Physical Sciences and Mathematics Commons^™

Development Of A Model Of Growth Of Grass/White Clover Swards For A Grassland Management Support System, A. Scott Laidlaw

IGC Proceedings (1997-2023)

No abstract provided.

In The Margins: Reconsidering The Range And Contribution Of Diazotrophs In Nearshore Environments, Corday R. Selden

OES Theses and Dissertations

Dinitrogen (N₂) fixation enables primary production and, consequently, carbon dioxide drawdown in nitrogen (N) limited marine systems, exerting a powerful influence over the coupled carbon and N cycles. Our understanding of the environmental factors regulating its distribution and magnitude are largely based on the range and sensitivity of one genus, Trichodesmium. However, recent work suggests that the niche preferences of distinct diazotrophic (N₂ fixing) clades differ due to their metabolic and ecological diversity, hampering efforts to close the N budget and model N₂ fixation accurately. Here, I explore the range of N₂ fixation …

Digitaria Eriantha Under Water Deficiency, H. Laborde, M. B. Toribio, M. N. Fioretti, R. E. Brevedan, S. S. Baioni

IGC Proceedings (1997-2023)

No abstract provided.

Monitoring Urine Distribution By Grazing Livestock, Keith Betteridge, Coby J. Hoogendoorn, Wendy Griffiths, Des A. Costall, Mark Carter, Patrick Laube

IGC Proceedings (1997-2023)

No abstract provided.

Critical Plant And Leaf N Concentrations Of An Ageing Timothy Sward, Gilles Bélanger, Gaëtan F. Tremblay

IGC Proceedings (1997-2023)

No abstract provided.

Effects Of Yearly Simulated Temperature Rise And Nitrogen Deposition On Soil Nutrient In The Songnen Meadow Steppes Of Northeast China, L. J. Hu, D. L. Wang, W. W. Wang, J. X. Guo

IGC Proceedings (1997-2023)

No abstract provided.

Effects Of Nitrogen Fertilizers On Growth And Turf Quality Of Kentucky Bluegrass, Yuling Deng, Yan Peng, Yukuan Wang

IGC Proceedings (1997-2023)

No abstract provided.

The Impact Of Different Grassland Land‐Uses On Earthworm Populations In A New Zealand Fragi‐Pallic Soil, Todd A. White, Trevor L. Knight, C. L. Goulter, W. J. Clarke-Hill

IGC Proceedings (1997-2023)

No abstract provided.

Sources Of Nitrogen In A Napier Grass/Legume Mixture On Smallholder Dairy Farms In Central Kenya, David Miano Mwangi

IGC Proceedings (1997-2023)

No abstract provided.

Spatial And Temporal Variation Of Nutrients In The Great Lakes-St. Lawrence Basin: Implications For Primary Production In Stream Ecosystems, Nolan Pearce

Electronic Thesis and Dissertation Repository

Growing human populations and associated land use activities has increased the amount of nutrients delivered to surface waters. Eutrophication from the over-enrichment of nitrogen and phosphorus has degraded ecosystem conditions in streams, lakes, and coastal areas worldwide. Thus, the management of anthropogenic nutrient loading is a global concern. This thesis employed a combination of field and experimental research to provide watershed managers with information on the spatial and temporal patterns in stream nutrient enrichment, and the associated ecological effects of anthropogenic nutrient loading in the Great Lakes-St. Lawrence basin. Four studies were completed to address this research goal. First, I …

Production, Botanical Composition And Nutrient Status Of An Originally Lolium Perenne--Dominant Sward Receiving Long‐Term Manure Applications, Wenju Liu, Y. G. Zhu, P. Christie, A. Scott Laidlaw

IGC Proceedings (1997-2023)

No abstract provided.

Nitrous Oxide Emission And Methane Oxidation Potential In The Pastoral Soil Under Intensive Dairy Farm Management, Z. Li, F. M. Kelliher

IGC Proceedings (1997-2023)

No abstract provided.

Response Of Natural And Cultivated Hay Meadows To Fertilizer Applied By Small Scale Livestock Farmers In The Mountainous Sandzak Region Of Serbia, Ian R. Lane, M. V. Stosic, G. Topisirovic, S. Reynolds

IGC Proceedings (1997-2023)

No abstract provided.

