cases, nutrient removal technologies are added in the sludge and centrate treatment process. This study used chemical equilibrium modeling to examine phosphorus removal and recovery in the centrate from dewatered anaerobic digestion sludge. The chemical equilibrium of two P recovery technologies (CNP's AirPrex P-recovery process, Ostara's Pearl® P-recovery process) and one P removal method (precipitation with ferric) are modeled using MINTEQ to understand how the overall water quality changes and how this could impact downstream processes. AirPrex and Pearl® produced struvite, which can be used as green fertilizer, have several factors that influence the formation of product including pH, temperature and concentration of ions such as phosphorus, ammonia and magnesium. One of the important differences between the AirPrex and Pearl® technologies is that AirPrex is installed between the anaerobic digestion and dewatering processes, while Pearl® is installed after dewatering. Through the model work, AirPrex could reach 98% P removal and 70% P recovery at the optimal situation from the digested sludge. Pearl® could reach 97% P removal and 96% P recovery at the optimal situation from centrate. The P removal method with ferric chloride could reach almost 100% phosphorus removal.Item Open Access Evaluation of cow peat as a plant growth media(Colorado State University. Libraries, 2018) Thena Surendran, Amrish Nath, author; Sharvelle, Sybil, advisor; Carlson, Kenneth, advisor; Qian, Yaling, committee memberAlmost 63% of non-CO2 greenhouse gases, mostly methane and nitrous oxide, are produced by the agricultural industry. As Livestock waste lagoons are designed to prevent the nutrient transport and treat manure, they are major contributors to the release of these non-CO2 greenhouse gases. They have to be controlled and one such way is to harness these gases by implementing anaerobic digestion. Anaerobic digestion of livestock waste has shown very good potential but, handling of digested solid end products require extensive management. One potential option is to recover fiber from the solid digestate to make a cow peat plant growth material. Peatlands are one of the most important natural ecosystems in the world which have key values for biodiversity conservation, climate regulation and support welfare, water regulation in drylands, acts as an enormous carbon sink and also an agricultural land. But overexploitation of peatlands has led to adverse effects on the environment. Peat mosses have well defined lignified cell structure as a soil material which makes them perfect media for plant growth. All these degradations and its effects have made peat extraction unsustainable and so search for alternatives have begun over the last decade. The fiber components of digested dairy manure (Cow Peat) have been evaluated by researchers as a suitable substitute for peat moss along with many other products such as biochar, rice husk, wheat straw, sewage waste, potato waste etc. Results have shown that the cow peat has similar physicochemical properties to peat moss and so, they have been widely used in the horticulture and floriculture industries as a replacement for peat moss. In this study, we assessed the potential to recover cow peat from a novel multi-stage anaerobic digester that processes high solids content manure. Edible crops were grown in the digestate and cow peat for the first time, as they have been already proven in the other industry such as the growth of perennial plants, strawberries, bedding plants etc. The study has been carried out in two trails without nutrient amendment. The first experiment was conducted with bean plants and 6 soil mixes with digested manure. The performance was compared with commercially available soil mixes including peat moss. The best performing soil mixes were utilized in a second experiment assessing two more plant types, beet, and lettuce. The results of both the experiments have revealed that digested manure (well composted digested manure solids) and fiber (component separated from manure solids by fractionation) component has produced plants with significantly similar (p > 0.05) shoot dry mass and root structure as commercially available plant media. The digested dairy fiber contains a significant amount of nutrients for the plant to germinate. Carbon/Nitrogen ratio was higher than recommended range and so may have had an adverse effect on pH and reducing the availability of micronutrients. Results demonstrate the potential for anaerobically digested fiber to replace peat moss as plant growth media providing growers with a local, renewable substitute for peat and a supplemental income for animal farm operators.Item Embargo Evaluation of salinity tolerance of pinto bean varieties(Colorado State University. Libraries, 2024) Paul, Winie Sharsana, author; Davis, Jessica G., advisor; Qian, Yaling, committee member; Andales, Allan, committee memberSalinity is an abiotic stress restricting agricultural crop production globally, primarily in arid and semi-arid areas. Saline soils are characterized by the accumulation of dissolved salts in the soil solution, which inhibits a plant's ability to absorb water and nutrients. Many crops are affected by high concentrations of salt in the soil. Dry edible pinto beans (Phaseolus vulgaris), very important in human nutrition around the world, are sensitive to salinity, and yield losses can occur in saline soils greater than 2 dS/m. The objective of this study was to assess the salinity tolerance of regular and slow darkening pinto bean varieties by evaluating the effect of different salt types on pinto bean germination, growth, and production. This project included three experiments: germination, greenhouse, and field studies. For the first two experiments, six varieties of pinto beans were evaluated: three slow-darkening pinto beans (Gleam, Mystic, Lumen) and three regular pinto beans (Othello, Cowboy, SV6139). In the germination experiment, treatments were arranged in a randomized complete block design with five replications, three saline solutions (NaCl, CaCl2, MgSO4.7H2O (MgSO4)), and control (distilled water) at 0.05 M, 0.1 M, and 0.15 M concentrations for each salt. For the greenhouse experiment, saline solutions with the same electrical conductivity (ECe) (dS/m), control (distilled water) and