ONE YEAR ROTATIONS 141 



injurious insects. By the growth of different plants the next year 

 these insects may be destroyed or caused to leave for want of 

 their special kind of food. The wheat midge is not injurious in a 

 corn field. The clover maggot does not affect the cotton crop. The 

 cotton boll weevil is not injurious to other crops. 



8. Plant diseases are often kept in control by rotation. For 

 example, club root of cabbage lives over in the soil and would 

 affect subsequent crops if cabbage is grown continuously. It may 

 also affect closely related crops, but it will not attack potatoes, 

 corn and many other crops. Similar affections living over in the 

 soil may be injurious to the roots of beets and raspberries. If 

 these plants be grown together or in succession the rotation must 

 be planned to destroy such diseases. 



9. Rotation may require a greater diversity of farming. This 

 in turn results in more sources of income than where one crop 

 only is produced for market. Some income is more certain when 

 several market crops are produced. If one crop fails the others 

 may not. If the market be poor for one it may be good for the 

 others. 



10. If rotation brings about more diversified farming it will 

 give more continuous work for men and teams, because the work 

 will be distributed more evenly throughout the year. One of the 

 great losses on many farms arises from the fact that man and 

 horse are not steadily employed in profitable work. In the one- 

 crop system much loss arises from this source. 



One-year Rotations. The farm may produce only one kind 

 of market crop. This is true in many lines of special farming. 

 Rotations are still possible. Cotton may be grown year after 

 year on the same field. The objections to this may be chiefly 

 overcome by establishing an annual rotation; that is, by the use 

 of a winter cover crop grown during the late summer, fall, and 

 winter and turned under in the spring as green manure, perhaps 

 a few w r eeks before cotton is planted. The winter cover crop may 

 be sown in the late summer or early fall between the rows of 

 cotton. An extra cultivation may be necessary to make the con- 

 ditions favorable for the seed. Some cotton growers use crimson 

 clover for this purpose. Much the same effect may be secured by 

 the growth of peanuts, cow peas, soy beans or other summer crops 

 between the rows of cotton or between the rows of corn. The 

 ground thus receives a different treatment and nitrogen is accumu- 

 lated by the legumes to supply nitrogen for the growth of cotton. 



