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Addressing Water Hyacinth (Pontederia Crassipes) Impacts On Aquatic Biota In Lake Okeechobee, Joseph Salerno

All HCAS Student Capstones, Theses, and Dissertations

The incursion of water hyacinth, Pontederia crassipes in Lake Okeechobee has resulted in management systems to be implemented to reduce the coverage of the invasive macrophyte. Its residence in the Lake Okeechobee ecosystem and the effects it has on organisms in the lake, whether it be positive or harmful is unknown. This study attempted to assess the potential effects that water hyacinth has on aquatic biota in Lake Okeechobee. Biotic data were collected on open water, water hyacinth covered, and native vegetation covered habitats via hook-and-line fishing, electrofishing, baited minnow traps, and the sampling of plant roots over a thirteen-month …

Tillage, Green Manuring And Crop Residue Management Impacts On Crop Productivity, Potassium Use Efficiency And Potassium Fractions Under Rice-Wheat System, Sandeep Sharma, Pritpal Singh, Hayssam M. Ali, Manzer Hussain Siddiqui, Javed Iqbal

Department of Agronomy and Horticulture: Faculty Publications

The conventional crop production practices including intensive tillage and open field crop residue burning in world’ largest rice-wheat system (RWS) are adversely affecting crop productivity besides deteriorating natural resources and ecosystems’ sustainability. In order to improve system productivity, potassium (K) use efficiency and apparent K balance, adoption of conservation tillage in a RWS with residue management is considered highly effective. We therefore, studied the effect of wheat straw retention and green manure (GM) in rice (main plot treatment), and tillage and rice residue management in subsequent wheat (sub-plot treatments) on crop productivity, K use efficiency and its transformation amongst different …

Conversion Of Native Grassland To Coniferous Forests Decreased Stocks Of Soil Organic Carbon And Microbial Biomass, Lidong Li, Elnaz Hosseiniaghdam, Rhae A. Drijber, Elizabeth Jeske, Tala Awada, J. Hiller, Michael Kaiser

Department of Agronomy and Horticulture: Faculty Publications

Aims Encroachment of woody species into grasslands is a global phenomenon that affects ecosystem services, including soil organic carbon (SOC) storage and microbial community structure. We determined stocks of SOC and soil microbial biomass as affected by conversion of grasslands to coniferous forests.

Methods We examined SOC and soil δ¹³C signatures under three vegetation covers: native grasslands, eastern redcedar (Juniperus virginiana), and ponderosa pine (Pinus ponderosa), at six soil depths (0 − 10, 10 − 30, 30 − 100, 100 − 170, 170 − 240, 240 − 300 cm). Fatty acid methyl esters (FAMEs) …

Creeper Legume, In Conjunction With Biochar, Is A Potential Tool To Minimize Soil Erosion, Sujani De Silva, Priyantha Indralal Yapa, Kushani Mahatantila, Saurav Das, Bijesh Maharjan

Department of Agronomy and Horticulture: Faculty Publications

Accelerated soil erosion and landslides are destructive consequences of road development and intensive agriculture in the central highlands of Sri Lanka. Properly designed vegetation covers can play a vital role in erosion control. Identifying a plant that can adapt to eroded land with a low-nutrient supply is critical for natural erosion management. A perennial creeper legume, Vigna marina, adaptable for marginal lands and used to control soil erosion in Australia, was introduced to Sri Lanka via the 2004 tsunami. The objective of this study was to assess V. marina under five different soil substrates, including a reference treatment (RT) …

