Agronomy 354
Course Syllabus, Spring 2016

The Agronomy 354 course homepage contains informaton on grading, old exams used the last term taught, sample homework problems, etc. and should be consulted. For reading materials, see electronic library and check under Agron 354. Two sections will be taught this spring semester, section 1 will be taught be Dr. Loynachan and section 2 will be taught by Dr. Ibrahim.

Specific Web pages have been developed to aid you in understanding the 354 material. In addition, we have identified other Web sites that will give background, add interest, or show practical use of the 354 material that are linked in the outline (many other sites are also available and we have just linked a representative few--use search engines to find others). If you find a link that is broken, please let us know.

Chem Review Questions Chemistry Review Growth Curves
Soil Physical Properties Nutrient Deficiency Key Nutrient Deficiency Symptoms
Deficiencies vs. Other Soil Sampling Problem Practice Problems

APPOINTMENTS: Dr. Loynachan has an open-door policy, come to his office (1126H Agronomy Hall), call (515 294-3064), or e-mail ( for an appointment. He has hours most days when available. Both Jaci and Melissa in Agron 1126 have access to his electronic calendar and can schedule an appointment for you. Dr. Ibrahim has an open-door policy as well, come to his office (1023 Agronomy Hall), call (605 690-9174), or email ( ). He has hours most days when available, just contact him to make an appointment. Please let us know anytime we can be of help.

DEPARTMENT CHAIR:  Dr. Kendall Lamkey,  2104 Agronomy Hall

PREREQUISITES:   Agron 154; Biol 101, 211, or 212; Chem 163

    A1    Getting Acquainted (Chemistry Review) (Periodic Chart)
    A2    Books and References:
    A21        Soil Fertility and Fertilizers , Havlin, Tisdale, Nelson, and Beaton, 8th Ed. (Text)     
    A22        References:   Required reading is in bold in the outline. Several books in the library can be used as further sources of information. These books will be referred to by their abbreviations below.  Reading in more than one book can clarify your understanding of the subject. Some required readings are available electronically from the ISU Library and others are not based on the fee the publisher charges to allow electronic posting...for some readings, you will need to visit the ISU Library and you may copy the materials if you desire). The readings are optional unless displayed in bold.

         1.  Soils and Soil Fertility, Troeh and Thompson,  6th Ed., (TT)
         2.  Nature and Properties of Soils, Brady and Weil, 14th  Ed. (B)
         3.  Soil-Plant Relationships, Jeffrey (Je)
         4.  Russell's Soil Conditions & Plant Growth,  Ed. Wild (W)

     A3     Grading and Exams see (Course Homepage.)

For items handed-in late,possible points will be reduced 10% per day M-F late (I expect items to be handed-in on time). If you must miss class, please notify me before missing. For those wishing additional experiences in soil-plant laboratory procedures, consider taking Agronomy 354L for 1 credit (the lab and lecture do not need to be taken concurrently).

A31   Makeup exams:  If you must miss a regularly scheduled exam, a makeup exam may be given as long as you notify the instructor that you will be absent before the exam.  Makeup exams may be oral exams and must be completed within five class days of the exam that was missed unless there are extenuating circumstances.

     A4  Cell Phones--Please be sure your cell phone is off before coming to class. A cell phone ringing is a rude interruption to your classmates and the instructor. Please don't plan on using your cell phone for text messages or as a calculator. Bring a nonprogrammable calculator for this purpose.

     A5   Please see the General Catalog concerning ownership of course-related presentations, where specific written permission to sell notes or recordings must be obtained from the presenter.

     A6   I will attempt to follow university policies on academic dishonesty, disability accommodation, dead week, harassment and discrimination, and religious accommodation. Click here to see recommended policies.   

     A7   The purpose of this course is for the student to gain an understanding of the principles of soil fertility and soil-plant relationships.Soil: The Foundation of Agriculture )

     A8   Plant growth in soils is an aspect of applied science concerned with the sources and availability of essential nutrients and the effect of soils to support plant growth.  Soil tilth and soil-plant relationships affect availability of nutrients and plant uptake and soil air-water relationships. To understand these concepts, it is necessary to build on general information about soils, chemistry (Chemistry Review), crops, and other subjects. The student is expected to be familiar with the basic concepts of soils: (1) formation and classification, (2) physical properties, (3) composition, (4) biological processes, and (5) soil and water conservation. Remember that we will cover principles in this course that are equally applicable if your interests are agronomy, horticulture, forestry, or environmental management.

