Agriculture Commons^™

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′′ …

Remediating Soil For Successful Vegetation Establishment Along Nebraska Highways, Shad Mills, Martha Mamo, Walt Schacht, Humberto Blanco-Canqui

Nebraska Department of Transportation: Research Reports

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

Establishment Of Wildflower Islands To Enhance Roadside Health And Aesthetics, Walter Schacht, Judy Wu-Smart

Nebraska Department of Transportation: Research Reports

Wildflowers are crucial in the ecological function of the low-input roadside plant communities in terms of water andnutrient cycling, nutrient inputs such as nitrogen, total plant canopy cover, stand longevity, and provision of habitat for numerous small animals. Further, wildflowers provide critical foraging and nesting resources for birds, insects, and other wildlife. Unfortunately, habitat loss from agricultural and urban development has led to rapid population declines in wild bees and other pollinators across the US, thereby jeopardizing not only food production but also the sustainability of our natural landscapes (Kearns & Inouye, 1997). One way to mitigate wild bee decline …

Pi‑Plat: A High‑Resolution Image‑Based 3d Reconstruction Method To Estimate Growth Dynamics Of Rice Inflorescence Traits, Jaspreet Sandhu, Feiyu Zhu, Puneet Paul, Tian Gao, Balpreet K. Dhatt, Yufeng Ge, Paul E. Staswick, Hongfeng Yu, Harkamal Walia

Department of Agronomy and Horticulture: Faculty Publications

Background: Recent advances in image-based plant phenotyping have improved our capability to study vegetative stage growth dynamics. However, more complex agronomic traits such as inflorescence architecture (IA), which predominantly contributes to grain crop yield are more challenging to quantify and hence are relatively less explored. Previous efforts to estimate inflorescence-related traits using image-based phenotyping have been limited to destructive end-point measurements. Development of non-destructive inflorescence phenotyping platforms could accelerate the discovery of the phenotypic variation with respect to inflorescence dynamics and mapping of the underlying genes regulating critical yield components.

Results: The major objective of this study is to evaluate …

Snowpack Properties Vary In Response To Burn Severity Gradients In Montane Forests, Jordan Maxwell, Samuel B. St. Clair

Aspen Bibliography

Wildfires are altering ecosystems globally as they change in frequency, size, and severity. As wildfires change vegetation structure, they also alter moisture inputs and energy fluxes which influence snowpack and hydrology. In unburned forests, snow has been shown to accumulate more in small clearings or in stands with low to moderate forest densities. Here we investigate whether peak snowpack varies with burn severity or percent overstory tree mortality post-fire in a mid-latitude, subalpine forest. We found that peak snowpack across the burn severity gradients increased 15% in snow-water equivalence (SWE) and 17% in depth for every 20% increase in overstory …

The Potential For Dickeya Dianthicola To Be Vectored By Two Common Insect Pests Of Potatoes, Jonas K. Insinga

Electronic Theses and Dissertations

Dickeya dianthicola (Samson) causing blackleg and soft rot was first detected in potatoes grown in Maine in 2014. Previous work has suggested that insects, particularly aphids, may be able to vector bacteria in this genus between plants, but no conclusive work has been done to confirm this theory. In order to determine whether insect-mediated transmission is likely to occur in potato fields, two model potato pests common in Maine were used: the Colorado potato beetle (Leptinotarsa decimlineata Say) and the green peach aphids (Myzus persicae Sulzer). Olfactometry and recruitment experiments evaluated if either insect discriminates between infected and …

Green Strategic Planning Approach For International Shipping Activities, Xiaofang Wu, Luoping Zhang, Huan Feng

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Sustainability is a long-term and ultimate goal for international shipping, although it is slowly making progress. The shipping perspective that moves away from “port-to-port” operations to “door-to-door” services also requires international shipping to take a long-term and holistic view instead of fragmented efforts. How to achieve the long-term sustainability goal becomes a key issue for door-to-door international shipping. Hence, green strategic planning for door-to-door international shipping was proposed with green development that puts forward the eco-centric point of view as its basic theory for sustainability. This study used a strategic decision-making approach, a so-called multi-dimensional decision-making (MDDM), coupled with the …

