Agronomy and Crop Sciences Commons^™

South Dakota Farmers’ Usage Of Diversified Crop Rotations, Tong Wang, Jim Ristau

South Dakota Farm Survey

Researchers at South Dakota State University (SDSU) conducted producer surveys in the eastern part of South Dakota in both 2018 and 2021. Producers could take the survey online or via mail and were asked questions about their farm, soil and water conservation practices, and their values. Using publicly available addresses from the Farm Service Agency, a random sample of 3,000 producers were sent the survey in 2018. 650 were ineligible, and 708 responded to the survey for a response rate of 30%. In 2021, the same producers who took the survey in 2018 were asked to take a follow up …

Field Evaluation Of Struvite As A Phosphorus Source, Niyi Sunday Omidire

Graduate Theses and Dissertations

Phosphorus (P) is an element that is crucial in many biological processes in all forms of life and is not substitutable. Excess P in wastewaters leading to the degradation of receiving waters or eutrophication once released is a major environmental concern. Removal of excess P from wastewater as the mineral struvite (MgNH4PO4·6H2O) could be a promising solution to reduce P discharge into receiving waters and can potentially provide a valuable fertilizer-P source for agricultural production. The objectives of this project were to evaluate the effects of: 1) chemically precipitated struvite (CPST), compared to triple superphosphate (TSP) and an unamended control …

Assessing Freezing Effect On Kiwifruit Cultivars And Mapping Suitable Areas For Growing The Crop In Eastern Texas, Lais De Oliveira Machado

Electronic Theses and Dissertations

Kiwifruit is a perennial vine originating from China where it has been grown for centuries. In the United States, green kiwifruit (Actinidia deliciosa) is primarily produced commercially in California. They are fuzzy, green fleshed and well known in the marketplace. Kiwifruit plants require low to moderate soil pH, adequate winter chilling and adequate precipitation to guarantee plant development and good fructification. Actinidia chinesis or golden kiwifruit are smooth skinned, feature golden flesh and are a more recent introduction into the global market. Kiwifruit crops have attributes that favor production in east Texas, including low pest problems, current long …

Climatic Factors Affecting Maize Grain Yield In Different Growing Areas Of The Philippines, Lakshman Kumara, Tonette Laude, Jose Hernandez, Pearl Sanchez, Moises Dorado, Jose Nestor Garcia, Gerardo Gauna, Pompe C. Sta. Cruz

The Philippine Agricultural Scientist

Seasonal climate variation is one of the problems faced by Filipino maize farmers, due to varying climatic elements such as solar radiation, rainfall, relative humidity, and air temperature. This study determined the seasonal productivity of selected maize varieties in the major growing areas in the Philippines, and identified the yield-limiting climatic factors specific to location and growing season. Grain yield, covering two wet and dry seasons (2016-2018) from seven field trials (representing 3 climatic types) of the National Corn Testing (NCT) were used in the study. Climatic data (2016-2018) were gathered from the PAGASA weather station nearest to the trial …

Flowering Regulation Of Potted Bougainvillea Plants Under Five Water Treatments [Research Note], Kuan-Hung Lin, Jui-Mei Li, Chun-Wei Wu, Yu-Sen Chang

The Philippine Agricultural Scientist

Bougainvillea (Bougainvillea buttiana) is a very popular evergreen landscape plant in the tropical and subtropical areas. The objective of this study was to investigate the growth, flowering, and physiological performance of bougainvillea ‘Taipei Red’ cultivar in response to water-stress conditions that can potentially be used to maximize the economic efficiency and benefits in the development and ACC potential of bougainvillea plants grown in controlled environments. Potted plants were subjected to five different levels of soil VWC: 60% (control), 40%, 20%, 1/3 of leaves visually observed to be drooping (equivalent to 18% VWC), and 2/3 of leaves drooping (15% …

Cover Crop Effects On Near-Surface Soil Aggregate Stability In The Southern Mississippi Valley Loess (Mlra 134), Chandler M. Arel

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Intensive agricultural cultivation within major land resource area (MLRA) 134, the Southern Mississippi Valley Loess, has led to soil erosion, soil compaction, and the overall destabilization of near-surface soil aggregates. The use of cover crops during the agricultural offseason has been shown to help alleviate soil compaction and provide stabilizing effects against soil erosion, which are particularly important as the silty soils of MLRA 134 have a large erosion potential. This study evaluated the effects of cover crop and no-cover crop treatment on silt-loam soils within MLRA 134. Treatments were implemented during Fall 2018 and Fall 2019 and consisted of …