the six pinto bean varieties were organized in a Complete Random Design (CRD) with 10 replicates. The field experiment was an observational study where six pinto bean varieties: three slow-darkening pinto beans (Gleam, Mystic, Vibrant) and three regular pinto beans (Othello, Cowboy, SV6139) were planted in a field with a subsurface irrigation system to correlate yield to ECe for each variety. The results demonstrated that germination percentage, speed of germination and hypocotyl length decreased as the salt concentrations increased. Othello's vegetative and reproductive parameters were significantly higher compared to the other varieties in the greenhouse under the saline conditions. There was no significant correlation between yield and ECe in the field experiment. Results indicated that Othello's early maturity may have enabled it to perform better under salt stress conditions than the other tested varieties.Item Open Access Genome-wide association study and drought tolerance evaluation of a winter wheat association mapping panel(Colorado State University. Libraries, 2015) Awad, Wahid, author; Byrne, Patrick, advisor; Haley, Scott, committee member; Qian, Yaling, committee member; Comas, Louise, committee memberTo view the abstract, please see the full text of the document.Item Open Access Graywater application for landscape irrigation: greenhouse studies(Colorado State University. Libraries, 2010) Shogbon, Alicia R., author; Sharvelle, Sybil E., advisor; Shackelford, Charles D., committee member; Qian, Yaling, committee memberOver the years, residential graywater application for landscape irrigation has garnered increasing popularity. Concerns however exist regarding the potential negative impacts that graywater pose to plant health and environmental quality. Due to the variability in field conditions such as graywater loading rate, soil type, climate and rainfall amount difficulty exists in accurately determining the potential for groundwater contamination. The need therefore arises to evaluate impacts of graywater irrigation in a controlled environment to develop scientifically justified conclusions regarding the fate of graywater constituents. The objective of this study was to conduct experiments in a greenhouse to evaluate the potential for groundwater contamination by conducting leachate analysis. Plant health was also evaluated throughout the duration of the experiment. The experiment setup involved the use of thirty-eight custom polyvinyl chloride (PVC) pots. These pots were setup in the Colorado State University greenhouse. Potable water served as a control for the experiments. Two different plants and two different turfgrasses were utilized. The turfgrasses were bermudagrass (a warm season grass) and tall fescue (a cool season grass). The landscape plants used were euonymous (a shrub) and lemon (a citrus). The pots were setup to allow for leachate collection from the bottom. The leachate volume was monitored and recorded and leachate analyses were conducted for boron, sodium adsorption ratio (SAR), nitrate, ammonium, total nitrogen (TN), total dissolved solids (TDS), total suspended solids (TSS), volatile suspended solids (VSS), total organic carbon (TOC), sulfate, conductivity and surfactants (linear alkylbenzene sulfonate (LAS), alkyl ethoxy sulfate (AES), and alcohol ethoxylate (AE)). Analysis of the leachate from the graywater irrigated pots revealed on average, elevated levels of TOC, TN, nitrate, ammonium, TDS, TSS, VSS, sulfate, conductivity, boron and SAR when compared to the concentrations measured in the leachate from the control systems. The average concentrations of TOC, TSS, VSS , ammonium, nitrate and TN measured in the leachate from the graywater irrigated plant/grass systems were however lower than the concentrations in the synthetic graywater. An expected increase in conductivity and TDS in the leachate from the graywater irrigated pots was found. Results further indicate the accumulation of boron and salts (indicated by SAR) in the graywater systems with a trend of increasing concentrations with time and a subsequent increase in measured leachate concentrations above the input concentration measured in the graywater. With the exception of boron and salts, there was substantial percentage retention of graywater constituents through the soil column such that there was lower measured concentrations of the graywater constituents in the soil leachate compared to the input concentrations.Item Open Access Increased chlorophyll efficiency of dark-adapted camellia foliage when treated with chlorine dioxide or hydrogen dioxide and blended with a non-ionic surfactant(Colorado State University. Libraries, 2013) Hammack, Heather Nicole, author; Newman, Steven E., advisor; Qian, Yaling, committee member; Pilon-Smits, Elizabeth, committee memberPhytophthora ramorum is a major risk to interstate trade of nursery stock. This work focused on chemical oxidant chemistry as a disinfectant of nursery grown camellia plants. Disinfection of nursery stock is crucial for shipping, but the impact on plant health and phytotoxic responses are also important. To determine plant stress responses to applied chemical oxidants, we measured chlorophyll activity (PSII maximum quantum efficiency) as measured by Fv/Fm values on dark-adapted camellia plants. Data were collected using a Li-COR 6400XT leaf chamber fluorometer (Li-COR, Lincoln, NE) to evaluate the potential phytotoxicity of camellia to foliar applied chlorine dioxide (ClO2) and hydrogen dioxide (H2O2), with or without sarcosinate surfactant with consecutive spray applications. Chlorophyll activity (Fv/Fm) of dark adapted foliage was greater when ClO2 and H2O2 were applied with sarcosinate surfactant to camellia foliage compared to treatments not containing sarcosinate surfactant. Chlorophyll activity decreased with increasing concentrations of ClO2 without sarcosinate. Higher Fv/Fm across seven measurement intervals were observed in ClO2 treatments compared to H2O2 treatments at the same concentration. Visual injury of camellia foliage increased with each of the five subsequent spray applications; however, foliar injury did not exceed a marketable threshold for most treatments, until after four consecutive spray applications at 400 mg·L-1 ClO2, with or without surfactant. This study demonstrated