Physical Sciences and Mathematics Commons^™

Morphogenetic And Structural Characteristics Of Clones Of Elephant Grass Managed Under Intermittent Stocking, Carlos Augusto Brandão De Carvalho, Priscila Beligoli Fernandes, Domingos S. C. Paciullo, Carlos A. M. Gomide

IGC Proceedings (1997-2023)

Morphogenetic studies of the growth dynamics of leaves and tillers of forage grasses have enabled the management strategies for grasses to be defined for various environmental conditions (Euclides et al. 2010). As the development of clones of Pennisetum purpureum is recent (Pereira e Lédo 2008), detailed information on their growth characteristic under pasture is necessary as a reference for the adoption of appropriate management practices. The objective of this study was to assess the morphogenetic and structural characteristics of basal and aerial tillers in pastures of two small-size clones of elephant grass managed under intermittent stocking for six grazing …

Canopy Height And Its Relationship With Leaf Area Index And Light Interception Of Tropical Grasses, Janerson José Coêlho, José C. B. Dubeux Jr., Erick Rodrigo Da Silva Santos, João Manoel Carneiro Leão Neto, Márcio V. Da Cunha, Mércia V. F. Dos Santos, Alexandre C. L. De Mello, Mário De A. Lira

IGC Proceedings (1997-2023)

Photosynthetic tissues, mainly green leaves, are the major component of forage growth and development. The amount of these tissues in a forage plant is influenced directly by the cutting management, which is based on cutting frequency and stubble height. It is usual to recommend as a management practice to cut (or graze) the forage whenever it reaches a given stubble height. Brougham (1956) stated that, when the forage canopy is intercepting 95% of the photosynthetic active radiation, this is the critical leaf area index (LAI), which means the forage is near its maximum growth rate without shading itself. There is …

Threshold Dynamics Of Vegetation And Their Management Implications In A Mongolian Shrubland, Takehiro Sasaki, Asuka Koyama, Toshiya Okuro

IGC Proceedings (1997-2023)

The concept of ecological threshold has spurred important advances in understanding the nonlinear behavior of ecosystems to various disturbances (Groffman et al. 2006, Suding and Hobbs 2009). Studies on lakes, coral reefs, and arid grasslands have shown that structural attributes of ecosystems can change abruptly along a disturbance gradient (Scheffer and Carpenter 2003, Mumby et al. 2007, Sasaki et al. 2008). Yet, such nonlinear response patterns are implicitly assumed to reflect the modification of system feedbacks and interactions. We know little about mechanistic linkages between nonlinear response patterns and underlying feedback mechanisms, and the irreversibility of nonlinear …

Leaf Epidermal Descriptors Of Forage From Caatinga, Ne Brazil, Mércia V. F. Dos Santos, Osniel F. De Oliveira, Márcio V. Da Cunha, José C. B. Dubeux Jr., Alexandre C. L. De Mello, Joelma Da S. Souza, Mário De A. Lira

IGC Proceedings (1997-2023)

In the Brazilian semi-arid region, the predominant vegetation is the Caatinga, which has a diversity of plant species, some endemic and presenting forage potential. The characterization of the plant anatomy is important for animal diet studies, using a microhistological technique (Scott and Dahl 1980) for estimating the diet botanical composition from ruminant faeces. This paper determined leaf epidermal descriptors for Caatinga species using microscopic slides.

Effects Of Livestock Grazing Intensity On Reproductive Changes In Festuca Ovina L., Somaye Alidoost, Masoume Amirkhani, Mousa Akbarlou, Mansour Mesdaghi

IGC Proceedings (1997-2023)

Reproduction and re-generation strategies, whether by sexual or asexual means, are important attributes of grazed plants. The Gramineae family is the main element of rangelands, grasslands and grassland ecosystems by virtue of their seed production and distribution mechanisms, and their tolerance of environment stresses (cold, heat, drought). Festuca ovina is a highly palatable and productive plant that has been recommended for drilling and sowing in the steppe and semi-steppe rangelands of Iran. The aim of this study, which was located in the Ghorkhoud region in North-east Iran, was to investigate the effects of different grazing intensities on reproduction of this …

Persistence Of Red Clover (Trifolium Pratense L.): Relationships Between Plant Population And Forage Yield, Fernando Ortega, Andrés Quiroz, Leonardo Parra, Juan Levío, Muriel Melo

IGC Proceedings (1997-2023)

