1. Soils for plant growth
1.1. Mineral ions
1.1.1. Nitrogen
1.1.1.1. makes aminoacids
1.1.1.2. avoids stunted growth
1.1.2. Phosphorus
1.1.2.1. respiration and growth
1.1.2.2. avoids discoloured leaves
1.1.3. Potassium
1.1.3.1. respiration and photosyntesis
1.1.3.2. avoids poor flower and fruit growth
1.2. Soil acidity
1.2.1. Concentration of hydrogen in soil
1.2.2. pH scale (0-14)
1.2.2.1. Fertile soils (5.5-8)
1.2.2.2. Acid soils (-5.5)
1.2.2.3. Alcaline soils (+8)
1.3. Texture
1.3.1. Mineral particles in soil
1.3.2. Sandy soil
1.3.2.1. Large pores wash water and nutrients out
1.3.3. Clayey soil
1.3.3.1. Small pores trap water
1.3.4. Loamy soil
1.3.4.1. Perfect for farming
1.3.4.2. Supplies air and water
1.3.4.3. Holds nutrients
1.3.4.4. pH 5.5-8
2. Types of agriculture
2.1. Arable
2.1.1. Growing crops
2.2. Pastoral
2.2.1. Livestock
2.3. Mixed
2.3.1. Both pastoral and arable
2.4. Commercial
2.4.1. Everything produced is sold
2.5. Subsistence
2.5.1. Farmers produce for themselves and their families
2.6. Shifting cultivation
2.6.1. After exhausting one plot of land, another is used
2.7. Intensive
2.7.1. Small plot of land
2.7.2. Technology
2.8. Extensive
2.8.1. Large plot of land
3. Soil preparation and techniques to increase yields
3.1. Irrigation
3.1.1. Supplies water
3.1.2. Canals
3.1.3. Rivers or lakes
3.1.4. Sprinklers
3.2. Chemicals
3.2.1. Herbicides
3.2.2. Pesticides
3.2.3. Fertilizers
3.2.4. Fungicides and insecticides
3.3. Selective breeding
3.3.1. The best crops are chosen
3.3.2. Increases crop`s efficiency
3.4. Mechanization
3.4.1. Tractors
3.4.2. Ploughs
3.4.3. Hoes
3.4.4. Sprinklers
3.5. Genetically modified crops
3.5.1. The best genes are chosen end incorporated
3.5.2. Increases food supply and efficiency
4. What is it?
4.1. Topmost and most important layer of Earth`s crust
4.2. What plants grow in
4.3. Loose materials above solid rock
4.4. Horizons
4.4.1. A
4.4.1.1. Gains new materials from decompsition of living beings
4.4.2. B
4.4.2.1. Accumulates materials from other horizons
4.4.3. C
4.4.3.1. Loose pieces of weathered rock
5. Composition
5.1. Organic matter
5.1.1. Plants and animals
5.1.2. Dead remains and waste
5.2. Mineral matter
5.2.1. Sand (mostly quartz)
5.2.2. Silt (mostly quartz)
5.2.3. Clay (iron oxide and silicates)
5.2.4. Weathered rocks below the soil
5.3. Water
5.4. Air
5.5. % varies in each place
5.5.1. wet season(water>air)
5.5.2. dry season (air>water)