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Full-Text Articles in Life Sciences

Influence Of Cover Crop Management Practices On Rainfed Corn Production In Semi-Arid Western Nebraska, Alexandre Tonon Rosa Jul 2020

Influence Of Cover Crop Management Practices On Rainfed Corn Production In Semi-Arid Western Nebraska, Alexandre Tonon Rosa

Theses, Dissertations, and Student Research in Agronomy and Horticulture

With the increased cover crop (CC) popularity, producers of semi-arid regions of western Nebraska are questioning whether they could successfully incorporate CC into their rainfed winter wheat (Triticum aestivum L.)-corn (Zea mays L.)-fallow rotations. The major concern is that CCs may deplete soil water affecting the subsequent crop. Therefore, three studies were established under rainfed conditions of western Nebraska to access the effects of CCs on soil water, soil compaction, nutrient cycling, weed demographics, residue coverage, and subsequent corn yield. The first study evaluated the influence of CC planting and termination times prior to corn establishment. Late termination ...


Transforming Unmanned Aerial Vehicle (Uav) And Multispectral Sensor Into A Practical Decision Support System For Precision Nitrogen Management In Corn, Laura J. Thompson, Laila A. Puntel Jan 2020

Transforming Unmanned Aerial Vehicle (Uav) And Multispectral Sensor Into A Practical Decision Support System For Precision Nitrogen Management In Corn, Laura J. Thompson, Laila A. Puntel

Agronomy & Horticulture -- Faculty Publications

Determining the optimal nitrogen (N) rate in corn remains a critical issue, mainly due to unaccounted spatial (e.g., soil properties) and temporal (e.g., weather) variability. Unmanned aerial vehicles (UAVs) equipped with multispectral sensors may provide opportunities to improve N management by the timely informing of spatially variable, in-season N applications. Here, we developed a practical decision support system (DSS) to translate spatial field characteristics and normalized difference red edge (NDRE) values into an in-season N application recommendation. On-farm strip-trials were established at three sites over two years to compare farmer’s traditional N management to a split-application N ...


Integration Of Cover Crops Into Midwest Corn-Soybean Cropping Systems And Potential For Weed Suppression, Joshua S. Wehrbein Dec 2019

Integration Of Cover Crops Into Midwest Corn-Soybean Cropping Systems And Potential For Weed Suppression, Joshua S. Wehrbein

Theses, Dissertations, and Student Research in Agronomy and Horticulture

Cover crops have potential to provide benefits to agricultural systems, such as improved soil productivity, nutrient scavenging, weed suppression, and livestock forage. There are several challenges associated with cover crop integration into traditional Midwest corn-soybean cropping systems. One of these challenges is timely establishment in the fall, which is limited by the relatively late harvest of corn and soybean. Cover crop effectiveness is related to the amount of biomass produced, thus maximizing the growth period in the fall is desired. To address this challenge, we evaluated the potential to utilize early-season soybean maturity groups (MGs) to allow for earlier soybean ...


Development Of A Nitrogen Recommendation Tool For Corn Considering Static And Dynamic Variables, Laila A. Puntel, Agustin Pagani, Sotirios V. Archontoulis Mar 2019

Development Of A Nitrogen Recommendation Tool For Corn Considering Static And Dynamic Variables, Laila A. Puntel, Agustin Pagani, Sotirios V. Archontoulis

Agronomy & Horticulture -- Faculty Publications

Many soil and weather variables can affect the economical optimum nitrogen (N) rate (EONR) for maize. We classified 54 potential factors as dynamic (change rapidly over time, e.g. soil water) and static (change slowly over time, e.g. soil organic matter) and explored their relative importance on EONR and yield prediction by analyzing a dataset with 51 N trials from Central-West region of Argentina. Across trials, the average EONR was 113 ± 83 kg N ha−1 and the average optimum yield was 12.3 ± 2.2 Mg ha−1, which is roughly 50% higher than the current N rates ...


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 Jan 2019

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

Agronomy & 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 containing ...