Du Undergraduate Showcase: Research, Scholarship, And Creative Works, Caitlyn Aldersea, Justin Bravo, Sam Allen, Anna Block, Connor Block, Emma Buechler, Maria De Los Angeles Bustillos, Arianna Carlson, William Christensen, Olivia Kachulis, Noah Craver, Kate Dillon, Muskan Fatima, Angel Fernandes, Emma Finch, Colleen Cassidy, Amy Fishman, Andrea Francis, Stacia Fritz, Simran Gill, Emma Gries, Rylie Hansen, Shannon Powers, Jacqueline Martinez, Zachary Harker, Ashley Hasty, Mykaela Tanino-Springsteen, Kathleen Hopps, Adelaide Kerenick, Colin Kleckner, Ci Koehring, Elijah Kruger, Braden Krumholz, Maddie Leake, Lyneé Alves, Seraphina Loukas, Yatzari Lozano Vazquez, Haley Maki, Emily Martinez, Sierra Mckinney, Mykaela Tanino-Springsteen, Audrey Mitchell, Kipling Newman, Audrey Ng, Megan Lucyshyn, Andrew Nguyen, Stevie Ostman, Casandra Pearson, Alexandra Penney, Julia Gielczynski, Tyler Ball, Anna Rini, Christina Rorres, Simon Ruland, Helayna Schafer, Emma Sellers, Sarah Schuller, Claire Shaver, Kevin Summers, Isabella Shaw, Madison Sinar, Claudia Pena, Apshara Siwakoti, Carter Sorensen, Madi Sousa, Anna Sparling, Alexandra Revier, Brandon Thierry, Dylan Tyree, Maggie Williams, Lauren Wols

DU Undergraduate Research Journal Archive

DU Undergraduate Showcase: Research, Scholarship, and Creative Works

Influence Of Biochar As A Soil Amendment On Soil Water Content And Wild Blueberry Physiology, Abigayl Novak

Electronic Theses and Dissertations

Maine wild (or lowbush) blueberries (Vaccinium angustifolium Ait.) continue to face challenges imposed by climate change. Reduced frequency of precipitation and increased drought conditions have negatively impacted this crop since it resides in sandy soils with limited retention of water and nutrients. The wild blueberry plants growing in water- and nutrient-poor sandy soils are likely to have poor resilience to drought, resulting in a decline in berry yield during drought years. Thus, there is an urgent need to find a drought management solution for wild blueberries. Compared with other drought management practices, such as irrigation systems, mulching, and adopting drought-resistant …

Morphological And Physiological Responses Of A Halophyte (Atriplex Halimus) To The Effect Of Heavy Metal Case Of Cadmium, Abderrezzeq Chebout, Hana Souahi, Zahia Kadi, Rania Gacem

Journal of Bioresource Management

Today, cadmium (Cd) contamination challenges the environmental quality and food security. This experiment was realized to study the morphological and physiological response of the halophyte species Atriplex halimus L to cadmium toxicity by applying different concentrations of Cd (0, 500, 1000, 1500, 2000 ppm) on the plant A.halimus for two weeks after 60 days of seeding. The morphological parameters and physiological wish evaluated the stem length (SL), root length (RL), leaf area (LA), chlorophylls (a, b, t and carotenoids), and the relative water content (RWC). The results show a decrease in stem elongation, (11.333 ± 3.512 cm in Cd treatments …

Non-Destructive Classification And Quality Evaluation Of Proso Millet Cultivars Using Nir Hyperspectral Imaging With Machine Learning, Laruen E. Doyle, Julia R. Loeb, Nader Ekramirad, Dipak K. Santra, Akinbode A. Adedeji

Department of Agronomy and Horticulture: Faculty Publications

Millet is a small-seeded cereal crop with big potential and remarkable characteristics such as high drought resistance, short growing time, low water footprint, and the ability to grow in acidic soil. There is a need to develop nondestructive methods for differentiation and evaluation of the quality attributes of different of proso millet cultivars grown in the U.S. Current methods of cultivar classification are either subjective or destructive, time consuming, not allowing for the whole population to be tested, and requiring trained operators and special equipment. In this study, the feasibility of using near-infrared (NIR) hyperspectral imaging (900-1700 nm) to predict …

Climate Change And Management Impacts On Soybean N Fixation, Soil N Mineralization, N2O Emissions, And Seed Yield, Elvis F. Elli, Ignacio A. Ciampitti, Michael J. Castellano, Larry C. Purcell, Seth Naeve, Patricio Grassini, Nicolas C. La Menza, Luiz Moro Rosso, André F. De Borja Reis, Péter Kovács, Sotirios V. Archontoulis