that Electro-BioCide at a rate predicted to eradicate Phytophthora ramorum (200 mg·L-1) should not visually damage camellia plants until after five consecutive spray applications. These findings indicate that Electro-BioCide has the potential to be implemented as a preventative foliar treatment for defense against foliar plant pathogens, without concern for detriment to plant health.Item Open Access Irrigation effects on growth, stress, visual quality and evapotranspiration of ornamental grasses(Colorado State University. Libraries, 2016) Hagopian, Sam R., author; Klett, James E., advisor; Qian, Yaling, committee member; Andales, Allan, committee memberDeficit irrigation research has proven extremely effective for reducing the amount of irrigation applied to various types of landscape plants including trees, shrubs, and herbaceous ornamental plants. This research has yet to delve into one of the most common classes of drought tolerant plants, ornamental grasses. Deficit irrigation treatments were based on evapotranspiration of a short reference crop (Kentucky bluegrass evapotranspirtation, ETo). In 2012 three ornamental grass species were planted, and an on-site atmometer was used to estimate ETo. The three species used for trialing were Panicum virgatum ‘Rotstrahlbusch’ (Rotstrahlbusch Switchgrass), Schizachyrium scoparium ‘Blaze’ (Blaze Little Bluestem), and Calamgrostis brachytricha (Korean Feather Reed Grass). Treatments were applied and data was collected in 2014 and 2015 on two separate studies. The first study was in-ground and consisted of four treatments based on ETo (0%, 25%, 50%, and 100%). The second study was a mini-lysimeter and consisted of three treatments based on ETo (25%, 50%, and 100%). Only Schizachyrium scoparium ‘Blaze’ (Blaze Little Bluestem) was used in the lysimeter study. Data collected in both studies included plant water potential, biomass accumulation, green up date, flowering date, height, width, circumference, floral impact, landscape impact, overall habit, self-seeding, and color. The in-ground component also measured infrared canopy temperature and soil water content, while the lysimeter study included daily weight measurements which were then transferred to evapotranspiration readings. Plants in the 0% treatment were smaller and not considered visually suitable for landscape use. All three species in the 25% treatment performed equivalent to the 50% and 100% treatments in all categories. The only exception was plants in the 25% mini-lysimeter study were more stressed than the 50% or 100% treatments during periods of drought. These plants were all considered visually suitable for landscape use based on visual ratings. This suggests that as long as ornamental grasses are kept on a strict weekly regiment of 25% ETo, and are never exposed to periods of drought, they will be physiologically as well as aesthetically usable in the landscape trade. A weekly amount of 0.25 inches of irrigation on weeks without precipitation was determined to be a usable number for those installing and maintaining ornamental grasses.Item Open Access Mimulus gemmiparus as a model for the ex situ propagation and study of propagule storage for a species of concern(Colorado State University. Libraries, 2017) Harden, Dyan, author; Klett, Jim, advisor; Steingraeber, David, committee member; Qian, Yaling, committee memberMimulus gemmiparus, W.A. Weber, budding monkeyflower, is a Colorado narrow endemic plant that could be at risk of extinction. Factors including rarity, a unique mode of clonal, vegetative, annual reproduction through petiole enclosed brood bulbils, specific microhabitat requirements, limited means of dispersal for migration, and vulnerability to stochastic events all play roles in M. gemmiparus survival. Conservation efforts by researchers and federal and state land managers have involved passive protection of existing known populations and active measures such as assisted establishment. A decision matrix to prioritize the active propagation of Colorado species of concern is presented that identifies M. gemmiparus as a high priority for action. Ex situ propagation from field collected M. gemmiparus propagules can provide large quantities of plant material for active conservation efforts, however, short term to long term storage parameters for propagules have not been empirically investigated. Propagation of M. gemmiparus was undertaken in order to multiply propagules to produce material for a cold storage experiment to support active conservation efforts, also in order to document a reliable, repeatable propagation method that can be used to create banks of plant and propagule material for conservation, propagation, restoration, research, and storage. Interactions between water, temperature, and desiccation tolerance characteristics of the vegetatively reproductive bulbil are key to determining optimal storage conditions. Categories of seed storage behavior, orthodox, recalcitrant, and intermediate, differentiated by seed characteristics such as desiccation and cold tolerance, were used as a basis for exploration of bulbil storage behavior. The basis of knowledge used to guide cold storage of multiplied propagules was built on viability assays, measurements of bulbil moisture content, and storage temperature exposure and duration response. An empirical study examined bulbil post storage temperature exposure germination response in 4 MIGE ex situ propagated populations at temperatures -20⁰, -3⁰ to 0⁰, and 3⁰ to 5⁰C for 24 hours, 1 month, 3 months, and 6 months compared to a control storage temperature of 20⁰C. Bulbil viability at moisture contents below 0.1 gH2Og-1DW, and longevity at subfreezing temperatures did not conform to typical orthodox or recalcitrant seed behavior. Propagules with a mean moisture content of 0.3877 gH20g-1DW stored for 6 months at 3⁰ to 5⁰C retained the highest rates of post storage temperature exposure germination observed over 12 weeks. A low moisture content threshold where germination observed over 12 weeks was ≤10% was found between 0.1350 and 0.1817 gH20g-1DW. There was not a higher post exposure germination response in low moisture content bulbils stored at subfreezing temperatures compared to high moisture content bulbils exposed to subfreezing temperatures. Storage behavior appeared intermediate in nature. Further