Resources Use Efficiency In Tall Fescue And Annual Ryegrass Pastures With Different Nitrogen Nutrition (Humid Pampa, Argentina), Mónica G. Agnusdei, M. A. Marino, F. Lattanz

IGC Proceedings (1997-2023)

No abstract provided.

Nitrogen Cycling In Intensively Grazed Pastures And Practices To Reduce Whole‐Farm Nitrogen Losses, Sterwart F. Ledgard, J. Luo

IGC Proceedings (1997-2023)

No abstract provided.

Pattern Of Nitrogen Integration And Its Ecological Implications In Clonal Plant Zoysia Japonica, Dezhi Li, Changai Wang

IGC Proceedings (1997-2023)

No abstract provided.

Evaluation Of Nitrogen And Phosphorus Removal From A Denitrifyingwoodchip Bioreactor Treatment System Receiving Silage Bunker Runoff, Jillian C. Sarazen, Joshua W. Faulkner, Stephanie E. Hurley

College of Agriculture and Life Sciences Faculty Publications

Leachate and storm-driven runoff from silage storage bunkers can degrade receiving water bodies if left untreated. This study evaluated a novel treatment system consisting of three treatment tanks with a moving-bed biofilm reactor and paired side-by-side denitrifying woodchip bioreactors for the ability to reduce influent nutrient mass loads. Flow-based samples were taken at four locations throughout the system, at the inflow to the first tank, outflow from the tanks prior to entering the woodchip bioreactors, and from the outflows of both bioreactors. Samples were analyzed for concentrations of nitrogen (N) and phosphorus (P) species. Inflow concentrations were reduced from the …

In Situ Plant Uptake Of Excess Nutrients And Consequential Alteration Of Rhizosphere Dynamics, Srusti Maddala

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

The use of phytoremediation in ecological remediation projects has numerous benefits including soil stabilization and nutrient uptake. Recently, microdialysis, a diffusion-based sampling technique commonly used in biomedical research, has been recognized as a candidate for monitoring chemical changes in the rhizosphere. The real-time, in situ data it provides about nutrient diffusion may improve the management and success of restoration projects. Therefore, the objective of this study was to employ the technique of microdialysis in the novel application of quantifying the diffusive flux of inorganic nitrogen compounds in the rhizosphere of native plants of Arkansas. The microdialysis technique was first optimized …

Biomass Of Grasses And Other Herbaceous Plants For Bioenergy Use, Žydrė Kadžiulienė, Lina Šarūnaitė, Vita Tilvikienė, Jonas Šlepetys, Zenonas Dabkevičius

IGC Proceedings (1997-2023)

Biomass supply for different uses, especially for bioenergy production, is becoming increasingly important. Independently of the purposes of biomass use, high yields per unit area and best possible quality need to be achieved. As a result, the selection of appropriate plant species is an important aspect. Cocksfoot (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.) and reed canary grass (Phalaris arundinacea L.) were investigated on a light loam (Cambisol) with a view to assessing the impact of nitrogen (N) and harvest time on biomass yield used for biogas. The biomass yield was influenced by cutting …

Forage Production Potential And Nitrate Nitrogen In Napier Bajra Hybrid As Influenced By Nitrogen Dose Under Shaded And Un-Shaded Environments, U. S. Tiwana, Sukhpreet Singh, Meenakshi Goyal, P. K. Kingra, Awtar Singh

IGC Proceedings (1997-2023)

Dairy farming is an important and prevalent subsidiary occupation along with agriculture in the state of Punjab. But because of declining land holding, the pressure on land is so high that there is little scope of expanding the area under forage crops. Crop intensification either in space (intercropping) or in time (sequential cropping) or both is the feasible option left to the farmers for enhancing the fodder production. The green fodder is deficit by about 25% in the state and there is around 65,000 ha area under Agroforestry. There is a need to explore possibility of growing fodder crops under …

Effect Of Nitrogen And Phosphorus Application On Productivity, Nutrient Uptake And Quality Of Teosinte (Zea Mexicana L.) Fodder, Magan Singh, A. S. Harika, P. S. Oberoi, Rakesh Kumar

IGC Proceedings (1997-2023)

