Conservation of Natural Resources 795 



tides, (2) the building of level spaces, known as terraces, on lands whose 

 slope is great enough to permit erosion, (3) the correct type of contour 

 plowing and the practice of strip cropping to reduce erosion to a mini- 

 mum, (4) the establishment of permanent grasslands by planting the 

 proper types of grasses in a soil supplied with the proper fertilizing in- 

 gredients to ensure growth, (5) the establishment of permanent wood- 

 lands where other crops are not feasible, (6) the building of dams across 

 streams and gullies, and (7) the increase in fertility of the soil, either by 

 natural or artificial methods, so as to promote greater plant growth. In 

 brief, there should be no barren soils, but each soil should promote the 

 type of vegetation for which it is best fitted. 



Loss and Conservation of Water. — As we look at the ocean or a large 

 lake we may wonder if it is necessary to conserve water. There may be 

 about as much water now as there has ever been, but it is not located 

 in the right places. Soils must contain a certain amount of water to en- 

 sure our water supplies and the proper plant growth. Any factors which 

 permit the rapid loss of water from the soil must be corrected if we are 

 to have sufficient supplies. Larger quantities of water are now being 

 used in homes and industries than formerly and this has aggravated the 

 problem still more. The greater use of water has reduced the "natural 

 water level" of the soil and this, in turn, diminishes the amount of plant 

 growth. Diminished plant growth results in greater loss of water, so that 

 the cycle is complete. 



Another important factor influencing the quantity and quality of avail- 

 able, usable water is the pollution of our water supplies with wastes from 

 oil wells, coal mines, various industries, and sewage. Sometimes a suf- 

 ficient supply may be available, but it is unsatisfactory for the purposes 

 desired. Many streams have been altered so that their waters "run off" 

 too quickly to permit their retention by the soils. Vegetation on their 

 banks has been removed, thus permitting more water to enter the streams 

 quickly. The presence of wastes, silt, etc., the lowering of the natural 

 water level, the consequent changes in animal and plant foods, and the 

 destruction of natural feeding and breeding areas are among the in- 

 fluential factors responsible for the diminished supply of fishes and other 

 aquatic life in our waters. 



Water conservation measures include (1) restoration of streams and 

 other bodies of water to their natural conditions as far as possible, (2) 

 prevention of unnecessary , pollution of water by wastes, (3) wiser and 

 more economical use of water, (4) replacement of the "vegetation 

 blanket" (trees, grasses, crops, etc.) on the soils in order to retain a 



