AGRI 101 Introduction to Agriculture

Agriculture Science, art, or practice of cultivating soil producing crops, and raising livestock, and the preparation and marketing of the resulting products

Agriculture Horticulture **most diverse and interesting field** Landscape Design Landscape Construction Landscape Maintenance Nursery Production – field and container Greenhouse Production – Tropical Foliage, flowering potted plants, cut flowers

Agriculture Horticulture (cont ’ d) Pomology Small fruits Tree fruits and nuts Olericulture Turf/Golf Course

Agriculture Agronomy – Field Crops Corn, soybeans, wheat, tobacco Fiber crops Forages Forestry Soils erosion and fertility Harvesting & Production of timber Management of Wild Areas Urban Forestry (horticulture)

Animal Sciences Cattle Dairy, beef Poultry Sheep/Goats Horse Swine Agriculture

Plant sciences Animal sciences Economic Sciences Mechanical/Engineering Sciences Soil Sciences

World Wide World ’ s surface area = 112 billion A Cropland is 3-4% Remainder is ice, water, mountains, etc. World Land Area 32 b A 29% of entire planet ’ s surface

The most popular photograph in history, taken from Apollo 17.

World Wide World Land Area 32 b A (29% of World Total) 11.5 b A Agricultural - 36% of Land Total 3.5 b A Cropland - 11% of Land Total 8 b A grazing - 25% of Land Total 10.6 b A forest – 33% of Land Total Remainder Desert or Ice or Mountains

United States, Number of Farms (1000)

United States, Average Farm Size (A)

World Population

Thomas Malthus Essay on the Principle of Population in 1798 Human population increases geometrically Resources increase arithmetically Therefore, POPULATIONS WILL GROW UNTIL THEY CRASH

Thomas Malthus Predicted Land Degradation Massive Famine Disease War Has this happened? Where?

Malthus ’ s Predictions USA & Developed Countries Predictions Delayed by Technology Fertilizer – more yield per acre Irrigation – more yield per acre and opened more land in arid regions Green Revolution Crops (Breeding) Human Birth Control Education of Women

World Population Growth

Causes for World Population Growth DDT/Malaria Childhood immunizations Education of females Green Revolution Crops Use of fertilizers and pesticides Religious Beliefs – large families, contraception

World Population How many people can the earth support? Who Knows, possibly 20 Billion

Conclusion: There has been a famine in the world almost every year since WWII Human Suffering Political Instability Causes are Manmade Natural

Consider World >> 6,000,000,000 persons Entire world depends on 25 crops of which 3 – 5 are heavily relied upon Risk mass starvation Susceptible to disease/insect damage

Irish Potato Famine Reliance on one food 1.5 A fed family of six, would take 8 A of wheat for same level! 1845 cool, wet summer Potato blight fungus imported from South America by mistake Spread by spores throughout country without notice

Irish Potato Famine When they dug tubers in the fall, half the crop was rotted Theories of the day Static electricity from new steam locomotives Mortiferous vapors from volcanoes Tubers contracted dropsy Tubers continued to rot but they did nothing to stop it

Irish Potato Famine Lasted from 1845 to 1851 Hunger, disease, weakened bodies Death from dysentery and others

Causes of Famine Irish Potato Famine Russian Famine African Famines Consecutive years of below average rain Political redistribution of land or food aid Robert Mugabe, Pres. Zimbabwe land reform

Reducing Famine Diversify food supplies Keep food reserves safe Population control Political stability Better transportation, highways and ports Education, better economic outlook

CHINA 1.28 Billion persons in X U.S. 20% of world ’ s population Land area slightly less than U.S. 10% Arable land vs. 19% in U.S.

China 1979 decided to limit pop to 1.2 B by 2000 One child per couple policy Couples rewarded money, vacation, more land to farm One child children get better education, housing, jobs

India Family planning less aggressive 947 million,.947 Billion persons Expected to reach 2 Billion by 2025 and become the world ’ s most populous nation

Name the top 3 World Crops Rice Corn Wheat What do they have in common? All grasses!! We have low diversity for Pest Resistance Nutrition

Green Revolution Feeding the Growing World

Green Revolution The most significant development of agriculture of the 20 th century Dr. Norman Borlaug 1970 Nobel Peace Prize

Landrace Varieties Tall Leafy Large root system Evolved to compete under high pest pressure and marginal production areas

Landrace Wheat

Green Revolution Wheat

Green Revolution Varieties Physical Changes to Plants Shorter plants Smaller leaves Stronger stems Smaller root systems

Results of G.R. Crops More plants/acre = higher yield India exports wheat now, not starving BUT Less competitive plants = more need for weed control, herbicides Genetic variability gone More fertilizer to produce higher yields

G.R. Crops Bottom Line Millions now fed Requires more management and inputs Has been criticized for this but

Soils Not just Dirt

Soil Importance Agriculture Construction Depository for waste Beauty

What is soil? Minerals from weathered rock Organic matter Decaying plants Decaying animals Decaying microbes Water Air Living Organisms

Functions of Soil 1.Provide physical support for plants 2.Provide nutrients 3.Provide water 4.Support biological activity of microbes, earthworms, etc.

