Agricultural Science Commons^™

A Chance-Constrained Linear Model For Beef Policy Analysis, Claudio F. Machado, S. T. Morris, C. Dake, A. Macdonald, I. M. Brookes, F. Di Croce, F. Gonzalez, N. J. Auza

IGC Proceedings (1977-2023)

A simple linear model to evaluate different bull beef policies (BBP) by incorporating the stochastic nature of pasture yield from a database with separate chance constraints (ChC) was developed. A 100 ha farm was used, and the model was run with five different BBP and set to different levels of pasture yield risk to maximise production.ha^-1.year^-1. Summer was the most risky season, and the optimum mix of policies changed at different levels of risk. Chance constraint represents an interesting and simple alternative to include pasture variation into a linear model.

Mapping Nitrogen Fixing Shrubs In Dry Unimproved Tussock Grassland, C. C. Boswell, W. L. Lowther, P. D. Espie

IGC Proceedings (1977-2023)

Global Positioning System (GPS) was used to both map the positions of individual nitrogen-fixing shrub plants and record individual plant height and breadth dimensions, within a small catchment of dry sub-humid unimproved short tussock grassland. The distributions of different species of shrubs varied with different landscape units within the catchment. The information will provide the base data for a first approximation of the role of the shrubs in the nitrogen balance of the ecosystem, which is pivotal to the sustainability of pastoral farming in the tussock grasslands.

Repeated Measurement Analyses Of Forages In Cropping Systems, A. R. De Freitas, O. Primavesi, L. De A. Corrêa, A. C. Primavesi, E. B. Pott, A. Dos S. Mascioli

IGC Proceedings (1977-2023)

Repeated measurements (RM) are common in forage experiments. The data used in this study were accumulated ammonia losses by volatilization (N) and dry matter production (DM) of Cynodon dactylon cv. Coastcross pasture from an experiment in blocks with five levels of urea: 0, 25, 50, 100 and 200 kg of N ha^-1, applied in five periods (cuttings). For N, RM were the averages of cuttings and nine days of observation. The F test for the hypothesis of no effect for Period and Level x Period interaction (DM) and for Days and Level x Days interaction was not affected …

Farmwi$E: A Flexible Decision Support Tool For Grazing Systems Management, A. D. Moore

IGC Proceedings (1977-2023)

CSIRO's new FarmWi$e decision support tool provides a framework that permits pasture-livestock systems and management policies of any level of complexity to be simulated. An underlying "modelling protocol" permits other simulation models to be added, further extending its domain of applicability. Management policies are specified in FarmWi$e by means of rules that govern when, whether and how management events take place. An example of the use of FarmWi$e to study lamb production is given.

Sward Height; Visual Estimate Compared With Plate Meter Height, W. B. Bryan, E. C. Prigge, E. L. Nestor, O. J. Gekara, M. A. Schettini

IGC Proceedings (1977-2023)

Sward height (SH) is widely used in pasture research and farm practice to evaluate pasture conditions. Visual estimates can take less time than actual measurements. This study compared visually estimated SH, of continuously grazed cool-season permanent pasture with plate meter height. Weekly estimates, by five people, were made on 12, 0.75 to 1 ha fields, grazed at two intensities. Paired data (visual estimate and plate meter height) were subjected to variance and covariance analyses and prediction equations were developed. Average visual height accounted for 86% of the variability in plate meter height. Inclusion of other sources of variability in the …

Sources Of Error For Ultrasonic Measurements Of Steer Compositional Traits In Grazing Studies, Glen E. Aiken, F. M. Rouquette Jr., A. H. Brown Jr.

IGC Proceedings (1977-2023)

Real-time ultrasound technology has potential use for measuring compositional traits in grazing studies. Sources of error with this application must be identified for designing experiments with adequate precision to determine treatment effects. A study was conducted to evaluate breed type (Angus x Brahman, AB; Simmental x [Angus x Brahman], SAB; Simmental x [Brahman x Hereford], SBH), initial body weight, and initial ultrasonic measures as sources of experimental error in the analyses of external fat (EF) depths and longissimus dorsi (ribeye) areas (LDA). Steers were ultrasonically scanned at the initiation and conclusion of a grazing study that examined stocking rate effects …

Grassland Management And Animal Product Quality, G. W. Sheath, J. B. Coulon, Q. A. Young

IGC Proceedings (1977-2023)

The expectations of consumers ultimately determine the specification of product quality; and grassland systems produce a wide range of animal-based products. Therefore, to provide focus, this paper deals only with food products that are destined for markets that exhibit strong discretionary choice. Quality expectations of consumers have traditionally been based on product attributes such as taste, freshness, nutritional value and appearance, but customer expectations are expanding to encompass food safety, environmental care, animal welfare and biotechnologies.