Department of Agronomy and Horticulture: Faculty Publications

Limited knowledge about how nitrogen (N) dynamics are affected by climate change, weather variability, and crop management is a major barrier to improving the productivity and environmental performance of soybean-based cropping systems. To fill this knowledge gap, we created a systems understanding of agroecosystem N dynamics and quantified the impact of controllable (management) and uncontrollable (weather, climate) factors on N fluxes and soybean yields. We performed a simulation experiment across 10 soybean production environments in the United States using the Agricultural Production Systems sIMulator (APSIM) model and future climate projections from five global circulation models. Climate change (2020–2080) increased N …

Microbiome Variation Across Populations Of Desert Halophyte Zygophyllum Qatarensis, Abdul Latif Khan, Lucas Dantas Lopes, Saqib Bilal, Sajjad Asaf, Kerri M. Crawford, Venkatesh Balan, Ahmed Al-Rawahi, Ahmed Al-Harrasi, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Microbial symbionts play a significant role in plant health and stress tolerance. However, few studies exist that address rare species of core-microbiome function during abiotic stress. In the current study, we compared the microbiome composition of succulent dwarf shrub halophyte Zygophyllum qatarensis Hadidi across desert populations. The results showed that rhizospheric and endosphere microbiome greatly varied due to soil texture (sandy and gravel). No specific bacterial amplicon sequence variants were observed in the core-microbiome of bulk soil and rhizosphere, however, bacterial genus Alcaligenes and fungal genus Acidea were abundantly distributed across root and shoot endospheres. We also analyzed major nutrients …

Microbiome Variation Across Populations Of Desert Halophyte Zygophyllum Qatarensis, Abdul Latif Khan, Lucas Dantas Lopes, Saqib Bilal, Sajjad Asaf, Kerri M. Crawford, Venkatesh Balan, Ahmed Al-Rawahi, Ahmed Al-Harrasi, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Microbial symbionts play a significant role in plant health and stress tolerance. However, few studies exist that address rare species of core-microbiome function during abiotic stress. In the current study, we compared the microbiome composition of succulent dwarf shrub halophyte Zygophyllum qatarensis Hadidi across desert populations. The results showed that rhizospheric and endosphere microbiome greatly varied due to soil texture (sandy and gravel). No specific bacterial amplicon sequence variants were observed in the core-microbiome of bulk soil and rhizosphere, however, bacterial genus Alcaligenes and fungal genus Acidea were abundantly distributed across root and shoot endospheres. We also analyzed major nutrients …

Impact Of Cover Crop Monocultures And Mixtures On Organic Carbon Contents Of Soil Aggregates, Daphne Topps, Imam Ul Khabir, Hagir Abdelmagid, Todd Jackson, Javed Iqbal, Boakai K. Robertson, Zahida Hassan Pervaiz, Muhammad Saleem

Department of Agronomy and Horticulture: Faculty Publications

Cover crops are considered an integral component of agroecosystems because of their positive impacts on biotic and abiotic indicators of soil health. At present, we know little about the impact of cover crop types and diversity on the organic carbon (OC) contents of different soil aggregate-size classes. In this study, we investigated the effect of cover plant diversity on OC contents of different soil aggregates, such as macro- (<2000–500 µm), meso- (<500–250 µm), and micro-aggregates (<250 µm). Our experiment included a total of 12 experimental treatments in triplicate; six different monoculture treatments such as chickling vetch (Vicia villosa), crimson clover (Trifolium incarnatum), hairy vetch (Vicia villosa), field peas (Pisum sativum), oilseed radish (Raphanus sativus), and mighty mustard (Brassica juncea), and their three- and six-species mixture treatments, including one unplanted control treatment. We performed this experiment usingdeep pots that contained soil collected from a corn-soybean rotation field. At vegetative maturity of cover plants (about 70 days), we took soil samples, and the soil aggregate-size classes were separated by the dry sieving. We hypothesized that cover crop type and diversity will improve OC contents of different soil aggregate-size classes. We found that cover plant species richness weakly positively increased OC contents of soil macro-aggregates (p = 0.056), whereas other aggregate-size classes did not respond to cover crop diversity gradient. Similarly, the OC contents of macroaggregates varied significantly (p = 0.013) under cover crop treatments, though neither monoculture nor mixture treatments showed significantly higher OC contents than the control treatment in this short-term experiment. Interestingly, the inclusion of hairy vetch and oilseed radish increased and decreased the OC contents of macro- and micro-aggregates, respectively. Moreover, we found a positive correlation between shoot biomass and OC contents of macroaggregates. Overall, our results suggest that species-rich rather than -poor communities may improve OC contents of soil macroaggregates, which constitute a major portion of soil systems, and are also considered as important indicators of soil functions.