Divergent Phenotypic Response Of Rice Accessions To Transient Heat Stress During Early Seed Development, Puneet Paul, Balpreet K. Dhatt, Jaspreet Sandhu, Waseem Hussain, Larissa Irvin, Gota Morota, Paul E. Staswick, Harkamal Walia

Department of Agronomy and Horticulture: Faculty Publications

Increasing global surface temperatures is posing a major food security challenge. Part of the solution to address this problem is to improve crop heat resilience, especially during grain development, along with agronomic decisions such as shift in planting time and increasing crop diversification. Rice is a major food crop consumed by more than 3 billion people. For rice, thermal sensitivity of reproductive development and grain filling is well-documented, while knowledge concerning the impact of heat stress (HS) on early seed development is limited. Here, we aim to study the phenotypic variation in a set of diverse rice accessions for elucidating …

Phylogenetic And Genomic Characterization Of The Host-Pathogen Arms Race Between Bacterial Pathogens And Gossypium Hirsutum, Anne Zimmerman Phillips

Arts & Sciences Electronic Theses and Dissertations

Hosts and pathogens are eternally intertwined in an evolutionary arms race. When a pathogen causes a disease outbreak, scientists must identify resistance strategies that can durably tilt the arms race in favor of the host. This requires a deep understanding of both the genetic and environmental contexts in which the outbreak occurs. In this thesis I investigate the bacterial pathogens Xanthomonas citri pv. malvacearum (Xcm) and Pseudomonas syringae that caused disease outbreaks on Gossypium hirsutum from 2011-2017. I use pathogen genomics and host transcriptomics to develop hypotheses for how these pathogens emerged and how they cause disease. Phylogenetics and virulence …

Deep Kernel And Deep Learning For Genome-Based Prediction Of Single Traits In Multienvironment Breeding Trials, José Crossa, Johannes W.R. Martini, Daniel Gianola, Paulino Pérez-Rodríguez, Diego Jarquin, Philomin Juliana, Osval Antonio Montesinos López, Jaime Cuevas

Department of Agronomy and Horticulture: Faculty Publications

Deep learning (DL) is a promising method for genomic-enabled prediction. However, the implementation of DL is difficult because many hyperparameters (number of hidden layers, number of neurons, learning rate, number of epochs, batch size, etc.) need to be tuned. For this reason, deep kernel methods, which only require defining the number of layers, may be an attractive alternative. Deep kernel methods emulate DL models with a large number of neurons, but are defined by relatively easily computed covariance matrices. In this research, we compared the genome-based prediction of DL to a deep kernel (arc-cosine kernel, AK), to the commonly used …

Future Climate Change Will Have A Positive Effect On Populus Davidiana In China, Jie Li, Guan Liu, Qi Lu, Yanru Zhang, Guoqing Li, Sheng Du

Aspen Bibliography

Since climate change significantly affects global biodiversity, a reasonable assessment of the vulnerability of species in response to climate change is crucial for conservation. Most existing methods estimate the impact of climate change on the vulnerability of species by projecting the change of a species’ distribution range. This single-component evaluation ignores the impact of other components on vulnerability. In this study, Populus davidiana (David’s aspen), a tree species widely used in afforestation projects, was selected as the research subject under four future climate change scenarios (representative concentration pathway (RCP)2.6, RCP4.5, RCP6.0, and RCP8.5). Exposure components of range change as well …

Plant Hormones Differentially Control The Sub-Cellular Localization Of Plasma Membrane Microdomains During The Early Stage Of Soybean Nodulation, Zhenzhen Qiao, Prince Zogli, Marc Libault

