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| This lesson is a detailed explanation of the backcross breeding process. Variations based on whether backcrossing is performed with dominant, recessive, or multiple traits are discussed. Calculations associated with backcross breeding are explained.
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El uso repetido del mismo herbicida, puede provocar poblaciones de malezas que consisten de biotipos susceptibles (S) que son controlados y biotipos resistentes (R), que escapan al control para producir y retornar semilla con la característica de resistencia, al banco de semillas del suelo. Esta lección se enfocará en la dinámica poblacional de una población de malezas mezclada con biotipos S y R. Se comparará y contrastará la tasa a la que aparecen malezas resistentes en una población bajo diversas presiones de selección. ****** Esta lección se enfocará en la dinámica poblacional de una población mezclada (biotipos susceptibles y resistentes a un herbicida), y comparar y contrastar la tasa a la cual aparece resistencia al herbicida, en una población de malezas mezclada, bajo diversas presiones de selección.
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Esta lección se focaliza en el impacto de las características de la planta y el herbicida, importantes para determinar el desempeño del herbicida. Se usarán imágenes visuales para ilustrar varios principios, incluyendo el sitio de absorción del herbicida en la planta, transporte, el sitio de acción sensible, y efectos del ambiente sobre el desempeño del herbicida. Esta información provee la base para maximizar la utilidad del uso de los herbicidas.
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Through the repeated use of the same herbicide, weed populations can consist of susceptible (S)-biotypes that are controlled and herbicide resistant (R)-biotypes that are left behind to produce and return seed with the resistance characteristic back into the soil. This lesson will highlight the population dynamics of a mixed weed population, containing S- and R-biotypes, and compare and contrast the rate at which herbicide resistant weeds appear in a population under a diversity of selection pressures. ****** This lesson will highlight the population dynamics of a mixed (herbicide susceptible and resistant biotype) weed population, and compare and contrast the rate of appearance of herbicide resistance in a mixed population under a diversity of selection pressures.
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This lesson contains information about the Asteraceae family.
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The selective control of broadleaf weeds in cereal grain crops by auxinic herbicides has made this group one of the most widespread and important herbicide families in use. These herbicides were the first organic herbicides developed that were selective or able to kill one group of plants, but not another (i.e. kill broadleaf, but not grass plants). This lesson will introduce the major features of these herbicides, discuss their major uses and describe the symptoms of the injury they cause as well as introduce how they kill sensitive plants.
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The selective control of broadleaf weeds in cereal grain crops by auxinic herbicides has made this group one of the most widespread and important herbicide families in use. These herbicides are thought to act as hormone mimics. This lesson will detail how these herbicides are related structurally and physiologically to the natural plant hormone, auxin (indole-3-acetic acid; IAA) and explain the biochemical mechanisms which may be involved in their action. The mechanism of cell to cell transport and cellular uptake of auxins will be reviewed as well as how they cause cell elongation and induce ethylene biosynthesis. Receptors, signal transduction pathways and changes in gene expression for the natural hormone, IAA, will be described and related their role in auxinic herbicide activity.
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This lesson reviews the basics of gene inheritance. It compares plants that are homozygous, heterozygous, and hemizgous for an allele and how gene expression is affected by the dominance of an allele. It also explains how to use a Punnett square to predict genotypic and phenotypic ratios of offspring.
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This lesson discusses the final stage of developing genetically engineered crops. The need for backcrossing, and the steps of this breeding method are described. Yield lag, yield drag, and gene stacking are also discussed.
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This scenario accompanies the online lesson, "Transpiration - Water Movement Through Plants", and is designed to allow you to apply the concepts learned in that lesson to a real-life problem.
