Physical Sciences and Mathematics Commons^™

Cattle Overwintering Areas In Middle-European Conditions - Important “Point” Sources Of Nitrous Oxide Emissions, M. Šimek, J. Hynšt, P. Brůček, J. Čuhel, D. Elhottová, H. Šantrůčková, V. Kamír

IGC Proceedings (1997-2023)

Nitrous oxide (N₂O) emissions in grazed grasslands are strongly influenced by animal excreta (Fowler et al., 1997). In addition, soil compaction caused by animal traffic significantly influences soil physical conditions and thus directly or indirectly impacts on the microbial processes producing N₂O. In the Czech Republic pastures are mostly located in hilly and mountain areas. During the growing season, cattle are typically grazing, while during the winter the animals are concentrated near the animal house on a relatively small plot called an "overwintering area". The objective of this study was to estimate the fluxes of …

Effect Of Dairy Effluent On Turnip Nutritive Characteristics, Joe L. Jacobs, G. N. Ward, Frank R. Mckenzie

IGC Proceedings (1997-2023)

In southern Victoria, high summer temperatures and low rainfall lead to low pasture growth and a decline in nutritional value until rainfall commences in autumn. Annual forage crops such as turnips often are used to fill the summer feed gap. Jacobs & Ward (2003) observed that dairy effluent applied at low rates could improve turnip DM yields and crude protein content. Results from the first two years of a 3-year study comparing a range of effluent application rates on turnip leaf and root nutritive characteristics are reported.

Agronomic Value Of Mixture Of Perennial Rye-Grass Cultivars: Preliminary Results, W. G. Do Nascimento, F. Surault, J. C. Emile, Christian Huyghe

IGC Proceedings (1997-2023)

Mixtures of grass and legume species are commonly used in sown grasslands. Mixtures have been shown to be favourable for stable production over cycles and years due to a succession of species over time (Mosimann & Charles, 1996 ; Nie et al, 2004). However, little is known whether the genetic variation in pure stands has an influence on the agronomic value and its variation over seasons.

Perennial Grass Emergence And Establishment Using A Micro-Nutrient Seed Treatment, Charlie D. Clements, J. A. Young

IGC Proceedings (1997-2023)

Resource managers have become increasingly frustrated with restoration seeding failures in semi-arid and arid environments. In response to this frustration, some resource managers have attempted restoration seedings using non-conventional methodologies such as propriety seed treatments. The exact nature of these propriety treatments is often confidential, but they generally consist of either nutrient or micro-nutrient enrichment or inoculation with unspecified micro-organisms. One of the more popular propriety seed treatment used in Nevada, USA, is GERM-N-8®. This product is a suspension of nutrients (N 2%, P 14%, and K 3%) applied to dry seed. Resource managers often report excellent success using these …

Effect Of Dairy Effluent On Turnip Yields, Joe L. Jacobs, G. N. Ward, Frank R. Mckenzie

IGC Proceedings (1997-2023)

Dairy effluent is a significant point source in the pollution of waterways. Only 50% of dairy farms in the dryland regions of Victoria, Australia, have suitable dairy effluent systems of which only 25% are managed effectively (IRIS Research 2000). Despite many farmers viewing effluent as an undesirable waste, it contains relatively large amounts of agronomically valuable nutrients especially nitrogen (N) and potassium (K). Results are reported from the first two years of a three year study comparing turnip leaf and root dry matter (DM) responses to a range of dairy effluent rates.

The Input Of Forage Legumes In Sustainable Grassland Systems, Žydrė Kadžiulienė, L. Sarunaite

IGC Proceedings (1997-2023)

There is increased interest in sustainable grassland systems. One step towards sustainability is expansion of legume use, because of their potential to fix and transfer nitrogen (N) to subsequent crops. However, legumes can also have negative aspects, such as difficulties in establishment (Porqueddu et al., 2003), lack of persistence, N loss (Scholefield et al., 2002) and accumulation of soil borne disease agents (Kadziulis, 2001). The large variability within legume swards and between years in pastures and leys has encouraged us to search for possibilities to achieve stability of their inputs in sustainable grassland systems.

