chapter15 Flashcards
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.
crop rotation
the planting of a series of different crops in the same field over a period of years.
contour plowing
plowing that matches natural contour of the land.
strip cropping
a special type of contour plowing, produces alternating strips of different crops along natural contours.
terracing
produces level areas and thereby reduces soil erosion
shelterbelt
a row of trees planted as a windbreak to redue soil erosion of agricultural land
agroforestry
concurrent use of forestry and agricultural techniques on the same land area to improve degraded soil and offer economic benefits.
organic fertilizers
include such natural materials as animal manure, crop residues, bone meal, and compost. Chemically complex, and their exact compositions vary. The nutrient minerals in organic fertilizers become available to plants only as the organic material decomposes. Slow-acting and long-lasting.
commercial inorganic fertilizers
manufactured from chemical compounds, and their exact compositions are known. They are soluble, they are immediately available for plants. Are avaiable in the soil for only a short period of time because they quickly leach away.
preserving soil fertility
it is environmentally sound to avoid or limit the use of manufactured fertilizers because of their high solubility, manufactured fertilizers do not improve the water-holding capacity of the soil as organic fertilizers do, source of nitrogen-containing gases that are pollutants, and their production of commercial inorganic fertilizers requires a great deal of energy.
soil reclamation
it is possible to reclaim land badly damaged by erosion. Involves two steps: 1. stabilizing the land to prevent further erosion 2. restoring the soil to its former fertility
mulch
placed on the surface of soil, around the bases of the plants. Helps to control weeds and increases amount of water in the upper levels of the soil by reducing evaporation, lowers the soil temperature in the summer and extends the growing season slightly by providing protection against cold in fall. Decreases erosion by lessening the amount of precipitation runoff.
soil conservation policies in the United States
Farmers are more likely to practice soil conservation during hard financial times and periods of agricultural surpluses, both of which translate into lower prices for agricultural products. When prices are high, with a good market for agricultural products, farmers are more inclined to put every parcel of land into production.
The Soil Conservation Act
1935 authorized the formation of the Soil Conservation Service; its mission is to work with US citizens to conserve natural resources on private lands.
Food Security Act (Farm Bill)
1985, contained provisions for two main soil conservation programs, a conservation compliance program (requires farmers with highly erodable land to develop/adopt a five-year conservation plan for their farms that includes erosion control measures. If they don’t comply, they lose federal agricultural subsidies) and the Conservation Reserve Program.