Soil Profile Vertical cross section showing horizons or layers Horizons determine value and use of land

0 – 25 in. Roots, highest biological activity, microbes, OM 25 – 36 in. Accumulation from A, more mineral, less OM, less oxygen, less biological activity 36 + in. Weathered parent rock C B A BEDROCK

Nutrients aka Fertilizer Macronutrients – used in large quantities Nitrogen – N – promotes leafy green growth Phosphorous – P – promotes flowering Potassium – K – promotes root growth and cold hardiness

Macronutrients Appear on the fertilizer label Always appear in order N – P – K 20 – 20 – 20 NPKNPK 0 – 60 – 0 33 – 0 – 0

Micronutrients Trace elements Needed in smaller quantities Mg Mn Cu Fe B Mo Zn

Macronutrients and Micronutrients CHOPKNS CaFe Mg CuZn BMo Cl Mn Know them for the exam

Organic vs. Inorganic Ferts. Organic – not wholesome and pure Denotes source of elements Organic – derived from living organisms Compost, sea weed, fish emulsion, manure

Organic vs. Inorganic Ferts. Inorganic – does not mean evil or wrong Designates source – processing or mining N – natural gas P and K - mined

Organic Ferts. Organic Ferts low in nutrients Manure <2% N Inorganic > 30% N Cost per pound of N? Ease of Application? Bonus with Organic – Adds OM

Slow Release Ferts. Organic – manure rots over time Inorganic – engineered to be slow release

Various particle sizes are coated with various thickness of a resin coating. Osmocote

Thin coating breaks down first Thicker coating breaks down last Osmocote

Availability All nutrients are available based not only on amount applied but also the pH

Availability

Environmental Concerns Runoff into surface waters Leaching through soil profile into groundwater

Biological Nitrogen Fixation 78% of atmosphere is nitrogen gas Inert Unusable as macronutrient

2 ways nature converts nitrogen gas to usable form 1.Lightning 2.Rhizobium bacteria 1. Found in symbiotic relationship with plants in legume (bean) family 2. Peas, redbud, alfalfa, locust, soybean, wisteria Biological Nitrogen Fixation

Rhizobium found in root nodules Free nitrogen, transportation, application Biological Nitrogen Fixation

Rhizobium nodules on roots

Black alder seedlings growing without N fertilizer Left: not growing with bacteria Right: with bacteria

Physical Properties of Soils

1.Color – indicates parent material, amount of OM, aerobicity or not of soil, clay content 2.Texture – proportion of sand:silt:clay

Soil Texture Triangle

What texture of soil is 20% Clay 15% Sand 65% Silt?

Agents of Soil Erosion 1.Wind - Dust Bowl, 1930 ’ s Great Plains 2.Water – Impact of raindrops, running water 3.Biological – cattle overgrazing 4.Temperature – changes in soil chemistry, mainly a problem in the tropics

Soils and Fertility in Horticulture

Types of Soils & Media Native Soils Soilless Media Sing. Medium, pl. Media Hydroponics Tissue Culture Sand/Gravel Culture Bag Culture

Soilless Media Used in Container Nursery Production All Greenhouse Crops Foliage Flower production Potted flowering plants

Soilless Media Field Soil is NOT used in containers Soil structure is destroyed Loss of pore space; long capillary tubes in soil that allow water and gasses to be exchanged are destroyed when placed into a pot Poor aeration Poor drainage POOR PLANT PERFORMANCE!!

Components of Soilless Media Sand – adds weight to hold the pot upright and adds porosity. Little water holding or CEC capacity

Components of Soilless Media Sand Bark - creates a lightweight portion that adds porosity Little water holding or CEC capacity

Components of Soilless Media Sand Bark Peat - holds water like a sponge with a high CEC

Components of Soilless Media Sand Bark Peat Compost – Less expensive alternative to peat that holds water, has a high CEC, and decomposes to N and P among others.