Department of Agronomy and Horticulture: Faculty Publications

Phytohormones regulate the mutualistic symbiotic interaction between legumes and rhizobia, nitrogen-fixing soil bacteria, notably by controlling the formation of the infection thread in the root hair (RH). At the cellular level, the formation of the infection thread is promoted by the translocation of plasma membrane microdomains at the tip of the RH. We hypothesize that phytohormones regulate the translocation of plasma membrane microdomains to regulate infection thread formation. Accordingly, we treated with hormone and hormone inhibitors transgenic soybean roots expressing fusions between the Green Fluorescent Protein (GFP) and GmFWL1 or GmFLOT2/4, two microdomain-associated proteins translocated at the tip of the …

Critical Time For Weed Removal In Corn (Zea Mays L.) As Influenced By Pre Herbicides, Ayse Nur Ulusoy

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

A weed control program that utilizes PRE herbicides and ensures a timely post-emergence weed removal could protect growth and yield of corn. The use of pre-emergence (PRE) herbicides for weed control could reduce the need for multiple POST applications of glyphosate in glyphosate-tolerant (GT) corn and provide an additional mode of action for combating glyphosate-resistant weeds. Thus, field studies were conducted in 2017 and 2018 at Concord, NE with the following objectives develop weed management recommendations that considers soil applied herbicides and determine proper timing of glyphosate based on the crop growth stage.

Therefore the material in this thesis is …

Performance Of 10 Slicing Cucumbers In Southwest Michigan, Ron G. Goldy

Midwest Vegetable Trial Reports

Fruit quality and yield were lower than in previous Southwest Michigan Research and Extension Center slicing cucumber trials. This may primarily be to lower bee activity affecting pollination, fruit set and fruit shape. However, from this trial Bristol, SVCS0927, LS 75-1011, Darlington, and Perfect 10 deserve consideration for further commercial planting in Southwest Michigan.

Evaluation Of Transplant Root Length On Bell Pepper Yield And Quality, Ron G. Goldy

Midwest Vegetable Trial Reports

Allowing bell pepper transplants to develop a taproot system was detrimental to early plant growth. However, it did not have a significant detrimental effect on most fruit yield and quality parameters measured, and by final harvest, plants of all three root length treatments had similar above ground plant weights.

Performance Of 18 Fresh Market And Eight Saladette Tomato Cultivars In Southwest Michigan In 2019, Ron G. Goldy

Midwest Vegetable Trial Reports

It was again a difficult year for growing tomatoes at the Southwest Michigan Research and Extension Center. Rain shortly after field planting induced early bacterial disease infection, leading to defoliation and decreased fruit quality. The best performers in the fresh market trial were Red Snapper, Camaro, Saybrook, Jolene, and Myrtle. It was difficult to get good separation in the saladette trial. No entries rose above the others.

Response Of Cucumber, Yellow Squash, And Zucchini To Six Nitrogen Rates, Ron G. Goldy

Midwest Vegetable Trial Reports

There were few significant differences across the six nitrogen levels for the traits measured for all three crops. No clear trends were observed as nitrogen level was increased from 50 to 175#/acre. Better separation may have been obtained with more replication. Results indicate growers of slicing cucumber, yellow squash, and zucchini should be able to obtain adequate fruit yields using a season total of between 75 and 100#/acre nitrogen.

Understanding Nitrogen Limitation In Soybean, Nicolas Cafaro La Menza

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

Meeting soybean demand on existing cropland area for a global population of 9.7 billion people by the year 2050 requires narrowing the existing gap between average producer yield and yield potential. Soybean relies on two sources on nitrogen (N): biological N2 fixation and indigenous soil N supply. As soybean yield continues to increase, it seems critical to know if there is a yield level at which potential contribution of indigenous nitrogen sources and fixation becomes insufficient to meet crop N requirements for high yields, while still maintaining or increasing protein and oil concentration. This study evaluated N limitation across 29 …

Integration Of Cover Crops Into Midwest Corn-Soybean Cropping Systems And Potential For Weed Suppression, Joshua S. Wehrbein