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Before a herbicide can kill a plant, it must be absorbed by the plant’s leaves or roots and enter a cell which possesses the metabolic pathway the herbicide targets. This lesson follows the fate of the herbicide after it has entered the plant via leaf or root tissue, and explains the factors controlling transport of a herbicide into plant cells. This lesson describes 1) the barriers to herbicide entry, such as the plant cell membrane, 2) the role that the herbicide’s chemical properties have on the rate of cellular absorption, and 3) experimental approaches to understanding herbicide absorption at the cellular level.
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Esta lección se enfoca en entender el sistema de clasificación en el cual están organizados los herbicidas. Terminología como clasificación, jerarquía de clasificación, ejemplos de clasificación y un breve resumen de los ocho modos de acción, se discuten en esta lección. Una vez que esto se entiende, es mucho más fácil comprender herbicidas similares y saber por qué estos pueden exhibir ciertos síntomas en malezas y cultivos. Objetivos: 1. Entender la forma en que se clasifican los herbicidas y su importancia en el manejo de la resistencia herbicida 2.Entender la importancia de la clasificación de los herbicidas por modo de acción, en vez de familias 3.Ser capaz de entender la diferencia entre modo de acción y sitio de acción 4.Ser capaz de diferenciar entre familias de herbicidas, modos de acción, y sitios de acción 5.Entender nombre común, nombres comerciales y sitios de absorción
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This is the first in a series of lessons specifically designed to instruct individuals without any formal training in genetics or statistics about the science of corn breeding. Individuals with formal training in genetics or statistics but without any training in plant breeding also may benefit from these lessons.
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This is the second in a series of lessons specifically designed to instruct individuals without any formal training in genetics or statistics about the science of corn breeding. Individuals with formal training in genetics or statistics but without any training in plant breeding also may benefit from taking these lessons.
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This is the fourth in a series of lessons specifically designed to instruct individuals without any formal training in genetics or statistics about the science of corn breeding. Individuals with formal training in genetics or statistics but without any training in plant breeding also may benefit from taking these lessons.
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This is the third in a series of lessons specifically designed to instruct individuals without any formal training in genetics or statistics about the science of corn breeding. Individuals with formal training in genetics or statistics but without any training in plant breeding also may benefit from taking these lessons.
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This lesson will discuss the corn rootworm complex, which consists of
the northern, western, and southern corn rootworm, focusing on the
northern and western species. The information in this lesson will focus
on the biology of corn rootworms in the north central Corn Belt,
including Iowa and Nebraska. Crop producers, crop scouts, students, and
the general public may find the information in this lesson helpful for
identifying corn rootworm, other corn pests, and the feeding damage
caused by each insect.
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This lesson will discuss economic thresholds and management options
related to the corn rootworm complex consisting of the northern,
western, and southern corn rootworm, with emphasis on the northern and
western species. The information in this lesson will focus on the north
central Corn Belt, including Iowa and Nebraska. Crop producers,
crop scouts, students, and the general public may find this lesson
helpful for obtaining information about developing a management plan to
control corn rootworm.
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This lesson discusses what DNA is and how it relates to genes and chromosomes. How and why DNA is extracted in the genetic engineering process is also covered.
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This lesson will discuss erosion control practices in the agricultural and construction environments. The impact of erosion management practices will be demonstrated with exercises using a USLE calculator.
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This lesson contains information about the history, life cycle, and host plants of the European corn borer and information relating to the history and biology of Bacillus thuringiensis.
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Herbicides must be absorbed into plants in order to be effective. Herbicide absorption can occur through leaves, roots or both. The process by which herbicides kill weeds, called mode of action, requires herbicide absorption and may also require herbicide movement or translocation within the plant. Translocation means that the herbicide moves from the site of absorption to some other plant part. Foliar applied herbicides that have the necessary characteristics to move in the phloem will translocate to areas of the plant that are actively growing; however, not all foliar-applied herbicides move from the leaves that intercepted the spray solution. Herbicides that are absorbed but not translocated are called contact herbicides, while herbicides that translocate to shoot or root meristems are called systemic herbicides. Absorption and translocation of xylem mobile herbicides will be discussed in another lesson.