Components of Soilless Media Sand Bark Peat Compost Vermiculite – Vermiculite is a sterile, lightweight mica heated to approximately 1800 degrees F plate-like structure expands, allowing it to retain large quantities of air and water

Vermiculite

Components of Soilless Media Sand Bark Peat Compost Vermiculite Perlite produced by heating volcanic rock to approximately 1800 degrees F sterile, lightweight, porous material

Perlite - Coarse

Tropical Foliage Plant Production

Hydroponic Production

Field Nursery

Container Nursery

Container Plant Production

Container Tree Nursery

Soilless Media

Commercial Media

Soilless Media Mixers

Soilless Media Plug Trays and Filling Machine

Peat Harvest

Importance of Crop Plants “ Plants are only important if like breathing or eating ”

Top 4 List Why crops are important 4.Primary producer in the food chain 3. Animals depend on them 2.Fossil Fuels 1. Humans use them for food, medicine, fiber, building materials, oxygen, aesthetics, waxes, perfumes, etc.

Plant Life Cycles Annual – a plant that completes its life cycle in one season Winter Annual – germinates in fall, establishes crown and root system in fall, overwinters, flowers and dies in spring. Vegetative Phase in Fall Sexual Phase in Spring Winter wheat, annual bluegrass, henbit, chickweed

Plant Life Cycles Annual – Winter Annual Summer Annual – germinates in spring, grows in summer, flowers, sets seed, and dies before winter. Vegetative Growth in Spring/Summer Sexual Growth in Late Summer/Fall Impatiens, beans, corn, sunflower, begonia

Plant Life Cycles Perennial – a plant that lives for more than one year, is herbaceous, and regrows each year from a perennating structure Hosta, daylily, iris, some ferns, heucheras, coneflower, vinca groundcover Distinct from shrubs-woody <10’, mult.stems trees – woody >10’ main trunk

Plant Life Cycles Biennials – Bi = two, ennial = years Intermediate life cycle between annuals and perennials Live for two years with distinct growth patterns for each year

Plant Life Cycles Year 1 – grow vegetatively Leaves, stems, roots Usually grow in a rosette Year 2 – grow reproductively (sexually) Send up flower stalk Set seed Die Hollyhocks, cabbage, carrots

Climate vs. Weather Climate includes temperature, precipitation, humidity, sky conditions, wind, and atmospheric pressure Climate is the average conditions over a long period Weather is the current and temporary atmospheric conditions Difference is time span

Climate Types Macroclimate describes the conditions over a relatively large area i.e. a portion of a state or county Local climate refers to more localized conditions i.e. a valley or mountain Microclimate is the conditions around a plant or leaf Microclimate can be modified by us to grow marginally hardy plants

Solar Radiation Source of heat and light – Sun 93,000,000 miles away, 9 min. travel at speed of light The wavelengths that reach earth ’ s outer atmosphere do not completely reach the surface- filtered

Solar radiation Absorbed Light absorbed by atmospheric components Ozone Water vapor (clouds) Dust Oxygen, Carbon dioxide UV (ultraviolet) and IR (infrared) light damaging to plants and absorbed in atm.

Solar Radiation Scattered Dust, smoke, water droplets, smog Small particles (gas molecules) scatter shorter wavelengths (blue) Large particles (dust, smoke) scatter longer wavelengths (red)

Solar Radiation Reflection Light bounces off components of atm. Clouds major reflector Ex. Flying on a cloudy day then breaking through the layer, the sunlight is very intense

Modifying Cold Temps

Modifying Temperatures Frost Protection Most effective and widely used is mist irrigation Can prevent damage down to 20F, but usually only to the upper 20 ’ s As the temp drops below freezing, ice forms, releases heat of fusion

Freezes and Frosts Radiational Freeze – calm conditions, radiational cooling, not a blanket of cloud cover to hold in heat

Radiational Freeze Sunset beginning a cold, clear night

Radiational Freeze 1. Reduce outgoing radiation Hotcaps Row cover Flooding (cranberries) Foams Straw covering (must be removed) strawberries Artificial fog Freezes and Frosts- Damage Control

Row Cover with Tomatoes

Radiational Freeze 2. Add heat Smudge pots Utilize the temperature inversion with fans or helicopters Overhead irrigation- water gives off heat when it freezes (80cal/g). Must constantly add water. As long as liquid water is present, the temp. remains at 0 F Freezes and Frosts- Damage Control

Temperature Inversion CALM NIGHT Very Cold Air, ie. 30 F Warmer Air, ie. 36 F Crop Will FREEZE!!!

Temperature Inversion Mix Air Air Mixture is Now 34 F and the Crop is Safe!