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

Cover crops have potential to provide benefits to agricultural systems, such as improved soil productivity, nutrient scavenging, weed suppression, and livestock forage. There are several challenges associated with cover crop integration into traditional Midwest corn-soybean cropping systems. One of these challenges is timely establishment in the fall, which is limited by the relatively late harvest of corn and soybean. Cover crop effectiveness is related to the amount of biomass produced, thus maximizing the growth period in the fall is desired. To address this challenge, we evaluated the potential to utilize early-season soybean maturity groups (MGs) to allow for earlier soybean …

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 …

Benchmarking On-Farm Maize Nitrogen Balance In The Western U.S. Corn Belt, Fatima Amor Tenorio

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

A nitrogen (N) balance, calculated as the difference between N inputs and grain-N removal, provides an estimate of the potential N losses. We used N balance with other N-related metrics (partial factor productivity for N inputs, and yield-scaled N balance), to benchmark maize yields in relation with N input use in the US Corn Belt. We first used experimental data on grain-N concentration (GNC) to assess variation in this parameter due to biophysical and management factors. Subsequently, we used N balance and N-related metrics to benchmark yields in relation with N inputs in irrigated and rainfed fields in Nebraska using …

Effects Of Different Water And Nitrogen Regimens On Yield Of Winter Wheat Produced In Nebraska, Joseph Emory Davis

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

Wheat is the 3rd most prominent crop in the USA and approximately 50% is exported annually. Nebraska wheat production is 11^th in the country, and it plays a major role in the state's agricultural economy, especially in western NE. Generally, wheat is grown under dryland conditions and the region grows much more wheat on unirrigated land than it does on irrigated. However, deficit irrigation has shown great value in producing high yielding wheat with much less water than needed for other crops. Finding new ways to leverage irrigation in wheat production may help address the need to produce food …

Use Of Uav Imagery And Nutrient Analyses For Estimation Of The Spatial And Temporal Contributions Of Cattle Dung To Nutrient Cycling In Grazed Ecosystems, Amanda Shine

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

Nutrient inputs from cattle dung are crucial drivers of nutrient cycling processes in grazed ecosystems. These inputs are important both spatially and temporally and are affected by variables such as grazing strategy, water location, and the nutritional profile of forage being grazed. Past research has attempted to map dung deposition patterns in order to more accurately estimate nutrient input, but the large spatial extent of a typical pasture and the tedious nature of identifying and mapping individual dung pats has prohibited the development of a time- and cost-effective methodology. The first objective of this research was to develop and validate …

Cover Crops As An Integrated Approach For Pest Suppression And Pollinator Promotion In Arkansas Watermelon Production Systems, Paige Laurel Hickman

Graduate Theses and Dissertations

Arkansas watermelon growers face a variety of insect pest and disease problems that have the potential to threaten yield. Integrated pest management tactics can provide control over these threats and are intended to cut down on pesticide use and its associated negative impacts like pesticide resistance, non-target effects, and runoff. Cover crops provide an array of benefits and can be useful in integrated pest management. Evidence has shown that certain cover crops can increase beneficial insects and suppress disease in the following cash crop. They can also provide important resources to pollinators. In order to build a better understanding of …

Evaluation Of Pheromone Mating Disruption For California Red Scale Control In Commercial California Citrus, Joel Timothy Leonard

Master's Theses

California red scale (CRS), Aonidella aurantii, is an increasingly injurious insect pest for the California citrus industry due to insecticide resistance, changing weather patterns, and shifting trade regulations. The presence of the insect on fruit, damages the rind of the fruit and high populations can cause dieback of branches as well as lower yields. Pheromone mating disruption of CRS has the potential to alleviate population control concerns and reduce insecticide use. The efficacy of the pheromone mating disruption technique for pest management of CRS was determined using the products CheckMate® CRS and Semios CRS Plus. CheckMate® CRS was evaluated …

Spring Black Rot-Resistant Cabbage Cultivar Evaluation, Chris Smigell, John Strang, John Snyder