study could confirm that the 3 to 5 year longevity at 5⁰C storage temperature potential predicted for intermediate seeds is applicable to MIGE bulbils. M. gemmiparus serves as a model that demonstrates the feasibility and efficacy of ex situ propagation and propagule storage for a species of concern. Creation and management of ex situ plant and propagule banks are intended as a compliment to, not a replacement for, traditional conservation of in situ populations. More study is needed using more controlled methods of desiccation or specialized pre treatments such as the application of cryoprotectants to bulbils or meristematic tissue to preserve germplasm for longer time frames at freezing temperatures.Item Open Access Minimum stomatal conductance: implications for describing the genetic control of transpiration(Colorado State University. Libraries, 2013) Reuning, Gretchen, author; Bauerle, William, advisor; McKay, John, committee member; Qian, Yaling, committee memberMinimum stomatal conductance (g0) makes a significant contribution to the rate of water loss in plants. The influence of g0 on water use efficiency (WUE) has implications for plant drought tolerance and adaptation, thus we propose that g0 can be used as a trait to describe the genetic control of water use in leaf transpiration models. In the model species, Arabidopsis thaliana, g0 exhibits both environmental and genetic variation. We explored one g0 quantitative trait locus (QTL) by measuring and simulating transpiration for two A. thaliana accessions Kas-1 and Tsu-1, as well as recombinant inbred lines (RILs) from a reciprocal cross of the two parental lines. Using a three-dimensional spatially explicit plant process model, MAESTRA, we aimed to: (1) test the accuracy of transpiration prediction for Kas-1 and Tsu-1 using measured g0 values, (2) parameterize MAESTRA with Tsu-1, Kas-1, and RIL g0 values to predict transpiration of RILs containing either Tsu-1 and Kas-1 alleles at the g0 QTL, and (3) determine if a relationship exists between g0 values under well-watered and drought conditions in A. thaliana. MAESTRA accurately predicted A. thaliana transpiration for Kas-1 and Tsu-1 accessions when parameterized with measured g0 values. There was no significant difference between measured and simulated transpiration estimates for both accessions, with Tsu-1 simulated transpiration 5.2% lower than the mean measured, and Kas-1 simulated transpiration 1.4% higher than measured. On average, Kas-1 transpired 73% as much water as Tsu-1. Due to the lack of specific knowledge of RIL physiology aside from g0, simulating RIL transpiration with varying g0 values yielded non-significant results. However, based on the simulated means for RIL transpiration using RIL, Kas-1, and Tsu-1 g0 values, we show that g0 parameterization predicts daily transpiration when all other parameters are held constant at Tsu-1 or Kas-1 measured and presumed physiology. This further points to the importance of g0 for transpiration predictions. Data on additional g0 QTL could aid in predicting transpiration from novel genotypes such as RILs containing multiple combinations of alleles from parental genotypes. We found that accessions with relatively high well-watered g0 values showed sharper declines in g0 during drought compared to accessions with lower g0 values under well-watered conditions (p < 0.0001). The use of plant physiological models for predicting transpiration of novel genetic lines will benefit from the further knowledge of the genetic control of g0.Item Open Access Organic nitrogen fertilizers influence nutritional value, water use efficiency, and nitrogen dynamics of drip irrigated lettuce and sweet corn(Colorado State University. Libraries, 2016) Sukor, Arina, author; Davis, Jessica G., advisor; Schipanski, Meagan E., committee member; Qian, Yaling, committee member; Argueso, Cristiana, committee memberFarmers usually rely on off-farm sources (fish emulsion, feather meal, blood meal) for the additional N needed during the growing season, and they are willing to pay the extra shipping cost. However, there is another fertilizer option being developed that could allow farmers to produce N on-farm, which is cyanobacteria, formerly known as the blue green algae. The general objectives of this study were to assess effects of organic N fertilizer application and N rates on nutritional value, water use efficiency, N dynamics of sweet corn and lettuce. A two-year field study was conducted in the summers of 2013 and 2014 at the Colorado State University Horticulture Research Center, Fort Collins, CO. The fertilizers used in this study were blood meal, feather meal, fish emulsion, and cyano-fertilizer. Both fish emulsion and cyano-fertilizer were supplied in four split applications over the growing season through drip irrigation, while the blood meal and feather meal were subsurface banded prior to planting. Lettuce and sweet corn were used as an indicator to evaluate effects of organic nitrogen (N) fertilizers on nutritional value, water use efficiency, and N dynamics. The aims of this study were to evaluate the effect of different types of organic N fertilizer on nutritional value; β-carotene, iron (Fe), zinc (Zn), marketable yield, water use efficiency (WUE), residual soil nitrate-N, N content, and N use efficiency (NUE) of horticultural crops, particularly lettuce and sweet corn. All fertilizer treatments in 2013 increased β-carotene concentration in leaf tissue compared to control, while only fish emulsion had a higher β-carotene concentration compared to other treatments in 2014. The high indole-3-acetic acid (IAA) applied in the fish emulsion treatment could have increased β- carotene concentration in lettuce in both years. Amount of IAA applied in the fish emulsion treatment was positively correlated with β-carotene concentration in both years. A significant negative correlation was found between marketable yield and β-carotene concentration in leaf tissue in 2014. High salicylic acid (SA) applied in the cyano-fertilizer treatment had a higher total leaf area compared to other fertilizers in both years. In lettuce, the blood meal treatment had a lower leaf Fe and Zn concentrations than other fertilizer treatments at 112 kg N ha-1. The cyano-fertilizer treatment had a higher leaf Fe concentration at 56 kg N