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Basics of Crop Production


Soil and Plant Fertility Soil Quality This is the most important factor in farm crop production. Soils will determine which plant species yields the most, the time of ... – PowerPoint PPT presentation

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Title: Basics of Crop Production

Basics of Crop Production
  • Soil and Plant Fertility

Soil Quality
  • This is the most important factor in farm crop
  • Soils will determine which plant species yields
    the most, the time of harvest, and ultimately the
    investment a landowner must make to yield an
    acceptable economic return from management.

Soil Profile
The soil profile shows the layers, known as
horizons that represent the soil.
Horizons formed over the centuries due mostly
form weathering.
A lettering system is used to name the different
Where can you find info on a farms soil?
  • In the County Soil Survey Map.
  • There are Tables on several land options such as
    Woodland Management and Productivity which
    provides a lot of valuable information on the
    potential for soil erosion, seedling mortality,
    species preference, and tree growth.

County Soils Map
  • There is even a table in the Soil Survey Map
    that evaluates sites for wildlife habitat.

Factors Controlling Plant Growth
  • Light
  • Mechanical Support
  • Heat
  • Air
  • Water
  • Nutrients
  • All except for light, involves soil

Major Components of Soil
Soil Terminology
  • Soil texture - concerns the size of mineral
    particles, specifically the relative
    proportion of various size groups in a given
  • Soil structure - the arrangement of soil
    particles into groups of aggregates

Soil Texture
  • Soil texture is separated into three soil
    separates based on particle size.
  • Sand
  • Silt
  • Clay

Soil Texture
  • Silt, clay - imparts a fine texture and
    slow water and air movement, also high water
    holding capacity
  • Sandy to gravelly - are referred to as
    lighter soils with lower water holding capacity

Soil Texture
  • Sandy soils are normally very well drained and
    often lack nutrients due to constant leaching
  • Mostly clay soils are at the opposite end of the
    soil spectrum. They tend to allow water to move
    through more slowly and will stay wetter longer.
    They will hold nutrients.

Soil Terminology
  • Pore space - is that portion of the soil
    occupied by air and water
  • - sandy soils have low soil porosity, while
    silt and clay soils have high soil porosity
  • Soil compaction - fine textured, wet soils
    are more easily compacted
  • - compaction reduces pore spaces

Soil Terminology
  • Soil depth
  • - defined as that depth of soil material
    favorable for plant root penetration
  • - deep, well drained soils are the best

Soil Terminology
  • Slope - land topography largely
    determines the amount of drainage, runoff,
    and erosion - the steeper the land, the
    more management is required

Soil Terminology
  • Organic matter - it consists of plant and
    animal residues in various stages of decay
  • - adequate levels benefit soil by
  • 1) improving physical condition
  • 2) increasing water infiltration
  • 3) improving soil tilth
  • 4) decreasing erosion losses
  • 5) supplying plant nutrients
  • 6) holding cation nutrients

Soil Terminology
  • pH - expression of both acidity and
    alkalinity on a scale whose values run from 0
    to 14 with 7 representing neutrality, lt7
    represents acidity, and gt7 represents
  • pH has a significant impact on the availability
    of soil nutrients
  • pH 6.5 - pH objective for most ag crops

pH Scale
The figure shows the break down of where acidity
to alkalinity is on the pH scale. PH 7 is
pH Effect on Nutrient Availability
This has a direct impact on plant health. For
most agricultural crop recommendations, the goal
is to have a 6.5 pH. At this pH most of the
essential plant nutrients are available.
This graphic shows how the major plant nutrients
change in availability with the increase and
decrease of pH.
The wider the black band in this graphic, the
more available the nutrient.
pH Preferences by Plants
As can be seen from the black bands, most plants
prefer a pH between 5.5 and 7.0.
This graphic shows the range in pH preferred by
plants. This shows that it is important for
producers to know the fertility and pH
requirements of the plants they plan to grow.
A pH below 5.5 is considered to be very acid and
above 7.0 is alkaline.
Limiting Factors
  • A layer which restricts the downward penetration
    of a plants root system
  • will reduce growth in direct relation
  • to the depth of the layer.
  • On rare occasions, a limiting layer may increase
    site productivity, such as on sandy soils where
    the layer may retard leaching of nutrients and
    increase available moisture.

  • Subsoilers have long shanks that physically dig
    down to break open the hard soil to form channels
    where plant roots can penetrate.