Taxonomic Microbiome Profiling And Abundance Patterns In The Cacao (Theobroma Cacao L.) Rhizosphere Treated With Arbuscular Mycorrhizal Fungi And Bamboo Biochar, Angelbert D. Cortes, Nelly S. Aggangan, Rina B. Opulencia

The Philippine Agricultural Scientist

Biochar and arbuscular mycorrhizal fungi (AMF) are agricultural interventions adopted by farmers to improve the growth of crops in nutrient-deficient acidic soil, which relatively influence the biological properties in the rhizosphere. This greenhouse study investigated the changes in prokaryotic diversity in the rhizosphere of cacao plants grown in acidic soil with AMF and bamboo biochar (BB) for 15 months under nursery conditions. Metagenomic analysis of the V3-V4 region of the 16S rRNA gene of the rhizosphere with AMF, 15% BB, and AMF + 15% BB revealed that the addition of AMF and BB reduced the sample's diversity, but the treatments …

Does Biochar Improve All Soil Ecosystem Services?, Humberto Blanco-Canqui

Department of Agronomy and Horticulture: Faculty Publications

Biochar is considered to sequester C and deliver other soil ecosystem services, but an overview that synthesizes the current knowledge of biochar implications on all essential soil ecosystem services is difficult to find in the ample biochar literature. Most previous research and review articles on this topic focused on a single ecosystem service and did not integrate all essential soil ecosystem services. This overview paper (1) synthesizes the impacts of biochar on water and wind erosion, C sequestration, soil water, nutrient leaching, soil fertility, crop yields, and other soil ecosystem services based on published literature and (2) highlights remaining research …

Coal Char Effects On Soil Chemical Properties And Maize Yields In Semi-Arid Region, Dinesh Panday, Maysoon M. Mikha, Xiaocun Sun, Bijesh Maharjan

Department of Agronomy and Horticulture: Faculty Publications

Soil amendments with high carbon (C) content can be effective in semi-arid regions where soils are characterized by low C. A field study was conducted in 2016–2018 to evaluate the effect of char on soil chemical properties and irrigated maize (Zea mays L.) yields in sandy loam fertilized with urea or composted manure. Carbon-rich char used was a product of coal combustion residue from a local factory in western Nebraska. The experiment was arranged in a split-plot randomized complete block design in four replications with char (0, 6.7, 13.4, 20.1, and 26.8Mg C ha⁻¹) as main and …

Responses Of Soil Surface Greenhouse Gas Emissions To Nitrogen And Sulfur Fertilizer Rates To Brassica Carinata Grown As A Bio-Jet Fuel, Dwarika Bhattarai, Gandura O. Abagandura, Thandiwe Nleya, Sandeep Kumar

Department of Agronomy and Horticulture: Faculty Publications

Carinata (Brassica carinata A. Braun), a non-food oilseed crop and an alternative bio-jet fuel feedstock, has received attention for its potential as a low-input option for production in the semi-arid region of the Northern Great Plains of the United States. Research addressing the impacts of nitrogen (N) and sulfur (S) fertilizers on soils and greenhouse gas (GHG; CO2, N2O, and CH4) emissions from carinata production are limited. Thus, objective of this study was to evaluate the impact of different rates of N and S fertilizers applied to carinata on soil properties and GHG emissions. Field experiments were conducted in 2017 …

