Physical Sciences and Mathematics Commons^™

Rhizobial And Nutritional Responses Of Desmanthus Clay Soils Of Queensland, N J. Brandon, R A. Date, R M. Jones, R L. Clem, G A. Bahnisch, P R. Spies, A Becerra, B A. Robertson, T.W G. Graham

IGC Proceedings (1993-2023)

The objective of these studies was to determine the reasons for chlorosis of desmanthus observed at some sites in southeast Queensland. Inoculation with Rhizobium increased growth of desmanthus in 2 of 4 soils in the field and 4 of 8 soils in pots. Greatest responses occurred in soils with few or no effective native Rhizobium. Most soils however, contained native strains that were effective. Omission of sulphur significantly reduced dry weight of desmanthus grown in pots in 5 of 7 soils by 30-51% relative to plants supplied with all nutrients. Omission of P and Mo resulted in similar yield reductions …

Biological Nitrogen Fixation In A Grass-Clover Pasture Grazed By Dairy Cows, F P. Vinther, K Søegaard, O Aaes

IGC Proceedings (1993-2023)

The objective of this study was to estimate the annual input of nitrogen through biological nitrogen fixation (BNF) to a grass-clover pasture (Lolium perenne L. - Trifolium repens L.) grazed by dairy cows. The input was estimated by combining measurements of BNF in non-grazed plots, BNF in urine affected plots and estimates of the proportion of the pasture affected by urine. Total BNF in non-grazed plot was 75 and 256 kg N ha-1 in 1994 and 1995, respectively. Urine affected BNF both by decreasing the proportion of clover and by decreasing the proportion of N derived from the atmosphere. The …

Phosphorus Requirements In Legumes: Calibration Of A Rapid And Simple Tissue Test, A Moron

IGC Proceedings (1993-2023)

The objective of this research was to adjust and calibrate a phosphorus (P) tissue test to diagnose in a simple and rapid manner the nutritional status of commonly used legumes in Uruguay. Field experiments conducted during 1993-94 with four legumes, showed a significant yield response to increasing P fertilizer rates. A colorimetric sap analysis was used to determine P status in legumes. A strong relationship was found between P sap analysis and relative yields. A critical level of 90-100 μg P/ml in sap to attain 90% of the maximum yield was obtained.

Evaluation Of Different Nitrogen Sources On The Production And Chemical Properties Of C4-Sub-Tropic Pastures, J F. Reckling, G.H J. Kruger

IGC Proceedings (1993-2023)

Digitaria eriantha fertilised with limestone ammonium nitrate (LAN 28 % N), although not statistically significant, resulted in higher dry matter production in comparison to those plants fertilised with urea (U 46% N). Significant lower (P<0.05) soil calcium levels were found in plots fertilised with LAN. Plants fertilised with urea had double the amount of Aspartic and Glutamic acid, indicating that urea did not convert to NO3 -, but was taken up as ammonium.

Effect Of Nitrogen And Potash Fertilization On Dry Matter Yield And Mineral Composition Of Pangolagrass, J B. Andrade, C L. Justo, J.L. V. Coutinho, R M. Peres, E Ferrari Junior, V T. Paulino, W Henrique, J C. Werner, H B. Mattos

IGC Proceedings (1993-2023)

The effect of nitrogen and potash fertilizations on dry matter and protein yields and chemical composition of pangolagrass (D. decumbens Stent.) was studied in a randomized block design with four replications using a 2 x 2 factorial arrangement. Nitrogen and potash were applied after each cut as an equivalent to 3 and 2% of dry matter (65°C) yield, respectively. There were great increases in dry matter and protein yields when nitrogen alone or combined with potash was used. Potash fertilization alone had no effect on the variables described above. Nitrogen fertilization improved forage pangolagrass composition, being particularly effective on crude …

Nitrogen In Stubble As A Limiting Factor Of Regrowth And Yield Of Orchardgrass After Cutting, T Matsunaka, T Ishii, M Jin

IGC Proceedings (1993-2023)

