Plant Sciences Commons^™

Temporal Changes In The Nutrient Content Of Cattle Dung In The Nebraska Sandhills Ecosystem, Amanda Shine, Martha Mamo, Gandura O. Abagandura, Walter Schacht, Jerry Volesky

Department of Agronomy and Horticulture: Faculty Publications

Dung excreted by cattle composes a significant portion of the nutrient inputs in a grazed ecosystem and can have wide-ranging effects on soil properties and vegetation. However, little research has been conducted on the nutrient dynamics of excreted dung in situ that has not been disturbed prior to field sampling. In this study, we analyzed 294 dung pats (1–24 days old) collected from a Nebraska Sandhills meadow to determine water-extractable organic carbon (WEOC), water-extractable nitrogen (WEN), water-extractable phosphorus (WEP), and percent dry matter (DM) changes over time. In addition, we investigated if sample handling - frozen storage – and the …

A Method For Visualizing Water Flow Through Modified Root Zones, Dallas M. Williams

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

As the number of impervious surfaces in urban environments increases, the ability of modified root zones to infiltrate water is becoming more important. Current methods of tracing water flow through soil profiles include excavating large pits in situ or analyzing soil cores in the laboratory with computed tomography or magnetic resonance imaging. While useful, these methods may not be suitable for urban settings or practical in every laboratory. We propose a new method that is less invasive, does not require extensive technical equipment and can reliably trace water movement through the soil profile in order to calculate flow rate based …

Statistical And Machine Learning Methods Evaluated For Incorporating Soil And Weather Into Corn Nitrogen Recommendations, Curtis J. Ransom, Newell R. Kitchen, James J. Camberato, Paul R. Carter, Richard B. Ferguson, Fabian G. Fernandez, David W. Franzen, Carrie A. M. Laboski, D. Brenton Myers, Emerson D. Nafziger, John E. Sawyer, John F. Shanahan

Department of Agronomy and Horticulture: Faculty Publications

Nitrogen (N) fertilizer recommendation tools could be improved for estimating corn (Zea mays L.) N needs by incorporating site-specific soil and weather information. However, an evaluation of analytical methods is needed to determine the success of incorporating this information. The objectives of this research were to evaluate statistical and machine learning (ML) algorithms for utilizing soil and weather information for improving corn N recommendation tools. Eight algorithms [stepwise, ridge regression, least absolute shrinkage and selection operator (Lasso), elastic net regression, principal component regression (PCR), partial least squares regression (PLSR), decision tree, and random forest] were evaluated using a dataset …

Tetracycline And Sulfonamide Antibiotic Resistance Genes In Soils From Nebraska Organic Farming Operations, Marylynn Cadena, Lisa M. Durso, Daniel N. Miller, Heidi M. Waldrip, B. L. Castleberry, Rhae A. Drijber, Charles S. Wortmann

Department of Agronomy and Horticulture: Faculty Publications

There is widespread agreement that agricultural antibiotic resistance should be reduced, however, it is unclear from the available literature what an appropriate target for reduction would be. Organic farms provide a unique opportunity to disentangle questions of agricultural antibiotic drug use from questions of antibiotic resistance in the soil. In this study, soil was collected from 12 certified organic farms in Nebraska, evaluated for the presence of tetracycline and sulfonamide resistance genes (n = 15 targets), and correlated to soil physical, chemical, and biological parameters. Tetracycline and sulfonamide antibiotic resistance genes (ARGs) were found in soils from all 12 …

Isolation And Analysis Of Microbial Communities In Soil, Rhizosphere, And Roots In Perennial Grass Experiments, Morgan R. Mcpherson, Peng Wang, Robert B. Mitchell, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Plant and soil microbiome studies are becoming increasingly important for understanding the roles microorganisms play in agricultural productivity. The purpose of this manuscript is to provide detail on how to rapidly sample soil, rhizosphere, and endosphere of replicated field trials and analyze changes that may occur in the microbial communities due to sample type, treatment, and plant genotype. The experiment used to demonstrate these methods consists of replicated field plots containing two, pure, warm-season grasses (Panicum virgatum and Andropogon gerardii) and a low-diversity grass mixture (A. gerardii, Sorghastrum nutans, and Bouteloua curtipendula). Briefly, plants …

