Term
| organic activity that creates soil (3) |
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Definition
- roots break rocks
- decomposition of dead creatures
- microorganism activity
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Term
| How does temperature affect chemical weathering? |
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Definition
| Heat increases the activity of organisms that cause decomposition. |
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Term
| What five factors are involved in soil formation? |
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Definition
- parent material
- organic activity
- climate
- land surface configuration
- geologic time (soil takes thousands of years to form)
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Term
| What phenomena cause physical weathering (disintegration)? |
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Definition
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Term
| What are the six major characteristics of soil? |
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Definition
- texture
- structure
- acidity
- nutrient content
- air content
- moisture content
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Term
| What is the ideal air content for soil? |
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Definition
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Term
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Definition
| the degree to which air and water move from the upper layers of soil to the lower levels |
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Term
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Definition
| the size and shape of the individual soil particle and the proportion in which they occur |
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Term
| name the four classifications for soil particles |
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Definition
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Term
| What determines soil texture? |
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Definition
| soil texture is determined by the percentage of clay, silt, and sand particles in soil |
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Term
| What characteristic of soil determines soil porosity? |
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Definition
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Term
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Definition
| a measure of the volume of pores or spaces per volume of soil and of the average distances between those spaces |
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Term
| What characteristic of soil determines soil permeability? |
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Definition
| soil porosity, the average size of the spaces or pores in a soil |
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Term
| What type of soil has the best combination of physical and chemical properties for growing most plants? |
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Definition
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Term
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Definition
| how soil particles are organized and clumped together |
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Term
| Which two soil structures allow for rapid flow of water? |
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Definition
| single grain and granular |
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Term
| Which two soil structures allow for moderate flow of water? |
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Definition
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Term
| Which two soil structures allow for slow flow of water? |
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Definition
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Term
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Definition
| the darkly colored material largely derived from the decomposing bodies of plants and animals as well as animal wastes |
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Term
| Name the 6 benefits of humus |
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Definition
- improves soil structure
- increases soil porosity
- increases workability of soil
- reduces soil erosion
- minimizes leaching of nutrients
- provides medium for soil organisms like bacteria and earthworms
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Term
| name 5 ways that soil gains nutrients |
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Definition
- nitrogen fixation
- decomposition
- animal wastes
- weathering of parent materials
- fertilizer
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Term
| Why is air content important in soil? |
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Definition
| For most of the microorganisms and plants that live in the soil, soil air supplies the oxygen and carbon dioxide necessary for life processes |
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Term
| plant functions involving water |
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Definition
- photosynthesis
- mineral and sugar transport
- formation of protoplasm (gives plants weight)
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Term
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Definition
| when pore spaces in soil are completely filled with water to the exclusion of air; caused by intensive irrigation and flooding |
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Term
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Definition
| half the pore space is filled with water and half with air |
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Term
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Definition
| the only moisture left in the soil is in the form of a thin film that lines the pore spaces and is extremely difficult for roots to absorb it (condition of drought) |
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Term
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Definition
| a cross-sectional view of the various horizons (layers) of soil |
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Term
| What type of ions make soil more acidic? |
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Definition
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Term
| What type of ions make soil more basic? |
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Definition
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Term
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Definition
- occur under forest cover in tropics
- occupy about 40 percent of the total land area in the humid tropics of Africa
- Congo basin, West Africa, Southeastern Africa, Eastern Madagascar
- low base nutrients
- continuous leaching
- much of the dead plant and animal material on the forest floor is rapidly decomposed
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|
Term
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Definition
- 6.2% of land in Africa
- hot to temparate & humid climate
- tropical woodland savanna climate
- horizons more distinctive than oxisols, though similar to oxisols
- low to moderate organic content
- Nigeria, Ghana, Ivory Coast, Liberia, Guinea, Sierra Leone, Kenya, Uganda, DRC, Rwanda, Burundi, and Zambia
- suitable for rubber, coffee, tea, banana crops
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Term
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Definition
- 10.5% of land area of Africa
- climate: tropical wet & dry, humid subtropical
- moderately leached; relatively fertile
- good humus development
- savanna regions
- high organic and clay content
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Term
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Definition
- usually develop on flood plains
- distributed along rift valley from Sudan to South Africa
- good for cotton, corn, sorghum, teff, and millet
- low workability due to clay content
- expands when wet, shrinks and cracks when dried
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Term
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Definition
- 24.5% of the land mass in Africa
- immature stage of soil evolutionary processes
- shallow and stony
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Term
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Definition
- 7.8% of Africa's land mass
- young soils good for cassava, rice, maize, and oil palm
- poor drainage can lead to malaria and other insect-borne diseases
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Term
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Definition
- less than 1% of the land area of Africa
- black or brown soils formed from volcanic material
- clay-rich sub-soil
- high fertility
- good for intensive cropping
- upper slopes of Mt. Cameroon, Kilimanjaro, Mt. Kenya, parts of the Ethiopian Highlands
- can store large quantities of water
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Term
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Definition
- 26.4% of Africa
- poorly developed, with little chemical weathering and infrequent leaching
- relatively low biomass densities
- low organic matter content
- salinization widespread
- irrigated agriculture is possible in areas with less saline soils
- desert soil
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Term
| What percentage of Africa's land is degraded? |
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Definition
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Term
| Name 8 causes of soil degradation in Africa |
|
Definition
- deforestation
- overgrazing
- overexploitation
- agricultural activities
- erosion by wind
- erosion by water
- chemical deterioration
- physical deterioration
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Term
| Name 5 ways of combatting soil degradation |
|
Definition
- intercropping
- crop rotation
- agroforestry
- contour plowing
- strip cropping
- grass strip
- terracing
- mulching
- mounding/ridging
- no- or reduced-tilling
- shelterbelts/wind breaks
- fallowing
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Term
| What is the most effective method for preventing erosion? |
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Definition
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Term
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Definition
| making a series of steps like a staircase on slopes to contain water from irrigation and percipitation |
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Term
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Definition
| rows of trees or other tall perennial plants along edges of fields to slow wind and reduce erosion |
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Term
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Definition
- thorny, leguminous tree
- used as part of large-scale sustainable agriculture, forest-management and rural economic-development strategies in Africa
- drought-resistant
- lateral root system stabilizes soil and controls erosion
- leaves and seeds make good fodder for livestock
- used in living fences
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Term
| positive aspects of eucalyptus trees |
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Definition
- fast growing
- high survival rate
- little maintenance
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Term
| negative aspects of eucalyptus trees |
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Definition
- require lots of nutrients and water
- high competition to companion plants
- can cause desertification
- longer decomposing period
- doesn't prevent soil erosion
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Term
| What makes Africa's agriculture particularly vulnerable to climate change? |
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Definition
| Africa's agriculture is climate-dependent and rainfed |
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Term
| What is the best known system for land capacity classification? |
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Definition
| The United States Department of Agriculture |
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Term
| What were negative aspects of the Copenhagen Accord (2009)? |
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Definition
- lack of binding force (voluntary pledges weren't honored)
- lack of funds available for adaptation projects
- only a small proportion fo the pledge funds benefits Africa
- existing climate financing mechanisms are socially unbalanced and "gender-blind"
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