     A9   Student Learning Outcomes:

         1.  Demonstrate a basic proficiency with soil-plant growth principles and terms.
         2.  Understand the positive and negative effects of soil tillage on plant growth and soil tilth.
         3.  Understand soil chemical, physical, and biological properties that impact nutrient cycling and plant growth.
         4.  Understand soil sampling and soil test recommendations; be able to critically access fertilizer recommendations and methods of application.
         5.  Explain the role of soil colloids, ions, cation exchange, and anion exchange capacities on plant growth.
         6.  Appreciate the effects of soil pH and application of liming materials on plant growth.
         7.  Understand saline, sodic, and high pH soils and the means of amelioration for plant growth.
         8.  Understand deficiencies, soil reactions, and fertilization of macro and micronutrients in relationship to plant growth.
         9.  Appreciate organic soil amendments as sources of nutrients and to improve soil properties for plant growth.
       10.  Develop an appreciation for the complexity and importance of plant/soil/nutrient interactions.
       11.  Develop higher order and critical thinking skills through applications of soil concepts.

B1    Principles of Growth (Growth Curves)
B11        Types of response curves
B12        "Law of the minimum," diminishing returns, optimum levels (Law of the Minimum)
B13        Mathematical expressions and concepts--Mitscherlich, Bray (Mitscherlich’s Law)
B14        Response curves and economics
B2    Crop, Soil, and Climatic Factors (Text 427-442)
B3    Other Factors--pests, diseases, insects, weeds, management (Deficiencies vs. Other) (Plant Disease Diagnostics) (Iowa Plant and Insect Diagnostic Clinic)(Nutrient Deficiences and Application Injuries in Field Crops)

C1    Functions--absorption, anchorage, and storage (Roots)
C2    Structure (Plants and Their Structure)
C21        Root hairs--size, composition, and absorption sites
C22        Internal cell components--nutrient uptake involvement
C3    Microbial Interactions
C31        Rhizosphere (Rhizosphere) (Rhizosphere Image Gallery)
C32        Nitrogen fixation (The N Cycle and N2 Fixation)
C33        Mycorrhizae (Mycorrhizae Movies) (Photos) (Flooded Soil Syndrome)
C4    Growth--response to compaction, wetness, and aeration

D.    SOIL TILTH (W 378-411) (B 266-309)
D1    Definition and Introduction (Managing Soil Tilth) (Soil Water Dynamics)
D2    Soil Structure and Mechanical Behavior(Soil Physical Properties) (ISU Soil Management)
D21        Aeration porosity(Aeration) (Putting Green Aeration)
D22        Pore continuity and length Water Movement into Aeration Holes)
D23        Ease of root penetration
D3    Formation and Destruction of Soil Structure (Understanding and Managing Soil Compaction)
D4    Cultivation/Minimum Tillage (Iowa Soil Loss and Residue Cover)
D41        Seedbed preparation (Prairie Restoration Seedbed Preparation)
D42        Compacted or restricted zones (Garden Compaction) (Garden Soil Management) (Variation in Corn Yield Across Planter Width)
D43        Moisture ranges for cultivation (Soil Compaction and Drainage) (Soil Compaction: Causes, Concerns, and Cures)
D44        Adverse effects--crusting, compaction, anaerobic layers, puddled structure
D5    Nature's Plow--the Earthworm (Earthworms and Crop Management) (Earthworm Movie) (Earthworms) (Agricultural Management Effects on Earthworm Populations)

E1    Elements Found in Growing Plants
E2    Essential Plant Nutrients (Nutrient Deficiency Key) (Elements Essential for Plant Growth)
E3    Nutrient Functions (Plant Nutrients)
E4    Deficiency Symptoms (Nutreint Deficiencies Field Crops) (Plant Nutrient Deficiency Symptoms)

