Digital Commons Network^™

Tamaulipan Thornforest Restoration: Factors Influencing Restoration Outcomes And Impacts Of Cover Crops During Replanting, Jerald Thomas Garrett

Theses and Dissertations

Though the rate of deforestation has slowed in recent years, it remains a primary cause of land cover change within forest ecosystems. The Lower Rio Grande Valley, Texas (LRGV) has lost nearly 95% of its native thornforest since the early 1900’s due to agricultural and urban expansion. The focus of this study is to assess the current vegetative state of restored thornforest sites located in the eastern LRGV and to evaluate the use of cover crops during replanting of native seedlings. Our assessment of restored thornforest sites revealed actively restored sites demonstrated higher overall averages of richness, abundance, and diversity …

Soil Moisture Dynamics In Cover Cropping Systems: From Local To Global Scales, Manish Gautam

Theses and Dissertations

Cover cropping systems, which have gained recognition for their ability to enhance soil health and promote sustainability are also associated with potential risks related with declining soil moisture and pose a dilemma for farmers considering the adoption of cover crops in water deficit semi-arid settings worldwide. To address this pressing issue, we conducted a participatory cover cropping trial in the Lower Rio Grande Valley (LRGV) region, encompassing four different farms and supplemented this experiment with a meta-analysis to answer our soil moisture and climate parameters and quantify the impact of cover crops on soil moisture levels. The findings revealed that …

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 …

Evaluating Soil Health Changes Following Cover Crop And No-Till Integration Into A Soybean (Glycine Max) Cropping System In The Mississippi Alluvial Valley, Alexandra Gwin Firth

Theses and Dissertations

The transition of natural landscapes to intensive agricultural uses has resulted in severe loss of soil organic carbon (SOC), increased CO₂ emissions, river depletion, and groundwater overdraft. Despite negative documented effects of agricultural land use (i.e., soil erosion, nutrient runoff) on critical natural resources (i.e., water, soil), food production must increase to meet the demands of a rising human population. Given the environmental and agricultural productivity concerns of intensely managed soils, it is critical to implement conservation practices that mitigate the negative effects of crop production and enhance environmental integrity. In the Mississippi Alluvial Valley (MAV) region of Mississippi, USA, …

Manipulating Species Diversity: Environmental Impacts In Row Crop, Livestock, And Grassland Agroecosystems, Alayna A. Jacobs

Theses and Dissertations--Plant and Soil Sciences

The diversity of living species in an agroecosystem affects both natural resources and agricultural production efficiency. The rise of managed plant monocultures has allowed agricultural yields to increase over time. However, simplifying agroecosystems affects the capacity of the system to sustainably provide clean air, water, and productive soils essential for continued food and fiber production. This dissertation manipulates species diversity in row crop and forage agroecosystems prevalent in the Eastern United States and tracks the associated environmental and agricultural production consequences.

In row crop agroecosystems, increasing plant diversity with winter cover crops has been suggested as a strategy to increase …

Examining The Efficacy Of Cover Crops As An Integrated Pest Management Tool In Organic Farms In The Lower Rio Grande Valley, Lili M. Martinez

Theses and Dissertations

The Lower Rio Grande Valley (LRGV) consists of a mix in subtropical and costal habitats, a combination that provides a favorable environment for the animals and plants that inhabit it. This is a problem for organic farmers as they refrain from using synthetic chemicals and therefore led them to seek other methods of dealing with insect herbivory. Of the many alternative methods available, we looked specifically at integrated pest management methods (IPM) to determine their efficacy in reducing insect herbivory among cash crops. Chapter II discusses an experiment performed in an organic farm in Edinburg, Texas consisting of a two-year …

Cover Cropping In Soybean-Corn Rotation System: Economic, Agronomic, And Soil Fertility Impact, Jose Rodolfo Mite

LSU Doctoral Dissertations

Planting winter-annual cover crops prevent soil erosion, reduces water runoff, and improves soil structure and soil quality. This research was conducted from 2017 to 2019 to evaluate the nutrient turnover of different species of cover crops in soils under different row crop production systems in Northeast and Central Louisiana. In Northeast Louisiana (Site 1, 2, and 3), treatments (cover crops and no cover crop) were arranged in a strip trial with three replications. At the Ben Hur Research Station, the treatments included three planting dates (September, October, and November) with [7 kg ha^-1 of phosphorus (P) and potassium (K)] …

Evaluating The Economic Costs And Land Value Implications Of Implementing Cover Crops In Kentucky, Robert C. Ellis

Theses and Dissertations--Agricultural Economics

This thesis is comprised of two essays regarding the costs and impact of land values due to cover crops. This first essay uses a linear-programming resource allocation model combined with sequencing and machinery selection to optimize the practices and machinery utilization of a hypothetical western Kentucky grain farm. This was accomplished through maximizing returns over selected costs at various acreage adoption levels. Additionally, a decision tool was developed to assess the costs related to cover crop adoption. The results show a $30 per acre cost to adopt 1000 acres of cover crops when no benefits were considered. The second essay …

Investigating Limitations To Nitrogen Fixation By Leguminous Cover Crops In South Texas, Stephanie L. Kasper

Theses and Dissertations

Many farms use leguminous cover crops as a nutrient management strategy to reduce their need for nitrogen fertilizer. Biological nitrogen fixation (BNF) depends on a symbiotic relationship between legumes and nitrogen-fixing rhizobia. Under certain conditions despite inoculation with appropriate rhizobial strains, this symbiosis fails to form. Such failure was observed in a 14-acre winter cover crop trial in the Rio Grande Valley of Texas when three legume species (forage pea, crimson clover, and hairy vetch) produced no signs of nodulation and nitrogen fixation. This study examined nitrogen, phosphorus, moisture, micronutrients and biotic interference as potential causes for the failure and …