A Systems Modeling Approach To Forecast Corn Economic Optimum Nitrogen Rate, Laila A. Puntel, John E. Sawyer, Daniel W. Barker, Peter J. Thorburn, Michael J. Castellano, Kenneth J. Moore, Andy Vanloocke, Emily A. Heaton, Sotirios V. Archontoulis Apr 2018

A Systems Modeling Approach To Forecast Corn Economic Optimum Nitrogen Rate, Laila A. Puntel, John E. Sawyer, Daniel W. Barker, Peter J. Thorburn, Michael J. Castellano, Kenneth J. Moore, Andy Vanloocke, Emily A. Heaton, Sotirios V. Archontoulis

Agronomy & Horticulture -- Faculty Publications

Historically crop models have been used to evaluate crop yield responses to nitrogen (N) rates after harvest when it is too late for the farmers to make in-season adjustments. We hypothesize that the use of a crop model as an in-season forecast tool will improve current N decision-making. To explore this, we used the Agricultural Production Systems sIMulator (APSIM) calibrated with long-term experimental data for central Iowa, USA (16-years in continuous corn and 15-years in soybean-corn rotation) combined with actual weather data up to a specific crop stage and historical weather data thereafter. The objectives were to: (1) evaluate the ...


Impaired Phloem Loading In Zmsweet13a,B,C Sucrose Transporter Triple Knock-Out Mutants In Zea Mays, Margaret Bezrutczyk, Thomas Hartwig, Marc Horschman, Si Nian Char, Jinliang Yang, Bing Yang, Wolf B. Frommer, Davide Sosso Jan 2018

Impaired Phloem Loading In Zmsweet13a,B,C Sucrose Transporter Triple Knock-Out Mutants In Zea Mays, Margaret Bezrutczyk, Thomas Hartwig, Marc Horschman, Si Nian Char, Jinliang Yang, Bing Yang, Wolf B. Frommer, Davide Sosso

Agronomy & Horticulture -- Faculty Publications

Crop yield is critical for human nutrition, yet the underlying machinery that ultimately determines yield potential is still not understood. Crop productivity under ideal conditions is determined by the efficiency with which plants intercept light, convert it into chemical energy, translocate photosynthates and convert these to storage products in harvestable organs (Zhu et al., 2010). In many crops, sucrose is the primary form for translocation inside the conduit (i.e. the phloem). A combination of SWEETmediated efflux from phloem parenchyma and subsequent secondary active sucrose import by SUT sucrose/H+ symporters is thought to create the driving force for pressure ...


Bacterial Leaf Streak Of Corn Confirmed In Nebraska, Other Corn Belt States August 26, 2016, Tamra Jackson-Ziems, Kevin A. Korus, Tony Adesemoye, Julie Van Meter Aug 2016

Bacterial Leaf Streak Of Corn Confirmed In Nebraska, Other Corn Belt States August 26, 2016, Tamra Jackson-Ziems, Kevin A. Korus, Tony Adesemoye, Julie Van Meter

Papers in Plant Pathology

Bacterial leaf streak disease of corn, caused by Xanthomonas vasicola pv. vasculorum, has now been confirmed in Nebraska, as well as in Colorado, Illinois, Iowa, and Kansas. The disease had not been previously identified in the U.S., but had been reported on corn in South Africa. Surveys are currently underway across the Corn Belt to identify the disease distribution. Initial observations and survey results suggest that it may be widely distributed throughout the Corn Belt. Unusual symptoms were first reported on corn samples received by the University of Nebraska Plant and Pest Diagnostic Clinic. Over the last two years ...


A Brief History Of Corn: Looking Back To Move Forward, Jon Derek Pruitt May 2016

A Brief History Of Corn: Looking Back To Move Forward, Jon Derek Pruitt

Doctoral Documents from Doctor of Plant Health Program

Maize was domesticated from teosinte in Mexico some 7,000 to 10,000 years ago and quickly spread through the Americas. It has become one of the most important crops at a local and global level. Two types, Northern Flint corn and Southern Dent corns provided the basis of the genetic background of modern maize hybrids. The development of hybrids, first double-cross and later single-cross hybrids, along with a transition to high input farming provided huge yield increases, which have continued to improve with improving technology.

Increase in maize production also caused a rise in Western corn Rootworm (Diabrotica virgifera ...


Corn (Zea Mays L.) Seeding Rate Optimization In Iowa, Usa, Mark A. Licht, Andrew W. Lenssen, Roger W. Elmore Jan 2016

Corn (Zea Mays L.) Seeding Rate Optimization In Iowa, Usa, Mark A. Licht, Andrew W. Lenssen, Roger W. Elmore

Agronomy & Horticulture -- Faculty Publications

Collecting soil, topography, and yield information has become more feasible and reliable with advancements in precision technologies. Combined with the accessibility of precision technologies and services to farmers, there has been increased interest and ability to make site-specific crop management decisions. The objective of this research was to develop procedures to optimize corn seeding rates and maximize yield using soil and topographic parameters. Experimental treatments included five seeding rates (61 750; 74 100; 86 450; 98 800; and 111 150 seeds ha-1) in a randomized complete block design in three central Iowa fields from 2012 to 2014 (nine site-years ...