F.     SOIL FERTILITY EVALUATION (Text 307-363) (Soil Sampling Problem) (ISU Soil and Plant Analysis Laboratory)
F1    Hidden Hunger
F2    Biological Tests for Soil Fertility
F21        Factorial-designed experiments
F22        Field tests--research, demonstration, field strips
F3    Plant Tissue Analysis (Sampling for Plant Tissue Analysis) (Apple Production) (Plant Tissue Analysis)
F31        Sap tests (quick tests) (Potato Fertility Management) (Sap Test in Tomato)
F32        Total analysis (Sampling for Corn Plant Analysis) (Turf Analysis)
F4    Soil Testing (General Guide for Crop Nutrient Recommendations in Iowa) (Soil Testing Kits) (LaMotte) (Recommended Chemical Soil Test Procedures)
F41        Correlation and calibration of soil tests
F42        Soil sampling and GPS/GIS (ISU--Take a Good Sample to Help Make Good Decisions) (Soil Sampling for Variable Rate Fertilizer Application)
F43        Interpretation of soil test data (ISU--Interpretating Soil Test Reports)

G.    ION EXCHANGE IN SOILS (Text 17-36)
G1   Introduction of Ion Exchange--soil colloids (quartz, hydrous oxides of iron and aluminum, silicate clay minerals, humus) (Soil Colloids)
G2   Cation Exchange--source of charge, cation exchange capacity (CEC) (B 310-357; TT 136-138, 159-161) (Cation Exchange) (Cation Exchange Capacity) (Cation Exchange Capacity)
G3   Anion Exchange, Amphoteric Substances (TT 161-162)(Amphoterism)

H1    Sources of Nutrients (Symptoms of Deficiency)
H11        Minerals, soil solution, air(Elements of Minerals)
H12        Availability of plant nutrients--chemical, positional, physiological
H13        Available nutrient pool--soil solution, exchangeable ions, soil solids
H2    Nutrient Delivery to the Root and Uptake (TT 306-311) Nutrient Transport in the Soil-Plant System)
H21        Root elongation (contact exchange), mass flow, diffusion (Fick's Law)
H22        Effect of other nutrients--cation constancy, competition, antagonism

I.      SOIL REACTION (Text 49-65) (B 358-400; TT 151-158)
I1     Chemistry of Soil pH--acidity and alkalinity (Soil pH) (Soil Quality Indicator: pH)
I11         Acidic cations--H+, Al3+, others; activity
I12         Base cations--Ca2+ Mg2+, Na+, K+; activity
I2     Colloidal Control of Soil pH (Coffee Pot Analogy)
I21         Percentage base saturation
I22         Resistance to pH change (buffer capacity)
I23         Nature and proportion of soil colloids Sorption of Chemicals)
I24         Kind and proportion of sorbed ions; lyotropic series (TT 150-151)
I3     Changes in Soil pH (Soil Acidity and Liming)
I31         Acid-forming factors--crop removal of bases, leaching, fertilizers, erosion, oxidation of reduced S, acid rain (Acid Rain)
I32         Base-forming factors--salt accumulation, mineral weathering, residue return

J1    Acidic Soils--active acidity, potential acidity, lime requirement (Causes of Soil Acidity)
J2    Soil pH for Crop Production (Soil pH and Landscape Plants) (Trees and Shrubs for Acid Soils)
J21         Influence of soil reaction on nutrient availability
J22         Crop response to liming (TT 165-173) (Crop Response to Liming)
J23         Effects of lime on soil:  physical, chemical, and biological
J3    Ca and Mg as Plant Nutrients (Soil Calcium:Magnesium Ratios) (TT 269-275) (Soil Cation Ratios for Crop Production)

K1    Lime Needs in Iowa and the United States (Understanding Value in Lime)
K2    Liming Materials (B 387-395) (Home/Garden Soil pH Adjustment) (Liming Vineyard Soils)
K3    Limestone Quality and Effectiveness (Iowa Limestone Law) (Liming Materials) (Choosing Between Liming Materials)
K4    Practical Aspects of Liming--rate, method, timing, and frequency of application; over-liming