ha-1. Leaf N concentration was positively correlated with Leaf Fe and Zn concentrations. Amount of NO3- -N applied in organic N fertilizers was negatively correlated with leaf Fe concentration. The cyano-fertilizer, fish emulsion, and blood meal treatments increased Fe concentration in sweet corn compared to feather meal. Amount of NO3- -N, Fe, and Zn applied in organic N fertilizers were positively correlated with kernel Fe concentration, while amount of NH4+ -N applied was negatively correlated with kernel Fe concentration. There was no N rate or treatment effect on leaf and kernel N concentrations in sweet corn. The amount of phytohormone, Ca, and Fe applied in organic N fertilizers may have affected field water use efficiency (fWUE), instantaneous water use efficiency (iWUE), kernel number, and leaf gas exchange components of sweet corn. Cyano-fertilizer apparently had a higher WUE, likely due to the high amount of SA applied. A positive relationship was observed between the amount of SA applied with iWUE and fWUE. The amount of Fe applied in organic N fertilizers had a positive correlation with leaf VPD and transpiration rate. The amount of Ca applied in the feather meal treatment may have contributed to increasing leaf temperature and decreasing net photosynthetic rate. The amount of NH4+ -N and Ca applied in the feather meal treatments were negatively correlated with both iWUE and fWUE. N rate effect was only observed in lettuce marketable yield and NUE in both years. Blood meal and feather meal fertilizers with higher percentage of N applied as NO3- -N compared to other fertilizer treatments had a higher residual soil NO3- -N concentration in 2013. Greater residual soil NO3 - -N was observed in the 0-30 cm depth compared to the 30-60 cm depth in 2014. Organic growers could achieve higher marketable yield and NUE when applying fertilizers at rates between 28 kg N ha-1 and 56 kg N ha-1 compared with 112 kg N ha-1. In sweet corn, the feather meal and fish emulsion treatments had a higher residual soil NO3- -N compared with other treatments. The fish emulsion, cyano-fertilizer, and blood meal had a higher leaf and kernel N contents and NUE compared with feather meal at 56 kg N ha-1. The cyanofertilizer treatment had a higher marketable ear yield and NUE compared with other treatments at 112 kg N ha-1 in 2014. The amount of C inputs and crop species may have affected soil permanganate oxidizable carbon (POXC) concentration in a single season study. Soil POXC concentration was higher in the cyanofertilizer treatment compared to the control treatment in sweet corn, while the opposite trend was found in lettuce. Depth effect was observed in soil POXC concentration at 0-30 cm compared to 30-60 cm in lettuce. Soil POXC concentration was higher at 112 kg N ha-1 compared to 56 kg N ha-1 in sweet corn, but there was no N rate effect in lettuce. Greater soil POXC concentration and marketable ear yield of sweet corn were observed in the cyano-fertilizer treatment compared to others at 112 kg N ha-1. Overall, our results indicate that organic N fertilizer, particularly cyano-fertilizer influenced soil POXC concentration over a short-term growing season of horticultural crops.Item Open Access Phenotypic variability, cold hardiness and flowering induction of saltgrass [Distichlis spicata (L.) Greene] clones(Colorado State University. Libraries, 2006) Rukavina, Hrvoje Harry, author; Hughes, Harrison G., advisor; Brick, Mark A., committee member; Panella, Lee, committee member; Qian, Yaling, committee memberWith increased population growth and periodic droughts in the semiarid U.S. west, there is interest in developing alternative turfgrass species that are water efficient and tolerate poor quality water. Colorado State University is currently evaluating saltgrass for its potential use as turf. Development of a new turfgrass cultivar requires an understanding of environmental factors that influence traits important for turf quality. Furthermore, cultivar development for northern climates and transition zones necessitates an understanding of cold hardiness. Finally, to enable hybridization throughout the year and make rapid progress in a breeding program, it is important to develop techniques and understand environmental stimuli that induce flowering in saltgrass. This study was initiated to: 1) characterize variation in morphological traits and time of leaf browning in fall among saltgrass clones relative to geographic and climatic variables at the location of clones' origin; 2) examine the relative freezing tolerance of saltgrass clones as related to climatic zone of origin as well as relationship between freezing tolerance and time of leaf browning in fall and 3) examine the influence of sampling time from the field, as well as burning and nitrogen fertilization on flowering induction of saltgrass clones from different environments. In the first experiment, traits of growth (morphology) and time of leaf browning in fall were measured on 53 saltgrass clones from 42 locations established at one location in Fort Collins, CO. Principal component analysis on the traits of plant morphology extracted the first principal component (PC-1) that explained 78% of variability and was used as the estimate of growth. Principal component analysis was followed by multiple regression of PC-1 and time of leaf browning in fall on the environmental variables at locations of clones' origin. Variation in saltgrass growth (morphology) was related to the seasonal climatic variables of summer drying and fall cooling that explained 50% of variability of morphological traits. Variation in time of leaf browning in fall was related to longitude and minimum winter temperature which together explained 60% of total variability of this trait. In the second experiment, rhizomes were sampled during 2004 and 2005 midwinters from 27 saltgrass clones from three cold hardiness zones established in Fort Collins, CO and then subjected to a freezing test. Saltgrass freezing tolerance was highly influenced by the climatic zone of clone origin in both years of the experiment. Clones with greater freezing tolerance turned brown earlier in fall in both seasons. This study indicated that saltgrass clones from northern (cooler) climates had greater freezing tolerance than clones from southern (warmer) areas. In the first