Diversifying Cornfields By Interseeding Cover Crops: Practical Implications And The Response Of Invertebrate Communities, Michael Bredeson

Electronic Theses and Dissertations

The lack of suitable habitat conditions for beneficial organisms in simplified agroecosystems leads to unstable invertebrate communities and overreliance on chemical control of herbivores. It is possible to manage pest populations without agrichemicals by manipulating farmland so that herbivores are impaired by plant-driven bottom-up and enemy-driven top-down antagonisms. Interseeding cover crops between established crop rows is a method used by farmers to improve habitat suitability for natural enemies and hinder host-finding, feeding and movement by herbivores. Here I address three important research gaps related to interseeding cover crops. A calcium carbonate seed coating, used to improve seed-broadcasting efficiency, was tested …

Conservation Agriculture In The Heartland: Farmer Perceptions Of Soil Health And The Adoption Of Cover Crops, Lillian Clarissa Cobo

Graduate Research Theses & Dissertations

The benefits of cover crops are widely recognized by those interested in conservation agriculture and soil health. These benefits include soil erosion control, nutrient loss reduction, and overall improvement of soil health. However, while these benefits are well-documented, the adoption rate of cover crops in the American Heartland remains astoundingly low. While some studies have attempted to determine the reasons for this low adoption rate, the information relating to how farmer perceptions of soil health impact cover crop adoption is almost nonexistent. Furthermore, there is a clear absence of mixed method studies in the literature relating to this subject. This …

Integrating Cover Crop Mixtures And No-Till For Sustainable Sweet Corn Production In The Northeast, Julie S. Fine

Masters Theses

Fall-planted forage radish (Raphanus sativus L. longipinnatus) cover crops have shown successful weed suppression and recycling of fall-captured nutrients. This research evaluated the nutrient cycling and weed suppressive benefits of forage radish cover crop mixtures to develop an integrated system for no-till sweet corn (Zea mays L. var rugosa) production that improves crop yield and soil health. Treatments included forage radish (FR), oats (Avena sativa L.) and forage radish (OFR), a mixture of peas (Pisum sativum subsp arvense L.), oats and forage radish (POFR), and no cover crop control (NCC). Subplots were assigned to …

Multifunctionality Of Cover Crops On Organic Vegetable Farms In South Texas, Savannah M. Rugg

Theses and Dissertations

Situated in deep South Texas, the Lower Rio Grande Valley (LRGV) is considered one the most productive agricultural regions in the southern US. With the highest concentration of organic farms in the state (Hidalgo county), finding management practices that comply with organic certification is increasingly pertinent. Cover cropping can serve multiple functions in an agroecosystem such as: suppressing weeds, increasing soil organic matter (SOM), increasing soil nitrates, and enhancing soil biodiversity. The four cover crops (lablab, sunn hemp, sudangrass, and pearl millet) were assessed to see their potential to increase soil nitrogen, to increase soil organic matter, and to suppress …

Nutrient Loading Reduction In A Tile Drained Agricultural Watershed Through Watershed-Scale Cover Cropping: A High Resolution Analysis, Benjamin Gerald Bruening

Theses and Dissertations

Nutrient pollution originating from agricultural regions in the Midwest is a serious issue, leading to pollution of drinking water sources as well as large hypoxic zones in the Gulf of Mexico. The source of much of this contamination has been shown to be runoff from agricultural fields in the Upper Mississippi River Basin. One method that has been shown to reduce this pollution from the Upper Mississippi River Basin is the planting of winter cover crops. Winter cover crops such as rye and tillage radish have been shown to significantly reduce nitrate exported from agricultural fields, even in tile-drained watersheds …

Soil Nutrient Cycling And Water Use In Response To Orchard Floor Management In Stone-Fruit Orchards In The Intermountain West, Catherine Mae Culumber

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An organic peach orchard trial evaluated the effectiveness of different organic management approaches to enhance soil quality and conserve water without compromise to fruit tree growth and fertility. Two tree-row treatments: ‘straw mulch’ (Triticum aestivum L.) and ‘living mulch’ (Lobularia maritima (L.) Desv.) were tested in combination with two alleyway groundcovers: ‘grass’ (Festuca rubra L. with Lolium perenne L.) and a legume, ‘Birdsfoot trefoil’ (Lotus corniculatus L.). The novel treatments were compared with tillage and weed fabric tree-rows with grass alleyways. After mowing, cuttings from the trefoil alleyway were deposited into tree-rows, which provided additional N …

Demonstrating Short-Term Impacts Of Grazing Cover Crops On Soil Health In South Dakota, Colin Tobin

Electronic Theses and Dissertations

Grasslands have been rapidly converted to croplands over the last decade in the northern Great Plains. This conversion can reduce soil health and increase the region’s ability to pollute the Missouri and Mississippi rivers. Therefore, the need for integrated crop livestock (ICL) practices that can protect the region’s native prairies are strongly encouraged. Introducing livestock into arable cropping systems can improve nutrient cycling, soil health, and provide economic benefits. However, the detailed information about the impacts of ICL system on soil health is still lacking in the Northern Great Plains region. Therefore, the present study was conducted under a corn …

An Economic Analysis Of Cover Crops In Corn-Dominated Production Systems, Sukirti Nepal

LSU Master's Theses

A survey data by Singer et al. (2007) was used to study the factors affecting the adoption of cover crops by the producers at the Corn Belt area of the United States. Data was collected from four states: Illinois, Indiana, Iowa, and Minnesota. Two binomial logit models were used for the econometric analysis. The first logit model was used to observe the factors affecting the adoption of cover crops by the producers. The second logit model was used to analyze the factors affecting the adoption of cover crops by producers in recent years, specifically, in past five years. The result …