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This lesson covers the utilization of gene cloning to isolate and copy a specific gene of interest. The transformation of bacteria with plasmids containing antibiotic resistance genes to make gene libraries and the selection of bacteria colonies that contain the specific gene of interest are described.
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This lesson describes how DNA molecules can be recombined to make recombinant DNA and how special DNA molecules called plasmids allow scientists to clone genes.
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This lesson teaches how a specific gene can be identified from among the thousands of genes that can be cloned from an organism.
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This lesson describes the three gene regions and their roles in gene expression. It also discusses how the regions of a gene can be altered to obtain desired trait expression.
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This lesson builds upon the gene region lesson discussing the gene construct of currently used hybrids and explaining how these combinations result in a particular gene expression.
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This lesson describes the steps involved in a cell as DNA sequence information is read to make RNA and RNA is read to make proteins.
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This lesson describes how changes in the DNA sequence of a gene can alter the synthesis of a protein and thus influence traits such as herbicide resistance.
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En esta lección se examinarán los herbicidas que afectan los procesos celulares relacionados con la utilización de la luz, causando así daños a las plantas. Existen cuatro mecanismos básicos que serán estudiados: herbicidas que obstruyen la síntesis de protoporfirina IX; herbicidas que inhiben la síntesis de carotenoides; herbicidas que obstruyen la transferencia de electrones en el fotosistema II; y herbicidas que substraen electrones del fotosistema I. Todos ellos comparten la misma habilidad de causar daños celulares en presencia de luz.
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This lesson focuses on understanding the classification system into which herbicides are organized. Terms of classification, classification hierachy, examples of classification and a brief overview of the eight modes of action are all discussed in this lesson. Once this is understood it is much easier to grasp similar herbicides and know why they may exhibit certain symptoms to weeds and plants alike. Objectives: 1.Understand how herbicides are classified and why it is important for managing herbicide resistance 2.Understand the Importance of classification and herbicides by mode of action rather than chemical family 3.Be able to tell the difference between mode of action and site of action 4.Be able to differentiate between herbicide families, modes of action, and sites of action 5.Understand common name, trade names and sites of absorption
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Historically, herbicides have been discovered by randomly screening collections of chemicals for activity on target weeds. While totally empirical, this approach has been surprisingly successful and has produced essentially all commercial herbicides currently in use. More recently, agrichemical companies have adopted directed strategies using in vitro assays, compound structure/activity relationships, and profiling assays of mRNAs, proteins, and metabolites. These latter approaches, in combination with high-throughput screens, are designed to exploit recent advances in technology and take advantage of our increased understanding of biological systems.
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This lesson will detail the biochemical mechanisms and genetics of herbicide resistance in weeds. Herbicide resistance is one of the major issues in weed science today; therefore, it is important to have a basic understanding of the process by which it occurred. The management and spread of herbicide-resistant weeds in relationship to the biochemical mechanisms and inheritance of resistance will be explained. Resistance based on changes in the target site versus resistance based on detoxification or other types of resistance will be described.
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This lesson will examine herbicides that adversely affect light-related processes, thereby causing damage to plants. There are four basic mechanisms that will be studied in this class of agents: herbicides that inhibit or block synthesis of Protoporphyrin IX; herbicides that inhibit synthesis of carotenoids; herbicides that block Photosystem II electron transfer; and herbicides that divert electrons from Photosystem I. All share the ability to cause cellular damage in the presence of light.
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En esta lección se detallarán los procesos bioquímicos que son afectados por los herbicidas que inhiben la síntesis de aminoácidos en las plantas. Se describirá también la importancia de los aminoácidos y las proteínas. De igual manera, se presentará un estudio detallado del herbicida glifosato [N-(fosfonometil)-glicina], incluyendo los avances hechos por la biotecnología.