Grassland forages and their management influence the intrinsic sensory properties of food. A dairy products case study is presented, indicating that pasture species and …

Priority Setting And Funding Of Agricultural Research, M. Petit

IGC Proceedings (1977-2023)

Agricultural research funding amounts and modalities have been profoundly transformed in recent years in many countries. For instance, competitive funding has become the norm rather than the exception in most countries and funding sources have been greatly diversified. In addition, in some major countries, the private sector has become a major actor In agricultural research, both as a funder of research and as a provider research results. This poses a major challenge to public research institutions, which remain the major agricultural research actors and employers of researchers in most countries. With these changes in funding, formal procedures for research priority-setting …

The Last Continuous Grasslands On Earth: Identification And Conservation Importance, Rheinhardt Scholtz, Dirac L. Twidwell Jr

Department of Agronomy and Horticulture: Faculty Publications

Grasslands are the most threatened and least protected biome. Yet, no study has been conducted to identify the last remaining continuous grasslands on Earth. Here, we used World Wildlife Fund (WWF) and International Union for Conservation of Nature (IUCN) classifications to measure the degree of intactness remaining for the world's grassland ecoregions. This analysis revealed three findings of critical conservation importance. First, only a few large, intact grasslands remain. Second, every continent with a grassland ecoregion considered in this study contains at least one relatively intact grassland ecoregion. Third, the largest remaining continuous grasslands identified in this analysis have persisted …

Dilemma: Increase In Human Food Production Or Use Of Grasslands For Environmental And / Or Social Purposes, A. D. Meister

IGC Proceedings (1977-2023)

In the title for this paper we find three major objectives: to feed the world, sustain the environment and provide resources for social purposes, and a dilemma. Even though the word ‘dilemma’ usually implies choice between undesirable alternatives, it is obvious that the alternatives here are not undesirable. Is the dilemma then, that we can only do one at the time, or that the consequences of favouring one over the other can lead to undesirable outcomes? It is my opinion that we are talking about the latter interpretation. It is the foreclosing of options by allowing one objective to dominate …

The Development And Prospect Of Chinese Grassland Economic System, Fuzeng H.

IGC Proceedings (1977-2023)

China is a country with an old agriculture civilization of the world. The arrangement of the crop and pasture area had developed from Han and Tang dynasty. (From A.C 206.to AD 907). Chinese livestock economic had undergone the winding development for a thousand years of feudal society, however, It still belong to a phase of the loose private ownership. From 1949 when The People's Republic of China was founded, the pasture was nationalized and collective management. Since 1980s, the planned economic changed into the market economic gradually. The pasture was public ownership, but management by contract, paid utilization and unchanged …

Contextual Factors In The Management Of Common Grazing Lands: Lessons From Mongolia And Northwestern China, R. Mearns

IGC Proceedings (1977-2023)

Seen in a global perspective, pastoral development is now increasingly motivated by social and environmental objectives rather than by production- or output-orientated objectives. Attention is shifting towards a broader concern with sustainability, both of grasslands, and of the livelihoods of those who rely on them (de Haan et al, 1997, Fratkin and Mearns forthcoming). Quite how these twin sustainability objectives may be achieved in particular contexts, however, is an empirical question. Drawing on examples from a diverse range of natural grassland-based livestock production systems under economic transition in Mongolia and northwestern China, this summary paper aims to show how an …

De-Intensification Of Grasslands: Understanding The Processes To Find The Balance, K. C. Hodgkinson

IGC Proceedings (1977-2023)

There is a growing trend in Australia and other developed countries for deintensification of animal production from grasslands and for grasslands to be used for purposes other than livestock grazing. These shifts are occurring for a variety of reasons including unsustainable land management practices, environmental pollution, loss of conservation value, poor commodity prices and declining rural infra-structure and communities. In Australia, the shifts are under way in agricultural grasslands, where sown pastures occur in a matrix of semi-natural woodlands, but less so in the other three major natural grasslands that forms the arid and semi-arid rangelands.

