ABSTRACT

I. Introduction ...................................................................................... 442 II. Natural Resources ............................................................................ 442

A. Land............................................................................................ 444 1. Degradation of Arable Land .............................................. 446 2. Degradation of Land Involved in Animal Husbandry ..... 446

B. Energy Resources ...................................................................... 447 C. Water .......................................................................................... 449 D. Phosphates ................................................................................. 449

III. Relation with Living Nature ............................................................ 450 A. Animal Husbandry in Uncultivated Areas............................... 451 B. Animal Husbandry on the Basis of Agricultural Produce ..... 452

IV. Pollution............................................................................................ 453 A. Local Effects............................................................................... 454 B. Surface-Water Pollution............................................................. 456 C. Regional Air Pollution............................................................... 457 D. Global Air Pollution .................................................................. 458

V. Conclusion........................................................................................ 458 References .................................................................................................. 459

Food is taken partially from nature and is partially obtained by agricultural practices. In industrial countries, most of the food is provided through agriculture. Still, however, considerable amounts of food may come from natural sources. For instance, in the United States, an estimated 4.3 million metric tons of wild plants and animals are annually harvested.