year of the third experiment, three clones (A1540 from Colorado, 1490 from South Dakota and C1660 from Nevada) were sampled from the field twice (in August and November). In the second year, two additional clones from the Colorado Front Range (A1180 and A1610) and an additional sampling time (January) were included. In the first year, nitrogen fertilization increased number of spikes in saltgrass. Compared with August sampling, sampling in November increased the number of spikes, and had a greater effect on clone A1540 than on clone 1490. The burning treatment increased number of spikes only in plants sampled from the field in August. In the second year, nitrogen fertilization increased the number of spikes to a greater extent when nitrogen was applied with burning than without the burning treatment. In comparison with August sampling, sampling in November increased number of spikes in all clones with the greatest effect in clone A1540. Sampling in January additionally increased number of spikes in clones 1490 and C1610 without a significant effect on number of spikes in clone A1540. Burning treatment had its greatest effect on number of spikes in plants sampled in August, as compared with November and January sampling.Item Open Access Phytoremediation with hemp (Cannabis sativa L.): a look at hemp's potential for environmental cleanup and economic recovery(Colorado State University. Libraries, 2022) Abernathy, Susan M., author; Pilon-Smits, Elizabeth, advisor; Pilon, Marinus, committee member; Qian, Yaling, committee memberThe aim of this thesis study was to test hemp's (Cannabis sativa L.) potential for phytoremediation (environmental clean-up). I tested hemp for tolerance and accumulation of four inorganic pollutants, to evaluate its remediating performance. Hemp has many properties that would make it a likely candidate for phytoremediation however, due to recent regulations, research of this versatile plant has been limited. Phytoremediation is a process of cleaning polluted sites using plants. In this clean-up method, plants may stabilize the pollutant in situ, or take-up the pollutant into the plant tissue. In the latter, there are a few different fates for the pollutant that include degradation, metabolization, sequestration, and/or volatilization. Phytoremediation is a clean process that reestablishes an onsite ecosystem and is a competitive alternative to more conventional scrape-and-remove methods. Hemp is a hardy, fast growing species that produces high biomass. Hemp has deep roots that can be used to reach pollutants deep in the ground. These properties make hemp a potential choice for phytoremediation. Contaminated sites create harsh growing conditions that require hardy plant properties in order for a species to survive. An added benefit to using hemp for remediation is the many economic uses of hemp biomass. Each part of the hemp plant can be used to make goods such as clothing, building material, cosmetics, lotions, animal bedding, fragrances, and medicinal products that have therapeutic qualities. In addition, hemp seeds are nutritious and can be added to the diet. In chapter one of this thesis, phytoremediation is reviewed to explain the remediation process. This review includes explaining the different phytotechnologies that are employed by plants which depend on the plant used and the type of pollutant encountered. Chapter one also reviews hemp, its history, biology, and the properties that make it a viable choice for phytoremediation. Chapter two of this thesis is an experimental chapter presenting data for testing hemp seedlings with four different oxyanions: arsenate (As), molybdate (Mo), vanadate (V), and tungstate (W). The parameters considered were biomass, chlorophyll content, chlorophyll fluorescence, pollutant accumulation levels, and pollutant fate. Brassica juncea (Indian mustard) was used as a reference phytoremediation species. The findings of this thesis study present promising results for hemp as a potential remediator. Arsenic was found to accumulate in the root at levels up to 2700 mg kg-1 DW. Tungsten also accumulated in the root at levels up to 3100 mg kg-1 DW. In both tests, hemp performed well, judged from photosynthetic measurements and relative chlorophyll content, but reduced biomass started at treatments with 3 and 24 mg As L-1 in the shoot and root respectively, and 40 and 80 mg W L-1 in the shoot and root, respectively. Molybdenum accumulated in the shoot at levels up to 4900 mg kg-1 DW and in the root at levels up to 2600 mg kg-1 DW. Biomass reduction of Mo started at treatment with 40 mg Mo L-1 for both shoot and root, while photosynthetic measurements and relative chlorophyll content remained unchanged. Lastly, V accumulated in the root at levels up to 2100 mg V kg-1 DW. Interestingly, hormesis (stimulated growth) was observed in hemp supplied with V: biomass increased at all tested levels. From this study, it was concluded that hemp may have potential for phytoremediation in cleaning contaminated sites with the four elements tested. Hemp performed competitively with the popular phytoremediation species, Indian mustard (Brassica juncea L.) in all levels tested for Mo, V, and W. Hemp's economic recovery with clean post-harvest biomass may offset phytoremediation costs giving this species a unique advantage over other popular phytoremediation choices.Item Open Access Soil carbon and nitrogen pools under perennial forage(Colorado State University. Libraries, 2010) Widiastuti, Dwi P., author; Davis, Jessica G., advisor; Mikha, Maysoon M., committee member; Qian, Yaling, committee memberTo view the abstract, please see the full text of the document.Item Open Access The evaluation of the potential for chlorine dioxide to prime plant defenses for a systemic acquired resistance in light red kidney bean plants inoculated with common bean bacterial wilt(Colorado State University. Libraries, 2015) Sandoval, Vanessa Marie, author; Newman, Steven, advisor; Ramsey, Craig, advisor; Pilon, Marinus, committee member; Qian, Yaling, committee memberThe induction of plant defenses is a great preventative tool for greenhouse and nursery managers to protect their plants. By priming plants with abiotic or biotic measures, managers can induce systemic acquired resistance (SAR) in plants to upregulate the ability to resist a