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This lesson will detail the biochemical mechanisms that are affected by herbicides which inhibit a plant’s ability to synthesize amino acids. The significance of amino acids and proteins will also be described. The herbicide glyphosate, will be studied at length, including the advances made by biotechnology.
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Herbicides that inhibit the production of the branched chain amino acids valine, leucine and isoleucine are used for total vegetation management and selective weed control in a wide variety of crops. There are currently four different chemical families that share this MOA. Before the development of glyphosate-tolerance crop technology, branched chain amino acid inhibitors were the mainstay for several major row crops. While this is still a very important herbicide MOA, the major increase in herbicide resistance weeds since 1980 has been the direct result selection pressure from these herbicides. There are currently more weed species resistant to branched chain amino acid inhibitors than any other herbicide MOA.
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Fatty acid synthesis and fatty acid elongation are two parts of a critically important pathway in plants. The endproducts are essential components of cell membranes, waxes, and suberin. Two chemical families of herbicide (groups that share similar chemical structures) inhibit fatty acid synthesis, while fatty acid elongation is inhibited by two other families. This lesson will provide an overview of fatty acid synthesis and elongation, and explain where herbicides inhibit the pathway. Mechanisms of resistance to these herbicides will be described.
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En esta lección se describe la naturaleza de la luz, la energía de los fotones y como dicha energía puede ser transferida a las biomoléculas. Se describen también tanto los procesos benéficos como los procesos dañinos por medio de los cuales las biomoléculas disipan la energía recibida.
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La transpiración es la pérdida de agua en forma de vapor por las plantas. El agua es absorbida del suelo por las raíces y transportada en forma líquida por el xilema hacia las hojas. En las hojas, unos pequeños poros permiten que el agua (H2O) escape a la atmósfera en forma de vapor, al tiempo que se permite la entrada de bióxido de carbono (CO2) para la fotosíntesis. De toda el agua absorbida por las plantas, menos del 5% es retenida y utilizada para crecimiento y almacenamiento. En esta lección se explicará porque las plantas pierden tanta agua, la ruta que ésta sigue dentro de la planta, como pudieran las plantas controlar la pérdida excesiva de agua y como las condiciones ambientales influyen en la pérdida de agua por las plantas.
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En esta lección se examinarán las dos principales clases de pigmentos fotosintéticos: las clorofilas y los carotenoides. Se analizarán sus estructuras bioquímicas y su biosíntesis, y se explicará además la organización de estos pigmentos en los sistemas fotosintéticos, que son complejos proteicos que colectan y convierten la energía luminosa en energía química.
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This lesson focuses on the process of eutrophication; the relationship between land application of manure and soil phosphorus (P) dynamics on P delivery to surface waters; and on the P dynamics in water bodies that result in increased P available to aquatic vegetation.
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This lesson describes how source factors, including soil characteristics and management practices, affect phosphorus (P) delivery to surface waters; and also discusses how crop producers can control these factors through their management practices.
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This lesson addresses transport factors that may contribute to phosphorus (P) delivery to surface waters. Erosion, runoff, subsurface flow, drainage, and distance to surface water are the main factors. In some places, wind erosion may also be important. The effects of management practices on P transport are discussed, and water-related P transport processes are described in detail.
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Descripción: El control selectivo de malezas de hoja ancha en cultivos de cereales utilizando herbicidas auxínicos ha hecho de éstos una de las familias de herbicidas actualmente en uso más ampliamente distribuidas e importantes. Estos herbicidas fueron los primeros herbicidas orgánicos desarrollados que presentaron selectividad; es decir, capaces de matar un cierto grupo de plantas sin afectar a otros grupos (por ejemplo: matar plantas de hoja ancha pero no las de hoja angosta; en este documento se utilizará el término "gramíneas" para referirse a las plantas de hoja angosta o cereales). En esta lección se presentarán las principales características de los herbicidas auxínicos, se discutirán sus principales usos y se describirán los síntomas de daño que causan. De igual forma, se indicará la forma en que estos herbicidas matan a las plantas sensibles.
