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The Use Of Biological Soil Health Indicators To Quantify The Benefits Of Cover Crops, Alexander Wu

Masters Theses

Soils provide many essential functions that support the world. With a decline in soil health, these functions also decrease in efficiency, and can threaten the health of billions of people around the world. Typically, soil health tests do not use biological indicators, however microbes drive and perform vital functions to increase soil health. One way to increase soil health is through the use of cover crops to reduce soil erosion during fallow periods, increasing soil organic matter, as well as collecting nutrients from soil into their biomass. These cover crops are then terminated through various methods such as herbicides, disk …

Assessment Of Nitrogen-Based Fertilizer Transport And Microbial Activities In Sandy Soil Profiles In South Texas, Gladys De La Rosa

Theses and Dissertations

Conventional farming is a common practice in Lower Rio Grande Valley (LRGV) and the application of nitrogen fertilizer is essential for plant growth and support. However, managing the rate of nitrogen that is applied can benefit farmers financially and reduce nitrate leaching that can have an adverse effect on the local environment and aquatic systems, e.g., rivers and estuaries. Sandy soils are more vulnerable to water infiltration due to the large proportion of macropores. This study aims to (i) assess how nitrate from a variety of fertilizers (i.e., synthetic and organic) distributes on the top 60 cm layer of a …

Effect Of Mycorrhizae Inoculation On The Growth And Success Of Three Taxodium Distichum Hybrids In Saline - Impacted Coastal Soils, Elif Ilhan

Electronic Theses and Dissertations

In 2008, Galveston Island was severely impacted by Hurricane Ike, resulting in high salt deposition in the soil and groundwater. This caused a loss of many native plant species. A study was initiated to determine effective ways to promote the growth conditions of three bald cypress genotypes (Taxodium distichum var distichum and Taxodium distichum var mexicanum crosses) in salt-affected soils. The treatments applied were mycorrhizae inoculation, fertilizer application, and a combination of mycorrhizae inoculation and fertilizer application. A total of sixty (60) trees planted in plots of three rows and divided into five randomized replication blocks of four treatments …

Adaptation Strategies For Wild Blueberry Growers In A Changing Climate: Mulching Effects On Crop Productivity And Fertility Effects On Blueberry Gall Midge, Rebecca Gumbrewicz

Electronic Theses and Dissertations

Wild blueberry (Vaccinium angustifolium Aiton.) cropping systems are considered resilient to environmental changes due to ecological and genetic diversity within each field. However, wild blueberries can be sensitive to weather fluctuations that cause extreme temperature or moisture regimes. Climate change in Maine is represented by increasing rates of warming temperatures, more intense precipitation events, and more frequent atmospheric “blocking” patterns. Warming temperatures result in the northward expansion of pest ranges and altered growing seasons. More extreme rainfall events lead to damaged plantings and soil erosion. Atmospheric blocking leads to an increased likelihood of heat waves and drought. Two experiments were …

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 …

Improving Sustainable Fertilizer Practices For Pomegranate By Leaf Nutrient Concentration Evaluation And Fertilizer Trials, Minh Le

Master's Theses

Fruit tree leaf nutrient concentrations are commonly used to determine fertilizer rates, but information is limited regarding nutrient requirements, seasonal N uptake and removal rates, and soil N dynamics for pomegranate. Relationships between fertilizer rates, leaf nutrient concentrations, fruit yield and quality were examined in five mature, commercial California ‘Wonderful’ pomegranate orchards. Site 1 was observed for two growing seasons (2018-2019) and sites 2-5 were observed for one season (2018 or 2019). In 2018, 150, 300, or 450 g N/tree was applied at sites 1-3 in a single application at early fruit development or in two equal applications at early …

Residual Soil Phosphorus In Tropical Oxisols: An Opportunity To Enhance Fertilizer Use Efficiency?, Lauren Bomeisl