Insect-Damaged Corn Stalks Decompose At Rates Similar To Bt-Protected, Non-Damaged Corn Stalks, R. Michael Lehman, Shannon L. Osborne, Deirdre A. Prischmann-Voldseth, Kurt A. Rosentrater Aug 2010

Insect-Damaged Corn Stalks Decompose At Rates Similar To Bt-Protected, Non-Damaged Corn Stalks, R. Michael Lehman, Shannon L. Osborne, Deirdre A. Prischmann-Voldseth, Kurt A. Rosentrater

Kurt A. Rosentrater

The relative decomposability of corn (Zea mays L.) residues from insect (Bt)-protected hybrids and conventional hybrids cultivated under insect pressure was investigated in two studies. Above-ground biomass, residue macromolecular composition, and stalk physical strength were also measured. In the first decomposition study, chopped residues (stalks and leaves) were used from a corn rootworm-protected (Cry3Bb1) hybrid and its non-Bt near isoline that were grown in replicated plots infested with corn rootworms (Diabrotica spp.). In the second study, residue (intact stalk sections) was used from three European corn borer (ECB, Ostrinia nubilalis Hübner)-resistant (Cry1Ab) hybrids representing different seed manufacturer/maturity ...


Optimizing The Oil Extraction/Water Adsorption Step In Sequential Extraction Processing Of Corn, Kathrine V. Miller, Mila P. Hojilla-Evangelista, Lawrence A. Johnson Jul 2001

Optimizing The Oil Extraction/Water Adsorption Step In Sequential Extraction Processing Of Corn, Kathrine V. Miller, Mila P. Hojilla-Evangelista, Lawrence A. Johnson

Food Science and Human Nutrition Publications

The Sequential Extraction Process (SEP) uses ethanol to extract oil and protein from cracked, flaked, and dried corn, and the corn simultaneously dehydrates the ethanol. The optimum conditions to reduce zein extraction in the oil extraction/water adsorption step of SEP involved a single–pass system using 15 length/diameter ratio extraction cells, 30% hexanes: 70% ethanol, and 56C extraction temperature, which improved the efficiencies of oil extraction from the corn and moisture adsorption from the ethanol. The extract contained only 0.1% protein in the desolventized solids. The moisture content of the solvent was reduced to 1.03%, and ...


Sterol Composition Of The Corn Root Lesion Nematode, Pratylenchus Agilis, And Corn Root Cultures, David J. Chitwood, William R. Lusby Jan 1991

Sterol Composition Of The Corn Root Lesion Nematode, Pratylenchus Agilis, And Corn Root Cultures, David J. Chitwood, William R. Lusby

Faculty Publications from the Harold W. Manter Laboratory of Parasitology

Sterols from mixed stages of the com root lesion nematode, Pratylenchus agilis, and uninfected corn root cultures were analyzed by gas chromatography-mass spectrometry. Twenty-eight sterols were identified in P. agilis, including nine not previously detected in nematodes. The major sterols were 24-ethylcholest-22-enol, 24-ethylcholesta-5,22-dienol, 24-methy1cholestanol, 24-ethylcholestanol, isofucostanol, and 24-ethylcholesterol. The principal corn root sterols were 24-ethylcholesta-5,22-dienol, 24-methylcholesterol, 24-ethylcholesterol, isofucosterol, and cycloartenol. Therefore, the major metabolic transformation of sterols by P. agilis was saturation of the sterol nucleus. In addition, very small amounts of 4α-methylsterols were biosynthesized by P. agilis. The 4-methylation pathway is unique to nematodes and was previously ...


The Effects Of Irradiating Dormant Maize Seeds With Xrays And Thermal Neutrons, Rosalind Morris, E. F. Frolik Dec 1961

The Effects Of Irradiating Dormant Maize Seeds With Xrays And Thermal Neutrons, Rosalind Morris, E. F. Frolik

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

In 1951 a research program was started at the University of Nebraska to compare the developmental effects of thermal neutrons and X rays on different crop seeds. Three crops, barley, tomato and maize, were chosen for additional information involving induced chromosomal aberrations and seedling mutations. The maize investigations are presented in this bulletin, along with a comparison among the three crops with respect to irradiation effects.