Two field trials were carried out to reexamine the role of total nonstructural carbohydrates (TNC) and nitrogen (N) of the stubble in regrowth of orchardgrass (Dactylis Glomerata L.) during 10 days after cutting and the yield of next cutting. The regrowth and the yield were independent of TNC content in the stubble. They increased with N content in the stubble derived from the different rate of previous N application. When the TNC content in the stubble at the time of cutting was more than about 18% (dry matter basis), the regrowth even in a darkroom was not affected by …

Effect Of Nitrogen Fertilization Upon Spring Growth In Thinopyrum Poticum In Alkaline Soils. Argentina, R Fernandez Grecco, A Sciotti, A Mazzanti, H Echeverria

IGC Proceedings (1993-2023)

Wheatgrass is a perennial forage grass adapted to low fertility alkaline soils in the Flooding pampa. It has an annual forage growth cycle characterised by a high spring-summer concentration and low values in winter. The objective of this study was to assess that it is possible to anticipate and increase forage growth and DM production of wheatgrass pastures applying nitrogen fertilization. The experiment was carried out at the Balcarce Experimental Station from 28/08/95 to 04/12/95. Using a completely randomized block design the effects of 6 levels of N: 0, 50, 100, 150, 200 and 250 kg Nha-1, added as NO3 …

Effect Of Nitrogen Fertilization Upon Winter Growth In Natural Pastures Of The South East Of Buenos Aires Province, Argentina, R C. Fernandez Grecco, A E. Mazzanti, H A. Echeverria

IGC Proceedings (1993-2023)

The effect of winter nitrogen fertilization upon herbage accumulation during the winter-spring period on a natural pasture of the Flooding Pampa dominated by cool season annual (Lolium multiflorum) and perennial (Stipa neesiana) grasses was evaluated. The experiment was carried out from August to November in 1994 and 1995. Fertilization treatments were: 0, 50, 100, 150, 200 and 250 kgN ha- 1 (N0, N50, N100, N150, N200 and N250, respectively). The experimental plots were set out in three randomized blocks. In 1994, maximum forage accumulation was reached at N150, and no significant differences were found among N150, …

Effectivity Of Arbuscular Mycorrhizas In Sustainable Grassland Agriculture Following Conversion From Intensive Management, W R. Eason, J Scullion, E P. Scott

IGC Proceedings (1993-2023)

With increased interest in sustainable agriculture, attention has focused on the role of arbuscular mycorrhiza (AM) in the productivity of agricultural systems. AM spores were taken from grassland and grass-arable systems with either a history of high-input, conventional, or low-input, organic management, and used as a source of inoculum in host plants (Allium amelioprasum, Trifolium repens and Lolium perenne). Spores from organic management systems produced a greater yield response than those from conventional systems. Where various spore inoculum produced differences in host growth responses, it was observed that the infected root of these host plants also produced similar …

Buffelgrass Forage And Seed Production Responses To N And Fertilization, W R. Ocumpaugh, M A. Hussey, B L. Burson

IGC Proceedings (1993-2023)

Forage and seed production responses to nitrogen (N) and phosphorus (P) fertilizer of Common buffelgrass (Cenchrus ciliaris L.) were evaluated for three years (1991-93). An incomplete factorial set of five rates of N and P were applied each year. Seed data were collected by hand stripping mature seed followed by a forage harvest. Seed quality characteristics were determined on each seed sample. No response to N fertilizer was observed in 1991 nor to P in any year. In 1992, there was a linear forage yield response to N fertilizer. In 1993, both the linear and quadratic effects of N …

Grassland Management In Central Area Of The Masurian Landscape Park, K Mlynarczyk, E Marks, E Korona

IGC Proceedings (1993-2023)

Permanent grassland occupy some 12% of the area of the Masurian Landscape Park. The Cirsio-Polygonetum plant association was distinguished on the semi-natural meadows situated on the peat-marsh soil. Changes in botanical composition of the meadow sward and the productivity of DM, against a background of different mineral fertilization, were examined in a medium-scale plot experiment. It was concluded that both aspects ofutilization must be accorded high priority in the case of extensively managed meadows: medium level of forage production and the landscape conservation.