Potential Amendments For Improving Productivity Of Low Carbon Semiarid Soil, Bijesh Maharjan, Dinesh Panday, Humberto Blanco-Canqui, Maysoon M. Mikha

Department of Agronomy and Horticulture: Faculty Publications

Applying soil amendments with high C content can potentially improve soil properties and increase crop yields. The objective of this 3-yr field study was to evaluate the effects of organic amendments on soil organic C (SOC), chemical properties, crop nutrient uptake, and crop yields in a low C sandy loam soil near Scottsbluff, NE. The field was planted to dry bean (Phaseolus vulgaris L.) in 2017, maize (Zea mays L.) in 2018, and sugar beet (Beta vulgaris L.) in 2019. Char at 22.3, 44.6, 66.9, 89.2, and 133.8 Mg ha^–1; biochar at 5.6 and 11.2 …

Coal Char Affects Soil Ph To Reduce Ammonia Volatilization From Sandy Loam Soil, Dinesh Panday, Maysoon M. Mikha, Bijesh Maharjan

Department of Agronomy and Horticulture: Faculty Publications

Ammonia (NH₃) volatilization loss adversely affects N availability in soil-plant systems, reduces crop yield, and negatively impacts environment. Char (coal combustion residue), which contains up to 293 g kg⁻¹ total C by weight, has been shown to reduce NH₃ volatilization due to its considerably high surface area and cation exchange capacity. The NH₃ loss can be greatly affected by a shift in soil pH or urea hydrolysis. A 21-d laboratory study was conducted to evaluate the effects of char on soil pH, N transformations, and subsequent NH₃ volatilization in sandy loam soil. Two …

Effects Of Char On Nitrogen Management In Agricultural Soils Of Semi-Arid Western Nebraska, Dinesh Panday

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Soils in western Nebraska are characterized by low soil organic C due to semi-arid environment in the region and further aggravated by disruption of soil aggregates and rapid C decomposition from intensive tillage, erosion, and frequent droughts. Proper management of soil C may improve soil properties, reduce N losses, and subsequently improve crop yields in this low C soil and low moisture condition. This dissertation focuses on C-rich coal char (henceforth “char”) as a potential strategy to overcome the existing problem of low C in semi-arid region. Char is an industrial by-product, resulting from inefficient coal burning during sugar beet …

Optimum Rates Of Surface-Applied Coal Char Decreased Soil Ammonia Volatilization Loss, Dinesh Panday, Maysoon M. Mikha, Harold P. Collins, Virginia L. Jin, Michael Kaiser, Jennifer Cooper, Arindam Malakar, Bijesh Maharjan

Department of Agronomy and Horticulture: Faculty Publications

Fertilizer N losses from agricultural systems have economic and environmental implications. Soil amendment with high C materials, such as coal char, may mitigate N losses. Char, a coal combustion residue, obtained from a sugar factory in Scottsbluff, NE, contained 29% C by weight. A 30-d laboratory study was conducted to evaluate the effects of char addition on N losses via nitrous oxide (N₂O) emission, ammonia (NH₃) volatilization, and nitrate (NO₃–N) leaching from fertilized loam and sandy loam soils. Char was applied at five different rates (0, 6.7, 10.1, 13.4, and 26.8 Mg C ha …

Continuous Cropping Alters Multiple Biotic And Abiotic Indicators Of Soil Health, Pervaiz Ahmad, Javed Iqbal, Qingming Zhang, Dima Chen, Hui Wei, Muhammad Saleem

Department of Agronomy and Horticulture: Faculty Publications

The continuous cropping (CC) of major agricultural, horticultural, and industrial crops is an established practice worldwide, though it has significant soil health-related concerns. However, a combined review of the effects of CC on soil health indicators, in particular omics ones, remains missing. The CC may negatively impact multiple biotic and abiotic indicators of soil health, fertility, and crop yield. It could potentially alter the soil biotic indicators, which include but are not limited to the composition, abundance, diversity, and functioning of soil micro- and macro-organisms, microbial networks, enzyme activities, and soil food web interactions. Moreover, it could also alter various …

