Physical Sciences and Mathematics Commons^™

Breeding Cool-Season Forage Grasses For A Warming Climate, D. P. Malinowski, J. Ford, A. Stewart, D. Woodfield, W. E. Pinchak

IGC Proceedings (1997-2023)

In many parts of the world, changing climatic conditions are resulting in increased temperatures and more variable precipitation, intensifying the duration and severity of drought, especially in summer. Warming climate is considered one reason for the increasing failure of traditional, summer-active cool-season perennial grasses at the margin of their zone of adaptation in naturally C4 grass-dominated ecosystems of the Southern Great Plains of the USA. Two cool-season perennial forage grasses orchardgrass (Dactylis glomerata L.) and tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) are of major economic and ecological importance in these regions. In 2008, we initiated a breeding program …

Exploring Profitable, Sustainable Livestock Businesses In An Increasingly Variable Climate, B. R. Cullen, M. T. Harrison, D. Mayberry, D. Cobon, N. Reichelt, A. Sinnet, Km Christie, F. Bilotto, D-A An-Vo, C. Stokes, L. Perry, T. Davison

IGC Proceedings (1997-2023)

Livestock production systems will need to change in many regions of the world to meet the dual challenges of adaptation to a changing climate and reducing net greenhouse gas (GHG) emissions. The ‘Nexus project’ is exploring these options using seven case studies in eastern Australia spanning a range of production systems from semi-arid beef production in northern Australia to mixed beef and sheep production in cool temperate climates of southern Australia. Regional reference groups, made up of 4-6 local farmers and advisers, identified a series of farm systems changes that could be made to meet these challenges. Options were categorised …

Public Policies For The Development Of A Sustainable, Forage-Based Cattle Sector In Colombia, Argentina, And Costa Rica: A Comparative Analysis, S. Burkart, M. Diaz, Moreno Lerma

IGC Proceedings (1997-2023)

Projected increases in global food demand highlight the importance of Latin America as one of the major future food suppliers, particularly regarding animal-source foods such as beef or milk. Despite the importance of the cattle sector for the region, its negative environmental impacts are numerous and the shift towards sustainability is perceived as slow and uncoordinated. This study aims to identify achievements and difficulties in the implementation of public policies for a sustainable cattle sector in Colombia, Argentina, and Costa Rica, for which policies focused on the use of silvo-pastoral systems and forage-based solutions are prioritized. Based on the review …

Fencing Lands To Enhanced Climate Change Resilience, Promoting Biodiversity Regeneration And Improved Livelihoods Of Climate Change In Makueni County, Frank Wesonga, Francis Keya

IGC Proceedings (1997-2023)

Kenya is a food insecure country, weather patterns are drastically changing and people are losing livelihoods and earnings when their lands dry, water for domestic supply lacks and livestock die further frustrating livelihoods of the poor. This paper briefly discusses Fencing of lands as prerequisite to biodiversity protection and faster water retention mechanism, through tree planting, enhancing CO2 sequestration as trees, shrubs and vegetation’s find suitable environment to grow. Baringo and Makueni County are characterized by unsustainable agriculture, environmental degradation resulting from soil erosion, high poverty levels and food insecurity due to unpredictable dry spells and climate change. The present …

Design And Management Of Saltbush-Based Forage Systems To Improve Productivity And Reproductive Performance Of Sheep, H. C. Norman, M. G. Wilmot, D. G. Masters, D. Blache, S. K. Maloney, S. N. Hancock

IGC Proceedings (1997-2023)

There is evidence that effective shelter can significantly improve lamb survival, but the majority of Australian studies have occurred in small paddocks where the ewes had no choice but to use shelter. In mixed farming systems with large open paddocks, it is unclear if ewes will choose to use shelter for lambing. Our multidisciplinary collaboration examines the use of woody shrubs as an opportunity to improve the survival of twin lambs. In a series of large experiments on commercial farms, we will evaluate the impact of different shrub planting configurations, orientations, and densities on microclimates at the sub-paddock scale. Twin-bearing …

Environmental Co-Benefits Of Improved Forages In Smallholder Dairy Systems Of Kenya, A. Notenbaert, S. Mwendia, S. Burkart, P. Karimi, E. Mwema

IGC Proceedings (1997-2023)

Livestock play a major role across Kenya, especially in smallholder mixed farms through provision of household nutrition and income through milk and meat. Equally, fertilization of cropland benefits from livestock manure, and livestock often act as insurance and saving. Despite the opportunities and benefits livestock production presents, livestock systems are also key drivers of environmental degradation, including increased nutrient loads, GHG emissions, water use, grassland degradation and land-use conversion. Low livestock productivity, largely due to use of low-quality crop residues and natural grasses often not endowed with nutrients key for animal performance, limits the potential positive contributions of livestock and …

