EXPERIMENT STATION BULLETINS. 



509 



or the raw rock should be used freely on these farms. If the former is made 

 use of 200 pounds or more should be applied per acre twice in a four year 

 rotation, whereas if the latter is used about 1,500 pounds should endure 

 six years. 



RIVEIR FLOOD PLAINS 



While no areas have been mapped as flood plains they really are of im- 

 portance even though they are small in extent. These soils are located 

 along the rivers and their tributaries, and are known as the bottom lands. 

 Such soils afford probably the most fertile lands in the area due to their 

 overflowing each year and soil material being deposited. This overflowing 

 is the controlling factor from the agricultural standpoint. Most of the land 

 is left to pasture, however, some is put under cultivation and late spring 

 crops seeded. The latter is not highly advisable, however, because of the 

 havoc wrought to crops, occasionally in early summer. It seems more 

 advisable to allow the land to stay in pasture and feed live stock as an occupa- 

 tion. It is along the larger streams that dairy farming is quite prominent, 

 large herds being grazed on the flood plain soils while the uplands are used 

 to grow the winter feed. 



COMPOSITION OF SOILS OF THE DETROIT AREA 