Coal Char Affects Soil Ph To Reduce Ammonia Volatilization From Sandy Loam Soil, Dinesh Panday, Maysoon M. Mikha, Bijesh Maharjan

Department of Agronomy and Horticulture: Faculty Publications

Ammonia (NH3) volatilization loss adversely affects N availability in soil-plant systems, reduces crop yield, and negatively impacts environment. Char (coal combus- tion residue), which contains up to 293 g kg−1 total C by weight, has been shown to reduce NH3 volatilization due to its considerably high surface area and cation exchange capacity. The NH3 loss can be greatly affected by a shift in soil pH or urea hydrolysis. A 21-d laboratory study was conducted to evaluate the effects of char on soil pH, N transformations, and subsequent NH3 volatilization in sandy loam soil. Two char rates (0 and 13.4 Mg …

Soil Carbon Increased By Twice The Amount Of Biochar Carbon Applied After 6 Years: Field Evidence Of Negative Priming, Humberto Blanco-Canqui, David A. Laird, Emily A. Heaton, Samuel Rathke, Bharat Sharma Acharya

Department of Agronomy and Horticulture: Faculty Publications

Applying biochar to agricultural soils has been proposed as a means of sequester-ing carbon (C) while simultaneously enhancing soil health and agricultural sustain-ability. However, our understanding of the long-term effects of biochar and annual versus perennial cropping systems and their interactions on soil properties under field conditions is limited. We quantified changes in soil C concentration and stocks, and other soil properties 6 years after biochar applications to corn (Zea mays L.) and dedicated bioenergy crops on a Midwestern US soil. Treatments were as fol-lows: no-till continuous corn, Liberty switchgrass (Panicum virgatum L.), and low-diversity prairie grasses, 45% big bluestem …

Do Coffee Agroforestry Systems Always Improve Soil Carbon Stocks Deeper In The Soil?—A Case Study From Turrialba, Costa Rica, Nilovna Chatterjee, P. K. Ramachandran Nair, Vimala D. Nair, Abhishek Bhattacharjee, Elias De Melo Virginio Filho, Rheinhold G. Muschler, Martin R.A. Noponen

Department of Agronomy and Horticulture: Faculty Publications

Shaded perennial agroforestry systems (AFS) are regarded as desirable land‐use practices that improve soil carbon sequestration. However, most studies assume a positive correlation between above ground and below ground carbon without considering the effect of past and current land management, textural variations (silt and clay percentage), and such other site‐specific factors that have a major influence on the extent of soil C sequestration. We assessed SOC stock at various depths (0–10, 10–30, 30–60, and 60–100 cm) in shaded perennial coffee (Coffea arabica L.) AFS in a 17‐ year‐old experimental field at the Centro Agronómico Tropical de Investigación y Enseñanza, (9°53′44′′ …

A Survey Of Soil Properties Affecting Vegetation Establishment Along Nebraska Highways, Shad D. Mills

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Vegetation along roadsides is important to prevent soil erosion, provide habitat and filter water running off the road. Along some highways in Nebraska vegetation does not readily establish and persist. It is thought that sodium and bulk density issues are the driving factor behind the lack of vegetation. After a construction project, the shoulder is seeded into the compacted soil, and salts can accumulate in the soil due to deicing agents being used during the winter. The purpose of our study was to determine if the bulk density and sodium are the driving factors of the vegetation cover. We also …

Dedicated Bioenergy Crops And Water Erosion, Bharat Sharma Acharya, Humberto Blanco-Canqui, Robert B. Mitchell, Richard Cruse, David Laird

Department of Agronomy and Horticulture: Faculty Publications

Information on the water quality impact of perennial warmseason grasses (WSGs) when grown in marginal lands as dedicated energy crops is limited. We studied how WSGs affected runoff, sediment, and nutrient losses and related near-surface soil properties to those of no-till corn (Zea mays L.) on an eroded soil in southwestern Iowa and a center pivot corner in east-central Nebraska. The experiment at the eroded soil was established in 2012, and treatments included ‘Liberty’ switchgrass (Panicum virgatum L.) and no-till continuous corn. The experiment at the pivot corner was established in 2013 with ‘Liberty’ switchgrass, ‘Shawnee’ switchgrass, low-diversity grass …

