Food Sources, Plant Needs & Soil Composition

Where Our Food Comes From

• Food sources include prairie fields, lakes, oceans, feedlots, and orchards

Basic Needs of Plants

• Plants require light, atmospheric gases, water, nutrients, minerals and space to survive

Soil Composition

• Soil consists of mineral grains, air, water, and organic material to support plant life
• Soil is structured in horizontal layers, known as a soil profile
• The topmost layer is surface litter, mainly composed of loose, partially decomposed organic matter
• The second layer is topsoil, which is dark and rich in organic matter mixed with minerals
• The third layer is subsoil, having less organic matter and fewer organisms than topsoil, accumulating nutrients leached from the topsoil
• The fourth layer contains rock particles without organic matter, its chemical makeup determines the soil's pH
• The fifth layer is bedrock consisting of a solid rock layer
• Humus is organic material, resulting from decomposed plant and animal matter
• Soil harbors a network of organisms, which create food chains and spaces for air and water to circulate

Soil Properties

• Porosity refers to the size and quantity of spaces between soil particles, impacting water movement
• pH measures soil acidity; a pH above 7 is basic, below 7 is acidic, and around 7 is neutral
• pH affects how easily nutrients are released, influencing plant growth

Key Plant Nutrients

• Nitrogen gives plants a dark green color
• Phosphorus aids in root, bud, and seed development
• Potassium boosts strength, disease resistance, and seed quality
• Magnesium is essential for photosynthesis
• Calcium is needed for the development of healthy cell walls

Agricultre

• Agriculture involves raising plants and livestock for food and other human needs

Monoculture and Crop Rotation

• Monoculture refers to growing a single crop over a large land area
• Repeated monoculture depletes specific soil nutrients
• Fertilizers are used to replenish depleted nutrients in monoculture systems
• Crop rotation is growing different seeds to use, and deposit, different nutrients back to the soil

Fertilizers and Aquatic Ecosystems

• The three main nutrients depleted from farmers' fields include nitrogen, phosphorus, and potassium
• Synthetic fertilizers boost crop yields but can harm aquatic ecosystems
• Excess nutrients from fertilizers washed into water sources result in algal blooms
• Algae die and bacteria consume large amounts of oxygen to decompose it, potentially killing fish and other aquatic life

Pest Control

• Pesticides are chemicals used to control unwanted fungi, animals, or plants
• The use of pesticides poses a risk of unintentionally killing non-target organisms
• Over time, chemical pesticides can accumulate

Irrigation

• Irrigation is a technique that adds water to agricultural fields, enhancing crop yield

Genetically Modified Organisms (GMOs)

• Genetically Modified Organisms (GMOs) are created by inserting a DNA segment (gene) from one organism into another
• Genetic modification can involve inserting a gene from a type of bacterium to kill insects that eat the crops
• Herbicide resistance is a genetic modification that allows farmers to spray a herbicide to kill the weeds and it will not affect the crop

Sustainable Agriculture

• Sustainable agriculture aims to produce food to meet current needs, without compromising future generations
• Companion planting is a sustainable agricultural practice, where two or more plant species are grown together for mutual benefit and this happens in a polyculture
• Polyculture contains a diversity of crop types

Ancient Aboriginal Polyculture

• Ancient aboriginal polyculture practices includes “three sisters”: corn, beans, and squash
• The corn serves as a structure for beans
• Beans enrich the soil with nitrogen to benefit squash
• And squash provides dense leaf coverage for moisture retention and weed suppression

Soil Conservation

• Soil conservation involves reducing soil erosion and maintaining soil fertility
• Crop rotation is the practice of growing different crops at different times on the same land
• Compost is made when microorganisms break down organic matter in the presence of oxygen
• Mulch provides protective ground cover

Integrated Pest Management (IPM)

• IPM is Integrated Pest Management
• IPM can include chemical substances and crop rotation
• Introducing organisms can biologically control pests

Renewable Energy Agriculture

• Renewable Energy Agriculture aims to replace fossil fuels with renewable energy sources such as solar power, wind, and hydropower

Organic Products

• Organic products exclude synthetic fertilizers, pesticides, hormones, certain additives, and genetically modified ingredients
• Irradiation is exposing food to radiation to eliminate microorganisms

Section 5.4

• Meat is a vital source of protein, iron, fats, and other nutrients which provide energy
• Dairy products also are a key protein source
• About 50% of livestock are raised in Confined Animal Feeding Operations (CAFOs)

Desertification

• Desertification involves converting arid and semiarid lands into deserts, through inappropriate farming practices or overgrazing
• Arid lands receive very little natural rainwater
• Farming practices in these areas need to be efficient

Confined Animal Feeding Operations (CAFOs)

• CAFO's are efficient in dispensing water and food for livestock
• CAFO challenges include high energy inputs, substantial waste generation, and increased likelihood of infectious diseases spreading among livestock

Grazing Techniques

• Rotational grazing confines animals to small pastures, and shifts them to new locations
• This method can prevent overgrazing by allowing the pasture to replenish

Aquaculture

• Aquaculture involves breeding, raising, and harvesting aquatic animals
• Aquaculture is expanding due to the increasing overexploitation of lakes and oceans, threatening certain aquatic species