FIELD CROPS. 895 



Clover was intended to be the third crop of every course, but repeated 

 failures of this cropled to the frequent substitution of beans in its stead. 

 Thus in the 11 courses clover was grown only 4 times, beans 7 times. 

 The yield of clover without manure averaged 3,000 lbs. per acre, which 

 amount was doubled by superphosphate or mixed minerals, and raised 

 to 6,800 lbs. when a complete fertilizer was applied to the turnip crop 2 

 years previous. The action of these fertilizers on beans was somewhat 

 similar. Both beans and clover yielded better on i)lats where the turnip 

 crop grown 2 years before had been fed on the land than on the plats 

 whence it had been removed. 



Both mixed minerals and a complete fertilizer applied to turnips 

 increased the yield of wheat in the fourth year after the application. 

 The retention of the turnips somewhat increased the yield of wheat in 

 the fourth year thereafter. 



On the unfertilized section and on that which had received minerals 

 alone, on both of which there was soil exhaustion, especially of nitrogen, 

 the wheat crop was somewhat larger after bare fallow than after the 

 leguminous crop which had been removed. On the other hand, the sec- 

 tion kept in a high state of fertility by the application of a complete fer- 

 tilizer to turnips, and thus capacitated for a luxuriant growth of beans 

 or clover (having a heavy crop residue), afforded larger returns in 

 wheat when this latter crop followed a leguminous crop than when it 

 was preceded by bare fallow. Thus on fertile soil the advantage of 

 growing a leguminous crop instead of fallowing consisted not only in 

 the value of the leguminous crop, but also in a slight increase in the 

 wheat crop. Subsequent turnip crops showed no marked difference 

 between the plats fallowed or bearing a leguminous crop 2 years 

 previous. 



Amounts of dry matter contained in the crops. — The amount of dry 

 matter, nitrogen, ash, phosphoric acid, and potash in turnips, barley, 

 clover and beans, and wheat, in rotation and in continuous culture, are 

 tabulated and discussed. 



The dry matter in turnips grown without fertilizer was practically 

 identical in rotation and in continuous culture, due to the failure of 

 the unfertilized crop grown under both conditions. When fertilized, 

 the turnip yielded more in rotation than in continuous culture. 



On the unfertilized section the grain and straw of barley grown con- 

 tinuously contained only about three fifths as much dry matter as in 

 rotation, and on the mixed mineral section considerably less than in 

 rotation. Especially marked was the difference in favor of rotation on 

 the area where turnips had been fed. On the section supplied with a 

 complete fertilizer continuous culture gave best results when the turnip 

 crop of the rotation was removed, but rotation excelled when the turnips 

 were fed. 



Under all conditions of manuring beans grown continuously yielded 

 only about half as much as when grown in rotation. A similar com- 



