140 



CROP ROTATIONS 



4. Diversification of crops means a variety of soil treatment, 

 as fertilizing, liming, plowing and cultivating at different times of 

 the year. Such a variety of treatment is usually better than 

 following the same tillage at the same season each year. By suit- 

 able planning soil moisture may be conserved by proper tillage at 

 the right season. 



5. Weeds are better kept in check. Annual weeds are seldom 

 injurious in hay fields. Most perennial weeds are less common in 



FIG. 92. Just right for hay making. Canada field peas and oats, when grown together, 

 are used for hay if cut when the peas are in blossom. They may be allowed to ripen and the 

 seeds threshed out together and ground for feed. When growing the peas are improvers of 

 the soil because they gather nitrogen from the air. The crop may be followed with timothy 

 or with alfalfa sown in August. 



grain fields and cultivated crops. Rotation therefore tends to 

 choke out each type of weeds. The growth of a cultivated crop 

 will help to destroy perennial weeds, and the growth of a perennial 

 crop will help to destroy annual weeds. 



6. Injurious matter in the soil exuded by roots during their 

 growth are somewhat poisonous to the one kind of plants. By 

 rotation this material may be used up or changed by the action 

 of plants of a different kind. 



7. Certain crops are often badly affected with special kinds of 



