344 THE SMALL GRAINS 



There are also the advantages of increase in nitrification, 

 increase in availability of mineral foods, and such a diver- 

 sification of crops as will permit the keeping of live-stock. 

 Ladd (1901, pp. 685-704) investigated the effects of humus 

 in the soil and emphasized the use of grasses in a rota- 

 tion, stating that plowed grass lands are more beneficial to 

 the following crop than green crops turned under. Brome- 

 grass in a rotation was recommended, as it " seems to 

 put the soil more nearly in the condition of native prairie 

 than timothy." 



372. Results of experiments. As early as 1899, 

 Shepperd and Ten Eyck (1899, pp. 451-^57) had obtained 

 6 years' results with rotations that began in 1892, after 

 9 years' continuous wheat cropping on all plats. Even 

 then, it was concluded from these experiments " that it 

 does not pay to raise wheat continuously. Land which 

 produced 3 crops of wheat and one cultivated crop in 

 4 years, gave almost as much wheat and more profitable 

 returns than land which produced 4 crops of wheat in 

 succession. Cultivated crops give better returns in the 

 following wheat crops than does the summer fallowing, 

 and if the (cultivated) crop produced will pay for the 

 growing, summer fallowing is an expensive practice." 



A 5-years' rotation which " is proving a decided success 

 on the Experimental Farm " at Brandon, Manitoba, in- 

 cludes (1) wheat, (2) wheat, (3) corn, manured preceding 

 fall, (4) barley seeded down with clover, and (5) clover. 

 This rotation, it is said, demonstrates the possibility of 

 eliminating summer fallow. The corn and clover at least 

 pay for themselves and leave the soil in condition for as 

 good a grain crop as summer fallow. In 1913 the profit 

 from barley after corn was $18.75 to the acre, while that 

 from barley after oats (in another rotation) was $11.51. 