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Descripción: El control selectivo de malezas de hoja ancha en cultivos de cereales por los herbicidas auxínicos ha hecho de éstos una de las familias de herbicidas actualmente en uso mas ampliamente distribuidas e importantes. Se cree que estos herbicidas actúan como simuladores hormonales. En esta lección se detallará la relación estructural y fisiológica entre los herbicidas auxínicos y la fitohormona natural auxina (ácido indol-3-acético; IAA por sus siglas en inglés) y se explicarán los mecanismos bioquímicos que pueden estar involucrados en su modo de acción. Se revisará el mecanismo de transporte de célula a célula y la absorción de las auxinas por las células, así como también la forma en que estas moléculas causan elongación celular e inducen la síntesis de etileno. De igual forma, se describirán los receptores, las rutas de transferencia de señales y los cambios en expresión genética inducidos por la fitohormona natural IAA y su relación con la actividad de los herbicidas auxínicos.
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This lesson will take an indepth view of how plants handle foreign chemicals (xenobiotics) such as herbicides. It will discuss the three main phases that plants use to handle toxic chemicals, which enzymes are involved in these biochemical conversions, how these processes help protect crops again phytotoxic chemicals and consider the importance of these processes to successful weed management.
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Objectives Upon completion of this lesson, nutrition professionals should be able to: · Define functional foods and give examples of them. · Recognize the potential for allergen removal from food. · List three different types of genetically engineered products that could impact nutrition practice. · Explain how biotechnology can be applied to food safety concerns. · Identify how biotech vaccines could be beneficial. · Identify current ethical concerns regarding biotechnology. · Explain how allergen introduction could occur when biotechnology is used to transfer traits between plants/foods.
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Lesson one is a general description of the overall process of genetic engineering. A basic explanation of the five steps for genetically engineering a crop is provided. Details for each step are given in later lessons of this course. The five steps are:
- Locating an organism with a specific trait and extracting its DNA
- Cloning a gene that controls the trait
- Designing a gene to express in a specific way
- Transformation, inserting the gene into the cells of a crop plant
- Plant breeding to get the transgene into an elite background
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This lesson will examine the two major classes of phototsynthetic pigments, chlorophylls and carotenoids, their biochemical structures and their biosynthesis. The organization of these pigments into photosynthetic pigment, which are protein complexes that harvest light and convert its energy into biochemical energy will be explained.
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The polymerase chain reaction laboratory technique is used in a variety of applications to make copies of a specific DNA sequence. This lesson describes how a PCR reaction works, what it accomplishes and its basic requirements for success. Examples of interpreting results are given. PCR's strengths, weaknesses and applications to plant biotechnology are explained.
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This lesson will focus on the impact of herbicide and plant characteristics important in determining herbicide performance. Visual images will be used to illustrate several principles including herbicide site of uptake, translocation, site of action sensitivity, and environmental effects on herbicide performance. This information provides a basis for maximizing herbicide performance.
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-Creating unique individuals or perfect little clones -Genetics of it all--Peas in Darwin's pods
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This lesson will focus on molecular principles involved in the detection of biotechnology derived proteins in crops, using the lateral flow ELISA.
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Real time PCR is a laboratory technique that can perform relatively accurate, reliable and reproducible measurements, to quantitatively determine the presence of specific gene sequences. Its value is being recognized in a variety of applications, including transgenic (GMO) detection. It is becoming increasingly important to know what percentage of a particular transgene is present in an export shipment, for example. Real time PCR can also be used to support more traditional plant breeding techniques, making the process of distinguishing allelic variations more efficient. This lesson explains the principles of real time PCR and its' application, with examples in plant breeding and GMO detection.