Reserving Pastures In Communal Grasslands By Agropastoralists Of Tanzania, M L. Kusekwa, A J. Mwilawa, J.K K. Msechu

IGC Proceedings (1993-2023)

Studies were conducted in “Maasai” and “Gogo” tribal communities to gain understanding of traditional management of reserved pastures. Survey techniques were used and forage production and chemical composition were estimated. Household heads were invariably old men who had no formal education. Household size averaged 14 and 11, in Maasai and Gogo tribes respectively. Most reserved pastures were privately owned. Over 90% of pastoralists preferred individual ownership of reserved grazing. Herbage production was 2510 kg DM/ha in Maasai and 3680 kg DM/ha in Gogo locations. Pastures and low protein content (5.1-6.5% CP). Constraints to reserve grazing strategies were land and water …

Impact Of Extensive Management On Demography Of One Invasive Species Of Permanent Grasslands, D Magda

IGC Proceedings (1993-2023)

The objective of this study is to show the effect of extensive practices on the population dynamics of a grassland species (Chaerophyllum aureum) in order to control invasion process. Fertilisation intensity (none or 45g/m2), number (none, one or two) and date of cutting (before or after seed maturity) have been experienced on permanent plots in fields to follow consequences on demography of adults and seedlings. Adult density is regulated through cutting effect and intraspecific competition process. Reduction of competition by cutting leads to a paradoxal highest adult survival rate in on cut treatment compared with abandoned invaded fields. …

Influence Of Drying Method And Temperature On Ruminal Degradable Protein Of Switchgrass, D E. Farnham, K J. Moore, J R. George

IGC Proceedings (1993-2023)

The nutritional value of herbage protein fed to ruminant livestock can be influenced greatly by the extent to which it is degraded in the rumen. This study was conducted to determine if drying method and temperature alters measurements of in situ ruminal escape protein (EP) of switchgrass herbage. Switchgrass harvested at the pre-heading stage was either air dried, freeze dried, or oven dried at 38, 49, 60, or 710 C. Samples from each of the six drying treatments were digested in situ in Dacron bags for 4, 8, 12, or 16 h. Drying treatment had a significant impact on EP …

Development Of Natural Horse Pastures In Finland In The 1900s, H Jansson, K H. Jansson, A Olin, T Talikka, J Pykala

IGC Proceedings (1993-2023)

The purpose of the study was to assess the importance of natural pastures as a growing environment for horses and, at the same time, to evaluate the landscape value of such pastures. Another aim was to look at possible ways of conserving areas which have been in use as horse pastures for a long period of time as traditional biotopes belonging to the Finnish horse grazing culture, and to examine how their management and care could be improved.

Relationship Of Soil To Native Pasture In A Flooding Pampa Area (Argentine), S P. Debelis, A A. Bozzo, A Bujan, M B. Barrios

IGC Proceedings (1993-2023)

The influence of the topography in soils found in the area surrounding the Chascomús lagoon is examined. The study of the profiles within the representative transect in each microenvironment reveals changes related to its traits. Its relationship with the vegetation present in each toposequence position was observed. The worsening of the natural drainage conditions, are related to reduction of organic matter, increase in the values of pH and PSI, greater intensity of hydromorphic traces and appearance of groups of characteristic species.

Extensification Of Sheep Grazing Systems: Effects On Soil Nutrients, Species Composition And Animal Production, C A. Marriott, I J. Gordon

IGC Proceedings (1993-2023)

The effects of ceasing fertiliser inputs to perennial ryegrass/white clover swards, combined with patterns of seasonal grazing, on soil nutrient status, floristic composition and animal production (ewes and single lambs) were studied in a long-term experiment at three upland sites in Scotland. Four unfertilised treatments had a factorial combination of seasonal grazing in summer and autumn at two sward heights (4 and 8 cm). There was also an ungrazed, unfertilised control and a fertilised treatment (140 kg N/ha plus maintenance P and K), grazed at 4 cm sward height in both seasons. All treatments were imposed annually from 1990/91. By …

Grassland Management For Geese: Sustainable Use For Conservation And Agriculture, S M. Percival, R Lilley

IGC Proceedings (1993-2023)

Increasing numbers of overwintering wild geese have caused considerable problems to agriculture but are often also of conservation concern as their populations are relatively small. Islay, Scotland, is one site where this problem is particularly acute. We studied the two goose species which use this site, the barnacle goose, Branta leucopsis, and the white-fronted goose, Anser albifrons flavirostris, and found that they preferred younger pastures located closer to their roost sites. These preferred areas could be important in developing a sustainable strategy for future goose management. Further non-sustainable population increases might be avoided by increasing disturbance in these areas.