Midwest Vegetable Trial Reports

Fourteen green fresh-market cabbage cultivars were evaluated at the University of Kentucky horticultural farm in Lexington in a replicated trial to evaluate their performance in Central Kentucky. Cultivars were listed in seed catalogs as having black rot (Xanthomonas campestris) resistance or tolerance. Cultivars were grown on bare soil following University of Kentucky recommendations to commercial cabbage growers. Plants were not inoculated with X. campestris, and Badge SC bactericide was applied once early in the season. ‘Lucky Ball’ was the top-performing early-season cultivar, being consistently tender, sweet to slightly sweet, and having little to no sulfur aftertaste. Its …

Evaluation Of A Global Spring Wheat Panel For Stripe Rust: Resistance Loci Validation And Novel Resources Identification, Ibrahim Elbasyoni, Walid M. El-Orabey, Sabah Morsy, P. S. Baenziger, Zakaria Al Ajlouni4, Ismail M. Dweikat

Department of Agronomy and Horticulture: Faculty Publications

Stripe rust (incited by Puccinia striiformis f. sp. tritici) is airborne wheat (Triticum aestivum L.) disease with dynamic virulence evolution. Thus, anticipatory and continued screening in hotspot regions is crucial to identify new pathotypes and integrate new resistance resources to prevent potential disease epidemics. A global wheat panel consisting of 882 landraces and 912 improved accessions was evaluated in two locations in Egypt during 2016 and 2017. Five prevalent and aggressive pathotypes of stripe rust were used to inoculate the accessions during the two growing seasons and two locations under field conditions. The objectives were to evaluate the panel for …

Influence Of Vermicompost Tea On Secondary Metabolites In Solanum Lycopersicum Within South Florida, Daphne K. Sugino Souffront

FIU Electronic Theses and Dissertations

Fresh Market Tomatoes provide a high revenue stream for Florida’s agricultural sector. To attain profitable yields, farmers introduce high inputs of pesticides to suppress pest invasion/damage. Heavy usage of pesticides has adverse effects on human and environmental health. A possible solution might be the incorporation of vermicompost in pest management. Typically used as a fertilizer, vermicompost has pest suppressant properties. Mechanisms influencing enhanced pest resistance are unknown. To identify such mechanisms, a study was conducted to evaluate physical and chemical changes of the BHN589 tomato plant following the addition of varying vermicompost tea treatments (T5%, T10%, and T20%) . Results …

Metabolic Dynamics Of Developing Rice Seeds Under High Night-Time Temperature Stress, Balpreet K. Dhatt, Nathan Abshire, Puneet Paul, Kalani Hasanthika, Jaspreet Sandhu, Qi Zhang, Toshihiro Obata, Harkamal Walia

Department of Agronomy and Horticulture: Faculty Publications

High temperature stress during rice reproductive development results in yield losses. Reduced grain yield and grain quality has been associated with high temperature stress, and specifically with high night-time temperatures (HNT). Characterizing the impact of HNT on the phenotypic and metabolic status of developing rice seeds can provide insights into the mechanisms involved in yield and quality decline. Here, we examined the impact of warmer nights on the morphology and metabolome during early seed development in six diverse rice accessions. Seed size was sensitive to HNT in four of the six genotypes, while seed fertility and seed weight were unaffected. …

Rice Response To Nitrogen Fertilization And Comparison Of Unmanned Aerial Systems And Active Crop Canopy Sensors Vegetative Index To Estimate Rice Yield Potential, Anna Coker

LSU Master's Theses

Nitrogen (N) fertilization is a key component in producing profitable, maximized rice grain yields because yield is directly affected by N fertilizer applications. Economical optimum N rate (EONR) is used to estimate where the N fertilization rate impacts rice grain yield but is still economically efficient. Three common response models, linear-plateau, quadratic-plateau, and quadratic models were used to determine the response of rice to N fertilizer to determine the optimum N fertilization rate. The objective of the first part of this study was to evaluate the models by assessing the coefficients of determination (R²), maximum rice grain yields …