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Overview: Herbicides must be absorbed into plants in
order to be effective. Plant roots and below ground shoots have few
barriers to herbicide absorption; however, interactions with soil
particles and soil organic matter have significant impacts on the
amount of herbicide available for plant absorption. Plant roots and
below ground shoots (hypocotyls or coleoptiles) are lipophilic by
nature and do not have thick, waxy cuticles like leaves. Lipophilic and
hydrophilic herbicides reach the root surface by bulk transport in soil
water; however, there are a few examples of herbicides that reach the
root as a vapor or gas. Soil-applied herbicides can translocate to the
shoot or remain in the root system. Soil-applied herbicides translocate
to the shoot in the xylem and tend to accumulate in mature leaves that
transpire the most water. The lipophilic/hydrophilic nature of the
herbicide will determine if the herbicide translocates to the shoot.
Absorption and translocation of phloem-mobile herbicides will be
discussed in another lesson.
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This lesson identifies some common rocks and minerals and how they influence soil formation.
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This lesson identifies the factors of weathering processes and how they influence soil formation.
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This lesson identifies the five major soil forming factors and discusses how they influence soil development.
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This lesson discusses the processes controlling soil formation and how these processes relate to the characteristics of a soil profile.
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This lesson discusses the characteristics of the 12 soil orders defined by the USDA soil classification system, the major factors involved with their formation, and their geographic distribution across the USA and the world.
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This lesson discusses soil resources and functions at the global scale.
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This case study addresses how soil formed in different geographical locations of the world influences food and fiber production.
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This case study addresses where geographically soil addition of
municipal organic wastes occurs and how this addition affects soil
profile development and the use of soils as a sustainable resource.
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This case study addresses how soil formed in different parts of the landscape influences productivy in the broad sense, of both economic and non-economic flora and fauna.
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Soils - Part 9 addressed how soil testing works and the proper method of taking soil samples. The purpose of soil testing is to provide a rational basis for making fertilizer recommendations. The impact of not having the optimum crop nutrition can be yield loss, economic expense and environmental contamination. For many years, it has been widely known that fertilizer recommendations for a given crop often vary widely, depending on who is making the recommendation. With the development of site- specific nutrient management, more emphasis is being placed on soil sampling as a basis for predicting response to applied fertilizer. This lesson will explain several approaches to making fertilizer recommendations and will discuss why recommendations may vary widely when different approaches are used to interpret soil tests.
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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Soil means different things to different people. To some, soil is something that must be swept away; to others it is just a material that sticks to your shoes. In both instances, soil is associated with unpleasantness. To the engineer, soil is something to be moved, manipulated or built upon. To the farmer and rancher, soil is the source of nutrients which crops use to produce the grain and with it the livestock needed to produce a profit on the farm and in agribusiness. For some of us, soils provide recreation through the development of landscapes or vegetable gardens. For all of us, soils are the medium that provides the food production that has been so successful in feeding our population.
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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Soil may look simple; however, it is an extremely complex system. It is most often described by its physical, chemical and biological properties and processes. Soil is organic or inorganic; inert or active; living or non-living. Soil contains many organisms: bacteria, nematodes, fungi, earthworms, and small animals. From a physical perspective the soil constitutes the building blocks upon which we walk, construct buildings, grow crops and filter natural and manmade compounds. Soil’s physical, chemical and biological properties and processes interact to enhance its value as a natural resource.
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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To most gardeners, organic matter is like Husker football—everybody is a fan, but not everybody understands the details of the game. Anyone who uses a soil should have an interest in its organic matter content because so much about the soil is influenced by its organic matter content. In this lesson, we will increase our knowledge about soil organic matter to be able to understand its importance.
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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Soil pH is one of the most important chemical characteristics of the soil. For example, soil pH can affect availability of plant nutrients. In addition, the soil pH can affect the performance of preemergence herbicides, activity of microorganisms, the need for lime, soil bacteria activity, the best crop to be grown, and other characteristics.
