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Full-Text Articles in Life Sciences
Nitrogen Application Timing And Cereal Rye (Secale Cereale L.) Cover Crop Influence Greenhouse Gas Emissions, Graig Reicks
Nitrogen Application Timing And Cereal Rye (Secale Cereale L.) Cover Crop Influence Greenhouse Gas Emissions, Graig Reicks
Electronic Theses and Dissertations
Dryland contributions to greenhouse gas (GHG) emissions are increased by N fertilizer applications and high soil water contents. Fertilizer timing and spring growth of cover crops prior to cash crop planting were investigated in separate studies to examine impacts on overall GHG emissions using a near continuous measurement system. There was a significant interaction between N fertilizer rate (0 vs. 224 kg N ha-1 surface-applied as urea) and application date (p= 0.01) for CO2 emissions. This interaction occurred because N fertilizer increased CO2 emissions by 35% for the 21 d interval following early spring application. When application was delayed until …
Integrating Early Season Clover Cover Crops As A Living Mulch In Broccoli And Transitional Organic Winter Squash Production In Eastern South Dakota, Alexis Rose Barnes
Integrating Early Season Clover Cover Crops As A Living Mulch In Broccoli And Transitional Organic Winter Squash Production In Eastern South Dakota, Alexis Rose Barnes
Electronic Theses and Dissertations
Managing weeds, improving soil health, and reducing the use of plastic mulch continue to be priorities for South Dakota vegetable farmers. Farmers have expressed an interest in integrating cover crops into their farm systems. Clover cover crops used as a living mulch within and along cash crop rows may aid in weed suppression, nitrogen fixation, and prevent soil erosion. However, prior research has shown challenges of incorporating living mulch due to yield decreases. Research conducted in 2022 and 2023 in eastern South Dakota investigated the effects of four clover and four in-row soil management treatments on broccoli and organic winter …
The Hutton Project: Long-Term Agricultural Impacts On Soil Loss And Carbon Dynamics In Eastern South Dakota, Eli Halverson
The Hutton Project: Long-Term Agricultural Impacts On Soil Loss And Carbon Dynamics In Eastern South Dakota, Eli Halverson
Electronic Theses and Dissertations
Long-term and intensified agricultural land management has resulted in increased rates of soil erosion and has altered much of the carbon cycle at regional and global scales. Anthropogenic degradation of soil resources is a barrier to sustainable production, soil functioning, and ecosystem services. It is difficult to quantify the scope of pedogenic changes due to the lack of legacy data and short temporal scales. This study utilized decades to century-old soil information to quantify historical soil erosion losses and changes in soil carbon pools of eastern South Dakota soils. The results show that soils in the region have been significantly …
Utilizing Soil Sensors To Assess Soil Health And Investigating Cover Crops Impact On Methane Emission, Shailesh Pandit
Utilizing Soil Sensors To Assess Soil Health And Investigating Cover Crops Impact On Methane Emission, Shailesh Pandit
Electronic Theses and Dissertations
Soil health is influenced by climate change, cultural practices, topography, crop rotations, cover crops, soil parent materials, and soil biota. Interactions between these factors can improve or reduce soil health. This thesis investigates two topics, using soil sensors to provide a rapid assessment of soil health, and the impact of cover crops on soil biological activity and greenhouse gas emissions. Chapter 1 explores the use of two types of sensors to measure apparent electrical conductivity (ECa) and provides examples on the use of these sensors. Even though both sensors measure ECa using different processes, they provide useful information about temporal …
The Relationship Between Soil Test Phosphorus And Soil Biology - A Natural Management Of Soil Phosphorus Through Conservation Practices, Clarence Frederick Winter
The Relationship Between Soil Test Phosphorus And Soil Biology - A Natural Management Of Soil Phosphorus Through Conservation Practices, Clarence Frederick Winter
Electronic Theses and Dissertations
Phosphorus (P) management is an ongoing challenge in modern agriculture. Due to the importance of P in agriculture, P fertilizer additions are made throughout the U.S. to avoid nutrient-depleted soil. However, the application of P is problematic, as an excess of P in an agricultural system elevates the risk of environmental degradation, and current synthetic P sources are a fleeting resource. Additionally, a majority of P found in agricultural soils are insoluble, in the form of secondary and primary P minerals, making this large pool of P unavailable to plants. Fortunately, soil fungi organisms, such as arbuscular mycorrhizal fungi (AMF) …
Plant Pathways Associated With Competition For Soybean Root Colonization By Bradyrhizobium Strains, Athira Sethu Madhavan
Plant Pathways Associated With Competition For Soybean Root Colonization By Bradyrhizobium Strains, Athira Sethu Madhavan
