786 SOILS; PROPERTIES AND MANAGEMENT 



as a deficiency in humus, lime, or drainage, should be 

 pointed out. Secondly, a detailed description of each 

 type following a uniform outline of properties, including 

 color, texture, depth, structural peculiarities, and minera- 

 logical and chemical features. Following this, attention 

 should be drawn to the location and extent of the type 

 in the area, and to its mode of origin, drainage conditions, 

 and economic relations, including the crop rotation and 

 extent of development. 



In making suggestions for the treatment of the soils a 

 clear distinction should be drawn between methods of 

 soil management and improvement, arid questions of farm 

 organization and management. The data collected by 

 the soil survey man will usually lead him to confine his 

 suggestions to the former group. 



631. The soil map (Fig. 84). The soil map is de- 

 signed primarily to show the geographic position and ex- 

 tent of each type of soil. Therefore an accurate base map, 

 showing important natural and cultural features as noted 

 above, is essential. The scale of the map must be adapted 

 to the amount of detail to be shown. The commonest 

 scale in use in the United States is one inch to a mile. In 

 reconnoissance surveys a scale of one inch to six miles is 

 usually employed. The map is printed in colors or in 

 symbols representing the different types of soil. Symbols 

 may be added to the color to indicate further variation, 

 such as the presence of much stone, occurrence of ledge 

 rock, or a swampy condition. On the right-hand border 

 of the map a legend to the colors or symbols is given, and 

 they may be arranged in accordance with the scheme of 

 classifying the soils to show their relationship. On the 

 left-hand border, the character of the profile of each type 

 of soil is indicated by a series of legends. 



