GEOG-120 Lecture Notes - Lecture 29: Algal Bloom, Agricultural Science, Biological Pest Control
22 Dec 2020
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Document Summary
38% of the earth"s land surface is devoted to agriculture. Intensi cation is a way to increase the productivity and carrying capacity of a given unit of land. Food security is the guarantee of an adequate and acceptable food supply to all people at all times. Green revolution with enormous increases in agricultural productivity during the mids-to late twentieth century. Extensi cation is increasing resource productivity by bringing more land into production. Inorganic fertilizers are mined or synthetically manufactured mineral supplement. Organic fertilizers consist of natural materials and include animal manure. Nitrogen and phosphorus runoff from farms and other sources can lead to phytoplankton bloom. Some nitrogen fertilizers can even volatilize into the air. Only 43% of water applied actually gets used by plants. Drip irrigation systems that target water directly to plants are one solution to the problem; they control where the water actually goes. Requires large amounts of pesticides and bring signi cant risks of catastrophic failure.