A Rapid Estimation Of Nitrogen Bound To Neutral Detergent Fibre In Forages By Near Infrared Reflectance Spectroscopy, Jérôme Bindelle, G. Sinnaeve, P. Dardenne, P. Leterme, A. Buldgen

IGC Proceedings (1997-2023)

Near infrared reflectance spectroscopy (NIRS) is widely used as a rapid method for the evaluation of the chemical composition or the nutritive value of foodstuffs (Givens et al., 1997). The determination of the neutral detergent fibre (NDF) bound N (NDF-N), which is highly variable in forages (Shayo & Udén, 1999), is expensive. The purpose of this study was to test the use of NIRS in the prediction of NDF-N in various forages.

The Effect Of Nitrogen Fertiliser And Season On The In Situ Degradability Of Irish Perennial Ryegrass In Cattle, V. Olsson, J. J. Murphy, F. P. O'Mara, K. O'Connell, J. Humphreys, F. J. Mulligan

IGC Proceedings (1997-2023)

In light of increasing environmental and economic pressure on agriculture to utilise resources more efficiently, protein feeding and its effects are fundamentally important. As grazed grass is the predominant feed in Irish dairy and beef cattle production systems, it is necessary to establish protein values for different grass varieties and cultivars fed. It is also important to investigate the extent of ruminal nitrogen (N) degradability for these grasses since this characteristic greatly influences environmentally damaging urinary N excretion.

Modelling Of Nitrogen Allocation And Partitioning Within Lucerne (Medicago Sativa) Shoot Tissues During Recovery From Defoliation: An Approach To Estimate Forage Production And Nitrogen Composition, F. Meuriot, A. Escobar-Gutiérrez, J-C. Avice, J-C. Simon, F. Lesuffleur, F. Gastal

IGC Proceedings (1997-2023)

Lucerne has been grown over centuries for forage. Its forage production is strongly correlated to the initial taproot and stubble N reserves (Avice et al., 1996; Meuriot et al., 2004). However, the influence of cutting management on the level of N storage and the contribution of these N reserves to forage production still remain unclear and need to be studied at the whole plant level. For this purpose, a deterministic model of N allocation within the different organs and partitioning within different biochemical N pools was developed for lucerne with high and low initial N status and cutting …

Urea Applied To Puccinellia-Based Pastures Increases Pasture And Sheep Production, M. L. Hebart, N. J. Edwards, A. D. Craig, E. A. Abraham, J. D. Mcfarlane, J. E. Hocking Edwards

IGC Proceedings (1997-2023)

In the 1950's large areas of native vegetation in the upper south east of South Australia (SA) were replaced with highly productive Hunter River lucerne. This maintained groundwater recharge at near pre-clearing levels. The area of lucerne was reduced dramatically in the late 1970's by a combination of lucerne aphids, wingless grasshoppers and drought. In 1981 severe flooding inundated large areas of the region, causing the saline groundwater to rise to the soil surface. Since that time, dryland salinity has been a feature of the local farming system and salt-tolerant pastures based on puccinellia (Puccinellia ciliata) were widely …

Effect Of Nitrogen On The Radiation Use Efficiency For Modelling Grass Growth, R. Lambert, A. Peeters

IGC Proceedings (1997-2023)

When nitrogen (N) is not at a sufficient level to permit maximum growth rate, dry matter production is reduced. Models of plant growth in relation to solar radiation intercepted by the crop have been largely used. According to these models, N deficiency can act on the leaf extension and thus on the quantity of radiation intercepted by the crop, but also by reducing the radiation use efficiency of the crop (RUE) (Bélanger, 1990). The effect of N on the RUE of ryegrass swards is determined and discussed.

Radiation Use Efficiency Of Ryegrass: Determination With Non Cumulative Data, R. Lambert, A. Peeters

IGC Proceedings (1997-2023)

The growth of a crop is generally described as biomass accumulation per unit time. Monteith (1977) developed a model of growth where biomass accumulation is related to solar radiation intercepted by the crop. This model has been largely used for different crops. The conversion factor between radiation absorbed or intercepted by the crop and the biomass production is called “radiation use efficiency” or “dry matter radiation quotient”. Radiation use efficiency (RUE) is usually calculated as the regression coefficient of the linear relationship between crop biomass measured repeatedly during growth and cumulated intercepted or absorbed solar radiation. Demetriades-Shah et al. …