Supplementary Files For: "Interactive Modeling Of Bear Lake Elevations In A Future Climate", Benjamin D. Shaw, Scout Jarman, Brennan Bean, Kevin R. Moon, Wei Zhang, Nathan Butler, Tommy Bolton, April Knight, Emeline Haroldsen, Abby Funk, Rebecca Higbee

Browse all Datasets

The water level, or elevation, of Bear Lake has a significant impact on agriculture, power, infrastructure, and recreation for communities around the lake. Climatological variables, such as precipitation, temperature, and snowfall, all have an impact on the elevation of Bear Lake. As the climate changes due to greenhouse gas emissions, the typical behaviors of these climate variables change, leading to new behaviors in Bear Lake elevation. Because of the importance of Bear Lake, it is vital to be able to model and understand how Bear Lake's elevation may change in the face of different climate scenarios and to gain further …

Plas 439: Organic Farming And Food Systems Faculty-Led Inquiry Into Reflective Scholarly Teaching Benchmark Portfolio, Christian Stephenson

UNL Faculty Course Portfolios

Organic Farming and Food Systems is a senior and graduate level course for students in the Department of Agronomy and Horticulture. This course was previously offered but has been significantly modified as I have taken on responsibility for the course. Goals for the course include student comprehension of the methods of organic and regenerative farming and the impacts of those methods on economic, environmental, and social sustainability. An additional goal is to build student competency in the evaluation of primary, secondary, and tertiary information resources and critical thinking surrounding issues in food production. Assessment for the course was through diverse …

Assessing The Use Of Regenerative Agriculture In California Almonds As Climate Change Resilience, Skyler M. Seamons

Master's Projects and Capstones

The agriculture sector is responsible for 10% of the United States’ greenhouse gas emissions. In turn, anthropogenic climate change threatens crops. With its Mediterranean climate, California is the country’s largest agricultural-producing state. Many California crops are at risk due to increasing temperatures and changed precipitation patterns. This paper investigates regenerative farming techniques as a tool to protect California crops from a changing climate. Almonds are used as a case study to analyze the soil management practices, finances, and policies underlying regenerative agriculture in California. A literature review and comparative analysis are used to compare regenerative and conventional soil management practices …

From Pixels To Plants: Remote Sensing Of California Invasive Plants, Kenneth Rangel

Master's Projects and Capstones

Invasive plants cause significant impacts to ecosystems, the economy, and human health. California has experienced significant plant invasions and is well suited to future invasion because of its Mediterranean climate and human disturbance. Eradication or control of invasive plant species requires a detailed understanding of their spatial distribution, which typically involves on the ground surveys that can be expensive or inconsistent. Remote sensing offers a potential alternative or supplement to in-person invasive plant mapping. This study performed a comparative analysis of 41 remote sensing studies that mapped the distribution of California invasive plants. I found that while high spectral resolution …

Reaction-Diffusions System Simulated On Irregular Shapes And Surfaces Model Petal Spot Patterns In Monkeyflower Hybrids, Emily Simmons, Arielle M. Cooley, Joshua R. Puzey, Gregory D. Conradi Smith

Biology and Medicine Through Mathematics Conference

No abstract provided.

