ENV 1101 Lecture : Class 12 - Soil & Food.docx
Document Summary
The 5 a s of food security: availability, affordability, accessibility, acceptability, adequacy. Food production not the real (current) problem. Keeping up with population growth: the green revolution. Transfer of technologies to developing nations: heavy equip, chemical pesticides, synthetic fertilizers, irrigation. Introduction of high yield hybrid varieties (hyvs) wheat, rice, corn: intensification (vs. extensification) Still going on: development of new crops; pest resistance; expansion into other regions, population growth 2%/year, wheat and rice 4%/year (up to mid 80 s) 90% of the world s food from land-based agriculture: 38% of land surface dedicated to agriculture. Maintenance of soil = cornerstone of civilizations. A mixture (system) of organic material, inorganic material, and living organisms. Some places have lots of good soil, other may have none at all. It takes decades or more to form a few inches of soil. Soil can be removed from poorly managed land in a single season. Larger soil particles have larger spaces between them (are more porous)