The Effect Of Grassland Management On Bovine Nitrogen Efficiency, N. J. Hoekstra, R. P. O. Schulte, E. A. Lantinga, P. C. Struik

IGC Proceedings (1997-2023)

Nitrogen (N) losses through grazing bovines are at the heart of the current debate on environment and agriculture. N utilisation of grazing bovines is predominantly determined by the form and amount of energy and protein in their diet, which in Ireland consists mainly of grazed grass. The two main problems of grazed grass with respect to animal N utilisation are 1) the imbalance between total N content and energy content, and 2) the lack of synchronisation between the release of N and carbohydrates in the rumen. It was hypothesised that both the balance and synchronisation of N and energy in …

Potential Yield Of Cocksfoot (Dactylis Glomerata) Monocultures In Response To Irrigation And Nitrogen, A. Mills, D. J. Moot, R. L. Lucas, P. D. Jamieson, B. A. Mckenzie

IGC Proceedings (1997-2023)

Cocksfoot is a widely sown grass in temperate pastures. However, while potential yield of cocksfoot can exceed 28 t DM/ha per year, it is often restricted by water, temperature and nitrogen (N). Of these, Peri et al. (2002) showed that N was severely limiting in all seasons. The aim of this study was to confirm the potential yield of cocksfoot and quantify the extent of yield reductions due to environmental constraints.

Blood Meal As A Source Of Histidine For Cattle Fed Grass Silage And Barley, R. Berthiaume, C. Lafrenière

IGC Proceedings (1997-2023)

Previous research has shown that cattle fed grass silage are responsive to protected amino acids (Veira et al., 1991). Methionine and lysine were suggested as the most limiting amino acids for grass silage diets. Recently, Korhonen et al. (2000) have shown that histidine is the first limiting amino acids for dairy cows fed grass silage and barley-based concentrates. However, histidine is not available in a rumen protected form and needs to be provided through dietary ingredients. Blood meal is rich in histidine. This trial was designed to determine the effect of increasing histidine supply through blood meal on …

Grassland Productivity And Water Quality: A 21st Century Issue, David M. Nash, P. M. Haygarth

IGC Proceedings (1997-2023)

1. Irrigation and other changes to the hydrological cycle can increase soil and water salinity.
2. Primary salinisation is a natural process that affects much of Europe, Asia, Africa, the Americas and Australia. Secondary salinisation is caused by human activities such as irrigation and land clearing that mobilise salt stored in the soil.
3. The critical water contaminants exported from grasslands are nitrogen, phosphorus, potential pathogens and sediment.
4. The mechanisms responsible for diffuse pollution from grasslands and mitigation strategies are most effectively investigated using a ‘source-mobilisation-transport’ framework.
5. There is a lack of coherent interaction across discipline boundaries that links pollutant sources to impact. …

Levels Of Autotrophy And Heterotrophy In Mesophotic Corals Near The End Photic Zone, Amy Carmignani, Veronica Z. Radice, Kathryn M. Mcmahon, Alex I. Holman, Karen Miller, Kliti Grice, Zoe Richards

Biological Sciences Faculty Publications

Mesophotic corals live at ~30-150 m depth and can sustain metabolic processes under light-limited conditions by enhancing autotrophy through specialized photoadaptations or increasing heterotrophic nutrient acquisition. These acclimatory processes are often species-specific, however mesophotic ecosystems are largely unexplored and acclimation limits for most species are unknown. This study examined mesophotic coral ecosystems using a remotely operated vehicle (Ashmore Reef, Western Australia at 40–75m depth) to investigate the trophic ecology of five species of scleractinian coral (from genera Leptoseris, Pachyseris, and Craterastrea) using stable isotope analyses (δ¹³C and δ¹⁵N) of host and symbiont tissues …

Nitrite Cycling In The Primary Nitrite Maxima Of The Eastern Tropical North Pacific, Nicole M. Travis, Colette L. Kelly, Margaret R. Mulholland, Karen L. Casciotti

OES Faculty Publications

The primary nitrite maximum (PNM) is a ubiquitous feature of the upper ocean, where nitrite accumulates in a sharp peak at the base of the euphotic zone. This feature is situated where many chemical and hydrographic properties have strong gradients and the activities of several microbial processes overlap. Near the PNM, four major microbial processes are active in nitrite cycling: ammonia oxidation, nitrite oxidation, nitrate reduction and nitrite uptake. The first two processes are mediated by the nitrifying archaeal/bacterial community, while the second two processes are primarily conducted by phytoplankton. The overlapping spatial habitats and substrate requirements for these microbes …