The conversion of natural …

De-Intensification Of Grasslands: Current State And Trends, Michael Duru, Bernard Hubert

IGC Proceedings (1977-2023)

De-intensified use of grasslands, and more generally of the livestock systems they support, has been triggered by a growing sensitivity of citizens to environmental quality (nitrogen) and quality of animal products, and by the warnings addressed to political authorities by scientists about the environmental consequences of economic imbalances (decreasing biodiversity, drop in soil fertility, greenhouse effect), and in particular of food overproduction in Europe.

From an ecological standpoint, grassland de-intensification must be envisaged whenever the techniques implemented disrupt resource sustainability. The grassland resource itself may be at risk when a rate of vegetation offtake by herbivores that is incompatible with …

The Future Of The Big Sagebrush Ecosystem: Plant Community Response To Grazing, Wildfire, And Invasive Annual Grass In A Changing Climate, Margaret Eleanor England

Theses, Dissertations and Capstones

Climate change is increasingly affecting the plant communities across the world. In the Western United States, these changes are affecting plant communities and their risk of invasive species, as well as the frequency and severity of wildfire. Big sagebrush (Artemisia tridentata Nutt.) ecosystems of the Western United States are facing threats of increasingly frequent wildfire and invasion of the annual grass cheatgrass (Bromus tectorum L.), which may be exacerbated by global climate change. Past studies have found cheatgrass to exhibit a positive feedback loop with wildfire, and climate change is expected to facilitate expansion of the cheatgrass …

A Phytobacterial Tir Domain Effector Manipulates Nad+ To Promote Virulence, Samuel Eastman, Thomas Smith, Mark A. Zaydman, Panya Kim, Samuel Martinez, Neha Damaraju, Aaron Diantonio, Jeffrey Milbrandt, Thomas Clemente, James R. Alfano, Ming Guo

Department of Agronomy and Horticulture: Faculty Publications

The Pseudomonas syringae DC3000 type III effector HopAM1 suppresses plant immunity and contains a Toll/interleukin-1 receptor (TIR) domain homologous to immunity-related TIR domains of plant nucleotide-binding leucine-rich repeat receptors that hydrolyze nicotinamide adenine dinucleotide (NAD+) and activate immunity. In vitro and in vivo assays were conducted to determine if HopAM1 hydrolyzes NAD+ and if the activity is essential for HopAM1’s suppression of plant immunity and contribution to virulence. HPLC and LC-MS were utilized to analyze metabolites produced from NAD+ by HopAM1 in vitro and in both yeast and plants. Agrobacterium-mediated transient expression and in planta inoculation assays were performed to …

Reduced Chelate Strength Increases Iron Bioavailability For Monocots In Hydroponic Culture, Paul Kusuma, Bruce Bugbee

Hydroponics/Soilless Media

Hydroponically grown corn (Zea mays) is highly susceptible to Fe-chlorosis. Iron (Fe) is essential for chlorophyll synthesis. Metals bound to chelates have reduced bioavailability (activity) compared to free ions.

Predicting Munsell Color For Turfgrass Leaves, William L. Berndt, Roch E. Gaussoin

Department of Agronomy and Horticulture: Faculty Publications

Linking turfgrass color to hue, value, chroma (H V/C) in the Munsell Plant Tissue Color Book is a visual comparison process for specifying and communicating plant color. If subjectivity of visual comparison can be mitigated, then accuracy of color matching may be improved. Research was conducted to develop an algorithm predicting H V/C from CIE-xyY color (xyY) in digital images of leaves of four turfgrasses. First, value-chroma (V/C) arrays for Munsell hue groups 5Y, 2.5GY, 5GY, 7.5GY, 10GY, and 2.5G were converted to xyY. Next, chromaticity (xy) plots from each array were fitted with …

Effect Of Essential Oils In The Control Of Fungal Diseases In Small Grains, Esneider Mahecha Bojaca