Red clover (Trifolium pratense L.) is an important forage species in temperate regions of the world; in Chile, it is a valuable resource for animal production and for the seed industry. However, the main limitation of this species worldwide is the lack of persistence related to the high mortality of plants due to a complex of multiple biotic and abiotic factors (Ortega 1996; Taylor and Quesenberry 1996). Therefore, in 1989, a red clover breeding program was started at INIA Carillanca Research Center, Chile, with the main objectives of improving the survival of plants, forage yield and persistence. Since then, …

Temporal Variations In The Carbon And Nitrogen Ecological Stoichiometry Of Lucerne, Zhennan Wang, Huimin Yang, Yuying Shen

IGC Proceedings (1997-2023)

Ecological stoichiometry has been of great help in research investigating the coupling between plant and environment (Sterner and Elser 2002). It provides some synchronized evidence to explain the response and adaptability of plants to the environment. Carbon and nitrogen ecological stoichiometry (C/N) also embraces the use efficiency of nitrogen in plants. Previous research has focused on the spatial responses of plant C/N to different environmental factors (Yang and Wang 2011). However, there is still insufficient attention on the temporal variation in C/N, in the hope that such effort will help elucidate the mechanisms underlying plant growth/regrowth. Lucerne (Medicago sativa …

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 …

Grass Species Population Studies In Freshwater Pools Of Sivaganga District, South India With Different Land-Use, Dorai Pandian Kannan, Zachariah Miller Paul

IGC Proceedings (1997-2023)

Vernal pools are seasonal wetlands which fill with water in the rainy season and dry down in the spring and remain desiccated throughout the summer. These extreme conditions create a unique ecosystem that supports high species diversity (King et al. 1996). Ephemeral water pools have recently received more attention where studies have monitored the vegetation dynamics as the system shifts from an aquatic and terrestrial environment (Gopal and Junk 2000; Pott et al. 2010). Landscape changes are considered important on the biodiversity aggregation of meadows (Monterio et al. 2013). The present study was carried out to analyze …

Si Nanocrystal Synthesis Via Double Implantation And Variable Implantation, James M. Gaudet

Electronic Thesis and Dissertation Repository

Silicon (Si) nanocrystals (nc) precipitated from silicon-implanted silicon oxide (SiO₂) are of interest as a novel light source for illumination, biomedical applications, optical computing, etc. They have some advantages over conventional III-V compound semiconductor nanocrystals produced by colloidal synthesis. They are compatible with Si/SiO₂ based semiconductor processing, are stable, non-toxic at point of synthesis and consumption, and their luminescence falls with the infrared transmission window of biological materials. Unfortunately, synthesis of Si-nc embedded SiO₂ is uneconomical and is not as amenable to precise control of the size distribution of nanocrystals as is the case for III-V …

The Effect Of Exclosure Grazing On The Distribution Pattern Of Two Important Shrubs In The Central Steppe Of Iran, Anahita Rashtian

IGC Proceedings (1997-2023)

As part of a program to improve management of rangeands, research is being undertaken on the effects of grazing intensity on vegetation communities, including the response of different plant species to long-term exclosure from grazing. Species dispersion patterns can be used as valid indicators for condition assessment of rangeland ecosystems. Landsberg et al. (2002) and Riginos and Hoffman (2003) found that excessive grazing changed the structure and composition of plant communities, increasing the abundance of some species and reducing the presence of others. Heavy grazing leads to the excessive defoliation of herbaceous plants, reducing their biomass, basal cover and …

The Effect Of Exclosures On Poa Bulbosa And Determination Of Predation: A Case Study In The Nodoushan Rangelands, Central Steppe Of Iran, Anahita Rashtian

IGC Proceedings (1997-2023)

In order to undertake investigations leading to reclamation management for rangelands, information is needed on the effect of exclosures on the production and morphology of key species such as Poa bulbosa. This paper describes a comparison of some morphological and ecological characteristics of P. bulbosa when subjected to grazing or protected long-term with exclosures. The investigation was undertaken on the Nodoushan rangelands of Yazd Province, Iran.

Sward Structure Effects On Light Interception In Rotationally-Grazed Orchardgrass (Dactylis Glomerata L.), Glenn E. Shewmaker, Laura K. Hooper

IGC Proceedings (1997-2023)

Grazing managers need to know the relationship of sward height and mass to photosynthetic capacity. The aim of this study was to measure the interception of photosynthetically active radiation (PAR) and relate it to sward structure throughout the grazing season on rotationally-grazed orchardgrass/cocksfoot (Dactylis glomerata L.) pastures.