Diagnosing Excess Nitrogen In Rice Using Post-Season Tissue Samples, Kyle Hoegenauer

Graduate Theses and Dissertations

Proper nitrogen (N) management in rice production can be difficult to achieve without the aid of tools such as soil and tissue tests. There are no tests currently available to rice producers that determine whether N has been managed properly throughout the season or that detect instances of over fertilization. Rice stalk samples were collected from N response trials within 3 days of harvest from the primary Arkansas rice growing region in 2016-2018. Stalk samples were analyzed for N concentration through a KCl extraction and spectrofluorometric quantification. Samples analyzed with leaf material intact contained statistically different N concentrations than samples …

Mechanical Aeration And Liquid Dairy Manure: Application Impacts On Grassland Runoff Water Quality And Yield, T. J. Basden, S. B. Shah, J. L. Miller

IGC Proceedings (1997-2023)

Wet weather on heavy soils reduces oxygen availability in the root zone and reduces forage yields. Mechanical aeration can improve forage yield in these soil conditions. Research has shown that under certain conditions, mechanical aeration can increase yield by improving drainage and aeration (Davies et al., 1989); aeration can also increase depression, storage and infiltration thus reducing surface runoff and improving nutrient distribution in the root zone. Aeration on sloping, fertilised grassland can provide environmental (Douglas et al., 1995) and agronomic benefits. The objectives of this study were to evaluate the runoff water quality and agronomic impacts of …

Assessment Of Nitrogen Nutrition Status Of Grasses Under Water Deficit And Recovery, V. G. Dugo, Jean-Louis Durand, F. Gastal

IGC Proceedings (1997-2023)

Grasslands are rarely irrigated. They are therefore systematically submitted to more or less severe water deficits: as well as mineral deficiencies, water scarcity often also results in a reduction of nitrogen (N) status. Although identified some time ago, qualitatively, the interaction with N still remains difficult to take into account in quantitative analyses of crop physiology under water deficits. This paper illustrates how the nitrogen (N) status of the crop changes under water deficits. A N nutrition index (INN) was defined as the ratio of the actual N concentration of forage with the theoretical N concentration under optimal conditions, the …

Nitrogen Mineralisation In Situ And In Controlled Environment, F. Pálmason

IGC Proceedings (1997-2023)

Net mineralisation may be underestimated by in situ soil core methods for at least two reasons: (1) absence of plant N uptake in the soil cores, causing higher immobilisation than in intact soil. Schimel & Bennet (2004) thus concluded that plants compete effectively with microbes, as strongly indicated by cases, where net mineralisation was lower than plant uptake. (2) Gaseous losses of N₂O in closed cylinders can lead to underestimation especially during long incubation periods, Abril et al. (2001) and Vor & Brumme (2002).

The Role Of Grass Tussocks In Maintaining Soil Condition In North East Australia, B. K. Northup, J. R. Brown

IGC Proceedings (1997-2023)

Soils of the grazing lands of north eastern Australia are inherently nutrient-poor. Heterogeneously distributed plants are important to the conservation of the limited amounts of nutrients, through storage in plant tissues or in soil sinks close to plants (Ludwig et al., 1997). Loss of perennial vegetation through disturbance reduces conservation of these resources, to the detriment of feedback mechanisms, and ultimately causes loss of soil condition. Large areas of north east Australia have been degraded, or threatened by degradation, through combinations of variability in precipitation and heavy grazing (Gardener et al., 1990). This study examined the inter-related responses …

Field Experiments To Help Optimise Nitrogen Fixation By Legumes On Organic Farms, A. Joynes, D. J. Hatch, A. Stone, S. Cuttle, G. Goodlass

IGC Proceedings (1997-2023)

During an organic rotation, the aim is to increase the nitrogen (N) content of the soil (and hence build up soil fertility) by recycling crop residues, applying manures/composts and from N fixed by legumes. IGER, with ADAS, Duchy College Cornwall and Abacus Organic Associates are developing improved guidance for organic farmers in the use of fertility-building crops. The main questions are: how to maximise N fixation and how to make the most efficient use of the fixed N? Available soil mineral N, which is generally thought to reduce N fixation, will be increased by manure applications, cutting/mulching and grazing. We …

