A SIMPLE CHANGE OF CROPS NOT ALWAYS BENEFICIAL 271 



Crop Rotation Increased the Yield of Winter Wheat* 



* Ohio Experiment Station bulletin 231, 1911. 



t One hundred sixty pounds each of acid phosphate and nitrate of soda, and 100 pounds 

 of muriate of potash applied annually to the wheat crop. 



t Fertilizers applied 3 times in each 5-year period 80 pounds each of acid phosphate 

 and muriate of potash to each corn and oat crop, and each wheat crop received the same 

 treatment as given each crop of wheat in continuous culture. 



It cannot be assumed that this increase on the unfertilized plot will con- 

 tinue indefinitely. 



Under the conditions of this experiment) rotation of crops is 

 much more favorable to the growing of winter wheat than continu- 

 ous cropping when yield and economy of production are considered. 



Rotation Can Not Take the Place of Fertilizers. Though 

 a proper rotation is a most important farm practice to aid in main- 

 taining and increasing soil fertility, yet it cannot take the place 

 of manure and commercial fertilizers. Whenever crop rotation 

 without fertilization increases the productivity of a soil, it is only 

 temporary; because when the yields are thus increased, the draft 

 upon the plant-food elements becomes greater, and this tends 

 towards more rapid soil depletion. It becomes more urgent, 

 therefore, to practice rational fertilization in order to secure the 

 best results from rotations. The results in the tables, pages 270 

 and 271 emphasize this fact. 



Rotation Only One of Several Factors in Maintaining Fertility. 

 It is well to keep in mind the several factors involved in main- 

 taining soil fertility, which are: (a) Thorough drainage; (6) proper 

 tillage; (c) crop rotation; (d) liming; (e) a rational use of manure 

 and cojrimercial fertilizers, and (/) green manuring. 



A Simple Change of Crops Not Always Beneficial. Farmers 

 have observed, and soil investigators have demonstrated, that a 

 simple change of crops may not always prove beneficial. In some 

 sections farmers experience unsatisfactory corn crops when grown 

 after sugar beets. The North Dakota Station has found that on 