Breeding Forage Grasses For Increased Heat Tolerance To Combat Climate Change, Eric D. Billman, J. S. Morrison, B. S. Baldwin

IGC Proceedings (1997-2023)

The onset of climate change brings many challenges for forage production in the southeastern United States, where it is projected to become hotter and dryer in the next century. To combat this climatic challenge, recurrent phenotypic selection was conducted in growth chambers on annual ryegrass (Lolium multiflorum Lam.) and orchardgrass (Dactylis glomerata L.) to select seedlings that can germinate and survive at temperatures of 40°C. Following three cycles of selection, germination was increased from < 5% to 45% in annual ryegrass, and from 20% to 80% in orchardgrass. The rate of germination also increased, in both species by a factor of 8x that of the base germplasm. Realized heritability also increased by 40 – 45% for each species by the end of the project. This work successfully improved a quantitative trait using recurrent phenotypic selection using growth chambers as a stable environment and provided the basis for combatting climate change in other outcrossing forage species.

Climate Change And Legume Performance In Grassland Agroecosystems, Lynn E. Sollenberger, M. M. Kohmann

IGC Proceedings (1997-2023)

We reviewed the literature to assess the effect of climate change factors on forage legumes. Whether growing in monoculture or mixtures with grasses, exposing legumes to elevated CO₂ (eCO₂) generally leads to sustained increases in forage accumulation (FA) and N fixation, but elevated temperature (eT) in conjunction with eCO₂ usually reduces magnitude of these responses. In legumes, nodules represent large C sinks, precluding photosynthetic acclimation to eCO₂ observed in non-N fixing plants. Greater N fixation in legume-grass mixtures exposed to eCO₂ is due to greater percentage of legume N derived from symbiotic fixation and …

Cool-Season Perennials And Stability In Year-Round Forage Production Systems, C. D. Teutsch

IGC Proceedings (1997-2023)

Changes in long-term climate normals have resulted in warmer and wetter summers and milder winters in the humid eastern United States. This will likely impact regional forage species adaptation in the long-term and varietal adaptation in the short term. Variety evaluation has been occurring at the University of Kentucky for almost 100 years. There are several considerations for selecting forage species and varieties including regional and local adaptation, productivity, distribution of growth, palatability, nutritive value, anti-quality factors, tolerance to stress, and persistence. Two of the most important criteria are long-term productivity and persistence under grazing, both of which are currently …

Discrepancies Between Observed And Predicted Climate-Driven Net Herbage Accumulation, Alec D. Mackay, Michael B. Dodd, K. J. Hutchinson, Ronaldo Vibart, F. Bilotto

IGC Proceedings (1997-2023)

The decline in net herbage accumulation (NHA) on the high phosphorus (P) fertilizer farmlet (HF) of a long-term P fertilizer and associated sheep grazing experiment in the last 25 years, aligns with the necessity to reduce the on-site nominal sheep stocking rates over the same period on this farmlet. This finding appears at odds with projected climate change driven modelling that forecast a largely positive outcome on pasture growth in summer moist environments. In this paper we explore the apparent discrepancies between the observed and predicted climate-driven NHA by using a climate-driven pasture growth module within a larger process-based model …

Length Of Multi-Year Precipitation And Primary Production Relationships Vary Regionally Across Grasslands In The Central U.S., A. R. Hudson, D. P.C. Peters

IGC Proceedings (1997-2023)

Grasslands in the central United States span large temperature and aridity gradients and regionally differ in their drivers of water availability. These differences likely determine how drought event periodicity and duration can influence grassland growth, and are important to consider as global warming changes energy and water distribution across these systems. Here, we explored frequency patterns in annual grassland plant growth (aboveground net primary productivity (ANPP)) and precipitation (PPT) relationships for over 20 years at six long-term research sites spatially distributed across the central grassland region. We identified the periods (>1 year) these relationships are strongest- and when they …

Response Of Reproductive Phenology To Soil Water Content Of Stipa Breviflora Under Warming And Nitrogen Application, L. Bai, H. Y. Ren, G. D. Han

IGC Proceedings (1997-2023)

Plant phenology is considered as the most direct and sensitive characteristic indicators of plant response to regional climate change. Based on the observation data of phenology and soil water content of Stipa breviflora in an experimental platform of warming and nitrogen application in Inner Mongolia desert steppe from 2009 to 2019. The results showed that warming and nitrogen application significantly advanced the reproductive phenological period (P < 0.001), and the interaction of warming and nitrogen application promoted the advance of reproductive phenological period (P < 0.05).