There are farm implements available that can
breakup soil hard pans and improve the crop
production in otherwise limited soils.
16 Essential Elements (part 1)
The primary elements are plant nutrients that are
needed and most used by plants for growth. The
primary nutrients can be found in commercial
complete fertilizers as the fertilizer number
reflects these three elements, i.e. 10-6-4.
  • Primary Nitrogen (N) Phosphorus
    (P) Potassium (K)
  • Secondary Sulfur (S) Magnesium
    (Mg) Calcium (Ca)

Secondary elements are the next most needed plant
nutrients. Magnesium and calcium are obtained
from liming materials. During the Industrial
revolution, most of our sulfur came from air
pollution (sulfur dioxide).
In recent years, producers have had to routinely
include supplemental sulfur to their crop
fertility programs as the air around us becomes
less contaminated with sulfur.
16 Essential Elements (part 2)
  • Micro-nutrients Iron (Fe) Manganese
    (Mn) Boron (B) Chlorine (Cl) Zinc
    (Zn) Copper (Cu) Molybdenum (Mo)

16 Essential Elements (part 3)
  • The final three (3) essential elements to plant
    growth come mostly from air and water.
  • They are Carbon (C) Hydrogen
    (H) Oxygen (O)

The Primary Elements
  • Nitrogen It gives plants their green color,
    promotes above ground growth, and regulates
    utilization of other elements.
  • Phosphorus It has favorable affect on
  • - cell division - stem strength
  • - crop maturation - root development
  • - flowering/fruiting - disease resistance

The Primary Elements (cont)
  • Potassium (K) - It is essential for starch
    formation and translocation of sugars. It is
    also essential to the development of
    chlorophyll. K helps plants to over-winter.

What is the nutrient content of commercial
  • Expressed as a percent called the guaranteed
    analysis or fertilizer grade.
  • Nutrient content always appears in this order
  • total nitrogen
  • available phosphate (P2O5), or
    phosphoric acid
  • soluble potash (K2O)

The Fertilizer Number
  • The fertilizer number refers to a ratio of N-P-K
  • 5-10-5 (1-2-1 ratio) has 5 N 10 P205
    5 K20 20
  • The other 80 of the material is called the
    carrier. This is typically some inert material.
  • 10 - 6 - 4 (2-1-1 ratio) 10 -10 -10
    (1-1-1 ratio)

What does a fertilizer guarantee mean?
This bag contains
nitrogen--10 phosphate--15 potash

2.5 lbs. nitrogen

5 lbs. phosphate

7.5 lbs. potash
Ag-Gro-Pro 5-10-15 50 lbs.
Common Fertilizers
  • Urea 46 - 0 - 0
  • Ammonium nitrate 34 - 0 - 0
  • UAN 30 - 0 - 0
  • Ammonium sulfate 21 - 0 - 0
  • Diammonium phosphate 18 - 46 - 0
  • Triple superphosphate 0 - 46 - 0
  • Muriate of potash 0 - 0 - 60

Determining Fertilizer Need
  • Production Goal Total lb/A N - P - K
  • soil reserve - N P - K
    crop residue - N
  • manure - N - P - K
  • ______________
  • Commercial fertilizer lb/A N - P - K

Example Calculating the Quantity of Commercial
Fertilizer Required to meet a Nutrient
  • Jasper Little Farm
  • needs 60 lbs./A of potash (K2O) on his soybean
  • broadcasts muriate of potash (0-0-60) pre-plant
  • see Example 4-1, p.18 in training guide

Calculating Quantity of Commercial Fertilizer
  • 1) RECORD recommended quantity of nutrient (see
    nutrient management plan).
  • 2) RECORD the percentage of nutrient in the
    preferred product, muriate of potash.
  • 3) CONVERT the percentage of nutrient to a
    decimal fraction by multiplying the by .01

60 lbs./A
60 x 0.01 .60
Calculating the Quantity of
Commercial Fertilizer CALCULATE the quantity of
muriate of potash required in lbs./A divide the
recommended quantity of nutrient by the nutrient
content expressed as a decimal fraction.
60 lbs./A 0.60 100 lbs./A
  • Little needs 100 lbs. of muriate of potash to
    supply 60 lbs. of potash. Done!