Going Back To The Soil: An Integrated Approach To Farming., Renée V. Christie

Theses and Dissertations (Comprehensive)

Agricultural productivity is often constrained by nutrient availability; as such, copious amounts of synthetic fertilizers are applied to maintain productivity. However, the intensive use of synthetic fertilizers has reduced the capacity of the soil to carry out crucial roles such as nutrient cycling because of shifts in the microbial community composition and structure. In addition, much of the applied synthetic fertilizers become lost to the environment through run-off, which contributes to soil degradation. With the increasing demand on agricultural systems to provide food and fibre and the adverse impacts of agricultural production on the soil resource, amendments that support soil …

Heterologous Expression Of Arabidopsis Thaliana Purple Acid Phosphatase Gene (Atpap15) In Crops For Phytoremediation Of Sites Contaminated With Excess Phosphorus, Jane Jeruto Bartonjo

Masters Theses & Specialist Projects

AtPAP15 is one of the purple acid phosphatases expressed by Arabidopsis thaliana that has been extensively studied. Purified AtPAP15 has been shown to exhibit both phytase and phosphomonoesterase activities in acidic pH with maximal activity at pH 4.5. AtPAP15 is a phosphorus starvation inducible (PSI) gene that is expressed highly during phosphorus deficient conditions. In the current study, AtPAP15 was overexpressed in Nicotiana tabaccum under cauliflower mosaic virus (CaMV35S) constitutive promoter. After PCR confirmation of the gene, plants were transferred to the greenhouse and allowed to grow in pots. The pots contained Sta-Green potting mix (Lowe’s Inc., Mooresville, North Carolina,U.S.). …

Nitrogen Deposition Contributes To Soil Acidification In Tropical Ecosystems, Xiankai Lu, Qinggong Mao, Frank S. Gilliam, Yiqi Luo, Jiangming Mo

Biological Sciences Faculty Research

Elevated anthropogenic nitrogen (N) deposition has greatly altered terrestrial ecosystem functioning, threatening ecosystem health via acidification and eutrophication in temperate and boreal forests across the northern hemisphere. However, response of forest soil acidification to N deposition has been less studied in humid tropics compared to other forest types. This study was designed to explore impacts of long-term N deposition on soil acidification processes in tropical forests. We have established a long-term N deposition experiment in an N-rich lowland tropical forest of Southern China since 2002 with N addition as NH₄NO₃ of 0, 50, 100 and 150 kg …

Crop Updates 2010 - Genetically Modified Crops, Nutrition And Soils, James Fisher, Désirée Futures, Peter Tozer, Mike Jackson, John Moore, Jamees Neilsen, Geoff Anderson, Wen Chen, Richard Bell, Paul Blackwell, Allan Herbert, Stephen Davies, Ross Brennan, Mike Bolland, James Easton, Ryan Guthrie, Rowan Madderm, Robert Belford, Wal Anderson, Ian Edwards, Reg Lunt, Bill Bowden, Nigel Metz, Peter Newman, Breanne Best, Chris Gazey, Joel Andrew

Crop Updates

GENETICALLY MODIFIED CROPS

1. Evaluation of the environmental and economic impact of Roundup Ready® canola in the Western Australian crop production system, James Fisher and Désirée Futures, York, Western Australia, Peter Tozer, PRT Consulting, Armidale NSW

2. Controlling wild radish (Raphanus raphanistrum) in Roundup Ready®¹ Canola: Outcomes from the Nufarm 2009 Roundup Ready small plot trial Program, Mike Jackson, Nufarm Australia Limited

3. Weed strategies for glyphosate tolerant crops, John Moore, Department of Agriculture and Food

4. Results of the 2009 Western Australia Roundup Ready® canola trials, Dr James Neilsen, Canola Systems …