Electronic Theses and Dissertations
Nitrogen is a crucial nutrient for the growth and development of plants. Legume crops like soybeans develop symbiotic associations with soil bacteria from the genus, Bradyrhizobium to obtain fixed nitrogen. In this mutualistic association, rhizobia are released into root nodules that provide a compatible environment for rhizobia to grow and fix nitrogen (Symbiotic Nitrogen Fixation (SNF)). A caveat in such beneficial associations is the competition between different rhizobium strains in soil for infection and nodule occupancy. The elite inoculant strains encounter competition by indigenous rhizobial population in the soil to infect and nodulate a susceptible legume host, because of which …
Ecophysiology Of Bradyrhizobium Diazoefficiens Usda 110, Armaan Kaur Sandhu
Ecophysiology Of Bradyrhizobium Diazoefficiens Usda 110, Armaan Kaur Sandhu
Electronic Theses and Dissertations
With increasing demand for soybean, maximizing plant yield is important yiel is dependent on nitrogen availability, but nitrogen fertilizers can meet the plant's needs but have severe environmental impacts. An economically and environmentally sustainable approach is to enhance nitrogen availability through Biological Nitrogen Fixation by symbiotic rhizobia, Bradyrhizobium, an efficient nitrogen fixer for soybean. This symbiosis begins with attachment of rhizobia to legume roots. Root and rhizobia surface properties play a significant role in this attachment. Another major factor affecting root colonization is bacterial competition ability. There is a lack of knowledge on the role of bacterial surface properties, competition …
Portable X-Ray Fluorescence Spectrometry For Sensing Salinity And Sodicity In Glacial Northern Great Plains Soils With Machine Learning Models, Adam Devlin
Electronic Theses and Dissertations
Saline and sodic soils are an increasing concern across the Northern Great Plains (NGP) due to factors of climate change and land management that are drawing geologically derived salts to the land surface. Traditional laboratory assessments, such as electrical conductivity (EC) and sodium adsorption ratio (SAR), are time and resource consumptive. Portable X-ray fluorescence (PXRF) may be a viable proximal sensing alternative, as it is able to provide elemental data in minutes, in situ or ex situ, and can directly quantify salinity-associated elements like Ca, Mg, and S. PXRF paired with predictive models has proven useful for a range of …
Developing Machine Learning Models For Selection Of Management Zones, Sravanthi Bachina
Developing Machine Learning Models For Selection Of Management Zones, Sravanthi Bachina
Electronic Theses and Dissertations
Soil sampling and analyses play a crucial role in optimizing nutrient management and enhancing crop productivity. However, collecting representative samples across diverse landscapes is challenging due to knowledge gaps about spatial variability of soil properties, large fields, multiple samples, and analysis costs. Collecting soil samples based on the management zones can help farmers gather precise information about soil properties with fewer samples. Recent developments in precision agriculture and machine learning. This study aimed to develop machine learning models that can learn, analyze, and refine landscape and soil properties data for automated selection of soil sampling zones and generating prediction maps. …
Various Surfactant Soil Conditioner Effect On Plant Nutrient Concentration, Soil Nutrient Depletion, Soil Volumetric Water Content, Plant Biomass And Yield In Corn, Timothy Veldkamp
Electronic Theses and Dissertations
Soil conditioners help improve soil structure by increasing aeration, water infiltration and water holding capacity leading to nutrient availability and reduced irrigation needs. The goal of this study was to evaluate the impact of multiple soil conditioners (SC1, SC2, SC3, SC4, and SC5) on corn (Zea mays L.) and their ability to reduce irrigation by 30%. This was evaluated in the field in 2022 and 2023 by Aurora, SD using a Randomized Complete Block Design with six replications. Conditioners were applied as broadcast pre-emergence treatments with 70% irrigation. Control treatments of 70% and 100% irrigation, respectively were included. SC1 application …
Monarch Butterfly (Danaus Plexippus) Oviposition Preferences And A Survey Of Fungal Pathogens On Native Milkweeds (Asclepias) Of The Northern Great Plains, Grace Damiano
Electronic Theses and Dissertations
North American monarch butterfly (Danaus plexippus) populations are experiencing significant declines due to habitat loss caused by land use changes. Much of the American Midwest where milkweed, the only host plant of the monarch butterfly, was once much more abundant has been converted to a predominantly agricultural landscape. There are nineteen species of milkweed native to the northern Great Plains region occupied by South Dakota, North Dakota, and Minnesota. Some of these milkweed species may be preferable to monarch butterflies for different reasons, including morphological factors such as stem length, species-level chemical factors, and temporal factors. As monarch …