Electronic Theses and Dissertations

Spring wheat (Triticum aestivum L.) and oats (Avena sativa L.) are important crops due to their high consumption in our daily diet worldwide. They are the main food of consumption per capita due to the high amino-acid content as well of vitamins. However, grain production is limited due to the negative impact of the diseases that cause significant yield loss. Diseases in oats, such as crown rust caused by Puccinia coronata f. sp. avenae (Pca), and in wheat such as Fusarium head blight (FHB) caused by the fungus Fusarium graminearum. Foliar diseases such as tan spot incited by the fungi …

Response Of Soil Biochemical And Physical Properties To Long Term Prairie Cordgrass And Kura Clover Intercropping System, Vaishnavi Varikuti

Electronic Theses and Dissertations

Prairie cordgrass (Spartina pectinata) (PCG) is a warm-season perennial grass that can be used as a biofuel feedstock and can be grown on marginal lands. Previous studies on intercropping of a perennial legume i.e., kura clover (Trifolium ambiguum) (KC) with PCG can improve soil biochemical properties, increase biomass production, mitigate greenhouse gas (GHG) emissions while reducing the chemical fertilizer requirement. However, there is a lack of evidence about the effects of PCG production on soil biochemical and physical properties during the cropping season and at deeper soil depths in reference to support plant growth, environmental implications and enhance the soil …

Southeast South Dakota Experiment Farm Annual Progress Report, 2022, Southeast South Dakota Research Farm

Agricultural Experiment Station and Research Farm Annual Reports

This is an annual report of the research program at the Southeast South Dakota Research Farm in cooperation with South Dakota Agricultural Experiment Station and the SDSU College of Agriculture, Food, and Environmental Sciences and has special significance for those engaged in agriculture and the agriculturally related businesses in the ten county area of Southeast South Dakota. The results shown are not necessarily complete or conclusive. Interpretations given are tentative because additional data resulting from continuation of these experiments may result in conclusions different from those based on any one year.

Garlic Curing: Post-Harvest Nutrient Remobilization From Leaves To Cloves, Mary L. Books

Graduate Theses/Dissertations

Garlic (Allium sativum L.) is grown on small and large scales worldwide. After harvesting, garlic undergoes a drying process for long-term preservation, called curing. Some producers cure with leaves intact, while others will remove and discard the leaves, curing only the bulbs. Due to the ability of plants to remobilize nutrients from leaves to underground storage organs, such as bulbs, the curing method of garlic may affect clove nutrient content. This study explores nutrient remobilization responses in garlic when cured with leaves intact compared to leaves separated from bulbs. Four cultivars of garlic, German White, Chesnok Red, Romanian Red, and …

Intercropping Grain Sorghum Into Established Rhizoma Peanut: Greenhouse And Field Studies, Erika Hm Cooperman

Graduate Theses/Dissertations

Land degradation and urbanization are among the top factors pushing the Kenyan Maasai community into an unstable future, with food insecurity and poverty amidst the most fragile components. Implementing conservation agricultural techniques into the Maasai nomadic lifestyle could potentially lead to a diversification of finances and food security. Intercropping is one technique of conservation agriculture that could provide the Maasai both. The main objective of this study is to evaluate the effects of creating an intercropped environment between rhizoma peanut and grain sorghum. A greenhouse study was conducted from late 2020 to 2021 in an effort to investigate the effects …

Biochar: Properties And Potential Benefits For Agricultural Soil In Rwanda, Andromede Uwase

Honors Program: Senior Projects (Public)

Physical and chemical soil degradation is becoming a major challenge for agricultural productivity in Rwanda, which is the most important part of the country’s economy. The wide spreading soil degradation in Rwanda is mainly a result of naturally poor soils coupled with unsustainable soil management leading to, for example, accelerated soil erosion, acidification, nutrient loss, compaction, and to decreasing yields. Biochar, as an end product of pyrolysis of biomass in the absence of oxygen, has been proposed as a soil amendment in remediation strategies because of its positive effects on soil productivity relevant parameters such as soil pH, structure, nutrient …

Effects Of Conservation Management Practices On Soil Health And Crop Yields In Eastern South Dakota, Alex Mclain