Maize Genomes To Fields: 2014 And 2015 Field Season Genotype, Phenotype, Environment, And Inbred Ear Image Datasets, Naser Alkhalifah, Darwin A. Campbell, Celeste M. Falcon, Jack M. Gardiner, Nathan D. Miller, Maria Cinta Romay, Ramona Walls, Renee Walton, Cheng-Ting Yeh, Martin Bohn, Jessica Bubert, Edward S. Buckler, Ignacio Ciampitti, Sherry Flint-Garcia, Michael A. Gore, Christopher Graham, Candice Hirsch, James B. Holland, David Hooker, Shawn Kaeppler, Joseph Knoll, Nick Lauter, Elizabeth C. Lee, Aaron Lorenz, Jonathan P. Lynch, Stephen P. Moose, Seth C. Murray, Rebecca Nelson, Torbert Rocheford, Oscar Rodriguez, James C. Schnable, Brian Scully, Margaret Smith, Nathan Springer, Peter Thomison, Mitchell Tuinstra, Randall J. Wisser, Wenwei Xu, David Ertl, Patrick S. Schnable, Natalia De Leon, Edgar P. Spalding, Jode Edwards, Carolyn J. Lawrence-Dill

Department of Agronomy and Horticulture: Faculty Publications

Objectives: Crop improvement relies on analysis of phenotypic, genotypic, and environmental data. Given large, well-integrated, multi-year datasets, diverse queries can be made: Which lines perform best in hot, dry environments? Which alleles of specific genes are required for optimal performance in each environment? Such datasets also can be leveraged to predict cultivar performance, even in uncharacterized environments. The maize Genomes to Fields (G2F) Initiative is a multi-institutional organization of scientists working to generate and analyze such datasets from existing, publicly available inbred lines and hybrids. G2F’s genotype by environment project has released 2014 and 2015 datasets to the public, with …

Assessing Explanatory Factors For Variation In On-Farm Irrigation In Us Maize-Soybean Systems, Katherine E.B. Gibson, Haishun S. Yang, Trenton E. Franz, Dean E. Eisenhauer, John B. Gates, Paolo Nasta, Bhupinder S. Farmaha, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Irrigation exhibits large variation across producer fields, even within same region and year. A knowledge gap exists relative to factors that explain this variation, in part due to lack of availability of high-quality irrigation data from multiple field-years. This study assessed sources of variation in irrigation using a large database collected during 9 years (2005–2013) from ca. 1400 maize and soybean producer fields in Nebraska, central USA (total of 12,750 field-year observations). The study area is representative of ca. 4.5 million ha of irrigated land sown with maize and soybean. Influence of biophysical (weather, soil, and crop type) and behavioral …

Changes Of Soil Biogeochemistry Under Native And Exotic Plants Species, Yujie Hua

FIU Electronic Theses and Dissertations

Invasive plant species are major threats to the biodiversity and ecosystem stability. The purpose of this study is to understand the impacts of invasive plants on soil nutrient cycling and ecological functions. Soil samples were collected from rhizosphere and non-rhizosphere of both native and exotic plants from three genera, Lantana, Ficus and Schinus, at Tree Tops Park in South Florida, USA. Experimental results showed that the cultivable bacterial population in the soil under Brazilian pepper (invasive Schinus) was approximately ten times greater than all other plants. Also, Brazilian pepper lived under conditions of significantly lower available phosphorus …

Crop Updates 2009 - Weeds, Catherine Borger, Abul Hashem, Mike Clarke, Aik Cheam, Harmohinder Dhammu, Vince Lambert, Chris Roberts, Russell Quartermaine, David Nicholson, Mike Jackson, Bill Campbell, John Moore, Mario D'Antuono, Paul Matson, Peter Newman, Sally Peltzer, Dave Minkey, Stephen B. Powels, Qin Yu, Mechelle Owen, Roberto Busi, Sudheesh Manalil, Leigh Smith, Peter White, Fiona Evans, Pippa Michael, Siew Lee, Rob Grima, Glenn Adam, Trevor Bell, Steve Davies, Glen Riethmuller