Functional Responses Of South African Rangelands In Contrasting Tenure Systems, Cristian A. Moreno García, Jürgen Schellberg, Frank Ewert, Anja Linstädter, Jan C. Ruppert, Susana B. Perelman

IGC Proceedings (1997-2023)

Land degradation in South African rangelands has frequently been studied in the context of tenure systems, because both governmental policy and range management practices were historically implemented in contrasting forms. We compared the functional response of vegetation along grazing gradients between a communal (CU) and commercial (CO) farming areas. One transect was established per farm from the waterpoint to a mid-field position. Six equally spaced plots (5 m × 5 m) were set up along each transect. Using a taxon-free sampling procedure, we recorded the response of 15 community-aggregated plant functional traits (CPFT) in: (1) mature standing biomass; and (2) …

Virtual Water Flows Embodied In International And Interprovincial Trade Of Yellow River Basin: A Multiregional Input-Output Analysis, Guilian Tian, Xiaosheng Han, Chen Zhang, Jiaojiao Li, Jinjing Liu

Information Systems and Analytics Department Faculty Journal Articles

With the imminent need of regional environmental protection and sustainable economic development, the concept of virtual water is widely used to solve the problem of regional water shortage. In this paper, nine provinces, namely Qinghai, Sichuan, Gansu, Ningxia, Inner Mongolia, Shaanxi, Shanxi, Henan, and Shandong in the Yellow River Basin (YRB), are taken as the research objects. Through the analysis of input-output tables of 30 provinces in China in 2012, the characteristics of virtual water trade in this region are estimated by using a multi-regional input-output (MRIO) model. The results show that: (1) The YRB had a net inflow of …

Exploration Of Factors Associated With Perceptions Of Community Safety Among Youth In Hillsborough County, Florida: A Convergent Parallel Mixed-Methods Approach, Yingwei Yang

USF Tampa Graduate Theses and Dissertations

Introduction: Youth perceived safety is not only linked to crime and violence in a neighborhood but is also associated with health risk behaviors and certain neighborhood characteristics. The purpose of this mixed-methods study was to measure the co-occurring effects of individual and community risk factors by conducting a secondary data analysis using structural equation modeling (SEM) and to explore reasons for youth feeling safe/unsafe in their community using photovoice methodology.

Methods: Syndemic theory/model served as the theoretical framework to guide this mixed-methods study with a convergent parallel design. The quantitative strand (first manuscript) utilized an existing dataset collected from middle …

Individual And Population Fitness Consequences Associated With Large Carnivore Use Of Residential Development, Heather Johnson, David L. Lewis, Stewart W. Breck

USDA Wildlife Services: Staff Publications

Large carnivores are negotiating increasingly developed landscapes, but little is known about how such behavioral plasticity influences their demographic rates and population trends. Some investigators have suggested that the ability of carnivores to behaviorally adapt to human development will enable their persistence, and yet, others have suggested that such landscapes are likely to serve as population sinks or ecological traps. To understand how plasticity in black bear (Ursus americanus) use of residential development influences their population dynamics, we conducted a 6-yr study near Durango, Colorado, USA. Using space-use data on individual bears, we examined the influence of use of residential …

Gj 1252 B: A 1.2 R⊕ Planet Transiting An M3 Dwarf At 20.4 Pc, A. Shporer, K. A. Collins, N. Astudillo-Defru, J. Irwin, X. Bonfils, K. I. Collins, E. Matthews, J. G. Winters, D. R. Anderson, J. D. Armstrong, D. Charbonneau, R. Cloutier, T. Daylan, T. Gan, M. N. Günther, C. Hellier, K. Horne, C. X. Huang, Eric L.N. Jensen, J. Kielkopf, E. Palle, R. Sefako, K. G. Stassun, T.-G. Tan, A. Vanderburg, G. R. Ricker, D. W. Latham, R. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, K. Colon, C. D. Dressing, S. Léepine, P. S. Muirhead, M. E. Rose, J. D. Twicken, J. N. Villasenor

Physics & Astronomy Faculty Works

We report the discovery of GJ 1252 b, a planet with a radius of 1.193 ± 0.074 _R⊕ and an orbital period of 0.52 days around an M3-type star (0.381 ± 0.019 _M⊕, 0.391 ± 0.020 _R⊕) located 20.385 ± 0.019 pc away. We use Transiting Exoplanet Survey Satellite (TESS) data, ground-based photometry and spectroscopy, Gaia astrometry, and high angular resolution imaging to show that the transit signal seen in the TESS data must originate from a transiting planet. We do so by ruling out all false-positive scenarios that attempt to explain the transit signal …