The Effect Of Forage Legumes On Mineral Nitrogen Content In Soil, M. Isolahti, A. Huuskonen, M. Tuori, Oiva Nissinen, R. Nevalainen

IGC Proceedings (1997-2023)

The cultivation of forage legumes is often suggested as a possibility to improve nitrogen (N) utilisation in farming. However, previous studies have indicated examples in which the cultivation of legumes such as white clover has led to accumulation of large amounts of N in soil (Adams & Pattison, 1985). In this study the potential risks of N leaching were estimated by determining amount of mineral N in the soil.

Cycling Of N And P In Grass-Alone (Brachiaria) And Mixed Grass/Legume (Brachiaria/ Desmodium Ovalifolium) Grazed Pastures In The Atlantic Forest Region Of Brazil, R. M. Boddey, R. Tarré, R. Macedo, C. De P. Rezende, J. M. Pereira, B. J. R. Alves, S. Urquiaga

IGC Proceedings (1997-2023)

There are estimated to be > 80 M ha of Brachiaria pastures in the tropical regions of Brazil. When continuously grazed with only modest fertiliser inputs (and no N) these pastures can maintain reasonable cattle weight gains (> 200 kg LWG/ha per year). However, without fertiliser and when overgrazed, LWGs fall rapidly to low levels. Recent studies have shown that N and P deficiency are the most important factors limiting productivity. The objective of this study was to study fluxes of N and P in the pasture system in order to understand resilience to poor management and minimum nutrient requirements to …

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 …

Analysis Of Indianapolis Waterways For Evidence Of Eutrophication And Contamination Induced By Urban Pollution, Kiley Grace Wardwell

Undergraduate Honors Thesis Collection

The focus of my research will be largely focused on the water quality of the White River throughout Indianapolis. I will be testing water samples from five different points along the White River to analyze three of its contents, assessing the differing levels of pollution along different points progressing down the river and through the city. The locations I have chosen to test coincide with water gauge sites along the White River and are as follows: Logan Street in Noblesville, 82nd Street, Broad Ripple Dam, Michigan Road and Raymond Street. The surface water at these five locations will be tested …

Initial Estuarine Response To Inorganic Nutrient Inputs From A Legacy Mining Facility Adjacent To Tampa Bay, Florida, Marcus W. Beck, Andrew Altieri, Christine Angelini, Maya C. Burke, Jing Chen, Diana W. Chin, Jayne Gardiner, Chuanmin Hu, Katherine A. Hubbard, Yonggang Liu, Cary Lopez, Miles Medina, Elise Morrison, Edward J. Phlips, Gary E. Raulerson, Sheila Scolaro, Edward T. Sherwood, David Tomasko, Robert H. Weisberg, Joseph Whalen

Marine Science Faculty Publications

Legacy mining facilities pose significant risks to aquatic resources. From March 30th to April 9th, 2021, 814 million liters of phosphate mining wastewater and marine dredge water from the Piney Point facility were released into lower Tampa Bay (Florida, USA). This resulted in an estimated addition of 186 metric tons of total nitrogen, exceeding typical annual external nitrogen load estimates to lower Tampa Bay in a matter of days. An initial phytoplankton bloom (non-harmful diatoms) was first observed in April. Filamentous cyanobacteria blooms (Dapis spp.) peaked in June, followed by a bloom of the red tide organism Karenia brevis …

Grassland Productivity And Water Quality: A 21St Century Issue, David M. Nash, P. M. Haygarth

IGC Proceedings (1997-2023)

Key points

1. Irrigation and other changes to the hydrological cycle can increase soil and water salinity.

2. Primary salinisation is a natural process that affects much of Europe, Asia, Africa, the Americas and Australia. Secondary salinisation is caused by human activities such as irrigation and land clearing that mobilise salt stored in the soil.

3. The critical water contaminants exported from grasslands are nitrogen, phosphorus, potential pathogens and sediment.

4. The mechanisms responsible for diffuse pollution from grasslands and mitigation strategies are most effectively investigated using a ‘source-mobilisation-transport’ framework.

5. There is a lack of coherent interaction across discipline …