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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Nitrogen (N) is one of the most abundant elements on earth, and after carbon (C), hydrogen (H), and oxygen (O), it’s the element living creatures need most. The atmosphere over each square foot of the earth’s surface — which is 78 percent dinitrogen (N2) gas — contains approximately 6,000 pounds of nitrogen. However, most of the earth’s nitrogen (98 percent) is in rock, sediment, and soils. The amount of nitrogen in rocks is about 50 times more than that in the atmosphere, and the amount in the atmosphere is approximately 5,000 times more than in soils (Stevenson, 1982).
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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Phosphorus fertilizers are second only to nitrogen in importance for growing crops in Nebraska; however, the principles affecting efficient phosphorus use are totally different. Nitrogen is a mobile nutrient, both in the plant and in the soil, while phosphorus moves very little in the soil. Additionally, total plant requirements are much lower for phosphorus than for nitrogen. For example, leaves commonly contain 10 times more nitrogen than phosphorus. However, phosphorus is concentrated in the grain so that only about 2.5 times more nitrogen is removed in harvested grain compared to phosphorus.
Potassium (K) is an essential plant nutrient. Next to nitrogen, crops absorb potassium in greater amounts than any other nutrient. It is a vital component of numerous plant functions including nutrient absorption, respiration, transpiration, and enzyme activity. Potassium is unique because it does not become part of plant compounds, but remains in ionic form in the plant. Potassium remaining in plant residues after harvest and in manure are quickly returned to the soil when water leaches through the plant residue.
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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Sixteen elements are known to be essential for plant growth. These are divided into two groups: macronutrients — those elements used in relatively large quantities and micronutrients — those needed in very small amounts.
Macronutrients | ||
Carbon (C) | Nitrogen (N) | Calcium (Ca) |
Hydrogen (H) | Phosphorus (P) | Magnesium (Mg) |
Sulfur (S) | Potassium (K) | Oxygen (O) |
Micronutrients | ||
Zinc (Zn) | Copper (Cu) | Boron (B) |
Iron (Fe) | Manganese (Mn) | Molybdenum (Mo) |
Chlorine (Cl) |
|
|
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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During the first seven lessons, we have discussed a variety of topics related to soils, ranging from their formation to how nitrogen reacts in the soil. In Soils - Part 8, we are going to shift gears and discuss some common fertilizers and their characteristics. These will include the common nitrogen and phosphorus fertilizers, as well as many fertilizers that provide micronutrients to the soil. In this chapter, no attempt is made to judge the value of each type of fertilizer.
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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Soil tests are part of a four-step process of determining and providing nutrients to agronomic crops. The four steps are:
1) soil sampling,
2) soil analysis,
3) result interpretation and decision making, and
4) fertilizer application.
This chapter will focus on Steps 1 and 3 — soil sampling and result interpretation and decision making. It will not examine specific laboratory procedures or address fertilizer application issues. Until very recently, soil testing was conducted on a field basis. Site-specific management and the associated technologies of fertilizer application and yield monitoring are enabling agriculture management to reduce the area associated with each soil test to the subfield level. The article, "Soil Testing and Nutrient Recommendations," from Nutrient Management for Agronomic Crops in Nebraska, includes further information on soil testing.
[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
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This lesson describes the nature of light, the energy within photons and how this energy may be transferred to biological molecules. In addition, the beneficial and harmful methods for de-exciting molecules will be described.
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This lesson explains the technique of tissue culture as used in plant transformation. It discusses important issues, such as the use of selectable markers, genotype specificity, and tissue culture alternatives.
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This lesson explains the procedure of introducing a new gene into a plant cell (transformation). It discusses the main goals of the transformation process and describes the four main methods of transformation.
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This lesson defines an 'event'. It explains the determining factors specific to an event, the qualities of a desirable event, and the identification and selection of desirable events.
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This lesson and its animation follows the journey of water through a plant from its uptake by roots to its evaporation from the leaf surface. How this journey is altered by plant characteristics such as stomata and cuticles as well as by changes in the environment will be described.
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