Teosinte (Zea mexicana L.) is popularly known as Makchari being a close relative of maize. It provides succulent, palatable and nutritive fodder during Kharif season for feeding the animals as green fodder or conserved fodder in the form of silage. Teosinte is an excellent multicut fodder which gives high yield of nutritious green lush fodder in 65-70 days with less inputs as compared to maize. Nitrogen is an essential component of proteins, nucleic acid, enzymes, coenzymes, chlorophyll and cell wall. Phosphorus plays a vital role in crop production as it is involved in CO₂ fixation, sugar metabolism, energy …

Management Effect On Rainfall Use Efficiency And Growth Rate Of Spineless Cactus Cv. Miúda In Northeast Brazil, Toni Carvalho De Souza, Mércia V. F. Dos Santos, Márcio V. Da Cunha, Felipe M. Saraiva, Alexandre C. L. De Mello, Mário De Andrade Lira, Ivan Ferraz, José C. B. Dubeux Jr.

IGC Proceedings (1997-2023)

Spineless cactus has a high rainfall use efficiency. Under water deficit, they open their stomata during the night to capture atmospheric carbon dioxide when the air temperature is lower and relative humidity higher (Taiz and Zeiger, 2009), losing less water to the atmosphere. The rainfall use efficiency (RUE) can be expressed as the amount of water used by the crop to produce dry matter (Han and Felker, 1997). The RUE showed by spineless cactus, a CAM plant, is three to five times greater than the one observed in C₃ and C₄ plants (Felker and Russel, 1988; Nobel, 1991). …

Tall Fescue (Festuca Arundinacea) Stockpiling Response To N Fertilizer In Southern Virginia As Affected By Biological Soil Quality, Christopher D. Teutsch, Robert Shoemaker, Alan J. Franzluebbers

IGC Proceedings (1997-2023)

Cattlemen in the eastern USA profitably utilize endophyte-infected tall fescue (Festuca arundinacea) for fall-stockpiled winter grazing. Ergot alkaloid concentration in fescue tends to decline in winter. This improves the quality of fescue for grazing when the supply of other forage becomes limited on most farms. Tall fescue dry matter yields generally respond favorably to nitrogen (N) inputs, but response can be limited with summer application due to accumulation of biologically available N in soil. Research is needed to characterize a diversity of pastures for response to N fertilizer during fall stockpiling.

Biological soil quality can be estimated with …

Soil Carbon And Nitrogen Stocks And Their Relationship With Plant And Soil Dynamics Of Degraded And Artificial Restoration Grasslands In An Alpine Region, Yuanyuan Li, Shikui Dong, Yu Wu

IGC Proceedings (1997-2023)

Land disturbances and management approaches can significantly alter grassland soils. Therefore, understanding the carbon and nitrogen storage accompanying plant and soil physical and chemical properties due to anthropogenic disturbance and different management strategies is important. In our study, we investigated carbon and nitrogen storage in artificial grasslands with different durations of restoration and native grasslands with different levels of degradation. We found that total carbon and nitrogen were significantly higher five years after restoration than after seven and nine years, but decreased due to grassland degradation. Furthermore, soil carbon and nitrogen had a close relationship with plant and soil factors, …

The Changing Patterns In Grasslands And Soil Fertility Along The Eastern Eurasian Steppe Transect Across China–Mongolia–Russia, Xiangyang Hou, Leonid Ubugunov, S. Tserendash, Haijun Chen, Wenjun Han, Xiangjun Yun, Ding Yong, Wang Zhen, Lei Ji

IGC Proceedings (1997-2023)

This paper analyses the adaptation and change in species along the north-south Eastern Eurasian Steppe Transect across China – Mongolia – Russia and considers the implications for climate change and management. The plant community diversity, above-ground biomass, N:P ratios of community and of dominant species, soil N (nitrogen), soil P (phosphorus) and AP (available phosphorus) contents were studied along a 1400 km north-south transect. The main findings were: (1) the community diversity and productivity decreased with the increase in latitude and a significant negative correlation was found between the many plant characteristics and latitude (P < 0.05) – decreasing diversity, biomass and N:P ratios; (2) soil AP content was lowest in Inner Mongolia, whereas no significant change in soil total P with latitude was found in China-Mongolia-Russia transect, a significant positive correlation was detected between the soil nutrient (N and AP) and latitude (P < 0.05); (3) a significant positive correlation was evident between plant community P content and soil AP content (P < 0.01), but a negative correlation was found between community N:P ratio and soil AP content (P < 0.05). The soil AP content can be used as a soil properties indicator to reflect the plant communities P content and N: P ratio. It is suggested that greater human activities in Inner Mongolia may be an important factor affecting soil AP content, community N:P and plant growth.