Determining Production Goal
  • Cropping history
  • Soil Survey Map/Soil Capability Chart
  • Investigate species/variety potential - other
    growers - field days - private and
    university trial results
  • FSA records
  • Experimentation

Determining Yield Goal
  • Take the average yield for typical years that a
    crop is grown in a certain field.
  • Estimate yields goal by averaging the yield from
    the best 3 of 5 growing seasons.
  • When actual yield data is not available,
    estimated yields for the soil type in the field
    can be found in MASCAP.

Soil Reserve
  • Soil test - university lab - private
  • Frequency of testing - depends on crop and
  • Typical test looks at P, K, Ca, Mg, O.M., and pH.
    Minors are as needed.

Fig. 1-1 Phosphate Recommendation (lbs/A) as a
function of soil fertility level (FIV-P) for corn
grain (yield goal-150 bu/A)
Crop Residue
  • Benefits left by a previous crop or cover crop
  • Previous crops leave little unless it was a
    leguminous crop
  • Leguminous crops leave nitrogen
  • The amount of N left depends on the species of
    legume and the stand density and maturity.
  • Cover crops are not harvested and will recover
    nutrients otherwise lost.

Manure Analysis is available from the University
of Marylands Soil Testing Laboratory.
How much of the nitrogen in manure is
  • It depends on
  • the nitrogen content
  • animal species
  • incorporation practices

Figure 2- 3b. Distribution of organic nitrogen
ammonium nitrogen in dairy manure
This dairy manure contains 12 pounds of total
nitrogen per ton.
Available Organic Nitrogen Only part of the
nitrogen in manure becomes plant-available --
through the process of mineralization -- the year
its applied.
Nitrogen Credits
  • Organic nitrogen in organic sources continues to
    break down or mineralize for several years after
  • The largest proportion of this organic nitrogen
    breaks down and becomes available in the year of
  • Organic sources include manure, biosolids
    (sludge), and composts.

Nitrogen Credits
  • Progressively smaller amounts of the organic
    nitrogen break down and become available in the
    subsequent years.
  • Credit needs to be given to this available
    nitrogen from previously applied manure to the
    current years nitrogen recommendation.

Figure 2- 4b Distribution of Available Nitrogen
from Organic and Ammonium Nitrogen
Components in Dairy Manure
0.6 lb
2.4 lb
6 lb
3 lb
This dairy manure contains 12 pounds of total
nitrogen and 5.4 pounds of available
nitrogen per ton
Dont Overload!
A funny slide to breakup the class. This could
be an Iraqi surface to air missile.
  • Manure Mineralization Factors
  • Vary by animal species.
  • See Table 2-1 in the Nutrient
    Applicator Guide.

The mineralization rate of manure varies between
animal species. A table explaining these
differences can be found in the Nutrient
Applicator Guide on page 10.
Available Ammonium Nitrogen
  • NH4 is a plant-available form of N.
  • When manure is left on the soil surface after
    application, it can be lost through the process
    of volatilization.
    Nitrogen Loss

Estimated Manure Values
  • Dairy (fresh, spread daily) 89 moist. 7 - 3
    - 6 (lb/T)
  • Dairy (stored outside, leachate lost) 87 moist.
    3 - 2.5 - 4 (lb/T)
  • Poultry (layer stored in pit) 65 moist. 25
    - 27 - 24 (lb/T)
  • Swine (storage tank beneath slotted floor) 95
    moist. 2.5 - 3 - 5 (lb/T)
  • Beef (bedded manure pack under roof) 80 moist.
    5 - 4 - 8 (lb/T)

Example Calculating Quantity of Dairy Manure to
Meet Crop Nutrient Recommendation Ralph Gonzales
  • PAN content of semi-solid dairy manure is 6
  • wants to supply the N for his corn crop
  • yield goal is 120 bu/A
  • incorporates the manure the same day as
  • see Example 4-2, p.19 in training guide

Calculating Quantity of Dairy Manure to Meet
  • Note The nitrogen recommendation for corn grain
    is 1 lb./A of PAN per bushel of yield.
  • 1) RECORD nitrogen recommendation (lbs./A) from
    the nutrient management plan.
  • 2) RECORD PAN of manure (lbs./T)

120 lbs./A
6 lbs./T
Calculating Quantity of Dairy Manure to Meet
Recommendation CALCULATE the quantity of manure
required in T/A divide the nitrogen
recommendation by the PAN of manure.
120 lbs./A 6 20 T/A
  • Twenty tons of a dairy manure with this PAN are
    needed to provide 120 lbs./A of
    PAN. Done!