Enhanced Glucose Electrooxidation At Ni-Cu Binary Oxide Nanocatalyst, Yaser M. Asal Mr., Islam M. Al-Akraa Dr, Ahmad M. Mohammad Prof, Mahmoud M. Abuzaied Eng

Chemical Engineering

The aim of this study is to fabricate a nickel (NiOx) and copper (CuOx) oxide nanocatalyst on a glassy carbon (GC) electrode (will be abbreviated as Ni-Cu/GC) for glucose oxidation (GO). A sequential electrodepositon mode was applied to assemble NiOx and CuOx in the fabrication scheme. The optimization of Ni loading on the GC surface (will be abbreviated as Ni/GC electrode) was achieved first to attain the maximum catalytic efficiency in terms of the specific current toward GO. This (409 Ag^-1)was obtained by applying 15 mC/cm² in the deposition of Ni. However, unfortunately the NiOx/GC could not …

State Of Knowledge In Tiller Dynamics, Cory Matthew, Mónica G. Agnusdei, Silvia G. Assuero, André F. Sbrissia, Omar Scheneiter, Sila C. Da Silva

IGC Proceedings (1997-2023)

Persistence of sown pastures is a concern for pastoral production worldwide. Fundamentally, when a pasture does not persist the problem can be expressed in terms of inadequate new tiller production or excessive tiller death. However, the collection of data to build an understanding of sward dynamics at this level is time consuming. Tiller survival diagrams are presented for a range of temperate and tropical grass species including Lolium perenne, Lolium multiflorum, Festuca arundinacea, Festuca pratensis, Phleum pratense, Bromus willdenowii, Cynodon dactylon, Brachiaria brizantha, Panicum maximum, Chloris gayana and Paspalum notatum. …

Grazing Management Flexibility In Pastures Subjected To Rotational Stocking Management: Herbage Production And Chemical Composition Of Kikuyu-Grass Swards, André F. Sbrissia, Valéria P. B. Euclides, Rodrigo A. Barbosa, Denise B. Montagner, Deisy A. Padilha, Gabriela T. Santos, Guilherme D. Zanini, Paulo G. Duchini, Sila C. Da Silva

IGC Proceedings (1997-2023)

Several recent papers published on tropical pastures have pointed out that under rotational stocking management regrowth should be interrupted when canopy light interception is 95% (LI). Further, these studies have revealed a positive and high correlation between LI and sward height, allowing LI management targets to be defined in terms of sward height. However, there are some indications that lower pre-grazing heights relative to those targets would result in similar leaf accumulation without interfering with sward persistence. The objective of this paper was to verify a possible flexibility of such pre-grazing height targets. A replicated experiment was conducted with treatments …

Modelling Pinniped Abundance And Distribution By Combining Counts At T Terrestrial Sites And In-Water Sightings, Steven L. Whitlock, Jamie N. Womble, James T. Peterson

United States National Park Service: Publications

Pinnipeds are commonly monitored using aerial photographic surveys at land- or ice-based sites, where animals come ashore for resting, pupping, molting, and to avoid predators. Although these counts form the basis for monitoring population change over time, they do not provide information regarding where animals occur in the water, which is often of management and conservation interest. In this study, we developed a hierarchical model that links counts of pinnipeds at terrestrial sites to sightings-at-sea and estimates abundance, spatial distribution, and the proportion of time spent on land (attendance probability). The structure of the model also allows for the inclusion …

Tactical Themes For Rangeland Research, Kris M. Havstad, Deb P. C. Peters, Brandon T. Bestelmeyer, Dawn Browning, Jason W. Karl, Darren James, Scott Schrader

IGC Proceedings (1997-2023)

The problems threatening the conservation and management of rangeland, over one-half of the world’s terrestrial surfaces, are significant and growing. Current assessments of drivers and externalities shaping these problems have resulted in strategies intended to result in sustainable development of these lands and their resources. However, how can individual scientists and individual research programs support the needed strategies and goals? What can we realistically contribute and accomplish? We believe that technology can connect individual scientists and their science to the problems manifest in rangelands over the world, in a more rapid exchange than has occurred in the past. Recognition of …

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 …

Botanical Composition And Nutritive Value Of Grazing Lands From Organic And Conventional Agrosilvopastoral Production Systems Of Tropical Southeastern Mexico, Claudia Delgadillo Puga, José Bernardo Sánchez Muñoz, José Nahed-Toral, Miguel Ángel Orantes Zebadua, José Luis Cruz Lopez, Mario Cuchillo Hilario

