How can we help?

You can also find more resources in our Help Center.

20 terms

AP enviro ch 15

STUDY
PLAY
Desertification
the progressive degradation of grassland and other productive lands into unproductive desert
Weathering process
a biological, chemical, or physical process that helps form soil from rock; rock is gradually broken down into smaller and smaller particles
Leaching
the process by which dissolved materials (nutrients or contaminants) are washed away or filtered down through the various layers of the soil
Illuviation
the deposition of leached material in the lower layers of soil
Soil horizons
the horizontal layers into which many soils are organized, from the surface to the underlying parent material
Soil profile
a vertical section from surface to parent material, showing the soil horizons
Mycorrhizae
a mutualistic association between a fungus and the roots of a plant. Enables plants to absorb adequate amounts of essential minerals from the soil
Clay
the smallest inorganic soil particles
Sand
inorganic soil particles that are larger than clay or silt
Humus
the black or dark brown organic material that remains after much decomposition has occurred
Agro forestry
agricultural and forestry techniques in which trees and crops are planted together to improve soil fertility in degraded soils
Conservation tillage
a method of cultivation in which residues from previous crops are left in the soil, partially covering it and helping to hold it in place until the newly planted seeds are established
No-tillage
a method of conservation tillage that leaves both the surface and subsurface undisturbed. Special machines punch holes in the sol for seeds
Crop rotation
the planting of a series of different crops in the same field over a period of years
Contour plowing
plowing that matches the natural figure of the land
Terracing
a soil conservation method that involves building dikes on hilly terrain to produce level, terraced areas for agriculture
Compost
a natural soil and humus mixture that improves soil fertility and soil structure
Shelter belts
a row of trees planted as a windbreak to reduce soil erosion of agricultural land
Soil conservation act
authorized the formation of the formation of a service whos mission is to work with US citizens to conserve natural resources on private lands
Food security act (85)
contained provisions for two main soil conservation programs, a conservation compliance program and the Conservation Reserve Program