Advective Freeze Large, cold air mass moves in from Canada Associated with windy conditions Freezes and Frosts

ADVECTIVE FREEZE Not much you can do. Freezes and Frosts- Damage Control

Freezes and Frosts

Radiational Freeze – calm conditions, radiational cooling, not a blanket of cloud cover to hold in heat

Advective Freeze Large, cold air mass moves in from Canada Associated with windy conditions Freezes and Frosts

Radiational Freeze 1. Reduce outgoing radiation Hotcaps Row cover Flooding (cranberries) Foams Straw covering (must be removed) strawberries Artificial fog Freezes and Frosts- Damage Control

Row Cover with Tomatoes

Radiational Freeze 2. Add heat Smudge pots Utilize the temperature inversion with fans or helicopters Overhead irrigation- water gives off heat when it freezes (80cal/g). Must constantly add water. As long as liquid water is present, the temp. remains at 0 F Freezes and Frosts- Damage Control

ADVECTIVE FREEZE Not much you can do. Freezes and Frosts- Damage Control

Vegetative (Asexual) Propagation

Vegetative Propagation Making more plants without sex (seeds) A form of ‘ cloning ’ that has been practiced for centuries Includes all techniques from rooting a houseplant in a glass of water to grafting fruit trees to tissue culture

Techniques of Asexual Prop. Divisions Herbaceous perennials – hosta, daylily, liriope Cuttings Leaf cuttings- African Violets Stem cuttings- Crape Myrtle Root cuttings- Blackberries Layering Houseplants, strawberry Grafting – roses, fruit and nut trees Budding – fruit and nut trees Tissue Culture – ornamentals, most agronomic crops

Vegetative Propagation Advantages: -all offspring are clones (plants derived from the same parent plant by asexual means and are genetically identical) -some plants can ’ t be propagated by seed -can decrease time to flower

Vegetative Propagation Disadvantages: -can only propagate a few from each parent (except tissue cultures) -requires a lot of labor -Diseases can be easily transmitted

Totipotency Plant cells contain all the genetic information needed to regenerate a complete organism Totipotency allows stem or leaf cuttings to grow roots and vice versa Allows the regeneration of entire plants from a single cell

Totipotency Chrysanthemum stem cuttings freshly harvested from the stock plant Cuttings will be dipped in a hormone to facilitate rooting and stuck into propagation tray

Totipotency Stem grows root cells and roots after several weeks Production tray full of rooted cuttings

Illustrated Examples of Asexual Propagation

DIVIDING CLUMPS

DIVIDING CLUMPS

OFFSETS Hen and Chicks

BULBS

HARDWOOD/SOFTWOOD CUTTINGS

LEAF CUTTINGS Leaf bud Leaf petiole Leaf blade Leaf Section

LEAF CUTTINGS

Leaves are cut from the plants and planted leaf to leaf in 10 x 20 trays filled with violet potting soil. African Violet Leaf Cuttings After about 4 to 6 weeks in the 10 x 20 trays small plantlets start appearing on the stems of the rooted cuttings.

African Violet Leaf Cuttings When the sprouting plantlets have taken over the 10 x 20 tray it's time to start breaking them apart and putting them into a roomier container. Four inch pots are allowed to grow pot to pot until the plants get bigger.

African Violet Leaf Cuttings A four inch violet is taped for shipping. The tape stops soil from falling out of the pot during transit.

LAYERING roots are formed on a stem before it is removed from the parent plant the stem is cut below the new root system and planted

LAYERING (Important Points) similar to cuttings advantages (water, nutrients, disease) hard to root plants accumulation of photosynthates and hormones encourage by bending, girdling, or wounding etiolation shoot elongation in the absence of light natural means of reproduction strawberry runners, Bermuda grass stolons, hen and chic offsets

PHYSIOLOGY LAYERING WOODY PLANTS remove a ring of bark (removing phloem and cambium) xylem remains intact (water continues to move up the plant) accumulation of photosynthates and hormones

LAYERING Tip Simple Compound/Serpentine

AIR LAYERING

LAYERING continued Mound / Stool layer Trench Layer

WHY GRAFTING OR BUDDING? cannot be propagated by other means decrease time to flower and fruit change variety of existing, mature tree special forms (dwarf trees, tree roses, weeping cherry, etc.) obtain desirable traits of rootstock (disease resistance, adaptation, etc.) repair damage

PHYSIOLOGY of GRAFTING Scion Root Stock Cambium

GRAFTING TYPES (Stock and Scion Same Sizes) Whip or Tongue Graft Saddle Graft Splice Graft

GRAFTING (Stock and Scion Different Sizes) Wedge graft Cleft graft Side graft

APPROACH GRAFTING

GRAFTING (TO REPAIR DAMAGE) Brace Graft Bridge Graft