IGC Proceedings (1997-2023)

In the current situation of agriculture, organic livestock farming has been not only adapted to ameliorate undesirable impacts on environment but also it is challenged to hold or improve agricultural yields obtain-ed by conventional agriculture. In the Mesoamerican biological corridor, a region recognized with an abundant diversity, almost all animal husbandry is based on extensive grazing and traditional agrosilvopastoral systems (Nahed-Toral et al. 2009; Nahed et al. 2010). Furthermore, the conversion of natural jungle areas to new farmland through deforestation is a prevalent problem for biological conservation. Therefore, precise knowledge for suitable agriculture and livestock product-ion are needed …

Performance Of Calves Receiving By-Products Of Oil Palm During The Dry Season In An Integrated Pasture-Forestry System In Pré-Amazonic Regions Of Brazil, Xerxes M. Tosta, Rosane C. Rodrigues, Maria Elizabeth Oliveira, Jose A. C. Junior, Ivan B. M. Sampaio

IGC Proceedings (1997-2023)

The integrated farming and livestock-forestry constitutes a viable alternative for the advancement of sustainable agriculture through its influence on social and ecological processes. Silvopastoral systems are integrated systems characterised by the management of animals in an agricultural-forestry association. These systems aim to provide shade for animals, stabilize forage production for meat production and/or milk products, forestry and various other environmental services (Maurício et al. 2010). Despite the benefits mentioned, the seasonality in the production of tropical forages needs to be considered. An efficient way to avoid losses in animal production in the dry season is with the use of …

Herbage Mass, Forage Accumulation And Nutritive Value Of Brachiaria Decumbens In A Silvopastoral System, Domingos S. C. Paciullo, Carlos A. M. Gomide, Carlos R. T. Castro, Carlos A. B. Carvalho, Rogério M. Maurício, Mirton J. F. Morenz

IGC Proceedings (1997-2023)

The use of silvopastoral systems has been suggested to ensure sustainability in animal production systems because of their potential to increase soil fertility, improve forage quality, promote animal thermal comfort and provide income diversification for the producer (Paciullo et al. 2011). Nevertheless, the shade provided by trees may affect plant growth and nutritive value of forage (Sousa et al. 2010).

This study aimed to assess the impact of shading on the allocation pattern of dry matter and on herbage nutritive value, under various shading regimes, in a silvopastoral system, during both the dry and rainy seasons.

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.

Animal Performance And Pasture Characteristics Of Brachiaria Decumbens Stapf., Gliricidia Sepium (Jacq.) Steud, And Mimosa Caesalpiniifolia Benth. In Silvipastoral Systems, Alexandre C. L. De Mello, Suellen Brandão De Miranda Costa, José C. B. Dubeux Jr., Mércia V. F. Dos Santos, Valéria Xavier De Oliveira Apolinário, Fernando Tenório Filho, Marcelo Santana Meireles, Camilla Gomes Pereira

IGC Proceedings (1997-2023)

Grasslands are the major source of feed for ruminants (Zanine 2005). Seasonality of production, however, is a constraint in forage-based systems. Silvopastoril systems combine different components (animals, trees, and forages) into one integrated system and may improve forage distribution across seasons. Resource use is usually more efficient both spatially and temporally, increasing land use efficiency (Nair 1993). Tree legumes present potential for silvopastoril systems because they can fix N from the atmosphere, improve cattle diet, and lead to a faster N cycle. In addition, trees provide shade and may reduce heat stress for grazing animals in warm-climate grasslands. Legume trees …

Effect Of Defoliation Frequency On Forage Yield From Intensive Silvopastoral Systems Compared To A Monoculture Grassland, L. Sarabia-Salgado, Francisco J. Solorio-Sánchez, Fernando Casanova-Lugo, Luis Ramírez-Avilés, Juan C. Ku-Vera, Jose A. Caamal-Maldonado

IGC Proceedings (1997-2023)

Livestock production in the tropical regions of the world faces serious constraints as a result of climate change. Monoculture based pastures require the use of large amounts of nitrogen fertilizers to sustain production throughout the year. In general terms, tropical grasses are of low quality and when consumed by ruminant species, contribute to the emission of greenhouse gases (methane, carbon dioxide and nitrous oxide) (Herrero et al. 2009; Place et al. 2009). The establishment of intensive silvopastoral systems (iSPS) with associated shrubs legumes and grasses can increase the yield and quality of forage as well as fixation and transfer of …