Use of Raw Manure
  • Heavy applications can throw off nutrient balance
  • Excess available N can lead to excessive growth
    and nitrate buildup in plant
  • Plants with high nitrates do not store as well
    and attract insects
  • Nitrogen and phosphorus are pollutants
  • Weed seeds pass through animals

Often Forgotten Sources of N
  • Carryover from past manure/biosolids
  • Cover crops ( fixed recycled N)
  • N released from soil organic matter
    (40-80 lb/A)
  • Nitrates in rain irrigation water
  • Weeds, plowed down have slow-release N, 85 lb/T
    pigweed, 80 lb/T lambsquarter
  • Crop residues, humus, bedding, and composts

The Nitrogen Cycle
Input to soil
Loss from soil
Atmospheric nitrogen
Industrial fixation (commercial fertilizers)
Atmospheric fixation and deposition
Crop harvest
Animal manures and biosolids
Plant residues
Runoff and erosion
Biological fixation by legume plants
Plant uptake
Organic nitrogen
Nitrate (NO3)
Ammonium (NH4)

The Phosphorus Cycle
Input to soil
Loss from soil
Atmospheric deposition
Crop harvest
Animal manures and biosolids
Mineral fertilizers
Plant residues
Runoff and erosion
Primary minerals (apatite)
  • Organic phosphorus
  • Microbial
  • Plant residue
  • Humus

Mineral surfaces (clays, Fe and Al oxides,
Plant uptake
  • Soil solution
  • phosphorus
  • HPO4-2
  • H2PO4-1

Secondary compounds (CaP, FeP, MnP, AlP)
Leaching (usually minor)
The Potassium Cycle
Input to soil
Loss from soil
Animal manures and biosolids
Crop harvest
Plant residues
Mineral fertilizers
Runoff and erosion
Exchangeable potassium
Plant uptake
Soil solution potassium (K)
Fixed potassium
Mineral potassium
The Sulfur Cycle
Input to soil
Loss from soil
Atmospheric sulfur
Atmospheric deposition
Crop harvest
SO2 gas
Mineral fertilizers
Plant residues
Animal manures and biosolids
Elemental sulfur
Runoff and erosion
Absorbed or mineral sulfur
Plant uptake
Organic sulfur
Reduced sulfur
Bacterial oxidation
Sulfate Sulfur (SO4)
Bacterial reduction
Fertilizer Application Terms
  • Broadcast - fertilizer is applied uniformly
    to entire field before crop emerges
  • Topdress - fertilizer is applied uniformly
    to entire field after crop emerges
  • Plowed down or tilled in - fertilizer is
    applied to field then is tilled in with a disk
    or a plow

Fertilizer Application Terms
  • Banded - fertilizer is applied directly
    over the top of the crop row, generally
    before the crop emerges, omitting the area
    between the rows
  • Side-dressed - fertilizer is applied
    directly to growing crop, generally in a band
    at the base of the plant

Calibrating Nutrient Application Equipment
  • Calibration is a way to set your application
    equipment to apply material uniformly at the
    desired rate.
  • It insures application of the required amount of
    nutrients without over-fertilizing.
  • Two common methods are used - weight-area
    method - load-area method

Basics of Calibration
Determining the square feet in an area is basic
to the calibration of farm equipment. The size
of an area can be determined by multiplying
length X width.
Area Length x Width
L e n g t h
L e n g t h
How to Calibrate Nutrient Application Equipment
  • Measure the actual rate of application.
  • Compare actual application rate to the
    recommended application rate.
  • If the application rate is substantially greater
    or less than the recommended rate, try -
    changing equipment settings, or - changing
    ground speed of the tractor

Load-Area Method
  • Know
  • capacity of the spreader
  • size of the area where manure is spread
  • Apply nutrient supplying material, then measure
    area of application. Project rate of application
    to a per-acre basis.

Weight-Area Method for Manure
  • 1. Arrange at least 3 plastic sheets in the
    center of the spreaders path.
  • 2. Drive the spreader over the center of the
    sheets at a known speed with specific equipment
  • 3. Collect weigh the manure on each sheet.
  • 4. Average the quantity applied to the sheets and
    project to T/A.

