Chapter 5-8 Flashcards
Non mineral nutrients (3)
Carbon (C)
Hydrogen (H)
Oxygen (O)
Mineral nutrients (Macronutrients)
Nitrogen (N)
Phosphorus (P)
Potassium (K)
Secondary nutrients
Sulfur (S)
Calcium (Ca)
Magnesium (Mg)
Micronutrients
Iron (Fe) Zinc (Zn) Manganese (Mn) Copper (Cu) Boron (B) Chlorine (Cl) Molybdenum (Mo)
17th nutrient
Sodium (Na)
Liebig’s Law of the Minimum
Plant production can be no greater than the level allowed by the growth factor present in the lowest amount (limiting factor) relative to the optimum for that factor
Von Liebig
Rainfall
Nutrients
Heat
Light
Elements essential to range plants
Silicon (Si)
Selenium (Se)
What makes nutrients essential
- Plants cannot complete lifecycle without element
- Deficiency symptoms for element can be corrected only by supplying said element
- Element is directly involved in nutrition of plant apart from its effect on chemical or physical properties of soil
Nutrients associated with crop yield and vegetative growth
Nitrogen
Sulfur
Nutrients immobile in soil
Phosphorus
what are the preferred forms of nitrogen taken by plants
Nitrate
Ammonium
Law of Diminishing Returns
If a growth factor is limiting, growth response will be greatest for the first increment added and least for the last increment added
Nutrient mobility concept
As the mobility of a nutrient in soil decreases the amount needed in the soil increases from a value equal to the product of maximum yield and optimum plant composition to a constant
Plant Nutrient Status Terminology
What is Sufficient
Nutrient concentration is adequate to support plant growth
Deficient
Occurs when concentration of nutrient is so low that crop yields are reduced
Toxic
Occurs when concentration of nutrient is too high causing reduced crop yields
Soil nutrient status determination
Visual examination
Chemical analysis
-soil /forage test
-More accurate
Signs of deficiency N-P-K
Nitrogen
- Chlorosis of leaves
- Starts at base of plant
Signs of deficiency N-P-K
Phosphorus
- Plants stunted
- Leaves darker green than normal
- Lower leaves often purplish between veins
Signs of deficiency N-P-K
Potassium
-Chlorosis of leaves beginning at margins and continuing toward center of plant
Benefits of soil testing
- Increases productivity
- Increases fertilizer use efficency
- Identifies polluted or contaminated soil
How to take a soil sample
- Sample before crop starts growing
- Collect 15 to 20 samples
- Zig Zag across field to recieve accurate representation
- Sample at proper depth where roots are
- Typically 4 to 6 inches deep
How to read a soil test report
- top part what is in soul what was tested
- bottom part interpretations of soil
pH scale
- Good range for plants is 5.5 to 7.5
- # below 7 more acidic
- # above 7 basic
- Legumes need to be more towards 7
- Grasses can handle a pH of 5.5
pH trend of Oklahoma
Eastern part of state
- more acidic that west
- due to more rainfall
- And different parient material
Correcting soil pH
Acidic soils
- Application of lime to increase pH
What is soil solution
- Water and associated solutes
- Many solutes are mineral ions that were once absorbed on soil particles
- Mineral ions the nutrients that plants absorb
Nitrogen cycle is characterized by what
- Inputs
- Transformation
- Losses
What are the inputs for the nitrogen cycle
- Bacteria
- lightning
- fertilizer
- organic matter
In the nitrogen cycle what are the transformations
- mineralization
- nitrification
- dentification
In the nitrogen cycle what are the losses
- runoff
- leaching
- plant consumption
- gaseous losses
What is the carbon to nitrogen ratio
in organic material determines which scenario occurs
Benefits of organic matter
- Nutrient supply
- Water holding capacity
- Soil structure aggregation
- Erosion prevention
What is soil
A dynamic natural body composed of mineral and organic materials and living organisms in which plants grow
Compositions of soil
25% air
25% water
45% minerals
5% organic matter
What are the 5 factors of soil formation
- Climate
- Living organisms
- Parent material
- Topography
- time
A horizon
Enriched with nutrients giving darker color
B horizon
Clay accumulation
Soil tilth
- Physical condition relates to tillage, planting, germination, and emergence
- Soil with good tilth will have adequate pore space to hold water and air and an adequate supply of nutrients
- This is a function of soil structure, soil texture, soil fertility, and soil organic matter
- Maintain soil tilth requires careful timing of farming operations and is improved by reducing tillage
What are the texture sizes
- clay
- silt
- sand
What are the anchored water nutrients
Soil provides plants with anchor, water and nutrients
What is the bulk density formula
Soil volume (cm)
the mass of soil per unit volume
What does high density make
root growth and tillage difficult
Forms of soil water
- Gravitational water
- Capillary water
- Hygroscopic water
What is gravitational water
Water that moves downward through soil profile due to the force of gravity
What is capillary water
Water that is held in the soil pore spaces against force of gravity
What is hygroscopic water
Water that is held tightly and forms film around soil particles
What are water conditions
Gravitational
Capillary
hygroscopic
What are the land capability classes and what are they used for
Class 1,2,3 -Row cropping Class 4,6 -Pasture land class 5 - flooding Class 7 -Woodland Class 8 -recreational
What are the soil properties
- texture
- structure
- soil organic matter
- density
- pore space
- aeration
- water content
Textures:soil particles size
Clay - smallest
silt - medium
sand - largest
What is aeration
the process by which in air in the soils os replaced by air from the atmosphere
What is percolation
the downward movement of water through soil
What is root penetration
How far down roots are capable of penetrating the soil
Soil organic matter is what %
5%
What are the benefits of soil organic matter
- Provides nitrogen (main one)
- supplies soil binding factors
- has colloidal properties
- increases water holding capacity
- improves soil aeration
- reduces soil erosion
- modifies soil temp
- acts as a soil buffer against rapid pH alterations
Total pore space
is usually lower and water content higher at greater depths
-50%
what is pore space occupied by
Air and water
What is the purpose of tillage
- Seedbed prearation
- Improves physical condition of soil
- Weed control
- Residue management
- incorpration of chemicals
- soil moisture mangement
Types of tillage
- conventional
- conservation
What is conservation tillage
Leaves crops residue on soil surface
fallos
soil mulches
conservation of soil nitrates
what is conventional tillage
buries crop residue
Intertillage
- Tilling in between row crops
- Primary purpose is weed control
Whats the difference between primary and secondary tillage implements
Primary cuts deeper into the soil than secondary
Depth of seeding
- The larger the seed the deeper it can be planted
- The dry the soil the deeper you can plant to put seeds into contact with moisture.