Electronic Theses and Dissertations

Conservation management practice adoption on agricultural land has increased in recent years due to increasing public and private investment. The anticipated impact of increasing conservation management practice adoption are reduced greenhouse gas emissions and improved soil, water, and air quality. Understanding how these conservation management practices affect agricultural producers economically is vital to properly incentivize these practices. The existing literature on how conservation management practices affect soil health and crop yields is mixed and generally has been conducted on experimental research stations. These studies may not fully account for the on-farm effects of conservation management practices. The objectives of this …

Field Validation Of A Farmer Supplied Data Approach To Close Soybean Yield Gaps In The Us North Central Region, José F. Andrade, Spyridon Mourtzinis, Juan I. Rattalino Edreira, Shawn P. Conley, John Gaska, Herman J. Kandel, Laura E. Lindsey, Seth Naeve, Scott Nelson, Maninder P. Singhi, Laura J. Thompson, James E. Specht, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

CONTEXT: Producer-reported data can be used to identify suites of management practices that lead to higher yield and profit. However, a rigorous validation of the approach in relation to its potential impact on farmer yield and profit is lacking.

OBJECTIVE: This study aimed to validate a producer-data approach on its capability to guide on-farm evaluation of management practices with greatest potential for increasing producer yield and profit. We show proof of concept using soybean in the North Central US region as a case study.

METHODS: We used a combination of regression tree analysis and a spatial framework to determine practices …

Ecological Intensification With Soil Health Practices Demonstrates Positive Impacts On Multiple Soil Properties: A Large-Scale Farmer-Led Experiment, Fernanda Souza Krupek, Daren D. Redfearn, Kent M. Eskridge, Andrea Basche

Department of Agronomy and Horticulture: Faculty Publications

Improving soil health is critical to reversing trends of soil degradation and is of increasing interest to a range of stakeholders including policymakers, agricultural industry leaders, food companies, and farmers. Crop and soil management practices focused on ecological functions can be effective in restoring fundamental biological, chemical and physical soil properties. The call for ecological intensification of agricultural systems has the potential to improve soil health and input-use efficiency. In this study, we developed a framework to classify spatial and temporal ecological intensification with soil health practices: tillage, crop rotation, cover crop, organic amendment, and crop-livestock integration. We applied this …

Phosphorus Use And Management Based On Fertilizer Placement, Rate Of Application, And Soil Biota In No-Till Situations, Brennan Alexander Bingham Lewis

Electronic Theses and Dissertations

Phosphorus (P) pollution has become a concern among multiple scientific organizations as it leads to eutrophication, an algal bloom that depletes lacustrine and marine ecosystems of native species. Multiple strategies can be implemented to reduce phosphorus loss from agriculture fields, which is often implicated as a cause of eutrophication. Soil phosphorus chemistry results in phosphate fertilizers absorbing to clay minerals over time. Soil phosphorus is lost from agricultural fields primarily through wind and water erosion. No-till practices prevent soil erosion, which reduces the phosphorus from loading into waterways. Fertilizer placement affects phosphorus loss. Surface application of phosphorus fertilizers increases the …

Getting To The Root Cause: The Genetic Underpinnings Of Root System Architecture And Rhizodeposition In Sorghum, Farren Smith

Graduate Theses, Dissertations, and Problem Reports (ETD)

Plants are some of the most diverse organisms on earth, consisting of more than 350,000 different species. To understand the underlying processes that contributed to plant diversification, it is fundamental to identify the genetic and genomic components that facilitated various adaptations over evolutionary history. Most studies to date have focused on the underlying controls of above-ground traits such as grain and vegetation; however, little is known about the “hidden half” of plants. Root systems comprise half of the total plant structure and provide vital functions such as anchorage, resource acquisition, and storage of energy reserves. The execution of these key …

"Demeter" Soil Monitoring System, Ryan Matthews, Rachel Rummer, Temilolu Fayomi, Alex Fuller

Williams Honors College, Honors Research Projects

The purpose of this project is to develop a soil monitoring system that can remotely sense and relay soil conditions back to a user. The deMETER soil probe, Demeter is the Greek goddess of the harvest, is designed to aid hobbyist gardeners, small-scale farms, and nurseries to monitor their dynamic soil conditions and maximize their harvest. The probe is a self-powered system that can monitor the moisture and essential nutrients of the soil profile to determine which areas should receive water and fertilizer. This would significantly cut water and fertilizer waste. The solution will include an embedded system with sensors …