L1    High Lime Soils--identification, pH, management
L2    Saline and Sodic Soils--identification, pH, management, reclamation (B 413-446) (Managing Saline Soils) (Managing Sodic Soils) (US Salinity Lab) (Salt-Affected Soils)
L3    Irrigation Water Quality (Irrigation Water Quality Criteria)
L4    Acidifying Soils (Soil Acidification) (Gypsum) (B 395-396; TT 173-175)

M.   SOIL ORGANIC MATTER MANAGEMENT (Text 451-476) (TT 105-126) (B 495-541) (Advanced Soil Organic Matter Management) (Soil Carbon Storage)
M1   Nutrient Reservoir (Importance)
M2   Changing Soil Levels of Organic Matter (Soil Health) (How to Increase Organic Matter in Soil) (Soil Organic Matter)
M21       Additions
M22       Deletions
M23       Reduced tillage
M3   Plant Residues versus Soil Humus--chemical structure
M4   Ligand Binding with Metals, especially Al and Cu (Soil and Applied Copper)

N.     NITROGEN IN THE SOIL (Text 117-161) TT 211-224)
N1    Nitrogen as a Plant Nutrient (Role in Plants)
N2    Nitrogen Fixation--symbiotic organisms, free-living organisms (Nitrogen Fixation by Forage Legumes)
N3    Forms of Soil Nitrogen--inorganic and organic (Iowa Fertilizer Law)
N4    Transformations of Nitrogen Forms in Soils (Transformations)
N41        Immobilization and assimilation
N42        Mineralization and dissimilation Nitrogen Availability from Organic Fertilizers)
N43        Nitrification (Nitrification Inhibitors)
N5    Losses of N by Erosion, Crop Removal, and Leaching
N6    Gaseous Losses of Nitrogen--volatilization of ammonia(Ammonia Volatilization), denitrification

O.     NITROGEN FERTILIZATION (Text 161-184) (TT 224-230)
O1    N Fertility Evaluation (Nitrogen Fertilizer Recommendations for Corn in Iowa) (Fertilizing Pastures) (Concepts and Rationale for Regional Nitrogen Rate Guidelines for Corn) (Nitrogen Rate Calculator)
O2    Organic Nitrogen Sources
O3    Inorganic Nitrogen Sources (Prices)
O31        Production Methods--cyanamide, Haber-Bosch
O32        Forms--solid, liquid, and gaseous
O4    Use of N Fertilizers (Understanding Fertilizers) (Lawn Care Plans) (Nitrogen Extenders and Additives)
O41        Time and method of application
O42        Recovery of applied N in the plant (N Management) (Don't Go 50oF or Below) (Cornstalk Nitrate Testing)
O43        Probability of losses by leaching and volatilization
O44        Urease Inhibitors (Urease Inhibitors)
O5    Effect on Soil Acidification
O6    Environmental Concerns and Eutrophication (Methemoglobinemia) (Hypoxia) (Nitrogen Management for Water Quality Protection)

P.     PHOSPHORUS IN THE SOIL (Text 185-208) (TT 231-240)
P1    Phosphorus as a Plant Nutrient (Calculate Nutrient Removal) Phosphorus)
P2    Phosphorus Content of Soils (P in Iowa Soils)
P3    Forms of Soil Phosphorus--soluble, inorganic, organic
P4    Factors Influencing Phosphorus in Soils--type of clay, time of reaction, soil pH, moisture, temperature, organic matter (Iowa P-Index Manure Management)

Q.    PHOSPHORUS FERTILIZATION (Text 208-221) (TT 240-249)
Q1   P Fertility Evaluation
Q2   Phosphorus Content of Fertilizers (P Sources for Corn Fertilization)
Q3   Classification of P Fertilizers by Solubilities--water-soluble, citrate-soluble, non-soluble
Q4   Phosphorus Fertilizers--rock phosphate, superphosphates, ammonium phosphates, others (Phosphorus Fertilizers) (Does Your Lawn Really Need Phosphorus?)
Q5   Behavior of P Fertilizer in Soils
Q6   Placement and Methods of Application of P Fertilizers (Phosphorus Fertilizer Placement)
Q7   Pollution Potential (Eutrophication) (Phosphorus Management and Water Quality)

