12 SOILS OF THE EASTERN UNITED STATES. 



from 15 to 18 bushels of wheat per acre from the Knox silt loam. In 

 this connection it is necessary to call attention to a rotation some- 

 times used upon this soil type, and one which has been effective also 

 for the increase of grain yields upon similar types of soil in the cen- 

 tral States. This rotation consists of the plowing down of sod frith 

 the production of either corn or tobacco upon the tilled area for the 

 first year. Either or both of these crops may be followed by a seed- 

 ing to wheat for the second year. In the third year wheat may again 

 be seeded in the more southern locations, or oats may be seeded in the 

 more northern latitudes. In either case a seeding to timothy and 

 clover should be made and the grass should be cut for hay during 

 the fourth and fifth year of the rotation. In this rotation it has 

 generally been found advisable to use all of the stable manure available 

 for the corn or the tobacco crop, and to use the commercial fertilizers 

 with the small grains. In addition, it is sometimes necessary to 

 apply lime preceding the final seeding to small grain and the accom- 

 panying seeding down to the mixed grasses. Where such a rotation 

 has been adopted and persistently followed, the yields secured from 

 the Knox silt loam have been materially increased over those portions 

 of the type where neither rotation nor adequate fertilization has been 

 attempted. It should be unnecessary to say that adequate surface 

 and subsoil drainage should be provided in order to make this or 

 any other rotation fully effective. 



In the total area devoted to crop production on the Knox silt loam 

 in Illinois, Iowa, and Nebraska, the oat crop is second only to corn 

 in importance, while it constitutes the principal crop, so far as acre- 

 age is concerned, in Wisconsin. The yields of oats reported for the 

 Knox silt loam are somewhat variable, averaging about 40 bushels 

 per acre in Illinois, 35 bushels per acre in Iowa, and 32 bushels per 

 acre in Wisconsin. Of course, the areas of this type which are most 

 effectively handled in all three of these States produce considerably 

 greater crops, amounting in each to 50 or CO bushels per acre on the 

 lands of the best farmers. In both Kentucky and southern Indiana 

 the climate is somewhat too warm for effective oat production, and 

 winter wheat replaces this crop. The acreage devoted to oats is, 

 therefore, decidedly subordinate to that of any other agricultural 

 crop adapted to the Knox silt loam. The yields of oats range from 

 20 to 25 bushels per acre, with an average of about 22 bushels. 



In the more northern areas where the Knox silt loam is developed 

 the acreage devoted to grass is second only to that devoted to oats or 

 corn, as the case may be. Timothy and medium red clover are ex- 

 tensively sown, with smaller acreages of clover seeded alone. In all 

 cases the yields are excellent, ranging from 1 to 2 tons per acre, with 

 a general average of about 1^ tons. In Illinois, Indiana, and Ken- 