Graduate College Dissertations and Theses

Phosphorus (P) is essential to life on Earth and often the limiting nutrient in agricultural systems. P fertilizer is thus an essential resource to maintain food security. In the last half century, agricultural intensification has led to an increase in P fertilizer consumption from 4.6 to 17.5 Tg of P/year to meet rising global food demand. Mineral P (i.e., phosphate rock) is a non-renewable resource in the context of the Anthropocene, and its price is vulnerable to global market fluctuations. Increased efficiency of P use on farms is considered the most effective strategy to conserve P. The soybean industry demands …

Optimizing Fertilizer And Compost Rates In Organic Reduced Till Agriculture, Nicholas W. Rowley

Electronic Theses and Dissertations

Interest in reduced tillage systems has been increasing and advanced by a need to practice agriculture in a sustainable way to limit environmental degradation. The focus on preserving soil integrity has become commonplace in all scales of agriculture. Recently trends in agricultural production have given rise to numerous small farms centered on local and sustainable farming. In turn, this has led to a growing desire to implement conservation tillage into these systems.

In 2015 and 2016 a collaborative effort between the University of Maine at the Maine Agricultural and Forestry Experiment Station: Highmoor Farm and Cornell University at the Homer …

Effects Of Application Timing And Soil Type On Optimal N Rate Requirement Of Sugarcane (Saccharum Spp.) And Changes In Soil Inorganic And Leaf N Concentrations, Joseph Martin Garrett

LSU Master's Theses

Research is limited on the effects of soil types and early nitrogen (N) fertilizer applications to N management strategies in sugarcane (Saccharum spp.) production in Louisiana. This study was established in 2015 at two locations in St. Gabriel, LA to 1) determine the effect of fertilizer application timing and soil type on the optimal N rate requirement and yield of sugarcane and 2) relate the relationship of soil and leaf N content to yield at different growth stages with sugarcane yield. Treatments were set in a randomized block design on a clay soil and in a complete randomized …

Effects Of Enhanced Efficiency Nitrogen Fertilizers On Agronomic Parameters And Loss Pathways In The Subtropical Mississippi Delta Region, Scott Michael Pensky

LSU Master's Theses

Minimizing nitrogen (N) loss is critical for improving N use efficiency (NUE) in crop production and reducing its effects on the environment. Management practices such as seasonal application timing of N fertilizers and the addition of enhanced efficiency N fertilizers (EENFs) were investigated for the high N requirement of the two most common cereal crops globally, corn (Zea mays L.) and wheat (Triticum aestivum L.), in the subtropical climate of Louisiana. Field research was established during the 2016 and 2017 seasons at the LSU Agricultural Center’s Dean Lee and Central research stations to examine the effect of different EENFs and …

Effects Of Fertilizer And Shade Management On Nitrogen Mineralization, Nitrifying Microbial Abundance And Nitrogen-Fixing Capacity Of Erythrina Poeppigiana In Coffee (Coffea Arabica) Agroforestry Systems In Costa Rica, Stuart E. Barker Iii

Electronic Theses and Dissertations

Worldwide chemical fertilizer use has increased by four times during the last 50 years. Conventional agricultural systems have a high nitrifying nature, resulting in a loss of nearly 70% of overall nitrogen (N) fertilizer inputs, an estimated economic loss of $81 billion. Over application of fertilizer is rampant in tropical developing nations in Central America, where coffee is major crop. Agroforestry offers ecologically sustainable land management strategies that promote the provision of ecosystem services such as, protection of biodiversity, climate change mitigation, and water and soil regulation. When legume trees are incorporated as the shade tree in coffee production, direct …

Evaluation Of Tillage, Crop Rotation, And Cover Crop Impacts On Corn Nitrogen Requirements In Southeastern South Dakota, Sara Louise Berg