Agroecology And Soil Stewardship: Values And Techniques Of Smallholder Farmers In Bernalillo County, Stephanie Olivas

Geography ETDs

Agrarian movements around the world use agroecology to build sovereignty and steward dynamic ecosystems. Research has shown that agroecological farmers steward more resilient crops, more resilient soil biomes, and greater biodiversity than conventional agriculture. GIS and remote sensing offer many tools to detect the impacts of these farmers on the environment, but it is less clear how such technologies fit into agroecological goals. This study asks: what values, experiences and knowledge do smallholder producers in Bernalillo County embody in their soil stewardship practices? Also, what experience or knowledge do smallholder producers in Bernalillo County have about remote sensing, and would …

And Food Justice For All: Advancing Access To Just And Sustainable Food Systems, Makenna Grace Landry

Graduate Student Portfolios, Professional Papers, and Capstone Projects

A collection of work exploring food justice and food access programming in Western Montana, as well as a critique of the Bayer-Monsanto merger.

Techniques And Trials In Pteridophyte Conservation And Cultivation, Jessica Bartel

Senior Theses and Projects

With the progressive nature of climate change conditions globally over the past century, there has been increasing focus on conservation of all species, but particularly those already endangered. Over 12,000 species of ferns live on Earth, and they do not produce seeds, so an investigation into their spores and how they reach maturity will allow us to preserve more genetic material in the future for these species. As a result, we investigated ex situ conservation and survivability of in vitro cultured gametophytes of within the genus Dryopteridaceae through herbarium sample germination rates across samples representing a wide age range ( …

Public Horticulture: Process And Design Of The Lincoln Botanical Garden, Brad Kindler

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Beginning in 2012, the local non-profit, The Lincoln Botanical Garden, began organizing the conceptual design and creation of a glass conservatory within a botanical garden in Lincoln, Nebraska. These proposed urban enhancements seek to fill a gap in garden amenities in the city by providing year-round access to public horticulture programming and education.

This project, Public Horticulture: Process and Design of the Lincoln Botanical Garden, documents these efforts and makes design recommendations for a themed Glacial Erratic Garden that could be constructed within the botanical garden.

Advisors: Ellen Paparozzi and Sam Wortman

Next-Generation Crop Monitoring Technologies: Case Studies About Edge Image Processing For Crop Monitoring And Soil Water Property Modeling Via Above-Ground Sensors, Nipuna Chamara

Dissertations and Doctoral Documents from University of Nebraska-Lincoln, 2023–

Artificial Intelligence (AI) has advanced rapidly in the past two decades. Internet of Things (IoT) technology has advanced rapidly during the last decade. Merging these two technologies has immense potential in several industries, including agriculture.

We have identified several research gaps in utilizing IoT technology in agriculture. One problem was the digital divide between rural, unconnected, or limited connected areas and urban areas for utilizing images for decision-making, which has advanced with the growth of AI. Another area for improvement was the farmers' demotivation to use in-situ soil moisture sensors for irrigation decision-making due to inherited installation difficulties. As Nebraska …

Soil Reclamation Strategies In Construction Disturbed Soil, Alexis Koelling

All Graduate Reports and Creative Projects, Fall 2023 to Present

The rapid urbanization occurring in arid environments like the Intermountain West region of the U.S. significantly alters soil conditions. Construction of roads, buildings, and other infrastructure leads to the disturbance of soil structure, nutrient depletion, and reduced fertility. This research addresses the need for sustainable soil management practices that may restore soil health post-construction. In this study, the effectiveness of various soil amendments and application methods on specific soil parameters and turfgrass establishment in construction-disturbed soils was evaluated. The study highlights the critical role of soil amendments, particularly municipal solid waste (MSW) compost, in improving soil quality and plant growth. …

Sustainable Fertilizer Management Practices For Container Nursery Production, Saroj Burlakoti

All Graduate Theses and Dissertations, Fall 2023 to Present

Growing nursery plants in containers requires a timely supply of mineral nutrients for optimum growth. However, there is a misconception among growers that the application of higher doses of fertilizers hastens plant growth; instead, it can lead to runoff and leaching loss of nutrients. Reducing fertilizer application while sustaining healthy plants can not only negate environmental consequences but also save fertilizer costs. For example, two ground covers, Lysimachia nummularia (creeping jenny, moneywort) and Vinca minor 'Bowles' (periwinkle), can be grown for three months by applying 6 mg/L of phosphorus (P) as reduction of P to single application of 6 mg/L …