| A | B |
|---|
| Horizon O | Top layer of Soil, contians leaves and twigs |
| Humus | sticky brown residue of partially decayed organic matter |
| Horizon A | Known as top soil,contains bacteria, bugs, humus |
| Horizon B | (subsoil)contains soils inorganic matter, broken down rocks of sand silt and clay,leaching occurs here |
| Horizon C | (Bedrock)solid rock or broken parent rock |
| leaching | water seeps down and dissolves various soil components |
| Brown and Black soil | Nitrogen rich soil |
| Gray, yellow, soil | low inorganic matter |
| Soil Texture | refers to the portion of sand, silt and clay |
| Sand | largest of soil particles, has greatest porosity |
| Silt | Medium size particle |
| Clay | smallest of soil particle, lowest porosity |
| Porosity | measure of the pore space per volume of soil, how well water flows through it. |
| Loam | Most fertile soil for farmers, 40% sand, 40% silt, 20% clay |
| Soil Triangle | This diagram shows proportions of sand,silt and clay |
| Lime | Added to Acidic Soil to neutralize it |
| Sulfur | add to soil, bacteria change it to sulfuric acid to make soil more acidic |
| Factors that effect erosion | wind,rain and temperature |
| Desertification | break down of soil in arid climates with no vegetation,and human activities |
| 2 factors that effect desertification | overcultivation and overgrazing |
| no till agriculture | soil is undisturbed, machine punches hole and seed is planted |
| alley cropping | trees are planted in strips with crops in between, roots of trees hold soil in place |
| contour farming and terracing | crops are planted across slops so water runs down |
| overgrazing | occurs when farmers put large numbers of livestock out to graze on arid grassland |
| sediments | This can wash into streams killing fish, destroying wetlands, killing coral reefs and carrying pollution into rivers |
| Salinization | accumulation of salt in soil, overwatering causes this by bringing salt to top layer |
| Subsidies | these encourage farmers to produce more crops which leads to overcultivation and soil erosion |
| Sustainable agriculture | This refers to the practice designed to maintain topsoil,and reduce the use of fertilizers and pesticides to encure a stable food supply |
| Organic Fertilizers | Contain plant and animal waste, such as plant an animal waste, have high water holding capacity, do not have exact amounts of necessary nutrients |
| Inorganic Fertilizers | Man made chemical formulas, contain exact amount of necessary ingredients for plants,easy to apply, poor water holding capacity, leach from the soil quickly and run into streams causing polluted water |
| Eutrophication | Caused by fertilizer run-off, algae bloom occurs, when it dies bacteria use up all oxygen in water killing fish called dead zone |
| Good Soil | Has these things: Good nutrients, good filtration and water holding capacity,good aeration and pH near neutral, and low salt |
| Chemical Soil Testing | pH, Salinity, and Organic contient -N, P, and K |
| Physical Soil Testing | Soil texture, water holding capacity, moisture content, particle density |
| Planting Legumes | way to increase nitrogen in the soil |
| Deciduous Biome | Leaves fall in autumn and decompose to make great humus layer |
| Grasslands | Ex. Prairie and Savanah for a large amount of organic matter that decomposes to form a good humus layer |