The Effects Of Thermal-Neutron Irradiation Of Maize And Barley Kernels, John W. Schmidt, E. F. Frolik Jan 1951

The Effects Of Thermal-Neutron Irradiation Of Maize And Barley Kernels, John W. Schmidt, E. F. Frolik

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

It is the purpose of this paper to report the effects of thermal-neutron irradiation of maize and barley kernels on subsequent germination, plant establishment, and early plant development. Comparisons are made with equivalent neutron treatments of maize pollen, results of which have been reported in part in previous publications.


Progressive Development And Seasonal Variations Of The Corn Crop, T. A. Kiesselbach Dec 1950

Progressive Development And Seasonal Variations Of The Corn Crop, T. A. Kiesselbach

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

The chief purpose of these studies has been to determine the normal growth changes that occur in the corn plant at successive intervals when growing in the field, and to observe annual yield variations in relation to prevailing weather conditions. Aside from supplying information regarding the physiology of this crop, the data are of interest to the corn grower because they indicate comparative yields, shelling percentages, moisture contents, and feed constituents at various stages of development. Some data also are presented concerning the effects of frost, drouth, day length, and the economic value of tillers and seminal roots.


Physiological Changes And Freezing Injury In Maturing Maize , Mohamed Mohamed Aboul-Ela Jan 1950

Physiological Changes And Freezing Injury In Maturing Maize , Mohamed Mohamed Aboul-Ela

Retrospective Theses and Dissertations

No abstract provided.


Growth Of The Maize Root Tip , Gabriel Baldovinos De La Pena Jan 1950

Growth Of The Maize Root Tip , Gabriel Baldovinos De La Pena

Retrospective Theses and Dissertations

No abstract provided.


Pollination Cycles And Pollen Dispersal In Relation To Grass Improvement, Melvin D. Jones, L. C. Newell Oct 1946

Pollination Cycles And Pollen Dispersal In Relation To Grass Improvement, Melvin D. Jones, L. C. Newell

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

The plant breeder is initially concerned with gaining a knowledge of the breeding behavior of his plant materials in order that improvement may be undertaken effectively. It is important to know the different characteristic pollination habits of these plants. To develop and apply techniques applicable to the improvement of a given grass crop, it is desirable to know the time of day and the number of days that the grass sheds pollen. The effects of temperature, humidity, light, and wind on pollination must be considered. Once superiority of germplasm is obtained, the most important consideration is the maintenance of this ...


Growth Correlations In Maize, Morris Evans Paddick Jan 1939

Growth Correlations In Maize, Morris Evans Paddick

Retrospective Theses and Dissertations

No abstract provided.


The Polysaccharides Of The Vegetative Tissues Of Maize , Calvin Guinn Barr Jan 1935

The Polysaccharides Of The Vegetative Tissues Of Maize , Calvin Guinn Barr

Retrospective Theses and Dissertations

No abstract provided.


The Regional Adaptation Of Corn In Nebraska, T. A. Kiesselbach, F. D. Keim Apr 1921

The Regional Adaptation Of Corn In Nebraska, T. A. Kiesselbach, F. D. Keim

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

The purpose of this investigation was to determine some of the factors involved in the regional adaptation of corn. The procedure has been to make a comparative study of native corn types, known to be locally adapted to various regional areas in Nebraska through long growth there. The work has been confined to the single species group - Zea mays indentata. No one variety of a common source is grown throughout the state, and therefore it has been impossible to keep within a single variety. It would appear that the data should indicate morphological and histological plant characteristics involved in the ...


Transpiration As A Factor In Crop Production, T. A. Kiesselbach Jun 1916

Transpiration As A Factor In Crop Production, T. A. Kiesselbach

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

The object of experiments reported in this bulletin has been to determine principles according to which water is used by crops. In many agricultural districts, water is frequently a seriously limiting factor in crop production. It has been thought that some means might be devised through a correct understanding of the principles involved, whereby economy in the use of water in farm practice could be increased. In this effort there are two chief points of attack, namely, (1) adjusting the external factors to the needs of the plant, and (2) selecting plants adapted to the conditions.


Zea Mays, Herbert M. Prouty Jan 1886

Zea Mays, Herbert M. Prouty

Theses and Dissertations

No abstract provided.