pathogen. The accumulation of salicylic acid (SA) has been well researched and supported to be necessary for inducing SAR against pathogens. In previous research it has been shown that the functional analog of SA, acibenzolar S-methyl, has induced SAR and reduced disease severity. Acibenzolar S-methyl induces SAR when applied to plant foliage, but it does not have any antimicrobial activity to kill any pathogens on the foliage at the time of treatment. In previous research ozone has been successful at inducing SAR to reduce disease severity. Applying ozone as a treatment for greenhouse and nursery managers is not practical or safe since it is hazardous to the respiratory system. Chlorine dioxide is a powerful oxidant disinfectant that can be applied as a foliar spray to kill harmful pathogens, but it has not been reported whether it could induce plant defenses. This research study investigated whether a commercial formulation of chlorine dioxide [Electro-biocide® (E-B)] could be used as a foliar application to plants to induce SAR. E-B is a proprietary blend of ClO2, pH buffer, and a sarcosinate surfactant. There were a total of four spray treatments that were evaluated on plants inoculated with a bacterial wilt and on a set of non-inoculated plants. The light red kidney bean plants were treated with E-B at 200 mg l-1 ClO2, E-B 400 mg l-1 ClO2, acibenzolar S-methyl (Actigard™) and a water control to evaluate disease resistance when inoculated with Curtobacterium flaccumfaciens pv. flaccumfaciens. Treated plants were evaluated for both inoculated plants and non-inoculated plants. SA concentrations were measured five days after treatment and one day after inoculation. Leaf samples were collected to measure SA every three hours over the course of the day starting at 0700 hours and ending 2200 hours. A second SA measurement was taken at the end of the study 61 days after planting (44 days after treatment) to observe if there were any changes in SA level. Chlorophyll fluorescence measurements were taken to observe stress in response to the spray treatments and disease infection. Carbon dioxide (CO2) gas exchange measurements were taken to observe the vigor or decline within the spray treatments and infection status. At the end of the study plants were harvested for foliage, pod, stem dry weight, and leaf area. The first photosynthesis measurements on non-inoculated plants E-B 200 mg ClO2 l-1 and 400 mg l-1 ClO2 treatments declined, but recovered to control levels one week later. Inoculated plants treated with E-B and Actigard™ showed either the same or increased photosynthesis rates when compared to water. Chlorophyll fluorescence measurements indicated there was no stress due to the spray treatments. Five days after spray treatments the SA measurements showed that both concentrations of E-B resulted in an increase in SA accumulation. E-B 400 mg l-1 ClO2 caused the greatest SA response. E-B 400 mg l-1 ClO2 treated plant’s had a 15 fold increase in SA concentrations at its highest peak when compared to water. E-B 200 mg l-1 ClO2 had the second highest SA concentrations. It had a 5.9 fold increase at its highest peak when compared to water control plants. Actigard™ treated plants did not result in different SA concentrations from the water control plants. The SA concentrations levels at 44 days after treatment for all plants that were not inoculated returned to normal levels. SA levels for inoculated plants and all spray treatments continued to rise for the duration of the study. There were no differences in biomass measurements between spray treatments. All non-inoculated plants had a greater biomass measurements when compared to all the inoculated plants. These results conclude that E-B 200 mg l-1 ClO2 and E-B 400 mg l-1 ClO2 were able to prime plant defenses for SAR response. The rise in SA concentrations confirm that E-B was able to interact within the leaf as an elicitor for SAR. Unfortunately the biomass measurements for inoculated E-B treated plants did not show any difference from inoculated control plants. This indicates that the E-B treatment was not able to reduce the disease severity with CFF. Actigard (acibenzolar-S methyl) has been successful with inducing SAR and reducing disease severity in other studies. In this study Actigard was also unsuccessful in reducing disease severity. This indicates that CFF may have had too great of pressure for the inoculated plants to overcome. E-B should be investigated further with other pathogens.Item Open Access The relationship between greenhouse and field performance of diverse cultivars of summer squash and watermelon grown under moisture stressed conditions(Colorado State University. Libraries, 2019) Ray, Deborah Kay, author; Uchanski, Mark, advisor; Qian, Yaling, committee member; Byrne, Patrick, committee memberDrought stress poses a major threat to the global food supply, and most domestic vegetable growers lack cultivar-specific information that would allow them to adopt best management practices to limit the impacts of these stressors. Summer squash (Cucurbita pepo) and watermelon (Citrullus lanatus) are two crops in the Cucurbitaceae family that are commonly grown and consumed in the U.S. Heirlooms and modern cultivars of these crops with reports of "drought resistance" are currently available on the market without concomitant recommended modifications to irrigation management. Many published greenhouse experiments have been used to screen cultivars and breeding lines for drought resistance, but often lack paired field trials to confirm results. We conducted a greenhouse dry-down study on nine summer squash and 10 watermelon cultivars, and sustained deficit irrigation (SDI) field trials on a selected 13. Our objective was to determine if crop characteristics identified in the greenhouse studies could be predictive of season-long field success under drought conditions. Colorado-bred conventional hybrids were used as control cultivars in both studies, and were hypothesized to have a more drought-sensitive response than cultivars with reports of drought resistance. Parameters evaluated in the greenhouse study included: days to death, percent soil moisture at death, root:shoot ratio, and root system characteristics. The cultivars that were then evaluated in the field study received one of three sustained deficit