Potential Climate Change Impacts On Beef Production Systems In Australia, David H. Cobon, K. L. Bell, G. M. Mckeon, J. F. Clewett, S. Crimp

IGC Proceedings (1997-2023)

There is increasing evidence suggesting that Australia's climate is changing due to enhanced levels of greenhouse gases and that it will continue to change (Pittock 2003). Climate changes are partly established, however the impact on systems, industries and process are unclear. Industry distribution reflects climatically imposed boundaries and the relative profitability of alternative land use. Climate change may negatively impact some existing industries but create opportunities for others. This study provides an assessment of the likely impacts of plausible climate change on the beef industry in central Queensland.

Yield Progress Of Perennial Ryegrass And Silage Maize - Genetic Gain Or Climate Change?, Antje Herrmann, A. Kornher, Friedhelm Taube

IGC Proceedings (1997-2023)

Gains in annual dry matter yield (DMY) from breeding achieved during the last decades are reported to range between 2.5 and 6% per decade for perennial ryegrass (Wilkins & Humphreys, 2003). In contrast, accelerated progress in improving DMY has been achieved for silage maize, varying between 8 and 13% per decade (Lauer et al., 2001). These gains are mainly attributed to (i) genetic yield potential increase, (ii) improved crop management and (iii) increased stress tolerance. The potential impact of climate change on yield progress, however, is disregarded in most studies. The objective of this study therefore was to quantify …

Shifts In N-Efficiency Of Different Farm Types In Response To Climate Change, S. Dueri, P. L. Calanca, Juerg Fuhrer

IGC Proceedings (1997-2023)

Climate change may affect European farms, but in contrast to individual crops - the sensitivity of whole farming systems has not been the subject of much research. At the farm level, where different farm units are linked through the availability and flow of nitrogen (N), effects on individual crops are interlinked, and through shifts in grasslands and related animal production with altered nutrient flows. Ideally, N flows into the system and N-export with products should be equal, and thus N-use-efficiency (NUE), expressed as the ratio of N export to N loss, would be maximal. The objective of this study was …

The Effect Of Extremes In Soil Moisture Content On Perennial Ryegrass Growth, A. Scott Laidlaw

IGC Proceedings (1997-2023)

Seasonal distribution of rainfall in the UK and Ireland is predicted to become more variable (Sweeney, 2003). The problems of excessive soil moisture on grass utilisation and the effect of deficit in soil moisture on grass growth are well known. However the effect of excess rainfall on the growth of sown grass is less clear and is usually not taken into account in grass growth models. This study was carried out to investigate the potential impact of excess moisture on perennial ryegrass growth in the field and to investigate the relative effect of soil moisture varying from deficit to excess …

Forage Grass Phenology In Relation To Climate Change, G. Żurek

IGC Proceedings (1997-2023)

Phenological phases of plants, such as heading or flowering are mainly driven by environmental factors such as pests, diseases, competition, soil properties, genetics, age and, most importantly, weather conditions (Menzel & Fabian, 1999; Menzel 2000). At the end of the last century there was an emerging recognition that phenological records can be especially useful in environmental monitoring and it has gained the UK government approval as an indicator of climate change (Sparks et al., 2000). The aim of this work was to analyse long-term trends in the mean heading date for Polish ecotypes of three forage grass species.

Long-Term Responses Of A Mesic Grassland To Manipulation Of Rainfall Quantity And Pattern, A. K. Knapp, J M. Blair, P. A. Fay, M. D. Smith, S. L. Collins, J. M. Briggs

IGC Proceedings (1997-2023)

Climatic variability is an inherent feature of grassland biomes, with large fluctuations in temperatures combined with precipitation regimes characterised by floods and severe drought occurring on both an interannual and seasonal scale. Global climate models and emerging data indicate that extremes in precipitation regimes are increasing worldwide coupled with increases in temperature. Thus, variability in spatial and temporal patterns of water availability in grasslands, as directly influenced by altered precipitation patterns and indirectly by increased temperatures, will likely increase in the future. The objectives of our experiments were to experimentally manipulate rainfall amount and temporal patterns (amount and timing of …

