12 SOILS OF THE EASTERN UNITED STATES. 



yields per acre are considerably greater, ranging from 1 5 to 20 bushels 

 or even more. Thus the climatic factors rather than the inherent 

 fertility of the type tend to determine not only the varieties of wheat 

 and other crops which may be produced, but also to a large degree 

 impose a maximum limit upon the yields per acre. 



Mixed timothy and clover, or clover alone, are the grasses princi- 

 pally seeded upon the Marshall silt loam east of the Missouri River. 

 These grasses are most frequently seeded with the oats and are 

 allowed to remain upon the land from one to three years. In the 

 latter case the area in grass is usually devoted to pasturage during 

 the third year. The yields of grass are satisfactory, but not abnor- 

 mally high, ranging from 1 to 1 tons for the averages in the counties 

 where the Marshall silt loam dominates. The yields of the type are 

 somewhat higher than this, averaging from 1 \ to 2 tons per acre, and 

 not infrequently exceeding the latter figure. Within recent years, 

 particularly in Illinois, the introduction of alfalfa has made rapid 

 progress on the Marshall silt loam. Wherever the subsoil drainage 

 of the type is adequate and wherever inoculation with the proper 

 bacteria is secured, either naturally or artificially, the crop thrives 

 upon the Marshall silt loam. Yields of 2J to 3J tons per acre are 

 frequently secured in three cuttings, and yields of 4 or 5 tons per 

 acre have been obtained when the utmost care in the preparation of 

 the land and in the seeding of the crop was observed. It is in the 

 more western portions of the territory occupied by the type, how- 

 ever, that alfalfa has occupied the dominant place in hay production. 

 In central and western Kansas and Nebraska alfalfa has been seeded 

 over thousands of acres of the Marshall silt locm and four or five 

 cuttings are secured each year with yields ranging from 3J to 5 tons 

 per acre per annum. The soft silty surface soil, the well-drained sub- 

 soil, and the calcareous nature of the subsoil furnish fundamental 

 requirements of the alfalfa plant. In many instances artificial inoc- 

 ulation is found to be unnecessary, although it is to be recommended 

 if there is any uncertainty in regard to the natural inoculation of 

 the fields. The extension of this very valuable forage crop upon the 

 Marshall silt loam in all the areas where it occurs is to be highly 

 recommended. 



These constitute the dominant crops raised upon the Marshall silt 

 loam. In addition, emmer, sorghum, and millet are produced as 

 forage crops, and Kafir corn and milo maize are grown, both for the 

 grain and for the fodder. Broom corn is grown only in the more 

 western areas where the type has been encountered, although this is 

 an important crop in some portions of Kansas. 



The lack of any systematic crop rotation upon the prairie farms 

 occupied by the Marshall silt loam has already been noted. In the 

 earlier days this lack was general. At the present time more and 