irrigation treatments: control, deficit, or drought, using a drip irrigation system in a split-plot design with three replications. Control treatments were reduced to approximately half the average recommended number of acre-inches of water per season for each crop, averaging 5.9 and 4.8 inches for summer squash and watermelon, respectively. Deficit and drought irrigation treatments were reduced 50% beyond the control during the treatment interval, which began after flowering and extended over the course of 12 weeks for the squash, and six weeks for watermelon. The deficit treatment plots received irrigations of equal frequency to the control, in half the amount, and the drought treatment plots received irrigations at half the frequency of the control, with the same volume of water as the control applied at each irrigation event. Squash were grown under rain exclusion and watermelons were grown in an open field with rainfall amounts factored into total water application calculations. Soil moisture and environmental conditions were monitored, and yield and quality measures were taken in both crops. Photosynthetic activity was also evaluated twice each season in the summer squash plot using a MultispeQ. Our results revealed that greenhouse performance was often not indicative of field performance, and that almost all squash cultivars produced acceptable levels of marketable yield under severe water deficits in the field. Watermelon cultivars produced marketable fruits in both years, but performance was inconsistent from year to year, and yield was low across all cultivars and treatments. Modern cultivars and heirlooms with reports of drought resistance, such as 'Desert King' watermelon and 'Desert F1' zucchini, did not necessarily out-perform hybrids or open-pollinated cultivars without such reports, such as 'Amiga' watermelon, and 'Jasper' and 'Dark Star' summer squash. By imposing a sustained deficit of more than 50% below recommended season-long rates, we identified five best-performing cultivars of summer squash that experience an approximate yield penalty of 30% under these conditions. The results of this study offer a prescriptive weekly method of irrigation management combined with recommendations for currently available cultivars that can be readily adopted by local, fresh-market growers to enable significant water savings without reductions in quality.Item Open Access Yield and quality of cool-season perennial grasses for forage and biomass feedstocks in Northeast Colorado(Colorado State University. Libraries, 2011) Gillette, Katrina Lynn, author; Hansen, Neil C., advisor; Brummer, Joe E., committee member; Qian, Yaling, committee memberThe burning of fossil fuels has led to an increase of the greenhouse gas CO2, which traps heat and increases temperatures of the global climate. The increases of the greenhouse gases, CO2, CH4 and N2O, have been attributed as the cause of the climatic warming during the industrial era. One identified GHG mitigation strategy is the use of long term perennial grass production for bio-fuel use and rangeland restoration. It is estimated that biofuels could offset 30% of current fossil fuel use. Switchgrass, a C4 grass species, was chosen by the DOE as the model crop for cellulosic biofuel because of the plant's perennial nature, high water use efficiency, wide range of exploitable genetics, and its ability to be grown in diverse regions. Yield potentials are often lower for cool-season grasses, but for warm-season grasses like switchgrass difficult establishment and winter stand loss from extreme conditions can be a problem for production. There are many C3 species utilized in the Northeastern and the Western of the United States for rangeland and pasture cattle production. Production difficulties are less likely in some of the hardier C3 grasses in cooler environments. C3 grasses have been historically utilized for animal forage because of superior digestibility and high feed values. The high digestibility is directly correlated to reduced lignin content. Lignin is a primary barrier to the bioconversion process to make ethanol. Increasing the polysaccharide to lignin ratio is one identified route to increasing bio-fuel feedstock quality. These qualities produced in C3 grasses could create a dual feedstock for both animal and bio-fuel production. This may even decrease competition for land resources between livestock producers and bio-energy crop production. Relying on a diversity of bio-energy crops in ecologically different regions will allow for greater stability, resistance, and resilience to climatic and environmental variability. The goals of this study are to compare forage quality analyses of C3 grasses, seasonal partitioning of dry matter (DM), crude protein content (CP), and neutral detergent fiber (NDF) and acid detergent fiber (ADF). Fifteen cool-season grasses were selected based on potential productivity under limited irrigation typical to Eastern Colorado. Two spring harvest dates were selected based on important production phases of the plant. The June 1, 2009 harvest (H1) corresponded to the boot to early heading stage. The average for the species statistically grouped the highest yield was 4500 kg/ha. The second spring harvest (H2) was on June 22, 2009 and corresponded to the mid to late heading stage and average yields for this harvest was 6390 kg/ha. These are high yields for the Eastern Plains of Colorado, but it is important to point out at that 2009 had an exceptionally wet spring and summer for the region. Tall, intermediate, crested and western wheatgrass were species that performed the best for the delayed harvest in terms of biofuels quality because they had the greatest increases in yield and structural carbohydrates, measured in NDF and ADF analysis. These species also had the greatest decrease in CP content. However, in general all species retained fairly high CP levels of over 10%, which is too high for biofuel quality standards, and an even further delay in harvest timing is recommended to decrease CP levels. This may be easily attained since forages evaluated decreased in quality at a rapid rate after seed head emergence. There are two major hurdles for the use of these forages as biofuels: 1) competition from feedstock and livestock feeders and 2) reducing the CP levels of the forages.