Sources And Sinks Of Greenhouse Gases From European Grasslands And Mitigation Options: The ‘Greengrass’ Project, Jean-François Soussana, V. Allard, P. Ambus, C. Amman, P. Berbigier, C. Campbell, P. Cellier, E. Ceschia, P. Ciais, J. Clifton-Brown, S. Czóbel, R. Domingues, T. De Groot, R. Falcimagne, C. Flechard, J. Fuhrer, G. Gaborit, L. Horváth, A. Hensen, M. B. Jones, S. Jones, G. Kasper, K. Klumpp, P. Laville, C. Martin, C. Milford, Z. Nagy, A. Neftel, E. Nemitz, J. E. Olesen, A. Patterson, K. Pilegaard, A. Raschi, R. Rees, U. Skiba, P. Stefani, S. Salètes, P. Smith, M. A. Sutton, Z. Tuba, A. Van Amstel, A. Van Den Pol-Van Dasselaar, N. Viovy, N. Vuichard, M. Wattenbach, T. Wedinger

IGC Proceedings (1997-2023)

Adapting the management of grasslands may be used to enhance carbon sequestration into soil, but could also increase N₂O and CH₄ emissions. In support of the European post-Kyoto policy, the European 'GreenGrass' project (EC FP5, EVK2-CT2001-00105) has three main objectives: i) to reduce the large uncertainties concerning the estimates of CO₂, N₂O and CH₄ fluxes to and from grassland plots under different climatic conditions and assess their global warming potential, ii) to measure net greenhouse gas (GHG) fluxes for different management which reflect potential mitigation options, iii) to construct a model of …

Impact Of Climate Change On Potential Distribution And Relative Abundance Of The Migratory Grasshopper (Orthoptera: Acrididae) In The Prairie Ecosystem Of Canada, Owen Olfert, R. Weiss

IGC Proceedings (1997-2023)

Climate is the dominant force determining the distribution and abundance of most insect pest species. There has been considerable concern in recent years about climatic warming caused by human activities and the affects of these changes on agriculture in North America. Warming conditions may affect insect populations by altering timing of emergence, increased growth and development rates, shorter generation times and reduced overwintering mortality (McCarthy et al. 2001). Given that the magnitude of predicted temperature change associated with global warming is beyond the historical experience of modern agriculture computer models are one method by which researchers can study the possible …

Net-Zero Target And Emissions From Land Conversions: A Case Study Of Maryland's Climate Solutions Now Act, Philip Hutton

All Theses

Many climate change “solution” plans include net-zero goals, which involve balancing the anthropogenic greenhouse gas emissions (GHG) with their removal. Achieving net-zero goals is particularly problematic for soils because they are often excluded from GHG inventories and reduction plans. For example, Maryland’s Climate Solutions Now Act (Senate Bill 528) put forward a target of net-zero emissions by 2045. To achieve these goals, the state of Maryland (MD) needs to quantify GHG emissions. Soils are currently excluded from MD’s GHG assessments. This study examines the challenges in meeting net-zero goals by using carbon dioxide (CO₂). The current study quantified …

Irish Dairy Farming: Effects Of Introducing A Maize Component On Grassland Management Over The Next 50 Years, A. J. Brereton, N. M. Holden

IGC Proceedings (1997-2023)

Typical management of Irish dairy units is based on a low-cost spring-calving strategy with 90% of annual feed derived from grass grown on the farm. Almost 70% of feed is from grazed grass managed by rotational grazing, the remainder is conserved forage and concentrates. The objectives of the work were to examine how the management system has to be modified when part of the dairy unit land is allocated to maize silage instead of grass silage production, and to examine how climate change over the next 50 years will impact on grass and maize management within the production system.

The Potential Of Grassland And Associated Forages To Produce Fibre, Biomass, Energy Or Other Feedstocks For Non-Food And Other Sectors: New Uses For A Global Resource, M. F. Askew

IGC Proceedings (1997-2023)

1. In developed countries increased areas of land will become available for non-food production. Recent reforms of the Common Agricultural Policy will further intensify this trend in Europe.
2. There is potential for grassland and associated species to contribute to large tonnage markets of energy and bulk fibres, to the supply of fermentation products and to speciality markets, but processes and approaches to the market are not as yet developed.
3. There is potential for the establishment of Graminaceous species - specifically for non- food use. For European conditions particular attention is being given to Miscanthus sinensis (Miscanthus), Arundo donax (Giant Reed), Phalaris …

Quantifying The Carbon Stored And Sequestered By The Trees On Pomona College’S Campus, Paola A. Giron-Carson

Scripps Senior Theses

We are experiencing a climate crisis that must be confronted with strategic mitigation. Pomona College contributes to the climate crisis through its emissions for which there is a baseline record. However there is no baseline record of the climate mitigation currently performed by the trees on Pomona’s campus through carbon storage. This study seeks to determine a current baseline quantity of carbon stored and sequestrated by Pomona’s trees as well as possible courses of climate mitigation for Pomona College to take. Initial information gathering was conducted through interviews with several stakeholders. This study was conducted using data collected prior to …