Crop Updates

This session covers twenty three papers from different authors:

Herbicides

1. New pre-seeding grass selective herbicides – How well do they work in zero or no-till systems? Dr Catherine Borgerand Dr Abul Hashem, Department of Agriculture and Food

2. Velocity®—An alternate mode of action for the control of wild radish in cereals, Mike Clarke, Bayer Cropscience Pty Ltd, Dr Aik Cheam, Department of Agriculture and Food, Dr Michael Walsh, WAHRI, University of Western Australia

3. Herbicide tolerance of new barley varieties, Harmohinder Dhammu, Vince Lambert, Chris Roberts and Russell Quartermaine, Department of Agriculture and Food

4. Herbicide tolerance of …

Microbial Content Of Abattoir Wastewater And Its Contaminated Soil In Lagos, Nigeria, A. O. Adesemoye, B. O. Opere, S. C. O. Makinde

Department of Plant Pathology: Faculty Publications

Microbial content of wastewater in two abattoirs and the impact on microbial population of receiving soil was studied in Agege and Ojo Local Government Areas in Lagos State, Nigeria. Wastewater samples were collected from each of the abattoirs over three months period and examined for microbial content. Soil samples contaminated with the wastewaters were also collected and analyzed for microbial content as compared to soil without wastewater contamination in the neighborhood (control). Some physico-chemical parameters of the samples such as total dissolved solid, chemical oxygen demand, etc., were examined. The wastewater samples from both abattoirs were highly contaminated; Agege abattoir …

'Living Soil' Seminar, Department Of Agriculture, Western Australia

Agriculture reports

Provides an opportunity for farmers and those involved in the agricultural service industry, to focus on what happens in the soil. Seminar reflects the interest detected amongst farmers in knowing more about the things that influence plant growth and a genuine concern about the environment.

The Agriculture And Land Description Of The Midlands, Wongan Hills And Dalwallinu Districts Of W.A., D N. Sawkins

Agriculture reports

This report deals with the area of responsibility of the Moora District Office of the W.A. Department of Agriculture. The Moora advisory district consists of seven shires which cover 2,811,400 hectares. Agriculture in the advisory district varies according to climate and soil type, Sheep and cattle production are the main enterprises in the high rainfall (coastal) areas. Mixed cereal sheep production is the main system in the medium and low rainfall areas with cereals increasing in importance as annual rainfall diminishes.

On The Kinetics Of Moisture Flow In Unsaturated Soils, James Wellington Biggar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The flow of fluids in porous media continues to be a widely studied phenomenon. Soil moisture relationships and particularly the flow of water in soil is perhaps the most widely investigated of the four edaphatic factors related to plant growth, namely moisture, aeration, temperature and compaction.

The Influence Of Temperature Gradients On Soil Moisture Flow, Luigi Cavassa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The isothermal movement of liquid water in saturated soil has been intensively studied, and a sound theoretical basis has been developed. Considerably less is known about the flow of water in unsaturated soils, but a general theory based on Darcy's law of flow is beginning to develop. A good theoretical basis exists for the vapor diffusion under isothermal conditions. Inconsistent data and theories are found in the literature concerning the movement of water in both the vapor and liquid phases, under the influence of thermal fields.

The Total Surface Of Some Soils As Related To Permeability And Water Retention Characteristics, Warren W. Rasmussen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

It is generally recognized that many of the chemical and physical properties of soils are dependent upon the surface activity of the finer soil fractions. The importance of the magnitude of the surface areas to such properties as base exchange, water-holding capacity, absorption of gases, and the plasticity of soils has been demonstrated. Attempts have been made to determine or estimate the surface of soils and soil fractions by various methods and to relate the values obtained to the physical and chemical characteristics exhibited by these materials. Most determinations have been based on calculations of surface area from mechanical analysis …