R.     POTASSIUM IN THE SOIL (Text 223-235) (TT 251-261)
R1    Potassium as an Essential Nutrient (Potassium Deficiency in Corn)
R2    Soil Origin and Content
R3    Potassium Equilibria in Soil (Potassium in Missouri Soils)
R31        Soluble K, exchangeable K, nonexchangeable K
R32        Readily available K, slowly available K, unavailable K
R4    Factors Affecting Potassium Equilibria in Soils
R5    Agricultural Significance of Potassium Equilibria:  availability, retention, legume-grass competition, root CEC, luxury consumption, placement, losses

S.     POTASSIUM FERTILIZATION (Text 236-238) (TT 261-268)
S1    Potassium Fertilizers
S11        Reaction in the soil (Potassium Fertilization Rate Effects)
S12        Response of crops, luxury consumption, relation to sodium
S2    Time and Frequency of Application (Getting Ready for Fall Fertilization)
S21        Rotation of crops
S22        Annual and perennial crops
S3    Placement and Method of Application (K Fertilization)

T.     SULFUR IN SOIL AND FERTILIZERS (Text 239-252) (TT 275-279)
T1    Sulfur as a Plant Nutrient (Sulfur Fertilization Response in Iowa Corn Production)
T2    Kinds and Behavior of Sulfur Compounds in Soils
T21        Organic S
T22        Inorganic S--sulfate, sulfides, elemental
T23        Practical aspects
T3    Sulfur Materials Added to Soils
T31        Fertilizers (Role of Sulfur in Plant Culture) (Ammonium Sulfate as a Lawn Fertilizer) (Soil and Applied Sulfur)
T32        Soil amendments (Effectiveness of Gypsum)

U.     MICRONUTRIENTS AND TOXIC ELEMENTS (Text 261-305) (TT 283-304)
U1    Functions in Plants (Micronutrient Functions)
U2    Iron: Deficiencies and Fertilizers (Iron Deficiency in the Home Yard) (Iron Deficiency in Soybean)
U3    Brief Overview of Each Micronutrient (Micronutrients in Crop Production)
U4    Influence of Soil Factors--clay, organic matter, moisture, pH
U5    Most Common Deficiencies In Iowa
U6    Toxic Elements

V.     ORGANIC WASTES AND FERTILIZERS (Text 409-420) (Managing Manure Nutrients) (B 694-708)
V1    Nutrients in Animal Manures--composition, availability, environmental concerns (Iowa Manure Management Action Group)
V2    Wise Use of Nutrients in Manures (Sampling Manure for Nutrient Analysis) (Iowa Manure Application)
V21        Minimizing losses (Iowa P Index) (10 Questions about the P Index in Iowa)
V22        Time and methods of application
V3    Value of Manures--crop responses, long-time effects (Value of Manure Nutrients) (How to Interpret your Manure Analysis) (What's Manure Worth Calculator)
V4    Compost, Sewage Sludge, Other Wastes (Composting Dead Livestock) (Organically Acceptable Inputs) (On Farm Composting) (Milorganite)
V5    Green Manures and Meadow Crops (Green Manure)

W.    FERTILIZER PLACEMENT (Text 373-409) (B 712-718; TT 195-202)
W1   Root and Soil Characteristics
W2   Methods of Placement (Fertilizer Placement) (Don't Underestimate the Valvue of Starter)
W3   Salt Index(Salt Index) (Managing Soluble Salts)
W4   Time of Application (Nutrient Uptake Timing by Crops) (Iowa Strategy to Reduce Nutrient Loss)
W5   Fertilization of a Rotation (Tillage and Fertilizer Placement for the Corn-soybean Rotation)

X.     ECONOMICS OF FERTILIZATION (Text 427-450) (TT 191-192, 200-202)
X1    Maximum Economic Yield (N Fertilizer Management) (Economics of Tile Drainage)
X2    Variables of Management and Input Costs(Nitrogen Rate Calculator)
X3    Price per Pound of Nutrient/Returns (Nonconventional Soil Additives) (Fertilizer Cost Calculator)
X4     Total Production System

Please schedule an appointment if you need help

with any aspect of the course. 


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