Weight-Area Method
  • Works well with calibrating fertilizer spreaders
    and planters.
  • Works well with calibrating both dry and liquid
    manure spreaders.
  • - pans can be used to catch liquid manure
  • - plastic sheets can be used to catch dry manure

Basics of Calibration Using Sheets and Pans
This diagram shows how pans and sheets can be
arranged in a field to calibrate a spreader.
Spread manure
Spread manure
Refer to your Nutrient Applicators Training
Guide for additional help
Lets take a quick look at some other materials
we apply to our soils.
  • Supplies calcium and magnesium
  • Mined calcium carbonate is the principle liming
    material, typically 50 oxides
  • CaCO3 equivalent is the basis for liming material
    recommendation rates
  • Comes in various forms and grades

Comparing Liming Materials
  • Effective Neutralizing Value
  • E.N.V.
  • This is a comparative value that refers to the
    ability of a liming material to modify soil pH
    within a year.
  • Reference Standard
  • Calcium carbonate (CaCO3)
  • E.N.V. 100

This means that liming materials are compared
(greater than or less than) to the neutralizing
ability of calcium carbonate. E.N.V. can be
found on the labels of liming materials and
fertilizer as an indicator of the products impact
on soil pH.
  • Mesh size determines how quickly it reacts in the
  • Good quality ag lime is typically 80 90-100
    mesh and 20 40 mesh
  • Ground dolomite (dolomitic lime) is over 10
    magnesium it is a good source of Mg when needed

Other Liming Agents
  • These are typically industrial byproducts
  • These include stack dust, sludge lime, and river
  • Domino Sugar lime is a new source
  • Solubility and oxides vary, so get an analysis
  • These contain mostly Ca and traces of other
    elements and materials

Liming Recommendations
  • Know the analysis, especially
    oxides -Application rate is based on lb/A
  • calcium and magnesium - may not need
    additional Mg
  • Oxide form of calcium (CaO) is readily available
  • Mesh size of carbonate form of Ca (CaCO3 )
    reflects its availability - smaller
    particles work faster

Liming Notes
  • Limestone recommendations are based on raising
    the pH of the plow layer (top 7-9) to 6.5
    except for special crops i.e. alfalfa.
  • Limited to 1,500 lb/A oxides/year when not
    incorporating i.e. pastures
  • Avoid applying liming products and fertilizer at,
    or around the same time.
  • Liming materials laying on the surface will
    neutralize pesticides.

Compost Decomposed Plant animal Matter
  • When correctly done
  • - pH is near neutral
  • - CN ratio is 151
  • - Majority of weed seeds disease organisms are
  • - Offers a well balanced slow release supply of
  • - As much as 1/4 of compost weight is microbes
    (dead alive)

Principles of Composting
  • Best composts come from piles with the highest
    microbial activity
  • Temperature is easiest sign of microbial activity
  • Good composts heat to approximately 140 - 1600 F
    within the first 3 or 4 days

Principles of Composting
  • Small particle size makes a greater surface area
    available to microbes - particles that are too
    small however can pack a pile
  • Adequate volume, or size of pile keeps it from
    cooling too quickly - piles 4 x 4 x 4 ft. do

Unfinished Composts
  • Can hurt crops
  • Chemicals formed in process are toxic to plants
  • N can be tied up
  • Good composts take 12 - 18 months
  • Moisture must be adequate (50 - 70) similar to a
    squeezed sponge
  • CN ratio in initial pile should be 301

Common CN Ratios
  • Undisturbed top soil 101
  • Alfalfa 131
  • Rotted barnyard manure 201
  • Corn stalks 601
  • Small grain straw 801
  • Oak 2001
  • Spruce 10001

Compost Problem Solving
  • Bad Odor
  • - not enough air
  • - turn the pile more frequently
  • Center of pile too dry
  • - not enough water
  • - moisten while turning

Compost Problem Solving
  • Pile is damp warm in center, but nowhere
    else - pile is too small - collect
    more material and mix the old ingredients into
    a new pile
  • Pile is damp and sweet smelling, but will not
    heat up - lack of nitrogen - mix in
    N-rich material like fresh grass, manure, or

Crop Rotation and Cover Crops
  • Benefits crop fertility - fixed and
    recaptured nutrients
  • Benefits soil structure (tilth) - cover crops
    add organic matter - variability in root growth
    improves soil pores and water penetration
  • Pest management - breaks the parasite life
  • Harvest vs. cover crop is the decision

Some Parting Advice
  • Seek help when you are not sure about what you
    are doing. There are a lot of resources out
    there for you.
  • Dont be like the old farmer who told the County
    Agent that he did not need any advice. He told
    the Agent that he has already worn out two farms
    and that he had his own way of doing things.