Abiotic Stress Mitigation: A Case Study From 21 Trials Using A Natural Organic Matter Based Biostimulant Across Multiple Geographies, Rachel L. Sleighter, Terry Hanson, David Holden, Kristen M. Richards

Chemistry & Biochemistry Faculty Publications

Crop productivity and yields can be greatly diminished by abiotic stress events including drought, extreme temperatures, excess moisture, and saline irrigation water. Multiple stressors occurring simultaneously can further exacerbate the strain on plants. Various types of biostimulants have been shown to mitigate abiotic stress and here, the results of 21 trials on corn, wheat, soybean, and various high-value crops are discussed in the context of the abiotic stress that either occurred naturally or was experimentally induced. Treatments in these trials included stressed and non-stressed plants, as well as either an untreated control or grower standard fertilizer applications alone and in …

How Impervious Are Solar Arrays? On The Need For Geomorphic Assessment Of Energy Transition Technologies, Charles Shobe

Faculty & Staff Scholarship

Staying within manageable global temperature rise scenarios (i.e., 1.5° C) requires rapid decarbonization of energy sources. Research on the energy transition typically focuses on engineering, socioeconomic, and political challenges related to implementation of renewable energy technologies. Yet many facets of the energy transition are intricately intertwined with earth surface processes. Projects that advance the energy transition affect surface hydrology, sediment transport, and landscape evolution. Geomorphic processes likewise set the feasibility of energy transition projects. Here I use the lens of a recent policy debate to examine a case study that illustrates the key role of surface processes in determining the …

Regenerative Agriculture Framework For Island Ecosystems Using São Miguel As A Case Study, Mya Hunter

Independent Study Project (ISP) Collection

Context: Regenerative agriculture is a farming approach that uses soil health as the entry point to contribute to multiple objectives, such as improved nutrient cycling and climate regulation. Farmers can apply different practices to reach these objectives. The objectives and practices, however, are not equally relevant or applicable for farming systems on island ecosystems and the local context.

Objectives: The main objective of this paper, therefore, is to find out how solutions towards regenerative agriculture can be identified and evaluated as such that they result in meaningful advice for farmers on island ecosystems in order to mitigate the …

Optimization Techniques For Soil Organic Carbon Prediction Using Mid-Infrared Spectroscopy, Minerva J. Dorantes

Graduate Theses and Dissertations

Resource-efficient techniques for accurate soil carbon estimation are necessary to satisfy the increasing demand for spatiotemporal data. In the last thirty years, mid-infrared (MIR) soil spectroscopy has developed as an accurate, rapid, cost-effective, and non-destructive technique for soil organic carbon (SOC) analysis. In soil spectroscopy, a calibration model relates spectral data to a corresponding measured soil property and is subsequently used to predict this value from new spectral data. Various optimization techniques have been used to improve the statistical performance of calibrations; however, there is little consensus on the conditions that make these techniques effective. The objectives of this research …

Vermont Global Warming Solutions Act: The Costs Of Inaction From Land Conversions, Grayson L. Younts

All Theses

The Vermont (VT) Global Warming Solutions Act (GWSA, 2020) sets greenhouse gas (GHG) emissions reduction targets as 26% below 2005 by 2025, 40% below 1990 by 2030 and 80% below 1990 by 2050 for energy-related emissions only. Vermont’s omission of GHG emissions from land conversions can result in significant costs of inaction (COI), which can hinder state’s mitigation and adaptation plans and result in a climate crisis-related risks (e.g., credit downgrade). Science-based spatio-temporal data of GHG emissions from soils as a result of land conversions can be integrated into the conceptual framework of “action” versus “inaction” to prevent GHG emissions. …

Methane And Nitrous Oxide Emissions From Grazed Grasslands, Harry Clark, C. Pinares-Patiño, C. De Klein

IGC Proceedings (1997-2023)

Key points

1. Emissions of methane (CH₄) and nitrous oxide (N₂O) from grasslands make a substantial contribution to total agricultural emissions of these two gases.

2. At present practical mitigation options that relate to grazing ruminants and grazed pastures are limited.

3. Research into agricultural greenhouse gas emissions is of low priority in most developed countries.

4. Direct manipulation of the rumen ecosystem provides the best opportunity for large reductions in CH₄ in the long term.

5. Reducing the amount of nitrogen (N) excreted by grazing animals is a priority in N₂O research, …