8 SOILS OF THE EASTERN UNITED STATES. 



without the interposition of any other crop, or even the fallowing of 

 the land between the successive crops of wheat. As a natural and 

 inevitable result, yields began to decline after several years of this 

 system of cropping. Then some variation was brought about through 

 the introduction of flax and the seeding of small areas to the tame 

 grasses. The climatic difficulty attendant upon the production of 

 known varieties of corn prevented the adoption of the more rational 

 crop-rotation systems of the more southern prairie States, and even 

 yet the development of acclimatized varieties of corn of quick maturity 

 has not proceeded sufficiently far to justify the planting of any 

 large acreage of this crop in the more northern regions. As a result 

 there is still a lack of some valuable intertilled crop which may take 

 its place in a rational and systematic crop rotation upon the Fargo 

 clay loam. It is to be hoped that proper varieties of corn may be 

 developed for this latitude, in order that the adoption of this crop as 

 a definite part of the rotation may be made economically possible. 



The greater proportion of the Fargo clay loam is adequately sup- 

 plied with organic matter in the surface soil, although those areas 

 marked by the lighter gray color, together with many square miles of 

 the type which have been exhaustively seeded to wheat for many 

 years in succession, would be decidedly benefited by the application 

 of all available organic manures. The increasing practice of seed- 

 ing in the tame grasses at some point in the rotation is to be recom- 

 mended in connection with the maintenance and restoration of or- 

 ganic matter in this soil. In fact, upon those areas where definite crop 

 rotation has been adopted, including the maintenance of a part of the 

 land in grass during a period of each rotation, the yields of grain are 

 being increased and the efficiency of the soil is being improved. 



The use of any fertilizer upon this soil has only been attempted in 

 a few localities upon an experimental scale. The use of stable manure 

 is practically unknown, and the need for fertilization of any portion 

 of the type has only been felt within the last few years, after nearly 

 30 years of occupation for the practically continuous production of 

 one or two different grain crops. The wonderful natural fertility of 

 the Fargo clay loam is as well shown through these circumstance- ;i- 

 th rough the yields of the crops which were produced in the earlier 

 days of its virgin state. 



LIMITATIONS UPON SPECIAL CROPS. 



The climatic limitation upon the production of crops practically 

 excludes the varieties of corn now known, except for production to a 

 limited degree, particularly for silage purposes. Many other crops 

 are excluded by the same factor of climatic environment. Others are 

 rendered undesirable by the level surface of the soil, by the somewhat 

 obstructed natural drainage, and by the heavy texture of both sur- 