- Seeds will emerge from greater depths in sandy soil or. clay soil
What is the objective in spacing crop plants
the maximum yield on a unit area without sacrificing quality
What is the pure live seed formula
100
What weed is illegal to sell
Thistle
What is dormancy
when a seed fails to grow immediately after maturity, even though external conditions favor germination, until they have passed through an after-ripening process
What is scarification
involves cutting the seed coat using abrasion, thermal stress, or chemicals to encourage germination.
What is stratification
the process of treating stored or collected seed prior to sowing to simulate natural winter conditions that a seed must endure before germination
What is inoculation
the inoculation of seeds with a specific culture of bacteria
What is germination
to develop into a plant or individual-the process where the embryo becomes activated and develops into a new plant.
Chemical compositions
Grasses store most of their food supply as carbohydrate while legumes store most of their food supply as fat and oil. Thus legumes have higher fat and oil content and grasses have high carb. Content.
Seed treatment
Scarification- scratching
Stratification-Chilling
Pesticides- more warmth and moisture more likely to prevent diseases.
Inoculation- seeds coated in inoculant
Rhizobium- microbe fix Nitrogen with Legumes
Mycorrhizae- Enhance nutrient and water uptake.
Conditions necessary for germination
- Ample supplies of water and nutrients
- Suitable Temperature
- Light
Germination test
- 100 seeds put into germination chamber
- Count how many germinated
- 4 separate tests needed
Classification of seeds and their meaning
Breeder-controlled by originator, or by sponsoring plant breeder Foundation- White Label-handled to most nearly maintain specific genetic identity and purity and that may be designated or distributed by an agricultural experiment station. Registered- Purple Label handled as to maintain satisfactory genetic identity and purity and that has been approved and certified by the certifying agency. This class of seed should be of a quality suitable for production of certified seed. Certified- Blue Label-handled as to maintain satisfactory genetic identity and purity and that has been approved and certified by the certifying agency.
test dates should be within how many years
5
What are some examples of seed by products
Rice Bran
Rice Hulls
Corn Gluten
Soybean Meal
Production system
- Inputs
- Seed, Water, Fertilizers, Labor, Pesticides, Energy - Biological Processes
- Photosynthesis
- Nutrient Cycling
- Nitrogen Fixation
- Biological COntrol
- Mycorrhizal Effects - Depletion of Inputs
- Crop Removal
- Nutrient Cycle Losses
- Leaching
- Erosion - cultivar
- human-made variations in plants achieved through plant breeding.
Difference between natural and agrosysytem
Agrosystem
- Limited diversity
- Constant disruption
- Nutrient losses replenished with external inputs
Natural ecosystem
- High diversity
- Equilibrium
- Nutrient cycling
Slash and burn
- Not Sustainable
- Land is cleared by slashing with tools then burned using ashes for fertilizer. After loss of nutrients land is abandoned/
Monoculture
- Cultivated population of a single species
- Easy to manage
- Limited diversity
- Less Adaptable
Polyculture
- Planting multiple crops in the same field
- Increased diversity
- More adaptable
- More complicated to manage
Seed storage
Increase disaster and maintain diversity
Purity test
- % other crops
- % common weed
- % restricted Noxious Weeds
- prohibited Noxious Weeds
- 3,000 seeds
Alley cropping
system in which one crop is planted in the open areas of another
Example: Planting squash with corn….Planting forage in a pecan orchard
Strip cropping
Planting crops in strips across the field
Example: Corn and alfalfa
Double cropping
Growing a second crop after the first crop of the season has been harvested
Example: Planting soybean after harvesting wheat
Cover cropping
Planting a crop after harvest of one cash crop and before planting another
Used to improve fertility and decrease erosion
Example: planting clover, pea, cowpea.
Nurse cropping
Overlap planting
Planted before desired crop to suppress weed growth while the economic crop develops in the field
Nurse Crop will then be controlled with chemicals
Examples: Onions with carrots, oats with alfalfa
Multiple cropping
Crop Rotation
- Biodiversity
- Growing a different crop in the same field each year
- Benefits- Pest Control and reduce fertilizer
What do plants compete for
-Light, Water and Nutrients
-They compete by
-Allelopathy- secrete toxic substance to harm plants around them
-Toxins harmful to herbivores
Ex.Prickly plants
-intraspecific- 2 lants of the same species
-Interspecific- 2 plants of different species
Agroforestry
Windbreaks - line of trees or shrubs planted to protect an area’s
Prevents soil erosion and protect crops, livestock etc.
Riparian Areas
Natural or planted woodland adjacent to streams or water bodies comprised of trees, shrubs, and grasses
Provide a buffer against pollution such as: excess nutrient and pesticide runoff.