Changes In The Content And Allocation Of Carbon And Nitrogen During Forage Regrowth, Huimin Yang, Zhennan Wang, Xiaoyan Zhang

IGC Proceedings (1997-2023)

Regrowth after cutting or grazing perennial grasslands sustains the production potential of forage and the persistence of grassland species. The changes in nature, content and allocation of compounds within plant parts are fundamentally correlated to the forage regrowth process (Lambers et al. 2008). These compounds are sourced from reserves and new assimilates. Carbohydrates and proteins stored mainly in the stem base and the root play an important role at the early stages of regrowth (Meuriot et al. 2004). The newly assimilated compounds include carbon from photosynthesis for the residual leaf and stem, and nitrogen absorbed by the roots …

Phyllochron And Leaf Lifespan Of Four C4 Forage Grasses Cultivated In A Silvopastoral System, Tiago C. Baldissera, Laíse Da S. Pontes, Raquel S. Barro, André F. Giostri, Keli C. S. Guera, Miquéias Michetti, Vanderlei P. Da Silva, Paulo C. De F. Carvalho

IGC Proceedings (1997-2023)

Silvopastoral systems are emerging as an option for more sustainable land use. However, the challenge is to optimize pasture production and the determine suitable management by understanding the growth and development of forages under trees canopy (Palma et al. 2007). In the silvopastoral system, trees change the environment that forages grow, and can influence the development of plants and, consequently, the sward dynamics. For instance, the light quantity (i.e. photon flux density) and quality (e.g. changes in red: far-red ratios) can vary as a result of the tree canopy (Beaudet et al. 2011).

Phyllochron …

Contribution From Tree Legumes To Mixed Grass-Legume Pastures, Valéria X. De O. Apolinário, José C. B. Dubeux Jr., Mário De A. Lira Jr., Rinaldo Luis Caraciolo Ferreira, Alexandre C. L. De Mello, Diego De Lima Coelho, Everardo V. S. B. Sampaio

IGC Proceedings (1997-2023)

Legumes and associated microorganisms may fix N from atmosphere and benefit grass on mixed grass-legume pastures. Nitrogen may be transferred by different mechanisms, including direct transfer of N compounds by roots, decomposition of nodules, roots, litter from legume (Nair 1993), and through animal excreta after legume intake by cattle. Silvopastoral systems including tree legumes may become a viable option in tropical regions, considering the increasing prices of N fertilizers compared to farm products such as beef and milk.

This experiment evaluated legume contribution on mixed grass-legume pastures in the coastal region of Pernambuco State, Brazil.

The Environmental Microbiome In A Changing World: Microbial Processes And Biogeochemistry, Stephanie Juice

Graduate College Dissertations and Theses

Climate change can alter ecosystem processes and organismal phenology through both long-term, gradual changes and alteration of disturbance regimes. Because microbes mediate decomposition, and therefore the initial stages of nutrient cycling, soil biogeochemical responses to climate change will be driven by microbial responses to changes in temperature, precipitation, and pulsed climatic events. Improving projections of soil ecological and biogeochemical responses to climate change effects therefore requires greater knowledge of microbial contributions to decomposition. This dissertation examines soil microbial and biogeochemical responses to the long-term and punctuated effects of climate change, as well as improvement to decomposition models following addition of …

Microdialysis: A Method For Quantifying In Situ Nitrogen Fluxes In Soil Microsites, Srusti Maddala, Mary C. Savin, Julie A. Stenken, Lisa S. Wood

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Microdialysis, a diffusion-based sampling technique commonly used in biomedical research, has recently been recognized as a candidate for monitoring chemical changes in the rhizosphere. The information it provides about nutrient diffusion may improve nitrogen use efficiency, leading to enhanced management and success of restoration projects. The objective of this study was to determine the efficacy of microdialysis sampling to quantify the relative recoveries (RR%) of nitrate-N and ammonium-N, the two inorganic nitrogen compounds typically found in soil. The effects of microdialysis flow rate, sample medium concentration, and the presence of both analytes in solution on the relative recoveries obtained from …