Formation Of B Horizons In Engineered Putting Green Soils, Glen R. Obear

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

Engineered turfgrass putting green soils are designed to drain quickly, while maintaining adequate water- and nutrient-holding capacity to sustain plant growth. These soils are designed to meet specific performance characteristics when they are constructed, but the process of soil formation changes these characteristics over time. Chapter 1 of this dissertation is a literature review of soil formation in engineered putting green soils. Pedogenesis of putting greens is such that A horizons form as organic matter accumulates near the surface, and B horizons form as particles and solutes are translocated to textural or pH boundaries in soil profiles. In the engineered …

American Burying Beetle, Plant Richness, And Soil Property Responses To Collapse Of Juniperus Virginiana Woodlands With Fire, Alison K. Ludwig

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

Grasslands are declining in the Great Plains due to land use changes, woody plant encroachment, and loss of historic fire cycles. Prescribed burn associations have utilized prescribed fire to collapse invading woodlands and allow the restoration of grasslands. This fire is considered “extreme” because it is capable of changing the structure and function of an ecosystem. Our study site is the Loess Canyons Experimental Landscape, a long-term, ecoregion-scale experiment to apply prescribed fire across the region to restore grasslands. The Nebraska Natural Legacy Project established the Loess Canyons ecoregion as a Biologically-Unique Landscape in 2005 with the state’s wildlife action …

Livestock Grazing Impacts On Crop And Soil Responses For Two Cropping Systems, Alyssa Kuhn

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

Diversified crop, forage, and livestock systems are assumed to be more sustainable and economically competitive than traditional cropping systems. Objectives of this study were to determine effects of integrating grazing livestock into corn (Zea mays)-soybean (Glycine max (L.) Merr.) (C-S) and corn-soybean-wheat (Triticum aestivum L.) (C-S-W) cropping systems on plant population, grain yield, soil nutrients and soil carbon dioxide (CO₂) flux following winter grazing corn residue (both systems) and an oat (Avena sativa) cover crop (C-S-W only) planted after wheat. For the 2019 and 2020 production seasons, neither corn nor soybean plant …

How Do Cover Crops Change Soil Health In A No-Till System?, Aysha Kirsten Tapp Ross

Electronic Theses and Dissertations

Nutrient levels and aggregation measurements are currently the most accurate means to measure soil health. It has been suggested that bacterial and fungal communities may prove to be a more accurate measure of soil health. In this study soil microbe communities and nutrient levels were compared in rye cover cropped soils to measure for differences between treatments. Effects between the microbial communities and environmental measurements were also measured within those treatments to test for correlations between soil health measures and microbial communities. The plots were put in a biennial corn (Zea mays L.) and soybean (Glycine max …

The Impact Of Beneficial Organisms In Corn Agroecosystems, Callie Rosalind Braley

Doctor of Plant Health Program: Dissertations and Student Research

Corn is one of the world’s, and Nebraska’s, most important crops. Millions of acres are planted to corn each year in the Cornhusker State. However, each year there are a plethora of arthropod, weed, and microorganism pests that rob farmers of reaching their maximum yield potential. There are many options available to manage these pests in corn agroecosystems, but one option is often underutilized: beneficial organisms. For each pest, there are a variety of natural enemies that can assist in mitigating the damage caused by pests.

Many beneficial organisms exist, and they can be grouped by the type of pest …

Intricacies In Agronomic Management: The Role Of Interdisciplinary Education, Adam M. Striegel

Doctor of Plant Health Program: Dissertations and Student Research

As a science, agronomy is built upon the connection of inter-disciplinary fields of study. Management (M) of various discipline considerations (and their subsequent interactions) can be influenced by and have significant effects on genetic by environment (GxE) expression. This has led to the promotion of GxExM systems. However, optimizing GxExM programs requires extensive, interdisciplinary knowledge. To evaluate interdisciplinary training provided in undergraduate education, 11 four-year universities were selected in the United States that offer baccalaureate degree majors in agronomy or crop science. Surveys of undergraduate programs of study were conducted, with all required coursework separated into general degree components (general …

Comparing Machine Learning Techniques With State-Of-The-Art Parametric Prediction Models For Predicting Soybean Traits, Susweta Ray

Department of Statistics: Dissertations, Theses, and Student Research

Soybean is a significant source of protein and oil, and also widely used as animal feed. Thus, developing lines that are superior in terms of yield, protein and oil content is important to feed the ever-growing population. As opposed to the high-cost phenotyping, genotyping is both cost and time efficient for breeders while evaluating new lines in different environments (location-year combinations) can be costly. Several Genomic prediction (GP) methods have been developed to use the marker and environment data effectively to predict the yield or other relevant phenotypic traits of crops. Our study compares a conventional GP method (GBLUP), a …

A Method For Visualizing Water Flow Through Modified Root Zones, Dallas M. Williams