Electronic Theses and Dissertations

Nitrogen (N) is a vital factor of corn (Zea mays) production. Previous work in South Dakota has shown that there is uncertainty as to whether nitrogen requirements are the same for corn raised under no-till (NT) versus conventional till (CT) production systems. The objective of this study was to evaluate whether N requirements continue to be greater under long-term NT versus CT production systems in southeastern South Dakota, while also considering effects from cover crops and crop rotation. This was a two year study conducted at the SDSU Southeast Research Farm near Beresford, SD; it was superimposed on a long-term …

Investigating The Effect(S) Of Contrasting Nitrogen (N), Phosphorus (P), And Potassium (K) Fertilizer Rates On Cassava Tuber Yield And Quality And Maize Grain Yield In Southern Africa, Ivan Bernardo Cuvaca

Masters Theses

Fertilizer is a major limiting factor to agriculture in southern Africa (SA). Coupled with this is lack of appropriate fertilizer recommendation rates for high productivity in existing agricultural systems. Field experiments were conducted to determine nitrogen (N), phosphorus (P), and potassium (K) fertilizer rates for high cassava tuber yield and quality for the coastal semiarid Dondo District of Mozambique, and high maize grain yields for both vertisol and inceptisol of Maphutseng in Lesotho. In general, the results showed that cassava tuber yield, cassava tuber quality as measured by tuber starch content, and maize grain yield were significantly increased by fertilizer …

Development Of Novel Organic Nitrogen Nutrient Solutions With Unique Bioreactors For Precision Nutrient Fertigation, Brian Ward

All Dissertations

A fertility study conducted comparing organic nitrogen versus synthetic nitrogen on yield, quality, mineral and phyto-nutrient content of sweet corn under conventional cultural practices.

Bioavailability/Toxicity Of Iron From Aerobically Processed Organic Fertilizer, Stacey Marie Wilson

Undergraduate Honors Capstone Projects

For an undergraduate Honor's project, I worked under the direction of Dr. Jeffery Hall to determine the bioavailability and toxicity of iron from Milorganite® fertilizer, an aerobically processed organic fertilizer. The Milorganite® Company is a subsidiary of the Milwaukee Municipal Sewage District and produces a fertilizer of high iron content (approximately 5-7%). The high iron content has resulted in concern about the toxic potential, which until now was unknown. This thesis paper will explain iron chemistry, bioavailability, requirements, absorption, toxicity, and treatments, followed by a description of fertilizer types and contents. This will be followed by a description and reasoning …

Market Structure Analysis Of Fertilizer Distribution In Utah, John C. Welty

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this paper was to ascertain the contribution of various structural variables to a growing, efficient system of fertilizer distribution in the state of Utah. A questionnaire to survey the fertilizer distributors was used as a source of data. Information was obtained about structural changes in a five-year period, 1965 to 1970. A multiple regression program was used to synthesize these data to determine which variables were most significant and how much they contributed to an increase in total value of fertilizer sales. While empirical data were obtained only for structural dimensions of the industry, marketing theory was …

The Yield And Thiamine, Riboflavin And Niacin Content Of Alfalfa Hay As Related To Fertilizer Treatment Of Soil, Rasik L. Pathak

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Alfalfa has long been recognized as an outstanding hay plant in terms of both yield and feeding value. It is high in digestible protein, minerals, and vitamins. Because of its long life it can be economically produced. It is of exceptional value in maintaining soil fertility by helping to control erosion, by improving the physical condition of the soil, and by accumulating large amounts of nitrogen.

The great importance of alfalfa growing in the United States is attested by its rapid and continued expansion. It is one of the most important forage crops and is grown on a greater acreage …

Fertilizer Trials On Dryland Winter Wheat, I. G. Sampson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wheat is one of the major crops of Utah and for more than 50 years farmers have been raising wheat on the dry lands of the state. The system they use is known as the alternate cropping or crop-follow system and consists of one year of crop alternating with one year of clean cultivation known as fallow.

Wheat removes a considerable amount of the natural plant food elements from the soil each year. This is especially true of nitrogen. According to Bracken and Greaves (9) the original low supply of nitrogen in most Utah soils together with the depleting effects …