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

As the number of impervious surfaces in urban environments increases, the ability of modified root zones to infiltrate water is becoming more important. Current methods of tracing water flow through soil profiles include excavating large pits in situ or analyzing soil cores in the laboratory with computed tomography or magnetic resonance imaging. While useful, these methods may not be suitable for urban settings or practical in every laboratory. We propose a new method that is less invasive, does not require extensive technical equipment and can reliably trace water movement through the soil profile in order to calculate flow rate based …

Recapture And Reuse Of Nitrogen And Phosphorus From Rendered Animal Materials To Enhance Nutrient Use Efficiency And Produce Quality In Agricultural Crop, Bhupinder Jatana

All Dissertations

The current fertilizer regime heavily relies on inorganic fertilizers to meet the crop nitrogen (N) and phosphorus (P) demand. However, the United States has a limited N production capacity, with 50% N demand met through imports. On the other hand, the nonrenewable natural reserves of P are being depleted at an unprecedented rate and are expected to be exhausted with in next 100 years. Additionally, high solubility/liability of the field applied inorganic fertilizers often results in lower nutrient use efficiency (NUE;

The MBM led to rapid N mineralization, with 35% of the applied N mineralized within the first five days …

Distillers' Grains: Past, Present, And Future Economic Analyses, Daniel E. Gertner

Department of Agricultural Economics: Dissertations, Theses, and Student Research

This thesis is comprised of four chapters, each of which discusses or conducts economic research related to the distillers’ grains market. The first three chapters are meant to be standalone papers. Chapter four provides potential paths forward in distillers’ grains research based on the findings of the first three chapters and concludes the thesis.

The first chapter conducts a comprehensive literature review that categorizes and summarizes economic research on distillers’ grains products. This section shows how the physical market has moved beyond the current academic understanding of market products and structure. Existing research finds that traditional distillers’ grains products positively …

The Medium-Term Impacts Of Integrated Crop–Livestock Systems On Crop Yield And Economic Performance, Teerath Singh Rai, Thandiwe Nleya, Sandeep Kumar, Peter Saxton, Tong Wang, Yubing Fan

Agronomy, Horticulture and Plant Science Faculty Publications

Integrated crop–livestock (ICL) systems are diverse production systems that can improve resource utilization through spatially or temporally rotating land among crop, livestock, and pasture uses. However, research on whether the enhanced resource utilization translates to greater crop productivity is still warranted. A field experiment was initiated at South Dakota State University in 2016 to determine the impacts of integrating cover crops and livestock grazing into a crop rotation of oat (Avena sativa L.)–maize (Zea mays L.)–soybean [Glycine max (L.) Merr.]. The objectives were to (a) determine the medium-term (4–6 yr) impacts of cover crops and livestock grazing …

Effects Of Nitrogen Management And Cultivar On Strawberry Production Under Disease Pressure, Kamille A. Garcia-Brucher

Master's Theses

Effects of nitrogen management and cultivar on strawberry production under disease pressure

Kamille Garcia-Brucher

California strawberry growers face increasing regulatory pressures to manage nitrogen (N) applications in their production system. Standard practice in the California strawberry industry is to apply a synthetic pre-plant controlled release fertilizer (CRF) to ensure the crop has sufficient N during winter establishment. Some research from the UC Cooperative Extension suggests this practice is not efficient at delivering N to the crop since most of the N is released from CRF before strawberry crop N uptake is significant. Another concern for California strawberry growers is loss …

Comparing Organic And Conventional Yield Responses To Climate Variations, Joost Wilken Meyer

Graduate Theses and Dissertations

This thesis compares the responses of organic yields and conventional yields towards climate variations. To achieve this objective, weather variables such as growing season weather conditions (average temperature, precipitation, cloud cover, relative humidity, drought index), weather anomalies, the occurrence of severe or extreme droughts and excessive rainfalls, are combined with 23 data sets gathered from previous studies that compare organic and conventional yields from the same location and time periods. To narrow the scope, the thesis focuses on soybean, maize, and wheat production in Europe and North America. Study-level fixed-effects models are used to control for any time-invariant factors such …

Nutrient Uptake And Management Strategies In Recirculating Hydroponic Systems, Lauren Leigh Houston

Graduate Theses and Dissertations

Nutrient management in recirculating hydroponic systems requires the periodic replenishment of water and nutrients to the nutrient solution reservoir. Common nutrient management strategies, such as replenishing the reservoir with fresh solution and maintaining a constant solution electrical conductivity (EC), can lead to ion accumulation and nutrient imbalances since nutrients are taken up by roots and depleted from solution at different rates. To avoid nutritional disorders, commercial growers typically dump and replace the hydroponic solution periodically, which is wasteful and has an economic cost. A potential alternative is to specially formulate the nutrient replenishment solution to balance the supply of nutrients …